Electricity production by PV is growing world-wide, and grid parity of PV-electricity can be found in many countries, even in low sunlight countries, such as Sweden (at latitude 58 degrees). High installation-rate of PV-systems poses a challenge to the grid-operator. Building-integrated PV-supply potential analysis was performed for Linkoping municipality in Sweden based on GIS-data for all the buildings in the municipality. The Linkoping model provides a high spatial resolution (>180 000 buildings). The data are sorted based on azimuth and tilt, categorized in steps of 10 degrees, and then used to construct hourly power supply data. The supply data are fed into the existing electricity load-profile of Linkoping municipality. The strength and novelty of the method is that it provides the possibility of varying the installation-rate in different spatial directions to better match the load-profile. The results indicate a solar supply-rate of 19, 43 and 88% respectively if using the tilted roofs (>900 kWh/m(2) x yr), the flat-roofs optimized with tilted panels for a winter solar supply and the fully available PV-area on existing buildings (8.1 km(2)). Nevertheless, in approximately 70,1400 and >3000 h/yr, respectively, surplus-power is created, which could be used to match a future load in a wider electromobility scenario. (C) 2016 Elsevier Ltd. All rights reserved.

This paper presents experiences from a recently built area with passive houses in Linkoping, Sweden and compares them with conventional buildings, mainly from an indoor environment perspective, but also based on energy use. The built area consists of 39 recently constructed terraced houses, of which nine are built according to the passive house standard. The aspects of thermal comfort as well as local discomfort are studied. The methodology is based on on-site measurements and two types of simulations - CFD and Building Energy Simulation. In addition a post-occupancy evaluation was made using a standardized questionnaire to relate the occupants perception of the indoor environment one year after the buildings were completed. The thermal comfort for these newly built passive houses is well within the limits in the local building code. However, some interesting findings related to local comfort such as cold floors are found in the post-occupancy evaluation as well as in the predictions. The occupants of the passive houses experience cold floors to a higher degree than in the conventional buildings. It was also shown that there are a higher number of complaints related to high temperatures during summer in the passive houses. It is worth noting that the buildings do not have external shading installed by default. The effect of varying temperatures was also observed in the passive houses to a higher degree than in the more conventional buildings, especially related to cooking and other heat-generating activities, which is normal in a more well insulated and airtight building.

PV electricity is booming world-wide and grid parity can be found in many countries. Nonetheless, animportant factor that still usually affects the economy of the PV project is the value of the power produced. Selfconsumptionis important in Sweden and on other markets where the bought electricity is higher valued than the soldelectricity. For many large roof tops, on-site batteries can be used as a measure for increasing self-consumption. Inthe present study, the logistics terminal owned by DB Schenker in Jönköping, Sweden, where a 20 kWp pilot plantwas installed in 2011, has been analyzed. The main focus is on the increasing self-consumption with batteries forelectric lifters. The results show that the self-consumption rate can increase 12 % (from 66 to 78 %) by using thepresent batteries for the electric lifters in the case-study, based on PV supply power (1 MWp) similar to the electricload capacity (1 MW). This enables 120 MWh per year more self-consumption out of annual 1000 MWh solar PVproduction. The conclusion for the Swedish case is that it is economically feasible to install battery inverters for onsitebatteries.

Time-use data (TUD) have a large potential for improving occupancy and load modelling and for introducingrealistic behavioural patterns into various simulations. In this article, previously developed models of occupancy,activities and energy use based on TUD are extended and described in a general framework. Two extensions arestudied: deterministic conversion of empirical TUD is extended into a complete thermal load model encompassingboth occupancy and various end-uses and a Markov-chain approach for generating synthetic TUD sequences isextended to include a model for load management. Three examples of building-related applications are presented:simulation of indoor climate in a low-energy building, household electricity load management in response to timedifferentiatedelectricity tariffs and simulations of load matching in a net zero energy building. The main conclusionis that the extended model framework can generate detailed and realistic behavioural patterns that allow diversityand correlations between end-uses to be taken into account.

