## 4 Case Studies  
Renewable energy is developing rapidly in Europe, and its installed proportion is relatively high. In view of the uncertainties and fluctuations of renewable energy and the reduction of fossil fuel power generation, Denmark has attached great importance to the development and promotion of commercially available and scalable high-performance distributed electrothermal energy systems in recent years. At present, the energy supply of Denmark mainly comes from green energy sources such as wind energy, biomass energy, and solar energy. Denmark pays attention to the interaction and  
Figure 5: The process of the optimization algorithm. complementarity between green renewable energy and energy storage systems, and combines solar, wind, and biomass energy with electric and thermal energy storage to make the whole energy system more flexible. Taking Svendborg, Denmark as an example, there are currently three solar power stations in Svendborg. One of them has an area of 6000 m\({}^{2}\) and annual power supply of 2736 MWh. \"Waste incineration and electrothermal energy storage\" is one of the main sources of thermal energy supply in Svendborg at present. Local waste incinerators burn about 70,000 tons of waste annually, including food packaging, cartons, and plastics. By using the latest technology, the combustion efficiency is up to 98%. The incinerator burns at a stable high temperature of 1000 \({}^{\circ}\)C, which reduces the emission of harmful gases such as CO\({}_{2}\). Through the complementary use of various forms of energy systems, the power generation efficiency of Svendborg has reached 49%. For demonstrating the effectiveness of the proposed coordinated dispatching model of IESs, an actual distribution system in Jianshan District, Haining, Zhejiang Province of China is presented. Due to many factors, such as renewable energy power generation subsidy policy, local photovoltaic panel capacity, and the effect of the demonstration zone, the installed capacity of renewable energy in Jianshan District has increased rapidly. By August 2018, the total installed capacities of grid-connected PV and WT in Jianshan District were 180 MW and 50 MW, respectively, which are expected to continue growing in the next several years. The high penetration rate of renewable energy leads to the great operating pressure for the dispatchers of the distribution network in the region. When the loads are low, the excess energy is evenly transferred to the transmission systems with high-voltage level. Taking one typical daily electrical load curve and the typical photovoltaic output data as example, the PV output can be considered as a negative load. Then, the loads with different output ratios of PV are shown in Figure 6.  
It can be seen from Figure 6 that when the output ratio of PV is more than 80%, the loads after adding the output of PV are less than 0. In order to improve the power grid structure and utilize the distribution network to transfer the excess energy, the measures to be taken in Jianshan District include improving the interconnection level of distribution networks and building energy storage devices. In 2016, Zhejiang Development Planning and Research Institute issued the \"Central Heating Plan of Haining\", which proposed to implement centralized heating in Haining. At the same time, Jianshan District has been clearly divided into four functional areas in the planning stage, and the development of EVs is encouraged. Under this background, the effect of coordinated dispatching of IESs considering the differences of multiple functional areas on renewable energy consumption in Jianshan District is analyzed. Figure 6: Loads after adding different PV output ratios. The geographical distribution of functional areas in Jianshan District is shown in Figure 7, where areas 1, 2, 3, and 4 represent the residential area, the office area, the commercial area, and the industrial area, respectively. The connection between functional areas is through tie lines 1-2, 1-3, and 1-4, respectively.