Optimal annual operation of the dry cooling system of a concentrated solar energy plant in the south of Spain

• A CSP plant with dry cooling is optimized using mathematical programming.
• The facility involves solar field, molten salts, steam and electricity generation and cooling.
• Dry cooling is more expensive and requires 5% of the produced energy.
• CO2 savings do not recommend dry system. Water scarcity does.

This work presents the optimization of the operation of a concentrated solar power plant with dry cooling over a year, evaluating the molten salts storage, the power block and the air cooling system as a function of the climate and atmospheric conditions. We locate the plant in the south of Europe, Almería (Spain), due to the high solar irradiation and for comparison purposes with a wet cooling based facility. The optimization of the system is formulated as a multiperiod MINLP (mixed integer non-linear programming problem) that is solved for the optimal production of electricity over a year defining the main operating variables of the thermal cycles and the cooling system. The power produced ranges from 9.5 MW in winter to 25 MW in summer, where 5% of this power is consumed by the air cooling system. The annual production cost of electricity is 0.16 €/kWh and the investment required is 265 M€, both slightly higher than when wet cooling is used, but with negligible water consumption. For the selected location, the wet based technology generates slightly less CO2 than the air cooled facility.