First U.S. Power Tower Creates Solar Electricity

Is this the breakthrough we’ve been waiting for?

The Sierra SunTower is getting plenty of hype. A project of California start-up eSolar, this solar thermal power plant uses 24,000 mirrors to concentrate solar radiation on two “power towers.” That heat is then used to create steam to spin a turbine and generate electricity. It’s the first of its kind in the United States.

Power towers have smaller feet

Power towers have some significant advantages over the more common concentrated solar power (CSP) plants, which use parabolic trough mirrors to focus sunlight on miles of black pipes with water flowing through them. Power towers allow for a relatively compact design. eSolar’s 5 megawatt demonstration project required only 20 acres of land. For comparative purposes, take Albiasa Solar’s planned 200 MW, 1,400 acre CSP plant in Arizona. A similar plant using eSolar’s power tower technology would require only 800 acres, a sizable difference.

Add to that eSolar’s modular design, which allowed the Sierra SunTower to be built and online in less than one year, and we get relatively low-cost solar power.

The immediate future

The 5 MW Sierra plant will produce enough power for roughly 4,000 California homes, but that’s just the beginning. eSolar plans to expand the Sierra plant to 46 MW over the next few years and also has plans for a 92 MW plant in New Mexico through NRG Energy.

eSolar has also licensed its technology for use by an Indian company, ACME Group, for use abroad.

The success of the Sierra SunTower should spell a big future for power towers and eSolar. It may also lead to the commercialization of new ways to store solar energy. This can be achieved by using molten salts in the towers rather than water. The salts can heat to much higher temperatures and retain that heat for longer, allowing the solar plant to continue to produce energy for hours after sunset. Such demonstration projects are already underway in Europe.

Tomorrow and beyond

If the power tower is the breakthrough that many in the industry hope for (none more than eSolar), where will it go from here? And how fast?

Should all the numbers continue to crunch in favor of this design, there would seem little reason to keep on with more conventional approaches when a power tower can produce the same power on half the land. A compact and modular design also allows for closer proximity to urban centers and existing transmission lines.

This could be vital for getting solar thermal plants, which are currently more efficient than photovoltaic plants, into areas where cheap, clean energy is needed most. Inner cities and poorer, usually minority-populated regions tend to be in the most desperate need for clean air and energy. Furthermore, brownfields and other tainted industrial plots of land seem to take residence in these areas as well.

Photo Credit: Wikipedia

Using potential breakthroughs like these power towers to reclaim such land could reinvigorate some of our poorest urban centers, putting people back to work while creating a better living environment for local residents.

But when will such breakthroughs reach more depressed regions? That’s a difficult question, although the answer begins to look more positive for those living in these historically neglected areas. More and more cities are looking to convert these plots of land that may not be suitable for other development into solar farms of some type. So far, photovoltaics have been the main focus for such applications, but eSolar’s modular, compact design could be just the ticket.

However, the type of solar energy application is not as vital as the growing opportunity to bring life and work back to our most depressed regions. It is a surefire way to reinvigorate our economy as it should be… from the bottom up.

Posted on August 13th in Solar Products by Dan.