Performance analysis of a linear Fresnel solar-aided coal-fired power generation system with peaking capability

To enhance the flexibility of solar-aided coal-fired power generation (SAPG), this paper proposes a new linear Fresnel solar-aided coal-fired power generation (LF-SAPG) system with thermal energy storage (TES). Based on this system, two flexibility improvement schemes are designed by sharing a set of TES units: (1) the molten salt TES peak regulation scheme (Case 1), (2) the molten salt coupled with the steam accumulator TES peak regulation scheme (Case 2). Moreover, the new system's thermodynamic, environmental, and peak regulation performances were studied. The research findings indicate that the new LF-SAPG system has increased the total exergy efficiency under all load conditions, reaching the highest value of 46.3% at a load rate of 90%. The carbon emission rate drops with decreasing load, reducing by up to 118.18 g/kWh at 50% load rate. In terms of flexibility improvement schemes, for the molten salt coupled with the steam accumulator TES peak regulation scheme, the minimum load during the heat storage process is 93.6 MW, accounting for 14.18% of the rated load, which is 109.9 MW lower than that of the original unit. During the heat release process, the maximum load is 726 MW, 66 MW higher than the original unit.