A BrightSource Power Tower
While previous designs, used a vast field of mirrors to focus the sunlight on water-filed boilers to produce steam to drive a turbine, this project will use a 750 foot tall "power tower" filled with molten salt instead of water. Molten Salt stores the heat from the day, so the tower can continue producing electricity throughout the night. This Hidden Hills project will have two such towers each surrounded by a field of 85,000 mirrors, called heliostats.
“The new, higher, 750-foot solar power tower allows the heliostat rows to be placed closer together, with the mirrors at a steeper angle,” the company stated in its license application. “This substantially reduces mirror shading and allows more heliostats to be placed per acre. More megawatts can be generated per acre and the design is more efficient overall.”
BrightSource on Wednesday announced it would incorporate molten salt storage in its power plants to extend their operating hours past sunset.
The company has set out an ambitious construction schedule, stating that it anticipates ground would be broken by the third quarter of 2012 and Hidden Hills would begin generating electricity in 2015.
By comparison, a nuclear plant typically takes 13 years to license and build.
This is a big improvement in the licensing delay, as it took state and federal regulators more than three years to approve the previous, similar, Ivanpah project. This isn't a breakthrough in streamlining bureaucracy, as much as cleverness on the part of Brightsource, which is avoiding Federal involvement by building on private land, and luck, in finding only two of the rare tortoises that delayed the Ivanpah site.
This article does not mention how many jobs will be created to build and operate these plants, nor does it mention what the cost per kilowatt hour this electricity will be sold at.
Special kudos to any reader who can discover this for us.
A closeup photo of non-Brightsource heliostats
10:04 PM PT: Martin LaMonica Econ 101: Solar panels increase home values
The National Bureau of Economic Research (NBER) recently released an analysis that found solar panels add between 3 percent and 4 percent to the value of a home. That result is consistent with a study released in April by Lawrence Berkeley National Laboratory which found that solar photovoltaic (PV) panels have a "sizeable effect" on home prices.
The NBER study looked at prices in San Diego and Sacramento, Calif., to measure the effect of solar panels. The homes studied have panels generate electricity (not hot water) and are connected to the grid so households draw from the regular electricity system when panels are not generating.
"Our evidence suggests that similar to other home investments such as a new kitchen, solar installation bundles both investment value and consumption value," conclude the authors, who are California-based economists. The "investment value" increases the sale price of a home and the "consumption value" is the benefit of having an environmentally friendly energy source.
Read more: http://news.cnet.com/...
11:18 PM PT: http://cleantechnica.com/...
That “Other” Solar Tower Technology
Brightsource has announced that the theory is now ready for the next construction project and calls the technology “LPT solar thermal energy system.” They have also added two refinements. Thermal (Rankine cycle) power plants need cooling. Because the technology is often used in deserts where water is scarce they have added air cooling. Hours of sunshine would normally limit the supplied power but thermal heat storage allows plant operation into the night.
duel tank heat storage
The storage system used is a two-tank molten salt storage system. In two tank systems, heat is stored in the tanks at two temperatures. A heat exchanger between them is used to heat up or cool down another medium like water or oil. By adding such a storage system, the hours of operation are increased.
Photovoltaics are around 19% in Arizona. Wind and solar towers without energy storage have capacity factors around 25%. Energy storage can increase the capacity factor of Concentrated Solar Power (CSP) plants like the solar power tower to over 60%.
Advantages: CSP technologies have an advantage over photovoltaics as they are already producing heat which suggests a technologically simple method of energy storage. The other CSP technology being built around the world is the solar trough collector. The Brightsource LPT solar thermal power-generating technology can reach higher operating pressure and temperature levels. This adds to increased efficiency and economic value.