It is widely cited that scaling up plant size is the Concentrated Solar Power (CSP) sector's silver bullet for lowering costs. CSP Today, however, argues that the reasons for scaling up could yet be flawed. Their new report provides a concise breakdown of the current levelised cost of electricity (LCOE) across a range of CSP parabolic trough plant sizes to deliver startling insight into why bigger isn't necessarily better.
Higher volume sales for CSP plants yield more competitive prices from suppliers, so the accepted argument is that increasing plant capacity means the relatively lower cost of components will contribute to a lower LCOE.
Although an increase in plant size may lead to a general decrease in the LCOE due to power block savings (ZAR/MW), the interaction between variables could erode this advantage. Carlos Salazar Marquez, the report's author, explains: "Increasing capacity by a factor of two does not simply entail enlarging the solar field by an equal amount." He also demonstrated how knock-on effects of enlarging the solar field could ultimately yield a negative effect on the LCOE.
"To combat pressure losses, for example, more pumping is required, leading to higher electricity consumption, reducing the nett power output, and reducing larger-scale LCOE benefits," says Salazar. Some of the other findings from the report ("CSP Parabolic Trough Report: Costs and Performance") include the following:
The LCOE of a plant with thermal storage could be up to 20% lower than that of a plant without storage.
Torque-box collector design has been the most widely deployed in recent years with over 350 MW of installed capacity.
Operating and maintenance costs (O&M) have a significant impact on costs. A 20% reduction in the cost of O&M could lead to a 5% reduction in the LCOE. However, the same reduction in the cost of the power block or thermal storage would only lead to a 2% LCOE reduction.
Source: Why bigger isn't necessarily better when it comes to CSP First published by South African National Energy Association, June 2011
For text: http://www.sanea.org.za/MediaCentre/SaneaTalkingEnergy/2011/05/04.asp
First published by South African National Energy Association
FMF Policy Bulletin/ 14 June 2011