Effect Of The Ambient Temperature On The Performance Of Small Size SCO2 Based Pulverized Coal Power Plants

The present work focuses on the analysis of a novel coal fired sCO2 power plant concept developed in the frame of sCO2-Flex H2020 EU funded project. Fossil fuel fired power plants are expected to improve their flexibility in the future energy scenario characterized by a large share of non-predictable and nondispatchable renewable energy sources. This upcoming context requires a new generation of coal fired power plants with a smaller size, a high flexibility and minor requirements for the installation site like no need of water consumption. Carbon dioxide in supercritical cycles is recognized to be a possible solution for this technology shift and could replace in the future common steam Rankine cycles. This paper focuses on the impact of ambient temperature variation on a small size coal fired sCO2 power plants equipped with a dry cooling heat rejection unit, with the aim of understanding the effect on plant operability and system performance. A dedicate tool is implemented for offdesign behavior assessment and different control strategies are investigated. Results show that without a proper design of the heat rejection unit a small increase of ambient temperature may drastically limit the maximum attainable power output of the plant. This penalizing effect is more pronounced in hot locations, but this issue can be limited by adopting a sufficient over-sizing of the cycle heat rejection unit (HRU) or wet-and-dry solutions.