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  • 151.
    Gustafsson, Stig-Inge
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Are Earth Tube Heat Exchangers of Interest when Heating Buildings?1993In: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 17, no 7, p. 597-604Article in journal (Refereed)
    Abstract [en]

    It is a well-known fact that the temperature of the soil, some metres below the surface, is relatively stable. If this heat could be utilized by use of an earth tube heat exchanger, significant benefits could occur when space heating for buildings is considered. The inlet ventilation air is then led through a long earth tube in which it will, depending on their relative temperatures, take up heat from, or leave heat to, the surrounding soil. In this paper two case studies are presented. The buildings of concern are sited in the vicinity of Linköping, about 200 km south of Stockholm, Sweden. One of the cases utilizes heat from the earth tube in an air-to-water heat pump, while the other uses an air-to-air heat exchanger. The studies show that the earth tubes only to a very low degree contribute to the need of added heat in order to achieve a desirable indoor climate. Hence, the extra cost for the tube will not be balanced by the decreased cost for space heating. This discouraging result may have depended on heat pipes that were too short or the fact that the difference in temperature between the passing air stream and the surrounding soil was too small.

  • 152.
    Gustafsson, Stig-Inge
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Climate Influence on District Heat and Electricity Demands1992In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 42, no 4, p. 313-320Article in journal (Refereed)
    Abstract [en]

    This paper describes the district heating and electricity load of Kalmar, Sweden. Unfortunately, it has not been possible to examine one full year because the monitoring of the energy use for district heating and electricity, and the outdoor temperature, did not exactly overlap. However, more than 7200 h, of the 8760 in a full year, have been examined. It is shown that the district heat load has a far higher correlation with the outdoor temperature (a coefficient of 0·89), than has the electricity load (0·33). Thus, it is much easier to predict the influence of, e.g. an insulation retrofit for the building stock where district heating is used compared with electricity space heating. It is also shown how an estimate can be made of the thermal transmission factor for the total building stock.

  • 153.
    Gustafsson, Stig-Inge
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Does postponed retrofitting save money?1995In: Heat Recovery Systems and CHP, ISSN 0890-4332, Vol. 15, no 5, p. 469-472Article in journal (Refereed)
    Abstract [en]

    When a building is to be retrofitted, or refurbished, it is always of importance to study the building as a complete energy system. At least in Sweden, the building process is divided between different professional categories, such as HVAC and ordinary building contractors. It is therefore not surprising that the HVAC contractor wants to maximise his profit by installing large and sophisticated equipment at the same time as the builder or architect wants to design a house with very thick walls and high performing windows. These competing interests will often result in a building where the heating system is not adjusted to the rest of the house, but is instead far too powerful. The recommendation from life-cycle cost analyses has therefore always been to study the building as a whole system and to apply an optimal solution at one specific base year; this is probably always the best solution in order to minimise the life cycle cost, but experience shows that the proprietor of the building often hesitates in doing so. The reason for this is his lack of money. Changing the building into an optimal energy system frequently requires a heavy investment in any one specific year, albeit the best solution in the long run. This paper will discuss what happens to the life-cycle cost when retrofits are postponed so as to fit into the proprietor's “10 yr budget”.

  • 154.
    Gustafsson, Stig-Inge
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Hot Water Heat Accumulators in Single-Family Houses1992In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 12, no 4, p. 303-310Article in journal (Refereed)
    Abstract [en]

    In Sweden, as in many other countries, there is a significant difference in electricity demand between day and night. In order to encourage the end use consumer to use less electricity during peak situations, time-of-use tariffs have become more common. The price differs from about 0.8 to 0.35 SEK/kWh, taxation included. (1ECU equals about 7 SEK.) If some of the electricity under the high price period, which falls between 0600 and 2200 during November to March, could be transferred to the low price hours, the electricity bill could be reduced. In Sweden it is common to use electricity for space and hot water heating, at least in single-family houses. By use of a hot water accumulator the need for heat could be produced during the cheap hours and the storage could be discharged when the high price hours occur. This paper describes the electricity use for hot water and space heating in a single-family house sited in Linköping, Sweden, where extensive monitoring has been utilized during 1987. Some 30 values for temperatures and electricity demands have been measured each hour, or sometimes even for shorter time intervals. These monitored data have been the base for examining if a water accumulator could be of interest for the proprietor of the building, i.e. if the cost for the accumulator is less than the money saved by the reduced electricity cost.

  • 155.
    Gustafsson, Stig-Inge
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Mathematical modelling of district-heating and electricity loads1993In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 46, no 2, p. 149-159Article in journal (Refereed)
    Abstract [en]

    In recent years it has been more common to use linear or mixed-integer programming methods for finding optimal solutions to the complicated operating options in modern Combined Heat and Power (CHP) networks. Electricity may be bought from the national grid or it may be produced in ordinary condenser or CHP plants owned by the utility. In the same manner, district heat can be produced by the use of waste heat from industries or from a CHP plant. Other options are burning garbage in an incineration plant, using heat pumps in a sewage water plant or just burning fuels in an ordinary boiler. Combining these options and including the possibility of using conservation measures in industry or in the housing stock will result in a very complex situation if one tries to find the optimal solution characterized by the the lowest Life-Cycle Cost (LCC). Load management equipment, such as hot-water accumulators, will aggravate the problem even further. By the use of modern computers, complicated problems can be solved within a reasonable period of time. The bases for the mathematical models are the thermal and electrical loads. Splitting these loads into finer and finer segments will yield a model that will depict reality more closely. Two methods have been used frequently, one where the high and low unit price hours in each month have been lumped together, resulting in 24 segments plus one segment showing the influence of the maximum electricity demand. The other method tries to model the loads by lumping the energy demand in six electricity-tariff segments, but also using about 15 elements for a more versatile picture of the district-heating load. This paper describes the two methods using monitored data for 1990-1991 from Kalmar in the south of Sweden. It also discusses which of the methods is preferable or whether a combination must be elaborated upon in order to model reality closely enough for practical use.

  • 156.
    Gustafsson, Stig-Inge
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Energy Systems.
    Optimal fenestration retrofits by use of MILP programming technique2001In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 33, no 8, p. 843-851Article in journal (Refereed)
    Abstract [en]

    When buildings are subject for refurbishment, it is very important to add the optimal strategy at that very moment. If other solutions are chosen and implemented, it will no longer be possible to change the building at a later occasion with the same profitability. A suitable criterion for optimality is the point where the life-cycle cost (LCC) has its minimum value. This point can be calculated by using so-called mixed integer linear programming (MILP). This paper shows how building and possible fenestration retrofits are described in such a MILP program. Changing existing double-glazed windows to triple ditto will of course make the U-values lower, but at the same time less solar radiation is transferred through the glass panes. This must be properly addressed in the MILP model. Of vital importance are also the heating system and the energy tariff connected to it. Nowadays, time-of-use rates are common practice both for district heating and electricity. These facts make it unsuitable to write, optimise and solve the MILP model "by hand", and instead a computer program has been designed for writing the model in the form of a standard MPS data file. This file can in turn be scanned and optimised by MILP-solving programs available at the market today. © 2001 Elsevier Science B.V. All rights reserved.

  • 157.
    Gustafsson, Stig-Inge
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Energy Systems.
    Optimal use of solar collectors for residential buildings2001In: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 25, no 11, p. 993-1004Article in journal (Refereed)
    Abstract [en]

    Solar radiation is an abundant free resource which may be used in the form of solar heated water. This is achieved in solar collectors which, unfortunately, are expensive devices and, further, the warm water must be stored in accumulators-items which also cost money. This paper shows how we have optimized the situation for a block-of-flats in Sweden. In order to find this point we have used the minimum life-cycle cost (LCC) concept as a criterion. The best solution is therefore found when that cost finds its lowest value. It is also examined under which conditions solar collectors are part of the optimal solution and further it is calculated what happens if this optimal point is abandoned, i.e. how much will the LCC increase if other than optimal solutions are chosen. LCC optimization for multi-family buildings almost always results in a heating system with low operating costs such as district heating or dual-fuel systems where a heat pump takes care of the base load and an oil boiler the peak. The installation cost must, however, be kept to a reasonable level. Expensive solar panel systems are therefore normally avoided if the lowest LCC shall be reached, at least for Swedish conditions. This is so even if the solar system has a very low operating cost. For buildings where the only alternative energy source is electricity, solar collectors seem to be on the rim of profitability, i.e. for an energy price of about 0.6 SEK kWh-1. Copyright © 2001 John Wiley and Sons, Ltd.

  • 158.
    Gustafsson, Stig-Inge
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Energy Systems.
    Optimization and simulation of building energy systems2000In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 20, no 18, p. 1731-1741Article in journal (Refereed)
    Abstract [en]

    The Mixed Integer Linear Programming (MILP) technique is a useful tool for the optimization of energy systems. However, the introduction of integers in linear models results in a severe drawback because the ranging process is no longer available. Therefore, it is not possible to study what happens to the solution if input data are changed. In this paper, we compare a MILP model of a building with a simulation model of an identical case. Both models describe a building with a number of possible retrofits. Using the MILP technique, the optimal retrofit strategy is calculated, after which certain input data are changed. The optimization results in the lowest possible Life-Cycle Cost (LCC) of the building, and the paper describes how much the LCC will change if the property owner chooses other solutions. An increase in a particular data value may cause the LCC to increase or decrease. It may also be unchanged. Only a few data reduce the LCC when their values are increased.

  • 159.
    Gustafsson, Stig-Inge
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Energy Systems.
    Optimization of drying kiln operation2000In: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 24, no 1, p. 19-26Article in journal (Refereed)
    Abstract [en]

    When timber is to be used in the form of furniture it must be dried. Green timber contains many times more water than wood and if it is placed indoors the water will slowly evaporate. When the fibre saturation point is reached the wooden parts start to shrink and the shape of the details will change. If the wood is dried before it is used for furniture parts this calamity is reduced because shrinking has occurred already in the drying kiln when the raw material was in the form of lumber. This drying process uses a lot of heat which is produced by electricity or by firing wood chips or oil in boilers. The cost for these energy sources varies during the season or, for electricity, also during the day. This paper describes how to optimize the use of energy in two drying kilns located at a small carpentry factory in the south of Sweden. Monitored values from the factory are used in order to describe the process in close detail. These values are then used as a basis for a mathematical model which is designed in the form of a mixed integer linear program. The method makes it possible to optimize the operating schemes for the two dryers. Copyright (C) 2000 John Wiley & Sons, Ltd.

