Research On Optimal Operation And Bidding Strategies Of The Flexible Combined Heat And Power Enterprise

With the global energy transformation,the development of clean,low-carbon,safe and efficient energy system is the goal of China.In the north of China,the renewable energy develop rapidly,and the proportion of Combined Heat and Power(CHP)units in thermal power units is increasing.During heating period,heating demand response will be given priority when the CHP units operate in the mode of determining power by heat,which occupy most of the power generation and lead to wind and solar power curtailment.In order to alleviate the above conflict,the operational flexibility improvement of CHP enterprises is promoted in China.The operation of units in the CHP enterprise will be significantly different and the additional heating equipment may be added,which will increasethe complexity of the structure and operation characteristics of the flexible CHP enterprise.Therefore,it is essential to model and evaluate the technical and economic characteristics of all types of CHP units and heating equipment.It is helpful to achieve the optimal coordinated operation of CHP units and heating equipment.Furthermore,the flexible CHP enterprise needs the optimal bidding strategies to participate in deep-down regulation market and spot market to maximize profits.In order to solve the above problems,the paper does the following research.Firstly,the feasible operation region models and coal consumption models of three kinds of CHP units are established,as well as the overall feasible operation region models and coal consumption models for the typical coal-fired extraction condensing units equipped with heating equipment.Aiming at the lack of quantitative evaluation for the diversified flexibility improvement schemes,the coal consumption on heating compensation is considered as the cost of down-regulation in this paper.Taking the cost as the core index,an evaluation model including down-regulation capacity,down-regulation cost,coal saving and emission reduction is established.The relationship and applicable scenarios of each improvement scheme are clarified through the example analysis,which provide the theoretical basis for CHP enterprises to formulate optimal operation strategies and arrange the heat and power equipment cooperatively.This paper proposes a general optimal model for the flexible CHP enterprises collaboration,which could optimize the operation of CHP units and heating equipment to meet the demand of heat and power.The model is suitable for most of the CHP enterprises with operational flexibility improving scheme in China.The main objective of the model is to minimize the cost of heat and power supply,and the mismatch between the scheduled electricity generation and the actual electricity generation is included in the objective,which enhances the applicability of the model.This model can help CHP enterpeises with the decision of optimal arrangement of inside the heat and power resources,participation in the power markets and overall flexibility evaluation.In different heating periods and different renewable energy integration scenarios,the effectiveness of the model and its applicability are verified based on the actual CHP plant in northern China.The paper focuses on the bidding decision of the flexible CHP enterprises participating in the real-time deep down-regulation market in the north of China.Based on the general cooperative optimal model,a bidding strategy based on opportunity cost for enterprise as the price taker is proposed,in which the characteristics of market such as unified clearing price,uncertain demand and limited market information are taken into account.Aiming at the three key issues about ability,cost and willingness,the minimum output model of plants,the twostage down-regulation marginal cost model and bidding decision model are proposed in this paper.Taking the actual CHP plant in the north of China as an example,the analysis and conclusion show that the proposed models can provide effective decision for most CHP enterprises in the north of China to participate in the real-time deep down-regulation market.Furthermore,the flexible CHP enterprises have a high profit in the deep down-regulation market.Finally,aiming at the bidding decision of flexible CHP enterprises participating in dayahead spot market,this paper proposes a bidding strategies.Considering the limited information at the beginning of the spot market of China,the enterprise takes the role of the price taker.Due to the time coupling of heat storage,the step-by-step decision is provided.Moreover,an optimal operation decision model and a segment bidding model based on the forecasting price are established.Based on the actual clearing prices,the model is verified with an actual CHP plant.Further,the adaptation of enterprises to the spot market and the effect of operational flexibility improvement schemes on profits under different scenarios are analyzed.The above research provides an operational decision tool for most of flexible CHP enterprises.The conclusion can provide a reference for authorities to formulate policies of the operational flexibility improvement.