Concentrating solar plants (CSP) generate solar thermal electricity (STE) while producing no greenhouse gas emissions, so it could be a key technology for mitigating climate change. In addition, the flexibility of CSP plants enhances energy security. Unlike solar photovoltaic (PV) technologies, CSP plants use steam turbines, and thus can provide most needed ancillary services. Moreover, they can store thermal energy for later conversion to electricity. CSP plants can also be equipped with backup from fossil fuels delivering additional heat to the system. When combined with thermal storage capacity of several hours of full-capacity generation, CSP plants can continue to produce electricity even when clouds block the sun, or after sundown or in early morning when power demand steps up.
Since 2010, generation of solar thermal electricity (STE) from concentrating solar power (CSP) plants has grown strongly worldwide, though more slowly than expected in the first IEA CSP roadmap (IEA, 2010).
Global deployment of STE, about 4 GW at the time of publication, pales in comparison with PV (150 GW). New markets are emerging on most continents including the Americas, Australia, China, India, the Middle East, and Africa.
This roadmap envisions STE’s share of global electricity to reach 11% by 2050 – almost unchanged from the goal in the 2010 roadmap.
Achieving this roadmap’s vision of 1 000 GW of installed CSP capacity by 2050 would avoid the emissions of up to 2.1 gigatonnes (Gt) of carbon dioxide (CO2) annually.
From a system perspective, STE offers significant advantages over PV, mostly because of its built-in thermal storage capabilities. Both technologies, while being competitors on some projects, are ultimately complementary.
The value of STE will increase further as PV is deployed in large amounts, which reduces mid-day peaks and creates or increases evening and early morning peaks.
Combined with long lead times, this explains why deployment of CSP plants would remain slow in the next ten years compared with previous expectations. Deployment could increase rapidly after 2020 when STE becomes competitive for peak and mid-merit.
Appropriate regulatory frameworks – and well-designed electricity markets, in particular – will be critical to achieve the vision in this roadmap.