Evaluation of Possible Next-Generation High-Temperature Molten-Salt Power Towers.

摘要

Since completion of the Solar Two molten-salt power tower demonstration in 1999, the solar industry has been developing initial commercial-scale projects that are 3 to 14 times larger. Like Solar Two, these initial plants will power subcritical steam-Rankine cycles using molten salt with a temperature of 565 deg C. The main question explored in this study is whether there is significant economic benefit to develop future molten-salt plants that operate at a higher receiver outlet temperature. Higher temperatures would allow the use of supercritical steam cycles that achieve an improved efficiency relative to todays subcritical cycle (approximately 50% versus approximately 42%). The levelized cost of electricity (LCOE) of a 565 deg C subcritical baseline plant was compared with possible future-generation plants that operate at 600 or 650 deg C. The analysis suggests that approximately 8% reduction in LCOE can be expected by raising salt temperature to 650 deg C. However, most of that benefit can be achieved by raising the temperature to only 600 deg C. Several other important insights regarding possible next-generation power towers were also drawn: (1) the evaluation of receiver-tube materials that are capable of higher fluxes and temperatures, (2) suggested plant reliability improvements based on a detailed evaluation of the Solar Two experience, and (3) a thorough evaluation of analysis uncertainties.