Robust optimisation for self-scheduling and bidding strategies of hybrid CSP-fossil power plants

This paper describes a profit-maximisation model for a hybrid concentrated solar power (CSP) producer participating in a day-ahead market with bilateral contracts, where there is no correlation between the electricity market price and the solar irradiation. Backup system coordination is included between the molten-salt thermal energy storage (TES) and a fossil-fuel backup to overcome solar irradiation insufficiency, but with emission allowances constrained in the backup system to mitigate carbon footprint. A robust optimisation-based approach is proposed to provide the day-ahead self-schedule under the worst-case realisation of uncertainties due to the electricity market prices and the thermal production from the solar field (SF). These uncertainties are modelled by asymmetric prediction intervals around average values. Additionally, a budget parameter is used to parameterise the degree of conservatism of the decision. The decision provides the optimal bidding strategies consisting in supply functions built not only for different budget parameter values, but also for different emission allowance levels. Finally, a realistic case study is presented to show the effectiveness of the proposed approach.