Energy use in the built environment represents a large part of total energy use in Sweden and is oneimportant sector where energy conservation needs to be significantly improved in order to meet thenational implementation of the European goals. One key question that needs to be investigated in relationto these goals is the performance and implementation of passive or low-energy houses. This paperpresents results and an evaluation of a newly built house in an area with passive houses in Linköping,Sweden. Nine passive houses were built with the aim to be energy efficient, with an annual space heatingdemand of 21kWh/m2, and at the same time to have the same visual appearance as any other buildingin the surrounding area.This study evaluates the energy performance of a residential area with low-energy buildings basedon Building Energy Simulation (BES) (IDA ICE 4), and measurements from the real object. Both annualand hourly validation is performed using room by room modeling and internal heat gains. A novelapproach to internal heat gain modeling is presented using time-use data (TUD). The resultsshowpossibleimprovements in the design, the building envelope and in the heating control.

The way that owners of PV systems are handled today gives, in practice, installations of very small PV systems relative to what would be possible if all appropriately oriented roof and facade surfaces were fully exploited. This problem occurs because there is a surplus of PV electricity for the system owner, who receives a zero or low value in relation to the electricity purchases that are avoided. For single-family houses, this means that without net billing it is economically optimal to install only up to about 2-7 m2 of the approximately 60 m2 that are available on the roof of a single-family house. Other end-user types, such as multi-family buildings, agriculture and industry, also show low use of available surfaces. With the current system, the major part of the possible PV production on buildings is hindered. This electricity production does not exploit any new land and has a potential in Sweden of about 10-15 TWh, assuming that 25% of the roof and wall surfaces that have at least 70% of optimum solar radiation are exploited.

The effects of five different scenarios, without and with monthly or annual net billing for an electricity consumer who is also a PV electricity producer have been studied for ten different building types, including three single-family houses, two multi-family buildings and five other properties. The implications for four actors – the solar electricity producer, the grid owner, the electricity trader and the Swedish state – have been calculated. It is thus 200 different combinations that are reported. For each combination the outcome at any system size can also be seen in the reported figures.

The amount of saved electricity for the PV owner depends substantially on the time-horizon of the net billing period. Monthly net billing would drastically improve the utilization of roof areas, but still limits the utilization. Annual net billing gives a similar additional improvement. With annual net billing, the roofs of all the studied types of properties could be covered either entirely with solar cells or as much as needed to cover the annual needs of electricity. A net billing limit, for example 63A=43.5 kW=313 m2, would be a size delimiter for larger buildings.

Grid owners would be affected in the form of reduced revenues for the electricity transfer, reduced losses in the local grid and increased revenue from excess electricity which the PV owner donates to the grid.

For electricity traders increasing system size means that sales to the PV owner decrease in the same way as bought electricity is saved for the PV owner. The balance responsible actor (BA), which takes care of generated solar electricity, can usually make a profit due to the price profile. This could also be the grid owner, or the BA designated by the grid owner, or an electricity trader chosen by the system owner depending on how the net billing is handled. If the same electricity trader is affected by the reduction in electricity sales and earnings due to the price profile, this will be favourable for the electricity trader.

Looking at tax from PV installations, net billing has the same economic effect as if the PV owner had made an energy efficiency measure. The calculations have not taken into account the state's tax revenue of the investment, which today is higher than the loss of revenue for energy tax and VAT.

For the further development of the PV market in Sweden it is of utmost importance to make it possible, as soon as possible, for PV system owners to get a reasonable compensation for their excess electricity. Net billing would be an easy way to solve this problem. The most practical and easiest way to achieve net billing would be if the grid owner could send a net value to the electricity trader. The period for net billing should be longer than one month if all available roof and wall areas are to be optimally utilized.

Dagens hantering av solelproducenter ger i praktiken installationer av väldigt små solelanläggningar i förhållande till vad som vore möjligt om alla lämpligt orienterade tak- och fasadytor skulle utnyttjas fullt ut. Problemet beror på att det uppstår ett solelöverskott för solelproducenten som får inget eller bara ett lågt värde i förhållande till sparad köpt el. För småhus innebär det att utan nettodebitering är det för solelproducenten ekonomiskt optimalt att endast installera upp till ca 2-7 m2 av de ca 60 m2 som finns tillgängligt på ett småhus. Även andra användartyper, som flerbostadshus, lantbruk och industri, uppvisar låg utnyttjandegrad. Med nuvarande system hindras då merparten av solelproduktionen på byggnader, som inte exploaterar någon ny mark och som har en potential i Sverige på ca 10-15 TWh antaget att 25% av de tak och fasadytor som har minst 70% av optimal solinstrålning utnyttjas.

