Research On Peak Regulation Economy Of Cogeneration Unit

Recently,with the rapid development of society and economy,the renewable energies have been the concerns of energy transition along with the economy improvements in China.Moreover,the increasing installed capacity of renewable energies brings a considerable challenge to peak shaving of power grid.The thermal power plants take up more than half of the overall power sources in China and will take on the peak regulation of the power grid in the near future.However,the load ratios of the CHP units deployed in the northern China keep at a high level and hard to decrease in the winter heating period due to the limitation of "power determined by heat",resulting in the insufficiently adjustable peak capacity and "wind-heat conflict" phenomenon.To alleviate the heavy peak shaving pressure,the peak shaving auxiliary services have been implemented on a trial base in multiple region in China,in which the units are encouraged to participate in peak shaving by economic compensation mechanism.For the sake of exploring the economy of cogeneration units participating in peak shaving of power grid,a detailed cost analysis of CHP units in terms of economy,environmental performance and safety indicator is investigated in the paper.Considering the electricity-heat coupling characteristics of the cogeneration unit,the unit cost model of power generation and heat supply is established based on an appropriate method of the content of heat and power.Thereafter,by integrating relevant power peaking policies with the peaking compensation and sharing mechanism,the peaking economy model of cogeneration units is established to reflect the economy of cogeneration units participating in peaking.The unit cost and peak shaving benefit of the case unit under pure conditions and heating conditions are calculated to analyze the peak shaving capacity.The results show that fuel cost accounts for a majority of the overall cost,thus,reducing the fuel cost is the key to improve the economic performance of the unit.The peak shaving capacity is restricted by the heat supply quantity.The electric heating characteristic curve of the CHP unit with technical renovation can be calculated for analyzing the peak shaving benefits of different heat supply scenarios.The heat supply capacity has been improved by the technical renovation and the unit output is decreased,which can provide a larger peak load regulation capacity for wind power penetration and effectively avoid the problem of "wind-heat conflict".