  • 160.
    Gustafsson, Stig-Inge
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Energy Systems.
    Refurbishment of industrial buildings2006In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 47, no 15-16, p. 2223-2239Article in journal (Refereed)
    Abstract [en]

    When a building is subject for refurbishment, there is a golden opportunity to change its behavior as an energy system. This paper shows the importance of careful investigations of the processes, the climate shield and the heating systems already present in the building before measures are implemented in reality. A case study is presented dealing with a carpentry factory. The building is poorly insulated according to standards today, and initially it was assumed that a better thermal shield would be of vital importance in order to reach optimal conditions. Instead, it is shown that the main problem is the ordinary heating system. This uses steam from a wood chips boiler and the wood chips come from the manufacturing processes. These wood chips are, therefore, a very cheap fuel. The boiler had, during decades of use, slowly degraded into a poor state. Hence, aero-tempers using expensive electricity have been installed to remedy the situation. These use not only expensive kWh but also very expensive kW due to the electricity tariff. It is shown that electricity for heating purposes must be abandoned and further, that this could be achieved at a surprisingly small cost. By stopping a large waste of steam, it was possible to find resources, in the form of unspent money, for further mending the existing heating system. Not only economy but also environmental hazards in the form of CO2 emissions urges us to abandon electricity and instead use heat from cheap biomass fired boilers. Such equipment saves environment at the same time it saves money. © 2006 Elsevier Ltd. All rights reserved.

  • 161.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Andersson, Susanne
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Karlsson, Björn G
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Factorial design for energy System Models1994In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 19, no 8, p. 905-910Article in journal (Refereed)
    Abstract [en]

    Mathematical models are extensively used in energy analysis and have increased in scope as better and faster computers have become available. With complicated systems, it is difficult to predict accurate results if doubtful input data are changed. Traditionally, sensitivity analysis with a change of one or more of the parameters is used. If the influence of a change is very small, the first result is believed to be accurate. Problems may arise when sensitivity analysis is applied to a vast amount of data. The aim of this paper is to examine whether the calculation effort can be decreased by using factorial design. Our model, called Opera (Optimal Energy Retrofit Advisory), is used to find the optimal retrofit strategy for a multi-family building. The optimal solution is characterised by the lowest possible life-cycle cost. Three parameters have been studied here: length of the optimisation period, real interest rate and existing U-value for an attic floor. The first two parameters are found to influence the life-cycle cost significantly, while the last is of minor importance for this cost. We also show that factorial analysis must be used with great care because the method does not reflect the complete situation.

  • 162.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Karlsson, Björn G
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Energy Conservation and Optimal Retrofits in Multi-Family Buildings1990In: Energy Systems and Policy, ISSN 0090-8347, Vol. 14, p. 37-49Article in journal (Refereed)
  • 163.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Karlsson, Björn G
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Heat Accumulators in CHP Networks1992In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 33, no 12, p. 1051-1061Article in journal (Refereed)
    Abstract [en]

    In a Combined Heat and Power (CHP) network, it is sometimes optimal to install a device for storing heat from one period of time to another. Several possibilities exist. If the electricity demand is high, while at the same time the district heating load is too small to take care of the heat from the CHP plant, it could be optimal to store heat from peak periods and discharge the storage under off-peak. It might also be optimal to store heat during off-peak and use it under the district heating peak load. The storage is then used for decreasing either the district heating demand or for decreasing the electricity load used for space heating. The paper shows how a mixed integer program is developed for use in the optimization process. As a case study, the CHP system of Malmö, Sweden, is used. Further, a sensitivity analysis is elaborated in order to show how the optimal solution will vary due to changes in certain input data.

  • 164.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Karlsson, Björn G
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Insulation and Bivalent Heating System Optimization: Residential Housing Retrofits and Time-Of-Use Tariffs for Electricity1989In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 34, no 4, p. 303-315Article in journal (Refereed)
    Abstract [en]

    Time-of-use tariffs, which reflect the cost of producing one extra unit of electricity, will be more common in the future. In Sweden the electricity unit price will be high during the winter and cheaper during the summer. A bivalent heating system, where an oil-fired boiler takes care of the peak load, when the electricity price is high, and a heat pump the base load, may decrease the cost of space heating substantially. However, insulation retrofits are also likely to reduce the peak space-heating load in a building. This paper shows how a bivalent heating system can be optimized while also considering the insulation measures. The optimization is elaborated by the use of a mixed integer programming model and the result is compared with a derivative optimization method used in the OPERA (optimal energy retrofit advisory) model. Both models use the life-cycle cost (LCC) as a ranking criterion, i.e. when the lowest LCC for the building is achieved, no better retrofit combination exists for the remaining life of the building.

  • 165.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Karlsson, Björn G
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Is space heating in offices really necessary?1991In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 38, no 4, p. 283-291Article in journal (Refereed)
    Abstract [en]

    New office buildings in Sweden are thoroughly insulated due to the Swedish building code. This code, however, does not consider the type of activity occurring in the building. This means that the heating equipment is designed as if no activity at all is going on. In modern offices there is a lot of equipment installed which uses electricity. This electricity is converted into heat which can be utilized for heating the premises, mostly in a direct way but also by the use of exhaust-air heat-pumps or heat exchangers. This paper deals with a modern office building plus office hotel complex located in Linköping, Sweden, about 200 km south of Stockholm. The tenants deal with the design of hard- and software for computers. The lighting and computers in the building use electricity which converts into heat. In this paper, it is shown that this electricity is all that is needed during normal conditions, i.e. when people work in the building. The building is also equipped with a district-heating system, which is designed as if no activity goes on in the building, so subsequently the heating equipment is larger than it need be. In this special case, it might have been better to install an electric heating device for hot-water heating and very cold winter conditions, instead of using district heating. This is so even if district heat is about half the unit price compared with that due to the dissipation of electricity. At present, when district heating is used, no measures for saving heat can be profitable due to the low district-heating price. The fact is that the tenants complain of too much heat instead of too little: the prevailing indoor temperature was about 24° C in January 1990 even though 20° C would have been sufficient. There is subsequently a need for a properly working regulation system. The one currently in use is designed to a modern standard, but is not able to maintain temperatures at a modest level.

  • 166.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Karlsson, Björn G
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Life-Cycle Cost Minimization Considering Retrofits in Multi-Family Residences1989In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 14, no 1, p. 9-17Article in journal (Refereed)
    Abstract [en]

    When a building is to be renovated it is important to implement the optimal retrofit combination. If this strategy is neglected it might not be profitable to change the building in order to improve it as an energy system. This paper deals with energy retrofits and how the strategy can be optimized considering one specific building. The best solution is found when the life-cycle cost for the building is minimal, and building envelope, ventilation and heating system retrofits are combined.

    In order to solve the problem, a mathematical model, OPtimal Energy Retrofit Advisory (OPERA), has been developed. Energy balance calculations are used in which the free energy from solar radiation and from appliances is taken into proper account. The interaction between different retrofits is emphasized. Provided that the optimal solution is implemented, the retrofits in the combination will have a minor interaction which, for most cases, could be neglected. This will also imply that the order of implementation is of no, or minor, importance. A case study for a real building sited in Malmö, Sweden, and a sensitivity analysis for some critical input parameters are discussed.

  • 167.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Karlsson, Björn G
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Linear Programming Optimization in CHP Networks1991In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 11, no 4, p. 231-238Article in journal (Refereed)
    Abstract [en]

    This paper shows how to simulate a CHP network (CHP = Combined Heat and Power) using the method of linear programming. This method makes it possible to optimize the mathematical model and subsequently find the very best combination of electricity production, electricity purchase and heat production in a district heating system. The optimal solution in the model is characterized by the lowest possible operating cost for year. The paper shows the design of the mathermatical model and furthermore a case study is presented using the district heating net in Malmö, Sweden, as an example.

  • 168.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Karlsson, Björn G
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Natural gas in Optimized Bivalent Heating Sytems1990In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 15, no 11, p. 993-999Article in journal (Refereed)
    Abstract [en]

    In accordance with a public referendum held in 1980, Sweden will phase out nuclear power completely by 2010. One way to compensate for an immediate, appreciable scarcity of electric power is to construct new fossil-fuel power stations. Another is to reduce the burden on electric power by converting some end-user facilities to operate on natural gas (NG) imported from Denmark through a new pipeline to southern Sweden. We show how an optimal solution can be found for NG operation of a system incorporating an NG boiler and an electric heat pump. Electricity is priced by a time-of-use tariff (TOU) requiring a discrete optimization method. The optimal solution is characterized by the lowest life cycle cost (LCC) for the building as an energy system.

  • 169.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Karlsson, Björn G
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Production or Conservation in CHP Networks1990In: Heat Recovery Systems and CHP, ISSN 0890-4332, Vol. 10, no 2, p. 151-159Article in journal (Refereed)
    Abstract [en]

    In Sweden, Combined generation of Heat and Power (CHP) is in common practice. Different fuels are burnt in a boiler and the steam is used for generating electricity. The heat that has to be transferred from the condenser in the plant is used in the district heating grid. This grid is thus used as a cooling facility necessary for electricity production. However, energy conservation the Swedish building stock is also encouraged, and if this is utilized in district heated buildings it results in fewer possibilities for electricity production. This might be a major drawback when nuclear power is abolished, as is the result from a consensus some years ago. This paper deals with the question of whether it is better to conserve both heat and electricity, to save only one of the energy forms or if it is cheaper to produce more energy, instead of saving. A case study is presented dealing with Malmö, in the South of Sweden, and it is shown that energy conservation in district heated buildings cannot yield profitability: neither can conservation in the electricity grid, even if it gets closer to profitable savings. It is assumed that the total cost of heating, insulation and electricity is paid by the society and the minimum point for this cost will characterize the best solution.

  • 170.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Karlsson, Björn G
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Why is Life-Cycle Costing Important when Retrofitting Buildings1988In: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 12, no 2, p. 233-242Article in journal (Refereed)
    Abstract [en]

    Using life-cycle costing (LCC) gives us a means to find the best retrofit strategy for an apartment block. This method also shows us how important it is to consider the whole existing building as an energy system. If the best heating system is put into the house almost every shield retrofit is unprofitable. Having heating systems, with high variable costs combined with exhaust ventilation air pumps, sometimes makes it unprofitable to caulk the windows and doors.

