In Sweden, district heating of buildings is in common use. This paper deals with the district heating tariff. Many economists argue that the tariff should be based on short-range marginal costs, but in practice this never occurs. Traditionally instead, the prices are set so they are lower than the alternatives. A case study is presented dealing with a residential building in Navestad, Norrköping. For this building, the life-cycle cost with extra wall insulation and the introduction of a heat pump has been calculated. A comparison of two perspectives, the present tariff and a tariff-based short-range marginal cost, is done. It is shown that there is a conflict between the two perspectives. For the tariff based on short-range marginal cost, neither extra insulation nor an introduction of a heat pump is profitable. However, with the present tariff, a bivalent system with a heat pump and district heating is profitable. Copyright © 2002 John Wiley and Sons, Ltd.

This paper studies the way in which CO2 emission levels are affected by different measures to reduce energy consumption in a building. A case study is presented which deals with a residential building in Navestad, a suburb of the Swedish city Norrköping. The building is supplied with district heating primarily delivered from a combined heat and power (CHP) plant. Three types of energy measures are studied: extra insulation, new types of window and the introduction of a heat pump. The first perspective is the city of Norrköping, with the system boundary encompassing the residential building and the CHP plants. A second worst case scenario is then presented: a Nordic perspective in which electricity produced in coal condensing power plants is assumed to cover the marginal electricity production. With the former perspective, the measures extra insulation and new windows reduce the CO2 emissions, and with the latter both measures increase the CO2 emissions. The measures extra insulation and new windows are ranked, with respect to cost for the first perspective, using a cost reduction curve for CO2 emissions. In the paper, costs from the ExternE research project are also used. © 2002 Elsevier Science Ltd. All rights reserved.

In this paper, a municipality with district heating supplied via boilers and combined heat-and-power (CHP) plants is studied. The electricity load in the municipality is provided for by the CHP plant and electricity bought from the Nordic electricity market. It is therefore desirable to produce as much electricity as possible during periods when the price of electricity is high. The variations in the price of electricity over a 24-h period are significant. The idea presented in this paper is that heat storage can be used to maximise the amount of electricity produced in the CHP plants during peak-price periods. It can also be used to minimise the use of plants with higher operational costs. For storing heat, both a hot-water accumulator at the CHP plant and storage in the building stock are suggested. The situation is analysed using a mixed integer linear-programming model and a case study is presented for the city of Linköping, a City of approximately 130,000 inhabitants, situated 200 km south of Stockholm in Sweden. A simple model for forecasting the electricity price on the Nordic electricity market is also presented. © 2004 Elsevier Ltd. All rights reserved.