Long-term impacts of heat demand reductions within the Aarhus district heating area

One of the goals set by the Danish government is that the Danish society shall be based on 100% renewable energy in 2050. A part of the change towards a renewable energy system is to implement heat saving measures in the existing building stock. Often the economic feasibility of heat savings is decided on the basis of short-term decisions based on the payback time of the investments compared to the current heat price. Since a large share of the Danish buildings are within district heating areas with a low marginal heat price, heat saving measures have a long payback time if it is only the current heat price that is taken into account. Often the long-term costs are not reflected in the heat price and since the benefits of investing in heat saving measures last for a long time, the decision should be based on long-term planning taking reinvestments in production capacity and distribution equipment into consideration. By reducing the demands there are many long-term benefits for society in the form of reduced resource use and production capacity.
In this article the long-term benefits are examined in the concrete case of the Danish district heating area Aarhus. The analysis takes departure in the expected production facilities of 2016 and the implementation of heat savings in three different scenarios, where heat savings of 50% are carried out gradually until 2050. The costs in all scenarios are compared though net present value calculations based on socio-economic costs. The results show that the benefits of implementing heat saving measures are large, especially savings in fuel and production capacity are substantial in the concrete case of Aarhus. In other district heating areas the result will be different, where some have large amounts of excess heat from e.g. local industries or waste incineration, but in areas where this is not the case, it should be beneficial to implement heat savings to a certain degree in the long-term.