Effekterna av fem olika scenarier, utan respektive med månads- eller årsnettodebitering för en elkonsument som även är solelproducent har studerats för tio olika hustyper, inkluderande tre villor, två flerbostadshus och fem andra fastigheter. Konsekvenserna för de fyra aktörerna solelproducent, nätägare, elhandlare och staten har beräknats. Det blir därmed 200 olika kombinationer som redovisas. För varje kombination kan dessutom utfallet vid godtycklig anläggningsstorlek utläsas i de redovisade figurerna.

Mängden sparad el för solelproducenten beror kraftigt på avräkningsperiodens längd. Månadsnettodebitering skulle drastiskt förbättra utnyttjandegraden av tillgängliga ytor, men begränsar fortfarande ytutnyttjandet. En ytterligare lika stor förbättring ger årsnettodebitering. Vid årsnettodebitering skulle de studerade hustypernas tak kunna täckas endera helt med solceller eller till så stor del som behövs för att täcka årsbehovet av el. En nettodebiteringsgräns, exempelvis 63A = 43,5 kW = 313 m2, blir en begränsning för större byggnader.

Nätägarna påverkas i form av minskade intäkter från den rörliga elöverföringsavgiften, minskade förluster i det lokala elnätet och ökade intäkter från överskottsel som solelproducenten skänker till nätet.

För elhandlaren innebär ökande systemstorlek att försäljningen till solelproducenten minskar på samma sätt som sparad köpt el ökar för solelproducenten. Den balansansvarige (BA) som får ta hand om solelproducenten kan i regel göra en profilvinst. Det skulle kunna vara nätägaren, eller av nätägaren utsedd BA eller en av solelproducenten valbar elhandlare beroende på hur nettodebiteringen hanteras. Om samma elhandlare påverkas av minskad elförsäljning och profilvinst blir detta i slutändan gynnsamt för elhandlaren.

Skattemässigt får solcellsinstallationerna vid nettodebitering samma ekonomiska effekt som om solelproducenten skulle göra en energibesparing. I beräkningarna har ingen hänsyn tagits till att statens momsintäkter vid investeringen idag är högre än förlorade intäkter för energiskatt och moms.

För den fortsatta utvecklingen av solcellsmarknaden i Sverige är det av yttersta vikt att man snarast möjliggör att solelproducenter kan få en rimlig ersättning för sin överskottsel. Nettodebitering skulle vara ett enkelt sätt att lösa detta problem. Det praktiska enklaste sättet att genomföra nettodebitering skulle vara att nätägaren skickar ett nettovärde till elhandlaren. Avräkningsperiodens längd bör vara längre än en månad om man vill kunna utnyttja alla tillgängliga takytor.

Grid-connected PV-systems receive extensive investment subsidies in Sweden. Due to lack of net debiting or other production credits, it is still not feasible to invest in PV-system, resulting in long economic payback time. This study shows the positive value of the periodic intermittency of solar power, based on daily production and electricity market price profiles. A rooftop PV-system was modelled with PVSYST-software and evaluated hourly, monthly and annually using historical prices 1996–2009 in the Swedish, Spanish and German electricity markets. The daily profile value is always positive for solar power, due to daytime production when electricity prices are higher, while the monthly profile value is usually negative. The total market value of solar power in all three countries is higher than for constant production of the same energy amount. The results show that annual net debiting would facilitate zero energy buildings and still be beneficial for the Power Company.

Significant uncertainties regarding the evaluation of environmental impact from the use ofenergy motivates the need for a unified evaluation approach. In this paper a marginalapproach for general evaluation of CO2 equivalent emissions from the use of district heat inSweden is proposed. A predefined national marginal heat production mix is used to define amarginal heat evaluation approach to calculate the greenhouse gas emissions from the use ofdistrict heating. The novel approach offers a method for justified comparisons of differenttypes of energy use. By using the marginal heat evaluation approach it was shown that theevaluation of the electricity used in heat production for district heating is significant for theCO2 equivalent emissions. A survey of general district heating CO2 emission evaluationexamples is also included in the paper. The marginal heat use approach generates high CO2equivalent emission values in comparison with earlier studies. The overall conclusion of thepaper is that there is a need for further research and discussion regarding development ofmethods for energy use evaluation. The general marginal heat use approach is part of thesolution to this problem.

