General Discussion
In reply to the discussion: The World's Largest Solar Plant Started Creating Electricity Today [View all]G_j
(40,367 posts)The plant, called Ivanpah, is funded by Google, NRG, and BrightSource, a company that specializes in whats called concentrated solar power, or CSP, a method of using focused sunlight to turn a steam generator. The technology isnt new: a small test plant that uses mirrored troughs to heat oil-filled tubes has been running in California for 20 years. Going back further, you could point to the French inventor Agustin Mouchot, who experimented with solar powered steam engines in the 19th century, thinking we were about to run out of coal. The current batch of plants are hugethousands of acresand use computer-controlled mirrors to heat boilers that sit on top of towers. (You can take a virtual tour of Ivanpah's triple-tower array here.) Three giant CSP plants are scheduled to go online in the next few months, and the companies that have spent years and billions of dollars building them hope theyll provide a valuable new source of renewable energy.
The main advantage of this type of solar plant is that its easy to store energy from it and save it for later use, something that will become more of an issue as we get more energy from windmills and solar panels. Energy from windmills and solar panels is cheaper, but its not always there when its needed: demand might be high on a windless or cloudy day, or low on a windy sunny one. A smarter power grid that can redirect power from renewable sources to where its needed can help cushion some of this streakiness, but were always going to need some reliable, always-availablethe industry term is dispatchablesource of power. Right now thats coal, gas, nuclear, and hydroelectric. The CSP industry is hoping solar can join that list, even providing power at night.
Ivanpah doesnt have storage, but Brightsource says its looking into storage for future plants. Two other large plants currently under construction are being built with energy storage. A 280 megawatt plant under construction in Arizona stores excess heat in vats of molten salt, allowing it to provide energy six hours into the evening, when air conditioning use is highest. A 110 megawatt plant in Nevada promises 10 hours of storage.
Its far cheaper to store energy in the form of heat than in a battery. A frequently cited comparison in the industry is that a thermos of coffee stores about the same amount of energy as a laptop battery, but one is $5 and the other is $150. With a CSP plant, when demand for energy is low, excess heat can be siphoned off and stored, then used to power steam generators when demand is high.
http://www.thedailybeast.com/articles/2013/09/28/solar-power-plant-in-the-mojave-could-power-140-000-homes.html