Prospection of Swedish District Heating : the status of solar energy

Abstract:

Due to the environment degradation and threats of the climate change, how to develop the technologies to use renewable energy and improve current energy systems to meet the increasing demand of human activities instead of using fossil fuels are amongst hot issues that being discussed nowadays. Due to the specific weather condition, district heating, which contains space heating and domestic hot water, is needed in Sweden. Solar energy is the most potential and environmental friendly energy resource. It can be utilized in many different aspects. The profitability of building solar heating plant for producing heat to supply the district heating in Sweden was discussed in the thesis. In order to achieve the result, central solar heating plant and solar combisystem were discussed. Information was collected from “Sciencedirect”, some related companies and institutions websites, and etc. Very few solar radiations are available during winter in Sweden, while the demands of district heating are the highest. During summer time, a lot of cities in Sweden can use the industrial waste heat to cover the district heating load, and in some cities where there is no industrial waste heat can operate biomass combined heat and power (CHP) plant to cover the heating load. Combined solar-biomass heating plant could improve the efficiency of biomass heating plant and reduce the unnecessary heat losses. Solar combisystem has a relatively high cost and complex system. The system which is able to supply some hot water for washing machine may have a good future, due to the possibility that the price of electricity in Sweden increases.

Large-scale solar heating plants are less attractive in Sweden due to the existence of industrial waste heat and CHP plant that supplied by biomass. Combined solar-biomass heating plant would be a good system to build if there is no available industrial waste heat and biomass heating plant is used to supply the district heating. Due to the current electrical price and the cost of combisystem, it is not that attractive to build this system. In the coming future, if the transportation cost and the price of biomass itself become too high to make the CHP plant no longer cost effective, and the price of the electricity become high, the solar energy will make more contribution to the district heating in the coming future.