    This article also shows the importance of using the accurate prices for the energy. Short-range marginal costs (SMRC) gives different retrofit strategies than normal tariffs used today. This also means that the retrofits do not correspond to the optimal use of the total national energy system and already scarce resources are used unnecessarily.

  • 171.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Karlsson, Björn G
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Window Retrofits: Interaction and Life-Cycle Costing1991In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 39, no 1, p. 21-29Article in journal (Refereed)
    Abstract [en]

    This paper deals with the interaction between different types of building energy retrofits. The means for finding this interaction has been via the OPERA model, which is used for energy retrofit optimization. The solution is an optimum when the total life-cycle cost, LCC, for the building, i.e. the sum of the building, maintenance and operating costs, is minimized. The model finds the candidates for the optimal strategy by calculating the total LCC for one retrofit after another, i.e., an incremental method is used. All the measures are implemented with respect to the building and the resulting LCC is calculated. Usually, the LCC for this combination is higher than the incremental LCC, i.e. the incremental way of calculation overestimates the savings. However, when window retrofits are considered, the opposite might happen due to the use of shading factors. These factors indicate the decrease in solar radiation through a window when an ordinary one is replaced by a window with enhanced thermal performance. The paper also shows that the interaction between the different measures usually can be neglected, as long as optimal retrofits are introduced.

  • 172.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Karlsson, Björn G
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Sjöholm, Bertil H.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Differential Rates for District Heating and the Influence on the Optimal Retrofit Strategy for Multi-Family Buildings1987In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 7, no 4, p. 337-341Article in journal (Refereed)
    Abstract [en]

    When renovating existing multi-family buildings it is very important to implement the best retrofit strategy possible in order to minimize the remaining life-cycle cost for the building. If the building is heated with district heating this strategy of course changes due to the energy rate used by the utility. It is also very important for the utility that the consumer is encouraged to save energy when there is a need for it, i.e. during peak load conditions. Our paper shows that an accurate cost differential rate provides all these facilities.

  • 173.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Lewald, Anders
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Karlsson, Björn G
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Optimization of Bivalent Heating Systems Considering Time-Of-Use Tariffs for Electricity1989In: Heat Recovery Systems and CHP, ISSN 0890-4332, Vol. 9, no 2, p. 127-131Article in journal (Refereed)
    Abstract [en]

    The cost for producing energy differs a lot due to the load coupled to the distribution grid. In Sweden the load has its maximum during the winter because of the climate. The cost for producing one extra unit of energy is then about 0.50 SEK kWh−1 (1 US$ = 6 SEK), while during summer the cost can be ten times lower. In order to encourage the consumers to save energy during the winter when the cost is high, it may be important to introduce a time-of-use tariff, which reflects the cost for producing the energy. Such a rate is present in Malmö, Sweden. when retrofitting buildings it is of course important to consider the applicable rate for energy, in order to decide the optimal retrofit strategy. In the time-of-use rate the peak load is expensive and a heating system that will use less of the peak energy becomes very desirable. A bivalent heating system, where the base load is provided by a heat pump and an oil boiler takes care of the building peak load can sometimes be found to be the best solution. In this paper two different methods are used for the optimization of such a bivalent heating system. One method uses derivative considerations, the OPERA model, while the other uses linear programming.

  • 174.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Lundqvist-Gustafsson, Helen
    Linköping University, Department of Management and Engineering. Linköping University, The Institute of Technology.
    ON YELLOW DISCOLORATIONS WHEN DRYING OAK, QUERCUS ROBUR2008In: DREWNO-WOOD, ISSN 1644-3985, Vol. 51, no 179, p. 29-44Article in journal (Refereed)
    Abstract [en]

    Growing trees many times contain more water than wood. When wood is to be utilized in the form of furniture it must therefore be dried in a kiln-dryer. In such a dryer the climate is very humid and warm which is ideal for many microorganisms such as bacteria and fungi. During their metabolism they change the chemical environment which sometimes lead to undisireable effects such as discolorations. In this paper we have examined specimen from oak, Quercus robur, collected from some parquet floor factories in Sweden. During drying some of these wood battens were affected with yellow streaks and spots which made the wood impossible to use for flooring. By examining small samples of the battens in light, as well as in scanning electron microscopes, we found that fungi grew inside the wooden tissue. By cultivation on agar plates we found several species where one has been identified as Penicillium roqueforti and another one as Paecilomyces variotii. We have also found that these fungi are extremely sensitive to high pH-values, so by spraying the wood with solutions of high pH already in the sawmill will probably make this problem much smaller.

  • 175.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Energy Systems.
    Rönnqvist, Mikael
    Optimal heating of large block of flats2008In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 40, no 9, p. 1699-1708Article in journal (Refereed)
    Abstract [en]

    District heating is used in many urban areas in Sweden. Almost always, the district heating utility is owned by the municipality and the municipality naturally encourages proprietors to connect their buildings to the grid, even if they cannot really force them to do so. The building owners are free to choose the best system, i.e. the cheapest one, for their need. Unfortunately, it is not always so easy to find the best solution. Mixed integer linear programming (MLIP) models might here come to help. By such computer programs it is possible to find the absolutely cheapest system of available alternatives, or even combinations among them. This paper shows how to design such a model and further how to closely depict the district heating, and electricity tariff. This is of course very important because the only interface between the proprietor of the building and the utility is found in this bureaucratic instrument. If the tariff is too high the building owners will choose other heating systems than district heating, or even worse, combining district heating with alternative base load sources. In Sweden, this has been of interest because ground-water coupled heat pumps can be profitable, operated by use of the relatively low electricity prices. In this paper we show that dual-fuel, and sometimes even triple-fuel systems, are of interest when the proprietor aims at minimising the cost for space and domestic hot-water heating. © 2008 Elsevier B.V. All rights reserved.

  • 176.
    Gustafsson, Stig-Inge
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Energy Systems.
    Rönnqvist, Mikael
    Linköping University, The Institute of Technology. Linköping University, Department of Mathematics, Optimization .
    Claesson, M
    Optimization models and solution methods for load management2004In: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 28, no 4, p. 299-317Article in journal (Refereed)
    Abstract [en]

    The electricity market in Sweden has changed during recent years. Electricity for industrial use can now be purchased from a number of competing electricity suppliers. Hence, the price for each kilowatt-hour is significantly lower than it was just two years ago and interest in electricity conservation measures has declined. However, part of the electricity tariff, i.e. the demand cost expressed in Swedish Kronor (SEK) for each kilowatt, is almost the same as before. Attention has thereby been drawn to load management measures in order to reduce this specific cost. Saving one kWh might lead to a monetary saving of between SEK 0.22 and SEK 914, this paper demonstrates how to eliminate only those kWh that actually save a significant amount of money. A load management system has been installed in a small carpentry factory that can turn off equipment based on a pre-set priority and number of minutes each hour. The question now is what level of the electricity load is optimal in a strictly mathematical sense, i.e. how many kW should be set in the load management computer in order to maximise profitability? In this paper, we develop a mathematical model that can be used as a tool both to find the most profitable subscription level and to control the choices to be made. Numerical results from a case study are presented. Copyright (C) 2004 John Wiley Sons, Ltd.

  • 177.
    Hallberg, Björn
    Linköping University, Department of Management and Engineering, Energy Systems.
    Spillvärmeåtervinning ur kylvattensystemet ismältverket på Sapa Profiler AB i Sjunnen2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The smelting process at Sapa Profiler AB in Sjunnen generates large quantities of waste heat which is absorbed by the cooling water when the aluminum is cooled down. This paper is the result of a Master’s Degree Project aiming to present the conditions for recycling the waste heat. The cooling water absorbs the heat from the aluminum at an average rate of 600 kW and the paper shows that it can be used to replace electrical power consumption for heating the production plant’s facilities. The total savings potential comes to 464 000 SEK/year which represents a yearly reduction of 10-420 tons in CO2 emissions. Measures were taken already during the ongoing project in order to improve the possibilities of recycling the waste heat, which is suffering from discontinuous flows and low temperatures. In the paper a model is presented of how relatively high temperatures and continuous flows can be attained with the help of a warm water tank. Once he continuous flow is created, the waste heat can be exchanged to a separate flow which serves to transport the waste heat to the local heat distribution systems. Despite the significant savings potential, the  necessary investment of 3 650 000 SEK makes for a pay-back time of at least eight years.

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  • 178. Order onlineBuy this publication >>
    Haraldsson, Joakim
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering.
    Improved Energy Efficiency in the Aluminium Industry and its Supply Chains2020Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Energy is an essential resource in the daily lives of humans. However, the extraction and use of energy has an impact on the environment. The industrial sector accounts for a large share of the global final energy use and greenhouse gas (GHG) emissions. The largest source of industrial GHG emissions is energy use. The production and processing of aluminium is energy- and GHG-intensive, and uses significant amounts of fossil fuels and electricity. At the same time, the global demand for aluminium is predicted to rise significantly by the year 2050. Improved energy efficiency is one of the most important approaches for reducing industrial GHG emissions. Additionally, improved energy efficiency in industry is a competitive advantage for companies due to the cost reductions that energy efficiency improvements yield.

    The aim of this thesis was to study improved energy efficiency in the individual companies and the entire supply chains of the aluminium industry. This included studying energy efficiency measures, potentials for energy efficiency improvements and energy savings, and which factors inhibit or drive the work to improve energy efficiency. The aim and the research questions were answered by conducting a literature review, focus groups, questionnaires and calculations of effects on primary energy use, GHG emissions, and energy and CO2 costs.

    This thesis identified several energy efficiency measures that can be implemented by the individual companies in the aluminium industry and the aluminium casting foundries. The individual companies have large potentials for improving their energy efficiency. Energy efficiency measures within the electrolysis process have significant effects on primary energy use, GHG emissions, and energy and CO2 costs. This thesis showed that joint work between the companies in the supply chains of the aluminium industry is needed in order to achieve further energy efficiency improvements compared to the companies only working on their own. The joint work between the companies in the supply chain is needed to avoid sub-optimisation of the total energy use throughout the entire supply chain. Better communication and closer collaboration between all the companies in the supply chain are two of the most important aspects of the joint work to improve energy efficiency. An energy audit for the entire supply chain could be conducted as a first step in the joint work between the companies in the supply chains. Another important aspect is to increase the use of secondary aluminium or remelted material waste rather than primary aluminium.

    The companies in the Swedish aluminium industry and the aluminium casting foundries have come some way in their work to improve energy efficiency within their own facilities. However, the results in this thesis indicate that cost-effective technology and improved management can, in total, save 126–185 GWh/year in the Swedish aluminium industry and 8–15 GWh/year in the Swedish aluminium casting foundries.

