Optimisation of Solar Aided Power Generation plant with storage system adopting two non-displaced extraction steam operation strategies

Abstract

Solar Aided Power Generation (SAPG) is one of cost-effective methodologies of integrating solar heat into fossil fuel fired power plant. For such system, solar heat used to displace extraction steam to high grade extraction steam is the best choice. However, strategies to adjust low grade extraction steam would also influence the plant performance. Two strategies exist: steady temperature (ST) and steady mass flow (SMF) strategies. In present study, the impact of storage integration on the SAPG plant adopting two strategies has been investigated. For the SAPG plant with storage system, the plant using ST strategy would have higher technical and economic performance than that using SMF strategy. With the increase of the solar multiply, the advantage of the ST strategy over the SMF strategy would be decreased. However, the increase of storage capacity can alleviate this trend, especially in high radiation regions. The Levelized cost of electricity (LCOE) of the SAPG plant with storage system would be greatly promoted in low solar multiple cases. When the solar multiple increases to about 2, the LCOE of the SAPG system with and without storage capacity becomes convergence. The results give a useful guide for operation of the SAPG plant with storage system.