UKCCSRC Call 1 project paper: Enhanced operating flexibility and optimised off-design operation of coal plants with post-combustion capture

The inherent nature of electricity necessitates a permanent balance between generation and demand in electricity systems. This has obvious implications for the operation of CCS power plants in decarbonised electricity systems with inflexible nuclear and variable renewable supply. The low variable costs of nuclear and some intermittent renewable technology allow them to run as base-load generators and shift fossil fuel plants from base-load to midmerit plants. CCS power plants can be expected to increasingly operate in ways to balance variations, sometimes simultaneously, in the production of some intermittent renewable technologies and variations in electricity demand, resulting in more frequent ramping and start/stop cycles. As a result, they may also operate over a wide output range to maintain the quality and security of electricity supply by providing ancillary services, e.g. capacity and energy reserve, to the electricity network. This work characterises the operating envelope, the performance and the corresponding compressed CO2 flow of coal power plants for a range of loads, with or without voluntary by-pass of the capture unit. Optimised part-load operating strategies provide novel insights into the additional capabilities of CCS power plants specifically designed for enhanced operating flexibility. The paper is available at http://www.sciencedirect.com/science/article/pii/S1876610214026010, DOI: doi:10.1016/j.egypro.2014.11.786.电力系统的固有属性要求发电与用电之间始终保持动态平衡。这对于脱碳电力系统中运行的碳捕集与封存（Carbon Capture and Storage, CCS）电厂的运营具有显著影响——此类系统中核电灵活性不足，可再生能源供应具有间歇性。核电与部分间歇性可再生能源技术的可变运营成本较低，使其可作为基荷发电机组运行，并将化石燃料电厂从基荷机组转变为中间负荷机组。可以预见，碳捕集与封存电厂将愈发频繁地承担平衡两类波动的任务：部分间歇性可再生能源技术的产出波动，以及电力需求的波动，有时甚至需同时应对这两类波动，这将导致其爬坡、启停循环的频次大幅增加。为此，它们可能需要在较宽的出力范围内运行，通过为电网提供容量、能量储备等辅助服务，保障电力供应的质量与安全性。本研究针对不同负荷工况下（含或不包含捕集单元的主动旁路运行）的燃煤电厂，刻画了其运行边界、运行性能以及对应的压缩二氧化碳（compressed CO2）流量特征。优化后的部分负荷运行策略，为专门设计以提升运行灵活性的碳捕集与封存电厂的额外性能提供了全新的研究视角。该论文可通过以下链接获取：http://www.sciencedirect.com/science/article/pii/S1876610214026010，DOI：10.1016/j.egypro.2014.11.786。