A new study has pointed out ways through which China can cut its climate action costs – by going for solar thermal energy.

The study recommends that China’s power systems operators must invest in renewable energy to meet climate commitments. Wind power and PV are the lowest cost renewables, but they only deliver power when it’s windy or sunny. Concentrated Solar Power (CSP) is capable of storing its solar energy relatively inexpensively, and for long durations, can deliver power at any time, day or night.

Surprisingly, even though it’s more expensive, CSP could ultimately prove less costly for a power system with a lot of renewable energy because of its ability to dispatch its solar power day or night.

The study finds that if CSP were substituted for between 5% and 20% of planned PV and wind power in Gansu Province and Qinghai Province it would bring the greatest benefit to power systems operators, reducing curtailment of wind and PV while lowering the operational costs of base load coal generators, that must ramp up and down to ameliorate fluctuating generation from solar and wind.

Previous studies have only analyzed the flexibility benefits of CSP from the point of view of maximizing ROI to potential investors and developers. The new study helps to fill a gap in economic research designed to maximize the long-term benefits of CSP to the overall power system.

A research team from Beijing’s Tsinghua University report their findings in the July issue of the journal Applied Energy, in their paper titled Economic justification of concentrating solar power in high renewable energy penetrated power systems. They analyzed the cost-benefit of various levels of CSP in place of planned Variable Renewable Energy (VRE) like PV and wind.

In two provinces in particular, Qinghai and Gansu, which plan to supply 83% and 104% respectively of their maximum load with VRE, the authors found that substituting CSP for between 5% and 20% of VRE would result in the lowest cost to the system operator.

Previous papers from these researchers have provided power system planning blueprints for China’s policymakers at the NDRC.

Lead author, Prof. Chongqing Kang, who heads the Electrical Engineering department at Tsinghua, is the much-cited author of over 300 studies on renewables and power system planning and operation. Second author, Associate Professor Ning Zhang, has been focused on the renewable energy analytics and optimization in the power system.

The study focused on the benefit of CSP specifically to the power systems in Qinghai and Gansu. Both provinces have excellent solar resources and good siting opportunities for large solar or wind plants, and very ambitious plans for deploying wind and solar technologies.

Qinghai plans to supply 82.3% of maximum load demand with a combined 13 GW of VRE; from 3 GW of wind power and 10 GW of PV. Gansu plans to supply 104.3% of maximum load demand from a combined 27 GW of VRE; 20 GW of wind and 7 GW of solar PV.

By combining the economic benefit of CSP as a flexible renewable energy generation resource that is able to dispatch solar on demand and further reduce wind power and PV curtailment, they derive a “levelized benefit” figure for CSP.

The study suggests an additional energy and flexibility benefit of between 18 and 30 cents per kilowatt hour if CSP replaced between 5% and up to 20% of the proposed solar PV and wind power in these provinces. The higher value of CSP’s energy and flexibility benefit justifies its relatively higher investment cost.