COAL AND SOLAR TOGETHER?

CSP bridging technology: Is the timing right for solar augmentation?
Bob Moser, 27 September 2010 (CSP Today)

"While demand for concentrated solar power augmentation of coal-fired plants is picking up, analysts and manufacturers say customers won't pull the trigger until costs come down…[T]here is about 10 GW of potential CSP currently on the drawing board and in some level of development…concentrated in five states in the American Southwest…[O]f the projects that could be completed within the next few years, all are stand-alone CSP plants.

"Heavy industry and power plants in the US have so far only considered CSP steam production to reduce their emissions if they've been mandated by the state to do so - primarily because augmenting fossil fuel-powered plants still isn't economically attractive…AREVA Solar has received a number of inquiries into CSP for emissions reduction from heavy industry in the US, but without mandates the bottom line is still far from competitive…"

schematic of a coal plant augmented by a parabolic trough solar power plant (click to enlarge)

"Working examples of CSP augmentation are few and far between. Only one coal-fired plant currently has CSP up and running…Xcel Energy's Cameo Generating Station in Colorado has [since July] had a 1 MW parabolic trough solar field running…[but will operate only] for six months as a tie-in to the plant's feedwater system before the coal plant is decommissioned at year's end. Xcel Energy hasn't stated what it plans to do with the CSP equipment…

"Cameo Station in Colorado is a very short-term test to prove the concept…But last week’s announcement by GDF SUEZ and Solar Power Group of their plans to develop a 5 MW thermal CSP plant to supply superheated steam to the 150 MW Mejillones coal-fired plant in Northern Chile indicates that demand for CSP augmentation is growing…Tri-State Generation & Transmission Association will augment its 245 MW coal-fired Escalante generating station in Prewitt, N.M., and NV Energy its 1102 MW gas-powered Lenzie facility near Las Vegas…[Both are] still settling on utility sponsorships…"

schematic of a natural gas plant augmented by a parabolic trough solar power plant (click to enlarge)

"Areva Solar's 3-MWe Liddell Solar Thermal Station in Australia has been operating a solar/coal-fired power augmentation since 2008. The company is adding 44 MW in solar thermal to the existing 750 MW Kogan Creek Power Station in Australia…[With mandates] there are significant savings in choosing CSP add-ons…An existing power plant or heavy industry has costly and time-consuming hurdles like transmission, power blocks, plant permits and manpower already in place. The capital, infrastructure, and O&M savings make CSP augmentation favorable.

"There are a number of greenfield power plants around the world that are being built as hybrids with CSP solar fields, with several in North Africa and the Middle East. The benefit of designing a CSP hybrid plant from scratch is that equipment can be tailored to accept a higher percentage of solar power…A key factor for CSP augmentation to work with existing power plants is the availability of land…Many new conventional power combined-cycle plants outside of the United States being built now are trying to adapt design to allow solar steam additions…"