Energy efficiency and circular economy goals, such as utilizing waste heat, are causing challenges for district heating systems; thus, a more versatile smart energy system is called for. In addition, previous research and practical experiences both have shown that waste heat utilization is unprofitable. Most commonly, district heat pricing for customers is formulated using production cost as a basis for a static yearly or monthly price. This pricing method does not take into account the actual costs of heat distribution, which is caused by heat losses and electricity consumed by pumps in the network. Extra costs are caused by “bottlenecks” in the distribution network, when existing distribution capacity does not allow sufficient heat delivery. Some previous studies have focused on dynamic pricing based on the hourly fluctuation of the production costs. However, there are no previous studies on spatial price formation of district heat, i.e. studies that have assessed how the actual costs of heat varies in different locations of the network due to production and distribution expenses. This information is important especially in large district heating systems with several production units as it also helps to estimate the value of waste heat and demand response actions in different locations of the district heating network.
The goal of this study is to investigate favorable locations for waste heat collection and demand side management from the networks perspective. The simulation method used in this study combines the production data from combined heat and power plants, heat only boilers and pumping stations. The network is divided into pumping zones that can have different heat balance compared to each other. The data used in this study is real production and heat network data from a large district heating network in Vantaa, Finland.
The preliminary results show that typically favorable locations for waste heat collection or demand side management actions are on the edge zones of the district heating networks. Surprisingly, some favorable locations are also sometimes close to production units. Favorable locations are found in places that have the largest temperature decrease of district heating water in all three simulated scenarios. Waste heat utilization at these locations would benefit the whole system since this would decrease the amount of energy needed to be produced at the power plants. There would also be a reduction in heat losses and pumping power.
4 lokakuuta 2019
Conference on Sustainable Development of Energy, Water and Environment Systems