    This thesis identified several demands regarding economics, product quality and performance, and environment placed on the companies and products in the supply chains that affect energy use and work to improve energy efficiency. These demands can sometimes counteract each other, and some demands are more important to meet than improving energy efficiency. This implies that improving the energy efficiency of the supply chains as well as designing products so they are energy-efficient in their use phase can sometimes be difficult. The results in this thesis indicate that it would be beneficial if the companies reviewed these demands to see whether any of them could be changed.

    Both the economic aspects and demands from customers and authorities were shown to be important drivers for improved energy efficiency in the supply chains. However, placing demands on energy-efficient production and a company’s improved energy efficiency would require those placing the demands to have deeper knowledge compared to demanding green energy, for example. Requiring a company to implement an energy management system to ensure active work to improve energy efficiency would be easier for the customer than demanding a certain level of energy efficiency in the company’s processes. Additionally, energy audits and demands on conducted energy audits could act as drivers for improved energy efficiency throughout the supply chains.

    This thesis showed that the most important barriers to improved energy efficiency within the individual companies include different types of risks as well as the cost of production disruption, complex production processes and technology being inappropriate at the site. Similar to the supply chains, important drivers for improved energy efficiency within the individual companies were shown to be economic aspects and demands from customers and authorities. However, the factors that are most important for driving the work to improve energy efficiency within the individual companies include the access to and utilisation of knowledge within the company, corporate culture, a longterm energy strategy, networking within the sector, information from technology suppliers and energy audits.

    List of papers
    1. Review of measures for improved energy efficiency in production-related processes in the aluminium industry: From electrolysis to recycling
    Open this publication in new window or tab >>Review of measures for improved energy efficiency in production-related processes in the aluminium industry: From electrolysis to recycling
    2018 (English)In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 93, p. 525-548Article, review/survey (Refereed) Published
    Abstract [en]

    The aluminium industry is facing a challenge in meeting the goal of halved greenhouse gas emissions by 2050, while the demand for aluminium is estimated to increase 2–3 times by the same year. Energy efficiency will play an important part in achieving the goal. The paper’s aim was to investigate possible production-related energy efficiency measures in the aluminium industry. Mining of bauxite and production of alumina from bauxite are not included in the study. In total, 52 measures were identified through a literature review. Electrolysis in primary aluminium production, recycling and general measures constituted the majority of the 52 measures. This can be explained by the high energy intensity of electrolysis, the relatively wide applicability of the general measures and the fact that all aluminium passes through either electrolysis or recycling. Electrolysis shows a higher number of emerging/novel measures compared to the other processes, which can also be explained by its high energy intensity. Processing aluminium with extrusion, rolling, casting (shape-casting and casting of ingots, slabs and billets), heat treatment and anodising will also benefit from energy efficiency. However, these processes showed relatively fewer measures, which might be explained by the fact that to some extent, these processes are not as energy demanding compared, for example, to electrolysis. In many cases, the presented measures can be combined, which implies that the best practice should be to combine the measures. There may also be a future prospect of achieving carbon-neutral and coal-independent electrolysis. Secondary aluminium production will be increasingly important for meeting the increasing demand for aluminium with respect to environmental and economic concerns and strengthened competitiveness. Focusing on increased production capacity, recovery yields and energy efficiency in secondary production will be pivotal. Further research and development will be required for those measures designated as novel or emerging.

    Place, publisher, year, edition, pages
    Elsevier, 2018
    Keywords
    Aluminum industry, Aluminum production, Energy efficiency, Electrolysis, Recycling, Efficiency measures
    National Category
    Manufacturing, Surface and Joining Technology Energy Systems
    Identifiers
    urn:nbn:se:liu:diva-148404 (URN)10.1016/j.rser.2018.05.043 (DOI)000440966900039 ()
    Funder
    Swedish Energy Agency, 40552-1
    Available from: 2018-06-08 Created: 2018-06-08 Last updated: 2020-04-20Bibliographically approved
    2. Energy Efficiency in the Supply Chains of the Aluminium Industry: The Cases of Five Products Made in Sweden
    Open this publication in new window or tab >>Energy Efficiency in the Supply Chains of the Aluminium Industry: The Cases of Five Products Made in Sweden
    2019 (English)In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, no 2, p. 245-Article in journal (Refereed) Published
    Abstract [en]

    Improved energy efficiency in supply chains can reduce both environmental impact and lifecycle costs, and thus becomes a competitive advantage in the work towards a sustainable global economy. Viewing the supply chain as a system provides the holistic perspective needed to avoid sub-optimal energy use. This article studies measures relating to technology and management that can increase energy efficiency in the supply chains of five aluminium products made in Sweden. Additionally, energy efficiency potentials related to the flows of material, energy, and knowledge between the actors in the supply chains are studied. Empirical data was collected using focus group interviews and one focus group per product was completed. The results show that there are several areas for potential energy efficiency improvement; for example, product design, communication and collaboration, transportation, and reduced material waste. Demands from other actors that can have direct or indirect effects on energy use in the supply chains were identified. Despite the fact that companies can save money through improved energy efficiency, demands from customers and the authorities would provide the additional incentives needed for companies to work harder to improve energy efficiency.

    Place, publisher, year, edition, pages
    Basel, Switzerland: , 2019
    Keywords
    energy efficiency, aluminium industry, supply chains, primary aluminium, secondary aluminium, extrusion, foundry, rolling mill, demands, focus groups
    National Category
    Energy Systems Environmental Management Metallurgy and Metallic Materials Manufacturing, Surface and Joining Technology
    Identifiers
    urn:nbn:se:liu:diva-153903 (URN)10.3390/en12020245 (DOI)000459743700046 ()
    Projects
    Increased energy efficiency in the supply chains of aluminium industry - a carbon neutral industry in 2050
    Funder
    Swedish Energy Agency, 40552-1
    Note

    Funding agencies: Swedish Energy Agency [40552-1]; Linkoping University Library

    Available from: 2019-01-18 Created: 2019-01-18 Last updated: 2020-04-20
    3. Energy efficient supply chain of an aluminium product in Sweden – What can be done in-house and between the companies?
    Open this publication in new window or tab >>Energy efficient supply chain of an aluminium product in Sweden – What can be done in-house and between the companies?
    2018 (English)In: eceee 2018 Industrial Summer Study proceedings / [ed] Therese Laitinen Lindström, Ylva Blume & Nina Hampus, Stockholm, Sweden: European Council for an Energy Efficient Economy (ECEEE), 2018, p. 369-377Conference paper, Published paper (Refereed)
    Abstract [en]

    According to the Energy Efficiency Directive executed by the European Union, each member state is obliged to set a national target on energy efficiency. This requirement constitutes the basis for governments to formulate policy measures directed towards industrial companies. Such policy measures, along with the demand for cost-effective production to remain competitive on the market, motivates industrial companies to improve their energy efficiency. The aluminium industry is energy intensive and consumes substantial amounts of electricity and fossil fuels, resulting in both direct and indirect greenhouse gas emissions. This paper presents a study of the production of an aluminium product in Sweden in terms of implemented energy efficiency measures in the supply chain and potential areas for further improvement. Most previous studies have focused on energy efficiency measures in individual companies (value chains). However, this paper presents and analyses energy efficiency measures not only in each individual company but also in the entire supply chain of the product. The supply chain studied starts with secondary aluminium production followed by the production of a part of an automobile motor and ends with installing the motor detail in a car. Empirical data were gathered through a questionnaire and a focus group. The study shows the great potential for further energy efficiency improvements in the value chains of each individual company and in the whole supply chain. The work shown here is a part of a larger research project performed in close cooperation with the Swedish aluminium industry.

    Place, publisher, year, edition, pages
    Stockholm, Sweden: European Council for an Energy Efficient Economy (ECEEE), 2018
    Series
    eceee Industrial Summer Study Proceedings, ISSN 2001-7979, E-ISSN 2001-7987
    Keywords
    Value chain, Supply chains, Aluminium industry
    National Category
    Energy Systems Manufacturing, Surface and Joining Technology Environmental Management Metallurgy and Metallic Materials
    Identifiers
    urn:nbn:se:liu:diva-148803 (URN)978-91-983878-2-7 (ISBN)978-91-983878-3-4 (ISBN)
    Conference
    Industrial Efficiency 2018: Leading the low-carbon transition, Berlin June 11-13, 2018
    Funder
    Swedish Energy Agency, 40552-1
    Available from: 2018-06-25 Created: 2018-06-25 Last updated: 2020-04-20
    4. Barriers to and Drivers for Improved Energy Efficiency in the Swedish Aluminium Industry and Aluminium Casting Foundries
    Open this publication in new window or tab >>Barriers to and Drivers for Improved Energy Efficiency in the Swedish Aluminium Industry and Aluminium Casting Foundries
    2019 (English)In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 11, no 7, article id 2043Article in journal (Refereed) Published
    Abstract [en]

    Industrial energy efficiency is important for reducing CO2 emissions and could be a competitive advantage for companies because it can reduce costs. However, cost-effective energy efficiency measures are not always implemented because there are barriers inhibiting their implementation. Drivers for energy efficiency could provide means for overcoming these barriers. The aim of this article was to study the importance of different barriers to and drivers for improved energy efficiency in the Swedish aluminium industry and foundries that cast aluminium. Additionally, the perceived usefulness of different information sources on energy efficiency measures was studied. The data were collected through a questionnaire covering 39 barriers and 48 drivers, divided into different categories. Both the aluminium and foundry industries considered technological and economic barriers as the most important categories. The most important category of drivers for the aluminium industry was organisational drivers, while the foundries rated economic drivers as the most important. Colleagues within the company, the company group and sector, and the trade organisation were considered the most useful information sources. Important factors for driving work with improved energy efficiency included access to knowledge within the company, having a culture within the company promoting energy efficiency, and networking within the sector. The policy implications identified included energy labelling of production equipment, the law on energy audit in large companies and subsidy for energy audits in small- and medium-sized companies, voluntary agreements that included long-term energy strategies, increased taxes to improve the cost-effectiveness of energy efficiency measures, and EUs Emission Trading System.

