6/11/09 – Visiting Professor from Tel-Aviv University

Prof. Kribus gave us a nice overview of the history of solar technology development in Israel, which has had a surprising influence on the industry. Some of the major contributions over the years are in the solar thermal space, a method of focusing the heat of sunlight with parabolic troughs or mirrors to heat a fluid (often but not always water) to produce electricity or heat for homes and industry.

One company that was instrumental in this industry was Luz (founded by Arnold Goldman), which eventually went bankrupt but has since returned in new form called BrightSource. This mention was of particular interest to me since BrightSource was one of the companies we visited with the Duke Clean Energy Field Study back in March. BrightSource has been doing some really impressive work using mirrors to focus sunlight on a central “power tower,” which is essentially a boiler like one might see in a coal or nuclear plant that heats water to turn a turbine and produce electricity. Most impressive is the fact that BrightSource claims these power towers will be capable of producing 100-200 MW of power, the equivalent of 100 or more large wind turbines. Today’s coal and nuclear plants provide 600 to 1500 MW of power each, so there is still a ways to go for scaling solar, but Prof. Kribus was quick to note that the amount of sunlight that falls on a chunk of Nevada every day would be enough to power the entire United States. This fact always serves as a good reminder that there is plenty of renewable energy out there; we simply need to find efficient ways of capturing and delivering that energy to people.

Some more futuristic technologies were mentioned, such as a cloth wind turbine being manufactured in Israel, and a more advanced solar thermal array being developed by AORA Solar that will heat a gas (hot air) turbine instead of water to co-generate both heat and power in distributed population centers. This particular technology holds promise because it does not require water, making it even more advantageous for desert climates where the best solar energy can be harvested. However, since it is a combine heat and power operation, 60% of the energy collected will go to heating and 20% will be used to produce electricity.

 This means that in order to capture that entire 80%, the plant must be built near a city or industrial facility that will make good use of the heat. So keeping the balance between site selection and system efficiency will likely present a challenge.

All of these technologies are promising for scaling up solar power to the levels necessary to power larger segments of our economy, and it is likely that we will see some of these plants being built both in Israel and in California over the next few years. A greener energy mix on the grid would be great for electric vehicles too, because the shift from oil to electricity as a fuel source will only yield major emissions reductions if we can clean up our electricity generation at the same time.