Energy and economic analysis of concentrating solar power plants based on parabolic trough and linear Fresnel collectors

This paper compares the performance of 1 MWe concentrating solar power (CSP) plants based on an organic Rankine cycle (ORC) power generation unit integrated with parabolic trough and linear Fresnel collectors. The CSP plants studied herein use thermal oil as heat transfer fluid and as storage medium in a two-tank direct thermal storage system. The performance of the CSP plants was evaluated on the basis of a 1 MWe ORC unit with a conversion efficiency of about 24%. The comparative performance analysis of the two CSP solutions was carried out by means of specifically developed simulation models and considering different values of solar multiple and thermal storage capacity. The results of the performance assessment demonstrate that CSP plants based on linear Fresnel collectors lead to higher values of electrical energy production per unit area of occupied land (about 50–60 kWh/y per m2 vs. 45–55 kWh/y m2 produced by solutions based on parabolic troughs). However, owing to their better optical efficiency, the use of parabolic troughs gives better values of energy production per unit area of solar collector (about 185–205 kWh/m2 vs. 125–140 kWh/m2) and, therefore, better conversion efficiencies (about 10.8–11.9% vs. 7.3–8.1%). The results of a preliminary economic analysis show that CSP plants based on linear Fresnel collectors are still not competitive with those based on parabolic trough owing to their higher energy production cost (about 380 E/MWh vs. 340 E/MWh).