    Place, publisher, year, edition, pages
    Basel, Switzerland: , 2019
    Keywords
    aluminium industry, foundry industry, energy efficiency, barriers, drivers, driving forces, information sources, questionnaire
    National Category
    Energy Systems Environmental Management Metallurgy and Metallic Materials Manufacturing, Surface and Joining Technology
    Identifiers
    urn:nbn:se:liu:diva-156237 (URN)10.3390/su11072043 (DOI)000466551600220 ()
    Projects
    Ökad energieffektivitet aluminiumindustrins värdekedjor – en klimatneutral bransch år 2050
    Funder
    Swedish Energy Agency, 40552-1
    Note

    Funding agencies:  Swedish Energy Agency [40552-1]; Linkoping University Library

    Available from: 2019-04-09 Created: 2019-04-09 Last updated: 2020-04-20
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  • 179.
    Haraldsson, Joakim
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering.
    Johansson, Maria
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering.
    Barriers to and Drivers for Improved Energy Efficiency in the Swedish Aluminium Industry and Aluminium Casting Foundries2019In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 11, no 7, article id 2043Article in journal (Refereed)
    Abstract [en]

    Industrial energy efficiency is important for reducing CO2 emissions and could be a competitive advantage for companies because it can reduce costs. However, cost-effective energy efficiency measures are not always implemented because there are barriers inhibiting their implementation. Drivers for energy efficiency could provide means for overcoming these barriers. The aim of this article was to study the importance of different barriers to and drivers for improved energy efficiency in the Swedish aluminium industry and foundries that cast aluminium. Additionally, the perceived usefulness of different information sources on energy efficiency measures was studied. The data were collected through a questionnaire covering 39 barriers and 48 drivers, divided into different categories. Both the aluminium and foundry industries considered technological and economic barriers as the most important categories. The most important category of drivers for the aluminium industry was organisational drivers, while the foundries rated economic drivers as the most important. Colleagues within the company, the company group and sector, and the trade organisation were considered the most useful information sources. Important factors for driving work with improved energy efficiency included access to knowledge within the company, having a culture within the company promoting energy efficiency, and networking within the sector. The policy implications identified included energy labelling of production equipment, the law on energy audit in large companies and subsidy for energy audits in small- and medium-sized companies, voluntary agreements that included long-term energy strategies, increased taxes to improve the cost-effectiveness of energy efficiency measures, and EUs Emission Trading System.

    Download full text (pdf)
    fulltext
  • 180.
    Haraldsson, Joakim
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering.
    Johansson, Maria
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering.
    Energy Efficiency in the Supply Chains of the Aluminium Industry: The Cases of Five Products Made in Sweden2019In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, no 2, p. 245-Article in journal (Refereed)
    Abstract [en]

    Improved energy efficiency in supply chains can reduce both environmental impact and lifecycle costs, and thus becomes a competitive advantage in the work towards a sustainable global economy. Viewing the supply chain as a system provides the holistic perspective needed to avoid sub-optimal energy use. This article studies measures relating to technology and management that can increase energy efficiency in the supply chains of five aluminium products made in Sweden. Additionally, energy efficiency potentials related to the flows of material, energy, and knowledge between the actors in the supply chains are studied. Empirical data was collected using focus group interviews and one focus group per product was completed. The results show that there are several areas for potential energy efficiency improvement; for example, product design, communication and collaboration, transportation, and reduced material waste. Demands from other actors that can have direct or indirect effects on energy use in the supply chains were identified. Despite the fact that companies can save money through improved energy efficiency, demands from customers and the authorities would provide the additional incentives needed for companies to work harder to improve energy efficiency.

    Download full text (pdf)
    fulltext
  • 181.
    Haraldsson, Joakim
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering.
    Johansson, Maria
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering.
    Impact analysis of energy efficiency measures in the electrolysis process in primary aluminium production2019In: WEENTECH Proceedings in Energy, 2019, Vol. 4(2), p. 177-184Conference paper (Refereed)
    Abstract [en]

    The Paris Agreement includes the goals of ‘holding the increase in the global average temperature to well below 2°C above pre-industrial levels’ and ‘making finance flows consistent with a pathway towards low greenhouse gas emissions’. Industrial energy efficiency will play an important role in meeting those goals as well as becoming a competitive advantage due to reduced costs for companies. The aluminium industry is energy intensive and uses fossil fuels both for energy purposes and as reaction material. Additionally, the aluminium industry uses significant amounts of electricity. The electrolysis process in the primary production of aluminium is the most energy- and carbon-intensive process within the aluminium industry. The aim of this paper is to study the effects on primary energy use, greenhouse gas emissions and costs when three energy efficiency measures are implemented in the electrolysis process. The effects on the primary energy use, greenhouse gas emissions and costs are calculated by multiplying the savings in final energy use by a primary energy factor, emissions factor and price of electricity, respectively. The results showed significant savings in primary energy demand, greenhouse gas emissions and cost from the implementation of the three measures. These results only indicate the size of the potential savings and a site-specific investigation needs to be conducted for each plant. This paper is a part of a research project conducted in close cooperation with the Swedish aluminium industry.

  • 182.
    Haraldsson, Joakim
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering.
    Johansson, Maria
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering.
    Review of measures for improved energy efficiency in production-related processes in the aluminium industry: From electrolysis to recycling2018In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 93, p. 525-548Article, review/survey (Refereed)
    Abstract [en]

    The aluminium industry is facing a challenge in meeting the goal of halved greenhouse gas emissions by 2050, while the demand for aluminium is estimated to increase 2–3 times by the same year. Energy efficiency will play an important part in achieving the goal. The paper’s aim was to investigate possible production-related energy efficiency measures in the aluminium industry. Mining of bauxite and production of alumina from bauxite are not included in the study. In total, 52 measures were identified through a literature review. Electrolysis in primary aluminium production, recycling and general measures constituted the majority of the 52 measures. This can be explained by the high energy intensity of electrolysis, the relatively wide applicability of the general measures and the fact that all aluminium passes through either electrolysis or recycling. Electrolysis shows a higher number of emerging/novel measures compared to the other processes, which can also be explained by its high energy intensity. Processing aluminium with extrusion, rolling, casting (shape-casting and casting of ingots, slabs and billets), heat treatment and anodising will also benefit from energy efficiency. However, these processes showed relatively fewer measures, which might be explained by the fact that to some extent, these processes are not as energy demanding compared, for example, to electrolysis. In many cases, the presented measures can be combined, which implies that the best practice should be to combine the measures. There may also be a future prospect of achieving carbon-neutral and coal-independent electrolysis. Secondary aluminium production will be increasingly important for meeting the increasing demand for aluminium with respect to environmental and economic concerns and strengthened competitiveness. Focusing on increased production capacity, recovery yields and energy efficiency in secondary production will be pivotal. Further research and development will be required for those measures designated as novel or emerging.

    Download full text (pdf)
    fulltext
  • 183.
    Hasan, A. S. M. Monjurul
    et al.
    Bangladesh Army Int Univ Sci and Technol, Bangladesh.
    Hoq, Md Tanbhir
    Univ Asia Pacific, Bangladesh.
    Thollander, Patrik
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering.
    Energy management practices in Bangladeshs iron and steel industries2018In: Energy Strategy Reviews, ISSN 2211-467X, E-ISSN 2211-4688, Vol. 22, p. 230-236Article in journal (Refereed)
    Abstract [en]

    The aim of this paper was to study energy management and improved energy efficiency among large iron and steel mills in Bangladesh. The results show that there are some barriers to energy management practices among large steel mills, the most important barriers being the perceived absence of cost-effective technical measures, high perceived risks due to uncertain future energy costs and poor information quality. However, this study has shown that the reduction in energy costs due to improved energy efficiency constitutes the most important driver for energy efficiency in the studied steel mills. The results also show that most of the steel mills have not had any technical energy efficiency improvement measures implemented in the production process. Moreover, the steel mills seem unfamiliar with the concept of including energy service companies, and the lack of information or awareness seems to be the main reason behind this. The paper also finds that energy efficiency is perceived to be able to be improved by 6%-8% through energy management practices.

  • 184.
    Hasan, A. S. M. Monjurul
    et al.
    Bangladesh Army Int Univ Sci and Technol, Bangladesh.
    Hossain, Rakib
    Bangladesh Army Int Univ Sci and Technol, Bangladesh.
    Tuhin, Rashedul Amin
    East West Univ, Bangladesh.
    Sakib, Taiyeb Hasan
    Bangladesh Army Int Univ Sci and Technol, Bangladesh.
    Thollander, Patrik
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering. Univ Gavle, Sweden.
    Empirical Investigation of Barriers and Driving Forces for Efficient Energy Management Practices in Non-Energy-Intensive Manufacturing Industries of Bangladesh2019In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 11, no 9, article id 2671Article in journal (Refereed)
    Abstract [en]

    Improved energy efficiency is being considered as one of the significant challenges to mitigating climate change all over the world. While developed countries have already adopted energy management and auditing practices to improve energy efficiency, the developing countries lag far behind. There are a limited number of studies which have been conducted in the context of developing countries, which mostly revolve around highly energy-intensive sectors. This study looks into the existence and importance of the challenges to and motivating forces for the adoption of energy management practices in Bangladesh, a developing country, focusing on the non-energy-intensive manufacturing industries. Conducted as a multiple case study, the results indicate the existence of several barriers towards adopting and implementing the management of energy practices in the non-energy-intensive industries of Bangladesh, where among them, other preferences for capital venture and inadequate capital expenditure are the most dominant. This study also identified a number of driving forces that can accelerate the acceptance of energy efficiency practices, such as the demands from the owner, loans, subsidies, and a lowered cost-benefit ratio. Findings of this study could assist the concerned stakeholders to develop beneficial policies and a proper regulatory framework for the non-energy-intensive industries of developing countries like Bangladesh.

