Application of Heat Storage in Heating Network for Surplus Wind Power Consumption
Among northern China, CHP is the main electric and heating source to provide electricity and heat. While, with the increasing integration of wind power, the peak regulation capacity is lacking. Wind power curtailment occurs frequently because of the contradiction between heating and electric load. District heating system plays the majority role in heating supply because of its efficiency and cleanness. There are enormous heat storage capacity contained in district heating system, if the stored heat energy could be utilized efficiently the contradiction between heating and electric load could be relieved and the wind power curtailment could be avoided considerably. This study presents an approach that takes advantage of the heat in the primary heating circuit to absorb surplus wind power. The expressions of the components in heating system are given to establish the mathematical model. Followed, the thermodynamic properties of heating pipelines are analyzed, the heat storage capacity and heat transmit delay characters are studied. Then, the consumption capacity of surplus wind power is discussed, and the temperature changes are also considered. The economic benefits are also analyzed.  Finally, a case study was undertaken to prove the effectiveness. The results show that by utilizing the heat in heating network, the wind power curtailment rate could be reduced by 20.6% which means about 219.4MWh surplus wind energy could be consumed during a valley electric load period.