东北辅助服务市场下热电厂配置电锅炉调峰的经济性分析

Economic Analysis on Peak Shaving of Combined Heat and Power Plant with Electric Boilers in Auxiliary Service Market of Northeast China

热电机组配置直热式电锅炉进行电热解耦改造,是提高机组下调峰能力并消纳弃风的有效手段。为分析主流机组改造的经济性,以东北调峰辅助服务市场为背景,建立了热电机组和电锅炉协调运行模型、消纳弃风的节煤量模型、下调峰的运行成本与效益模型,以及以投资回收期为指标的投资经济性评价模型。以实际数据为基础,对当前东北电网典型热电机组在不同场景下的经济性进行了计算分析。结果表明,在当前调峰机制下,在供热中期热负荷较大时,对于中小规模弃风,热电厂没有启动电锅炉消纳的动力;而为在大规模弃风时获取正收益,机组需要配置较大容量电锅炉,这又给热电厂带来了很大的投资风险。通过分析表明,降低机组最小出力可减小电锅炉的配置容量,从而提高投资经济性以降低风险。

The heat and power decoupling retrofit of combined heat and power(CHP) units with electric boilers is an effective way to improve the downward peak shaving and accommodate the curtailed wind power. In order to analyze the retrofitting economy of the mainstream power units, by taking the peak-shaving auxiliary service market of Northeast China as background, the coordination model of CHP with electric boiler, the coal saving model for accommodating curtailed wind power, the costs and profits model for downward peak shaving, and investment economic evaluation model with the index of pay-back time period are built. On the basis of the real data, the economics of typical CHP units in the Northeast China power grid are calculated in different scenarios. The results show that, in the current peak shaving mechanism, when the heat load is large during the heat-supply medium term, for small-scale wind curtailment, the CHP plants have no motivation to use electric boiler for accommodation;for the large-scale wind curtailment, the CHP unit needs to be equipped with large-capacity electric boiler to obtain the positive benefits, which increase the risk for new investment. Through analysis, it shows that reducing the minimum output of the CHP units can reduce the capacity of the electric boiler, and thereby improve the economics of providing downward peak shaving service.