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  • 185.
    Hasan, A. S. M. Monjurul
    et al.
    Bangladesh Army Int Univ Sci and Technol, Bangladesh.
    Rokonuzzaman, Mohammad
    Deakin Univ, Australia.
    Tuhin, Rashedul Amin
    East West Univ, Bangladesh.
    Salimullah, Shah Md.
    Bangladesh Army Int Univ Sci and Technol, Bangladesh.
    Ullah, Mahfuz
    Bangladesh Army Int Univ Sci and Technol, Bangladesh.
    Sakib, Taiyeb Hasan
    Bangladesh Army Int Univ Sci and Technol, Bangladesh.
    Thollander, Patrik
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering. Univ Gavle, Sweden.
    Drivers and Barriers to Industrial Energy Efficiency in Textile Industries of Bangladesh2019In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, no 9, article id 1775Article in journal (Refereed)
    Abstract [en]

    Bangladesh faced a substantial growth in primary energy demand in the last few years. According to several studies, energy generation is not the only means to address energy demand; efficient energy management practices are also very critical. A pertinent contribution in the energy management at the industrial sector ensures the proper utilization of energy. Energy management and its efficiency in the textile industries of Bangladesh are studied in this paper. The outcomes demonstrate several barriers to energy management practices which are inadequate technical cost-effective measures, inadequate capital expenditure, and poor research and development. However, this study also demonstrates that the risk of high energy prices in the future, assistance from energy professionals, and an energy management scheme constitute the important drivers for the implementation of energy efficiency measures in the studied textile mills. The studied textile industries seem unaccustomed to the dedicated energy service company concept, and insufficient information regarding energy service companies (ESCOs) and the shortage of trained professionals in energy management seem to be the reasons behind this. This paper likewise finds that 3-4% energy efficiency improvements can be gained with the help of energy management practices in these industries.

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  • 186.
    Heidari, Tari Mehrdad
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering.
    Söderström, Mats
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Energy Systems.
    Modelling of thermal energy storage in industrial energy systems the method development of MIND2002In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 22, no 11, p. 1195-1205Article in journal (Refereed)
    Abstract [en]

    Industrial energy efficiency is of vital importance as regards environment and industrial profitability. Optimisation of industrial energy systems may show a way towards improved use of resources in energy supply as well as in production processes. The deregulation of the electricity market in some countries increases flexibility in electricity contracts. Taking advantage of the price structure in these contracts is one of the ways to minimise the energy costs and decrease the influence on the environment. Thermal energy stores are very suitable facilities for achieving these goals, having the capability of moving energy use from one period of time to another and thereby influencing not only energy cost but also costs related to power demand if electric energy use is involved. In this paper, the influence on energy costs, energy and material flows resulting from the use of energy storage is discussed. Energy storage has been modelled by using MIND (Method for analysis of INDustrial energy systems) in the form that has recently been developed by the author. A case study from the pulp and paper industry has been used to verify this. © 2002 Elsevier Science Ltd. All rights reserved.

  • 187.
    Henning, Dag
    et al.
    Linköping University, Department of Mechanical Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Amiri, Shahnaz
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Holmgren, Kristina
    Linköping University, Department of Mechanical Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Modelling and optimisation of electricity, steam and district heating production for a local Swedish utility2006In: European Journal of Operational Research, ISSN 0377-2217, E-ISSN 1872-6860, Vol. 175, no 2, p. 1224-1247Article in journal (Refereed)
    Abstract [en]

    District heating may help reduce environmental impact and energy costs, but policy instruments and waste management may influence operations. The energy system optimisation model MODEST has been used for 50 towns, regions and a nation. Investments and operation that satisfy energy demand at minimum cost are found through linear programming. This paper describes the application of MODEST to a municipal utility, which uses several fuels and cogeneration plants. The model reflects diurnal and monthly demand fluctuations. Several studies of the Linköping utility are reviewed. These indicate that the marginal heat cost is lower in summer, a new waste or wood fired cogeneration plant is more profitable than a natural-gas-fired combined cycle, material recycling of paper and hard plastics is preferable to waste incineration from an energy-efficiency viewpoint, and considering external costs enhances wood fuel use. Here, an emission limit is used to show how fossil-fuel cogeneration displaces CO2 from coal-condensing plants. © 2005 Elsevier B.V. All rights reserved.

  • 188.
    Henning, Dag
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Danestig, Maria
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Local development possibilities for sustainable energy supply and use in Sweden2007In: In B. Frostell, Å. Danielsson, L. Hagberg, B.-O. Linnér, E. Lisberg Jensen (eds., Science for Sustainable Development - The Social Challenge with emphasis on conditions for change, Proceedings from the 2nd VHU Conference, Linköping 6-7 September, Uppsala: VHU, 2007Conference paper (Other academic)
    Abstract [en]

    Large structural changes are necessary to reduce the resource use in industrialised countries to a sustainable level. Modifications of municipalities’ normal operations can contribute to a more ecologically, economically and socially sustainable society through, for example, promotion of measures concerning energy conservation and renewable energy supply. In the Swedish Energy Agency’s Sustainable municipality programme, it is developed how spatial plans of ground use and building development can promote local renewable energy sources and efficient energy utilisation. Energy issues can be integrated in spatial planning through scenarios of future energy supply and use, which are discussed by local stakeholders. It can be shown how wall insulation, solar heating and heat recovery can reduce primary energy demand and that switching from electricity to biofuel can reduce CO2 emissions. The indicator heat load density depends on building structure and shows, for instance, preconditions for district heating, which often is a favourable heating option. If the local energy utility is involved in spatial planning, it may facilitate the introduction of temporary solutions, such as pellets boilers, to make more customers chose district heating in areas where the network is delayed. District heating systems enable efficient electricity generation in combined heat and power (CHP) plants, which can be elucidated by an optimisation model that considers economy and environment. Strategic spatial planning can promote establishment and expansion of district heating networks.

  • 189.
    Henning, Dag
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Danestig, Maria
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Holmgren, Kristina
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Gebremedhin, Alemayehu
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Modelling the impact of policy instruments on district heating operations: experiences from Sweden2006In: 10th International Symposium on District Heating and Cooling, Hanover, Germany, 2006Conference paper (Refereed)
    Abstract [en]

    Emission allowances aim at reducing carbon dioxide emissions in the European Union. Feed-in tariffs and green certificates increase renewable electricity generation in some countries. Undesired energy carriers, such as fossil fuels, can be taxed to decrease consumption. In Sweden, monetary policy instruments have been used for many years, which has influenced district-heating utilities’ operations and investments.

    The energy system optimisation model MODEST may help elucidating the impact of policy instruments on choices of fuels and plants. The model can minimise operation and investment costs for satisfying district heating demand, considering revenues from electricity sales and waste reception. It has been used to analyse heat and electricity production for 50 local Swedish utilities. This paper shows how some plants, systems and policy instruments have been modelled and results from some case studies. It may help analysts who face policy instruments, which probably will have a growing influence on district heating operations.

    Policy instruments should reflect external costs and induce behaviour that is beneficial from an overall viewpoint. Swedish fossil-fuel taxes hampered cogeneration during many years. Earlier, fuel input could be freely allocated to output energy forms and wood was often used for heat production and coal for electricity generation to minimise taxes. Now, lower taxes promote fossil cogeneration but green certificates make it more profitable to invest in renewable electricity generation.

    Carbon dioxide emission allowances can reduce local emissions due to districtheating and electricity production significantly at current price levels but the impact depends on allowance price. With emission trading, investment in a natural-gas-fired cogeneration plant may be beneficial for some utilities due to high electricity prices in the European electricity market, partly caused by emission allowances.

    District-heating demand can enable utilisation of resources that otherwise would be of no value. A landfill ban now increases waste incineration, which may reduce industrial waste heat utilisation and heat disposal from cogeneration plants and thereby decrease electricity production. A tax on incinerated waste may reduce the profitability of investing in waste incineration.

  • 190.
    Henning, Dag
    et al.
    Optensys Energianalys .
    Gebremedhin, Alemayehu
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Energy Systems.
    Future biofuel utilisation for small-scale heating and large-scale heat, electricity and automotive fuel production2008In: World Bioenergy 2008. Taking you from Know-how to Show-how,2008, 2008Conference paper (Refereed)
    Abstract [en]

         

  • 191.
    Henning, Dag
    et al.
    Optensys Energianalys, Linköping, Sweden.
    Trygg, Louise
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Reduction of electricity use in Swedish industry and its impact on national power supply and European CO2 emissions2008In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 36, no 7, p. 2330-2350Article in journal (Refereed)
    Abstract [en]

    Decreased energy use is crucial for achieving sustainable energy solutions. This paper presents current and possible future electricity use in Swedish industry. Non-heavy lines of business (e.g. food, vehicles) that use one-third of the electricity in Swedish industry are analysed in detail. Most electricity is used in the support processes pumping and ventilation, and manufacturing by decomposition. Energy conservation can take place through e.g. more efficient light fittings and switching off ventilation during night and weekends. By energy-carrier switching, electricity used for heat production is replaced by e.g. fuel. Taking technically possible demand-side measures in the whole lines of business, according to energy audits in a set of factories, means a 35% demand reduction. A systems analysis of power production, trade, demand and conservation was made using the MODEST energy system optimisation model, which uses linear programming and considers the time-dependent impact on demand for days, weeks and seasons. Electricity that is replaced by district heating from a combined heat and power (CHP) plant has a dual impact on the electricity system through reduced demand and increased electricity generation. Reduced electricity consumption and enhanced cogeneration in Sweden enables increased electricity export, which displaces coal-fired condensing plants in the European electricity market and helps to reduce European CO2 emissions. Within the European emission trading system, those electricity conservation measures should be taken that are more cost-efficient than other ways of reducing CO2 emissions. The demand-side measures turn net electricity imports into net export and reduce annual operation costs and net CO2 emissions due to covering Swedish electricity demand by 200 million euros and 6 Mtonne, respectively. With estimated electricity conservation in the whole of Swedish industry, net electricity exports would be larger and net CO2 emissions would be even smaller.

  • 192.
    Henning, Dag
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Trygg, Louise
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Gebremedhin, Alemayehu
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Enhanced biofuel utilisation in Swedish industries, buildings and district heating2006In: the World Bioenergy 2006 Conference and exhibition on Biomass for Energy, Jönköping, Sweden, 30 may – 1 June, 2006, p. 198-203Conference paper (Refereed)
  • 193.
    Henning, Dag
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Trygg, Louise
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Glad, Wiktoria
    Linköping University, The Tema Institute, Technology and Social Change. Linköping University, Faculty of Arts and Sciences.
    Gustafsson, Stig-Inge
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Socio-technical analyses of energy supply and use in three Swedish municipalities striving toward sustainability2005In: Proceeding of the 1st VHU Conference on Science for Sustainable Development, Västerås, Sweden, 14-16 April, 2005, p. 133–142-Conference paper (Refereed)
  • 194.
    Hermansson, Henrik
    Linköping University, Department of Management and Engineering, Energy Systems.
    Kryogen uppgradering av biogas med kyla från värmedriven absorptionskylmaskin2009Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This is a master thesis that has been carried out at Göteborg Energi AB. It refers to investigate ifcryogenic upgrading of biogas with advantage can be done by producing necessary cold with a heatdriven absorption cooling machine. Göteborg Energi is one of three actors that together will build abiogas plant in Lidköping that will be up and running in 2010. The plant will produce 30 GWhliquefied biogas annually.

