Feasibility for solar district heat in region Västra Götaland

Abstract

The interest in large-scale solar heating has increased all around Europe from 140 MW in 2007 to 750 MW in end 2015. It can play an important role in the heating sector as it can increase the share of renewables and together with district heating system can increase the overall efficiency. The major advantage of solar heat is the non-limitation and availability all over. Sweden was one of the first countries to develop large-scale solar heat, but due to a very positive development for biomass fuel and changed rules for energy performance for building in Europe the development of large-scale solar heating decreased in Sweden. The positive development in biomass has led to a transition from fossil fuel used in heating plants to solid wood fuel which today creates opportunities to complement with solar heat. This since many heating plants often consists of a wood fuel fired boiler that runs all year around and an oil fuel fired boiler running during peak demand. During the summer month when the heat demand is low, the wood fuel fired boiler will be running on low power with low efficiency. Solar district heating systems connected to existing wood fired boilers with a central water tank as heat storage will make it possible to run the wood boiler on higher efficiency which will decrease emissions and operation costs. However, there is a major lack of awareness and knowledge about the potential with district heating and large-scale solar heat. This together with the low price for wood fuels has led to poor incentives to invest in solar system. The region Västra Götaland consists of 49 municipalities. The region is associated with the EC project SDHp2m about solar district heating that has a focus on technologies for large-scale solar district heating plants and their implementation into the district heating network. The aim of the study is to identify and select feasible heating plants within the region that have the opportunities of complementing solar heat to existing district heating systems. At least four existing boilers have been identified. The aim for further work is that at least one of these plants will move on to be used as a demonstration plant during 2017-2018 for other interested actors in the future. The thought is that through a demonstration plant, the gap between the actual status of existing technologies and knowledge about these technologies can hopefully be reduced and thereby increase the incentives.