Vilken påverkan har vårt vardagsliv och de aktiviteter som sker i hemmet på vår miljö lokalt och globalt sett? Hur bidrar vi till den nu så aktuella frågan om global uppvärmning? Vanliga företeelser såsom matlagning, dörrar och fönster som öppnas, att ta ett bad eller en sådan grundläggande sak som vår närvaro är alla exempel som påverkar det globala energisystemet.

Om en dörr öppnas eller om en ugn sätts på påverkas inomhusklimatet genom förändringar i inomhustemperatur och luftkvalité. Som en följd av detta påverkas även energianvändningen i huset vi bor i samt det lokala energisystemet vi befinner oss i. Förändringar i lokala energisystem får i sin tur följder för det globala energisystemet och därmed klimatet på global nivå. Därmed är det inte sagt att allt vi i vardagen gör indirekt har negativa konsekvenser på det globala klimatet. De två följande frågorna utgör grunden till denna rapport: Vad kan göras för att minska de negativa effekterna av en energipåverkande aktivitet? Och vad finns det för möjligheter att göra detta?

Ett alternativ är att förbättra våra byggnader så att den värme som kommer från solen, våra kroppar och aktiviteter tillvaratas på ett optimalt sätt, just detta är grundtanken med konceptet passivhus som under det senaste årtiondet fått alltmer gehör. I ett passivhus använder man sig av ett välisolerat klimatskal samt värmeväxling för att uppnå ett behagligt inomhusklimat samtidigt som en minimering av uppvärmningsbehovet sker.

Denna studie omfattar ett antal nybyggda passivhus och ett antal konventionella hus i bostadsområdet Lambohov i Linköping. Här undersöks hushållsaktiviteters påverkan på energibalansen i båda hustyperna samt vilka effekter en omfattande ombyggnation till passivhus kan ha på Linköpings energisystem. Studien jämför hur uppvärmningsystemet påverkar inomhusklimatet för de boende. I studien ingår även en undersökning om de förväntningar de nyinflyttade har på passivhusen samt de förväntningar som bostadsbolaget har på hyresgästerna. Vidare undersöks de faktorer som motiverade byggandet utifrån bostadsbolagets samt staden Linköpings perspektiv.

Denna rapport går bakom kulisserna på passivhusen i Lambohov och söker information kring aktörer och hyresgäster av dessa passiva radhus-hyreslägenheter. En bottom-up-metod används för att få en realistisk bild av hushållets verksamheter som bidrar till den passiva uppvärmningen av byggnaden. Mätningar av energianvändning och termiskt inomhusklimat sker i precisionen 5-sekunder och extrapoleras i både tid och rum från hushållet till byggnaden och sedan över till kommunal nivå i syfte att identifiera miljöeffekter globalt.

Studien är tvärvetenskaplig i den bemärkelse att den innehåller användning av teori och metoder för analys och insamling av information som traditionellt används inom olika vetenskapliga discipliner. Ett systemtänkande tillämpas som bygger på idén om att utföra en analys av passivhusens energisystem som sträcker sig över flera systemnivåer. Den första systemnivån där studien startar är hushållsnivån, den innefattar hyresgästerna och de termiska laster som genereras från vardagliga hushållsaktiviteter. Från hushållsnivån går studien vidare upp till byggnadsnivån där egenskaperna hos själva byggnaderna samt värme och ventilationssystem analyseras inom ramen för inomhusklimat och energibalans i byggnaden. Slutligen nås den lokala nivån för att ta reda på vilka motiv som fanns för kommunen och bostadsbolaget att investera i passivhus från första början. Här ingår även en optimeringsstudie om effekterna av en omfattande ombyggnation till passivhus. De olika nivåerna i energisystemet som beskrevs här illustreras i figuren nedan.

In this study a number of new built passive and conventional houses in the residential area of Lambohov, Linköping, are studied. The effect of household activities on the building’s energy balance is investigated along with an investigation of the effects of an extensive adaptation to passive houses in the energy system of Linköping. The study compares how the heating system affects the thermal indoor climate for the tenants. Further on, the study also contains in-depth interviews on the expectations on the passive houses of the recently moved in tenants. Also the expectations from the housing company on the tenants and the factors that motivated the actual building of the passive houses are investigated, both out of the housing company’s perspective and the perspective of the City of Linköping.