    This thesis investigastes whether it is advantageous, to upgrade biogas with heat driven cooling, in aperspective of economy, energy use and environment. It compares cryogenic upgrading with coldproduced by electricity, but also by other techniques. Two different process simulation softwares havebeen used as support to this thesis; Hysys and DESIGN II.

    The result shows that energy usage increases when the necessary cold is produced with heat instead ofelectricity; 0,47 kW/Nm3 rawgas for cryo upgrade with absorptions cooling and 0,29 kW/Nm3 rawgaswith cold produced by electricity. If it’s possible to use the waste heat to warm the digester, the energyconsumption for the upgrading can be reduced to 0,29 kW/Nm3 for the system with heat-driven cold,and 0,15 kW/Nm3 rawgas for cold produced by electricity. In comparison with other techniques forupgrading, 0,47 kW/Nm3 rawgas is a high value while 0,29 kW/Nm3 rawgas is among the lowestvalues for energy use.

    The impact on the climate emerges from the use of electricity and when methane slips out from theupgrading plant. The result shows that the impact on the climate is slightly decreased for cryogenicupgrading when the cold is produced with a heat driven absorption machine instead of electricity. Theresult varies a lot due to how one calculate the emission of carbon dioxide from the electricity on themargin. In comparison with other upgrading techniques, the climate impact from cryogenic upgradingis less, other than the COOAB-technique that is superior because of its low methane slip and lowdemand of electricity.

    An economical comparison shows that the cost for energy usage is about the same for cryogenic as forother techniques; approximately 0,03 SEK/kWh upgraded gas. If one can utilize the waste heat, thecost would be decreased to 0,024 and 0,02 SEK/kWh upgraded gas for the system with cryogenicupgrading with cooling from absorption machine respectively cooling produced with electricity.

    My conclusion is that the utilization of the waste heat is essential if one wishes to get good economyand low energy use for the upgrading of biogas with cryogenic methods. A slightly increasedenvironmental improvement can be received if one change the cold production from electricity to heat,otherwise it is always more advantageous to use electricity for cryogenic methods.

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  • 195.
    Hjalmarsson, Linnea
    et al.
    Linköping University, The Tema Institute, Technology and Social Change. Linköping University, Faculty of Arts and Sciences.
    Mårten, Larsson
    Royal Institute of Technology.
    Olsson, Linda
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Wikström, Martina
    Royal Institute of Technology.
    Pathways to a renewable road transport system in Stockholm 20302011Report (Other academic)
    Abstract [en]

    In order to mitigate global climate change, anthropogenic emissions of fossil carbon dioxide (CO2) need to be cut drastically. Road transport is a major source of CO2 emissions, and in urban areas road transport also involves problems such as congestion, noise and particle emissions. Stockholm, the Swedish capital and one of the busiest regions in Sweden, has the ambition to be a pioneer in addressing environmental problems; CO2 emissions in particular. One of the political visions incorporated in Stockholm’s environmental work is to achieve a practically renewable transport system by 2030.

    This study investigates if there are favourable conditions to achieve a renewable road transport system in Stockholm by 2030. Three aspects are considered; technology, private economy and regional planning policy. The study is based on three sub-studies, one for each aspect, and conclusions are drawn from the integration of the sub-studies. A scenario assessment implies that the technology to transit to a completely renewable road transport system could exist, and that a mix of technologies would be preferable. Cost optimisations show that renewable fuels and electric vehicles are cost-competitive given certain incentives. Hence, private persons could shift their transportation choices towards alternative vehicles and fuels. Interviews with regional institutional actors and analysis of regional planning documents reveal that integrating energy and transport systems in planning policy could enable the transition to a renewable road transport system in Stockholm. The work has been carried out under the auspices of The Energy Systems Programme (primarily financed by The Swedish Energy Agency).

    The study concludes that favourable conditions for a renewable road transport system do exist. However, the main challenge is to coordinate the simultaneous implementation of necessary measures and the study shows that this is best organised at a regional level.

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    Pathways to a renewable road transport system in Stockholm 2030
  • 196.
    Holm, Björn
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Göransson, Mikael
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Analys av energikartläggningar och framställning av metodik för Dalkia AB2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    During the last decade, the awareness of energy usage has increased in Sweden, especially within the industrial sector. This is most likely the cause of ever increasing energy prices, increased taxation and regulations and a focus on negative environmental factors associated with energy usage.

    It is also to be noted that Swedish industry has previously enjoyed comparatively low electricity prices, in comparison to her European neighbors (outside of Scandinavia where the situation is similar to that of Sweden). This has led to a situation in which Swedish industries have evolved with limited awareness of their own energy usage and with a low overall effectiveness (again in comparison to European neighbors outside of Scandinavia).

    Energy optimization is now a high priority for many industrial companies in order to lower costs and remain competitive on the international market. This has led to an excellent business opportunity for the company Dalkia AB, the Swedish branch of the multinational French company Dalkia.

    Dalkia AB performs various services all related to the usage, optimization and supply of energy. In order to optimize energy usage an energy audit is usually performed in order to map a company’s current energy use and recommend energy efficiency measures.

    At the request of Dalkia AB this master thesis had the goal of analyzing their energy audit method in order to find weaknesses and thereafter suggest improvements. All the steps involved in Dalkia AB ́s energy audit method where investigated.

    From the analysis it was discovered that they lacked experienced and capable auditors to audit industrial processes, that there were no relevant programs within the company to calculate the total energy usage of an audited object and finally that the reports presenting results from the audit left the salesmen confused as to how the results were calculated and what estimations they were based upon. The confusing reporting was potentially complicating the final sale to the customer.

    In order to rectify the problems development started on the following components which were to be eventually taken over by the engineers at Dalkia; a guide to follow for industrial audits, a program to use to calculate energy usage and a report structure to use to present results from the energy audit in a clearer fashion.

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    Analys av energikartläggningar och framställning av metodik för Dalkia AB
  • 197. Order onlineBuy this publication >>
    Holmgren, Kristina
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    A System Perspective on District Heating and Waste Incineration2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Energy recovery by waste incineration has a double function as waste treatment method and supplier of electricity and/or heat, thereby linking the systems of energy and waste management. Both systems are undergoing great changes, mainly due to new regulations. Important regulations within waste management in Sweden are a ban on landfill of combustible waste and organic waste, and a tax on landfill of waste. New waste incineration facilities are being built in order to increase capacity to meet these demands.

    The aim of this thesis is to investigate impacts on Swedish district heating systems of increased use of waste as a fuel in economic and environmental terms, the latter mainly by assessing emissions of carbon dioxide. Of importance is the influence of various policy instruments. To highlight the connection between the energy and waste management systems and how these influence each other is another goal, as well as the function of district heating systems as user of various waste heat supplies. An important assumption for this thesis is a deregulated European electricity market, where the marginal power production in the short term is coal condensing power and in the long term natural gas based power, that affects the conditions for combined heat and power in district heating systems. The method used is case studies of three Swedish municipalities that utilise waste in their district heating systems. In two papers, the scope is broadened from the energy utility perspective by comparing the energy efficiency of energy recovery and material recovery of various fractions, and the effect of including external costs for CO2 as well as SO2, NOx and particles. The ambition is that the results can be part of the decision making process for energy utilities and for policy makers in the energy sector and waste management.

    It is economically advantageous to use waste as a fuel in the energy sector and regulations in the waste management sector and high taxes on fossil fuels contribute to profitability. Waste incineration plants are base suppliers of heat because they derive revenue from receiving the waste. Economic conditions for waste incineration are altered with the introduction of a tax on incinerated municipal waste. A conflict may arise between combined heat and power production in district heating systems and waste incineration, since the latter can remove the heat sink for other combined heat and power plants with higher efficiencies. Combined heat and power is the main measure to decrease carbon dioxide emissions in district heating systems on the assumption that locally produced electricity replaces electricity in coal condensing plants. It can be difficult to design policy instruments for waste incineration due to some conflicting goals for waste management and energy systems. Comparing the energy efficiency of material recovery and energy recovery is a way to assess the resource efficiency of waste treatment methods. From that perspective, if there is a district heating system which can utilise the heat, biodegradable waste and cardboard should be energy recovered and plastics and paper material recovered. To put costs on environmental effects, so called external costs, is a way to take these effects into regard in traditional economic calculations, but the method has drawbacks, e.g. the limited range of environmental effects included and uncertainties in the monetary valuation of environmental effects.

    List of papers
    1. Waste incineration in Swedish municipal energy systems: modelling the effects of various waste quantities in the city of Linköping
    Open this publication in new window or tab >>Waste incineration in Swedish municipal energy systems: modelling the effects of various waste quantities in the city of Linköping
    2004 (English)In: Sustainable development of energy, water and environment systems, Dubrovnik, Croatia; 2004, 2004Conference paper, Published paper (Other academic)
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-14201 (URN)
    Available from: 2007-01-04 Created: 2007-01-04 Last updated: 2009-05-19
    2. Modelling a district heating system: introduction of waste incineration, policy instruments and co-operation with an industry
    Open this publication in new window or tab >>Modelling a district heating system: introduction of waste incineration, policy instruments and co-operation with an industry
    2004 (English)In: Energy Policy, ISSN 0301-4215, Vol. 32, no 16, p. 1807-1817Article in journal (Refereed) Published
    Abstract [en]

    The capacity for waste incineration in Swedish municipalities is increasing due to regulations aimed at decreasing landfill with waste. This has a large impact on the municipal energy systems, since waste is an important fuel for district heating production. The object of this study is a municipality, Skövde, which is planning to build a waste incineration plant to produce electricity and heat. The municipality is also planning to extend the district heating grid to include a large industrial heat consumer. The economic effect on the energy system of these measures is analysed as well as environmental effects in terms of carbon dioxide emissions. The consequences of two different policy instruments, green electricity certificates and a tax on waste incineration, are also studied. Economic optimisations show that the advantage of co-operation with industry is twofold: lower heat production costs and a considerable reduction of carbon dioxide emissions. It is economically feasible to invest in a waste incineration plant for heat production. An important measure to lower carbon dioxide emissions is to introduce combined heat and power production on the assumption that locally produced electricity replaces electricity produced by coal condensing power.

