Research On Offshore Integrated Energy Optimization Based On Electrical Thermal Coupling

With the advancement of the strategy of building a powerful marine country and the increasing shortage of fossil resources,offshore renewable energy power generation has developed rapidly.However,due to the imbalance of load and renewable resources power generation,and the limited adjustment capacity of island power grids,wind and solar energy utilization rates It is not high,and the phenomenon of abandoning wind and light occurs from time to time.In addition,the increasing load of electricity,water,hydrogen,cooling and heating on offshore islands also brings certain pressure to the island power grid.Under the background of improving quality and efficiency,and double carbon,the grade difference between different energy sources has been paid attention to.Establishing a two-layer optimization model that takes into account both economy and energy efficiency is the only way to optimize comprehensive offshore energy.Considering the multi-agent energy cooperation game of offshore islands under the power market environment is a preliminary exploration related to future development.Therefore,based on the electrical-thermal coupled offshore integrated energy system,this paper studies a two-layer optimal configuration model with energy grades,considers the optimal operation strategy of waste heat recovery of CSP stations,and explores the optimal strategy of multi-agent cooperative game on the island.The main research contents and results of this paper are as follows:(1)The energy quality coefficient is proposed to characterize the grades of different energy sources in offshore islands,and a two-layer optimal configuration model for multi-energy coupling systems in offshore islands is established considering exergy efficiency.Firstly,an offshore island multi-energy coupling system including small CSP stations is constructed.Secondly,the energy quality coefficients of electricity,gas,cold,heat,natural gas and renewable energy are analyzed and quantitatively characterized,and then used to calculate the comprehensive energy of the island.The exergy efficiency of the system,and then,the upper model considering the minimum annual value of the life cost of offshore islands is established as the objective function,and the lower model considering the maximization of exergy efficiency as the objective function.The lower model is linearized using the KKT condition and the Big-M method and transformed into the linear constraints of the upper model.Finally,through the simulation comparison between the double-layer exergy efficiency model and the single-layer economic model,it is verified that the proposed double-layer model can effectively improve the exergy efficiency of the multi-energy coupling system of offshore islands.(2)Established an offshore island multi-energy coupled energy system involving both electrical-thermal coupling and water-hydrogen cooling,using the organic Rankine cycle to absorb the waste heat of the CSP station,fully considering the offshore island multi-energy coupling system and considering the heat waste Various constraints of the recovered solar thermal power station,with the objective function of minimizing the cost of purchasing energy from the outside for the island within 24 hours,to establish a day-ahead economic dispatch model for the offshore island.Finally,through the simulation and verification of three types of models,it is concluded that the multi-energy coupling system considering the waste heat recovery of CSP station reduces the total cost of purchasing energy for the island,and at the same time improves the consumption of offshore island scenery.(3)Established a multi-agent energy system including internal renewable energy ecommerce sellers,external e-commerce sellers,and seawater desalination companies in offshore islands,and successively studied the optimization goal of maximizing its own income and its own structure as a constraint.Internal and external sales e-commerce model and seawater desalination business model.Then,according to the idea of cooperative game,the optimization model of the three-agent cooperative game is given,and the cooperative game model is transformed into a right model and a left model by using the mean inequality and its equation establishment constraints,and the right model improves and maximizes the benefits of each subject.For the optimization goal,the left model takes the maximization of the benefit promotion product of each subject as the optimization goal.Then,using the Alternating Multiplier Method(ADMM),the right model is decomposed into the main electricity model of the electricity retailer of renewable energy inside the island,the electricity model of the electricity supplier of the electricity retailer outside the island,and the electricity model of the main electricity supplier of the seawater desalination business on the island;the left model is decomposed into The main electricity price model of the electricity retailer of renewable energy inside the island,the electricity price model of the electricity supplier of the electricity supplier outside the island,and the electricity price model of the main body of the island desalination business.The iterative solution is used to obtain the transaction electricity price and electricity volume between each subject,and the necessity of the equation constraint and the accuracy of the model are verified by numerical example simulation.