Study On Low-carbon Power Dispatch Strategies Considering Carbon Emission Permit And Peak Shaving By Pumped Storage

For a long time,the proportion of thermal power capacity in China’s power source is too high,which lead to the power system becoming the largest emitter of greenhouse gases in our country.Therefore,it has important significance in theory and reality to dispatch the power system to reduce carbon emissions.Low-carbon dispatching is the only way to sustainable development of power industry,which need to do a full range of considerations in all aspects,such as scheduling models and algorithms,low-carbon management measures and other technical means,improving the proportion of clean energy in the power source,to achieve the goal of low-carbon power.In order to realize the low-carbon dispatch in power system,the mainly research aspects are as follows:A minimal cost flow algorithm of graph theory,considering the network structure and net loss,is used to establish the daily low-carbon dispatching model of power system including power generation and transmission sections.The grid diagram is corresponding to the network flow graph,and the network flow is corresponding to the active power in the grid.Accordingly,the carbon emissions flow in grid can be intuitively reflected,which has practical significance to low-carbon generation scheduling.The model is solved by the mature software LINGO11,which is fast convergence and suitable for solving large-scale low-carbon scheduling problems in practical power systems.The IEEE-6 node and actual provincial daily load scheduling examples verified the feasibility and practicability of the proposed model and algorithm.In order to verify the effect of carbon emissions trading and generation rights trading on carbon emissions reduction,the largest benefit of thermal power is proposed in pure thermal system considering carbon emissions trading and generation rights trading;meanwhile,the generation rights and carbon emissions initial allocations are allotted by the unit capacity.Numerical examples show that the generation rights trading and carbon emissions trading are helpful for the current implementation of“substituting small units with large ones”.The optimal benefit models of thermal power and pumped storage are established in the case of pumped storage buying generation rights from thermal power,which can effectively reduce the CO₂ emissions in power system.The hydropower selling generation rights to efficient thermal units is also analyzed when reservoir inflow is insufficient,which can not only reduce the loss of hydropower,but also increase the income of thermal power in the economy;however,the level of CO₂ emissions in power system is increased.The use of pumped storage technology is an important way to improve the ability of absorbing clean energy into the grid,hence it is necessary to research the reasonable capacity and operation strategy of pumped storage.The comprehensive evaluationmethod including entropy theory,the improved principal component analysis and the combination of the two methods are applied to determine the appropriate pumped storage capacity considering several representative evaluation indexes.The result is more objective and convincing,which can avoid the subjectivity and partiality of previous single index judgments.The correctness and feasibility of the methods are verified by the example of the actual provincial power system.A grid-source coordinated energy storage strategy is proposed for absorbing large-scale intermittent clean energy into power system.On the power supply side of clean energy,distributed energy storage system or small pumped storage are used to smooth the output of clean energy,while on the grid side,the large capacity of pumped storage is used to absorb large-scale clean energy into the grid.Aiming at the shortage of peak shaving capacity in power system dominated with thermal power,the extended peak shaving method is proposed to dispatch a daily load to achieve the minimum carbon emissions in power system including hydrothermal power,wind power and pumped storage.The variable speed characteristics of pumped storage is considered,which can full play the role of peak shaving function and further reduce the carbon emissions.At present,the large continuous variable speed pumped storage units were not put into operation in our country,therefore the analysis has a reference significance to the grid situation.The feasibility of the extended peak shaving method is verified by daily low-carbon dispatch analysis of the actual provincial power grid under low and high wind power penetration.The low-carbon power generation dispatch strategies and their analyses proposed in this paper can reduce the greenhouse gas emissions of power system and mitigate climate change,which has great theoretical and practical significance to promote the sustainable development of power industry and social economy.