    Keywords
    Waste, Energy recovery, District heating, Policy instruments, Industrial co-operation
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-14202 (URN)10.1016/S0301-4215(03)00168-X (DOI)
    Available from: 2007-01-04 Created: 2007-01-04
    3. Role of a district heating network as a user of waste heat supply from various sources: the case of Göteborg
    Open this publication in new window or tab >>Role of a district heating network as a user of waste heat supply from various sources: the case of Göteborg
    2006 (English)In: Applied Energy, ISSN 0306-2619, Vol. 83, no 12, p. 1351-1367Article in journal (Refereed) Published
    Abstract [en]

    District-heating (DH) networks can utilise heat that would otherwise be of limited use. This study analyses a municipal DH system, which uses waste heat from industries and waste incineration as base suppliers of heat and is currently investing in a natural-gas fired combined heat-and-power (CHP) plant. An important assumption in this study is of the establishment of an integrated European electricity-market, which means higher electricity prices than are traditional in Sweden. The study shows that there is space in the DH system for all three energy carriers; heat from industries, waste incineration and CHP plants. The new CHP plant replaces mainly other heat sources, i.e., hot water boilers and heat pumps. The new CHP plant’s operating time is strongly dependent on the electricity price.

    Keywords
    District heating; Waste incineration; Cogeneration; Waste heat; Modelling; Policy instruments
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-14203 (URN)10.1016/j.apenergy.2006.02.001 (DOI)
    Available from: 2007-01-04 Created: 2007-01-04
    4. Modelling the impact of policy instruments on district heating operations: experiences from Sweden
    Open this publication in new window or tab >>Modelling the impact of policy instruments on district heating operations: experiences from Sweden
    2006 (English)In: 10th International Symposium on District Heating and Cooling, Hanover, Germany, 2006Conference paper, Published paper (Refereed)
    Abstract [en]

    Emission allowances aim at reducing carbon dioxide emissions in the European Union. Feed-in tariffs and green certificates increase renewable electricity generation in some countries. Undesired energy carriers, such as fossil fuels, can be taxed to decrease consumption. In Sweden, monetary policy instruments have been used for many years, which has influenced district-heating utilities’ operations and investments.

    The energy system optimisation model MODEST may help elucidating the impact of policy instruments on choices of fuels and plants. The model can minimise operation and investment costs for satisfying district heating demand, considering revenues from electricity sales and waste reception. It has been used to analyse heat and electricity production for 50 local Swedish utilities. This paper shows how some plants, systems and policy instruments have been modelled and results from some case studies. It may help analysts who face policy instruments, which probably will have a growing influence on district heating operations.

    Policy instruments should reflect external costs and induce behaviour that is beneficial from an overall viewpoint. Swedish fossil-fuel taxes hampered cogeneration during many years. Earlier, fuel input could be freely allocated to output energy forms and wood was often used for heat production and coal for electricity generation to minimise taxes. Now, lower taxes promote fossil cogeneration but green certificates make it more profitable to invest in renewable electricity generation.

    Carbon dioxide emission allowances can reduce local emissions due to districtheating and electricity production significantly at current price levels but the impact depends on allowance price. With emission trading, investment in a natural-gas-fired cogeneration plant may be beneficial for some utilities due to high electricity prices in the European electricity market, partly caused by emission allowances.

    District-heating demand can enable utilisation of resources that otherwise would be of no value. A landfill ban now increases waste incineration, which may reduce industrial waste heat utilisation and heat disposal from cogeneration plants and thereby decrease electricity production. A tax on incinerated waste may reduce the profitability of investing in waste incineration.

    Keywords
    Energy policy, taxes, green certificates, emission allowances, CHP
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-14204 (URN)
    Available from: 2007-01-04 Created: 2007-01-04 Last updated: 2009-05-18Bibliographically approved
    5. Comparison between material and energy recovery of municipal waste from an energy perspective: A study of two Swedish municipalities
    Open this publication in new window or tab >>Comparison between material and energy recovery of municipal waste from an energy perspective: A study of two Swedish municipalities
    2004 (English)In: Resources, Conservation and Recycling, ISSN 0921-3449, Vol. 43, no 1, p. 51-73Article in journal (Refereed) Published
    Abstract [en]

    The aim of this study is to compare material recovery to waste incineration with energy recovery from the criteria of energy efficiency. Material recovery saves virgin material and also energy since production processes using recovered material are less energy intensive than processes using virgin material, whereas energy recovery saves other fuels that differ among various energy systems. Optimisations are made for the district heating systems in two Swedish municipalities, showing that it is profitable for the energy utilities in the municipalities to invest in plants using waste as a fuel for electricity and heat production. The fuels replaced by the waste differ between the municipalities. For one it is mostly wood chips, and for the other, a lot of biomass is replaced, but the largest saving is in oil. Energy savings by material recycling of the waste are calculated. Non-combustible waste, such as metals and glass save energy in various extensions when material recycled, but give no heat contribution when incinerated. It is more complicated to compare material and energy recovery of combustible waste fractions, such as cardboard, paper, plastics and biodegradable waste since they can be recycled in both fashions. For these fractions it is important to consider the configuration of the energy system. The conclusions from the two municipalities are that even if there is a district heating system able to utilise the heat, from the energy-efficiency view point; paper and hard plastics should preferably be material recovered, whereas cardboard and biodegradable waste is more suited for energy recovery through waste incineration. These calculations are done with the assumption that biomass should be regarded as a limited resource and when saved eventually eliminates fossile fuel combustion in other facilities.

    Keywords
    Waste management, Material recovery, Waste incineration, Energy recovery, District heating, Energy savings
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-14205 (URN)10.1016/j.resconrec.2004.05.001 (DOI)
    Available from: 2007-01-04 Created: 2007-01-04
    6. Internalising external costs of electricity and heat production in a municipal energy system
    Open this publication in new window or tab >>Internalising external costs of electricity and heat production in a municipal energy system
    2007 (English)In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 35, no 10, p. 5242-5253Article in journal (Refereed) Published
    Abstract [en]

    Both energy supply and waste treatment give rise to negative effects on the environment, so-called external effects. In this study, monetary values on external costs collected from the EU′s ExternE project are used to evaluate inclusion of these costs in comparison with an energy utility perspective including present policy instruments. The studied object is a municipal district heating system with a waste incineration plant as the base supplier of heat. The evaluation concerns fuels used for heat production and total electricity production, for scenarios with external costs included and for a scenario using the present policy instrument.

    Impacts of assumptions on marginal power producers (coal or natural gas power plants) are investigated, since locally produced electricity is assumed to replace marginal power and thus is credited for the avoided burden. Varying levels of external costs for carbon dioxide emissions are analysed. The method used is an economic optimisation model, MODEST.

    The conclusion is that present policy instruments are strong incentives for cogeneration, even when external costs are included. Waste is fully utilised in all scenarios. In cases where coal is the marginal power producer, more electricity is produced; when natural gas is the marginal power producer, less is produced. There are several uncertainties in the data for external costs, both methodological and ethical. In the ExternE data, not all environmental impacts are included. For waste incineration, ashes are not included, and another difficulty is how to treat the avoided burden of other waste treatment methods.

    Keywords
    External costs, Combined heat and power, Waste incineration
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-14206 (URN)10.1016/j.enpol.2007.04.026 (DOI)
    Available from: 2007-01-04 Created: 2007-01-04 Last updated: 2017-12-13
    7. Energy recovery from waste incineration: linking the technical systems of energy and waste management
    Open this publication in new window or tab >>Energy recovery from waste incineration: linking the technical systems of energy and waste management
    2006 (English)In: Conservation and Recycling of Resources: New Research, Nova Publishers , 2006Chapter in book (Other (popular science, discussion, etc.))
    Place, publisher, year, edition, pages
    Nova Publishers, 2006
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-14207 (URN)
    Available from: 2007-01-04 Created: 2007-01-04
    Download full text (pdf)
    FULLTEXT01
  • 198.
    Holmgren, Kristina
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Energy recovery from waste incineration: linking the technical systems of energy and waste management2006In: Conservation and Recycling of Resources: New Research, Nova Publishers , 2006Chapter in book (Other (popular science, discussion, etc.))
  • 199.
    Holmgren, Kristina
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Role of a district heating network as a user of waste heat supply from various sources: the case of Göteborg2006In: Applied Energy, ISSN 0306-2619, Vol. 83, no 12, p. 1351-1367Article in journal (Refereed)
    Abstract [en]

    District-heating (DH) networks can utilise heat that would otherwise be of limited use. This study analyses a municipal DH system, which uses waste heat from industries and waste incineration as base suppliers of heat and is currently investing in a natural-gas fired combined heat-and-power (CHP) plant. An important assumption in this study is of the establishment of an integrated European electricity-market, which means higher electricity prices than are traditional in Sweden. The study shows that there is space in the DH system for all three energy carriers; heat from industries, waste incineration and CHP plants. The new CHP plant replaces mainly other heat sources, i.e., hot water boilers and heat pumps. The new CHP plant’s operating time is strongly dependent on the electricity price.

  • 200.
    Holmgren, Kristina
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Amiri, Shahnaz
    Department of Technology and Built Environment, Division of Energy and Mechanical Engineering, University of Gävle, Gävle, Sweden.
    Internalising external costs of electricity and heat production in a municipal energy system2007In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 35, no 10, p. 5242-5253Article in journal (Refereed)
    Abstract [en]

    Both energy supply and waste treatment give rise to negative effects on the environment, so-called external effects. In this study, monetary values on external costs collected from the EU′s ExternE project are used to evaluate inclusion of these costs in comparison with an energy utility perspective including present policy instruments. The studied object is a municipal district heating system with a waste incineration plant as the base supplier of heat. The evaluation concerns fuels used for heat production and total electricity production, for scenarios with external costs included and for a scenario using the present policy instrument.

    Impacts of assumptions on marginal power producers (coal or natural gas power plants) are investigated, since locally produced electricity is assumed to replace marginal power and thus is credited for the avoided burden. Varying levels of external costs for carbon dioxide emissions are analysed. The method used is an economic optimisation model, MODEST.

    The conclusion is that present policy instruments are strong incentives for cogeneration, even when external costs are included. Waste is fully utilised in all scenarios. In cases where coal is the marginal power producer, more electricity is produced; when natural gas is the marginal power producer, less is produced. There are several uncertainties in the data for external costs, both methodological and ethical. In the ExternE data, not all environmental impacts are included. For waste incineration, ashes are not included, and another difficulty is how to treat the avoided burden of other waste treatment methods.

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