BrightSource Energy builds massive concentrated solar thermal power projects in desert locations.

Unlike the photovoltaic solar panels that are common on the roofs of homes and commercial buildings, solar thermal technology concentrates the sun’s rays to boil water and generate steam. 

Q One of the big advantages of solar thermal technology over photovolatic solar panels is storage: the ability to store the heat after the sun goes down, usually in the form of molten salt. Does the Ivanpah project have storage?

A Ivanpah doesn’t have storage, but you’re going to see storage in our future projects, those that are being built in 2017 and beyond. As more and more renewables come online, the intermittency issue (it’s not always windy, and clouds can lead to a drop-off in solar production) is a very real one. The value of storage to utilities has gone up dramatically. The other issue is that the peak, when demand for electricity use is greatest, is shifting to later in the day. If you can deliver electricity in the 5 p.m. to 7 p.m. window, you have a lot of value.

Q The use of water in the desert has always been a contentious issue, and the drought has made water an even bigger issue in the West. Are state regulators and utilities paying more attention to water?

A We were the first solar company to use "dry-cooling," which allows the project to reduce water usage by more than 90 percent over solar thermal technologies that use "wet-cooling" systems. We use water in two ways: to clean the mirrors, and to produce steam for electricity generation. To conserve water, we use a dry cooling process to condense the steam back to liquid, which is then recycled back to the boiler in a closed loop cycle. All power plants use water; dry cooling uses less water than nuclear or coal plants. Now everybody is following us. The best decision we ever made was to go to dry cooling.

Q To date, most of BrightSource’s projects are in California: Ivanpah, and the proposed Rio Mesa plant in Riverside and Hidden Hills in Inyo County. What about abroad? What’s the global market for solar thermal?

A There’s going to be a lot more activity around the world. We have a solar demonstration facility in Israel’s Negev Desert. We’re looking at potential projects in South Africa and Australia, as well as North Africa and the northern rim of India and China.

Q When Solar Trust of America went bankrupt, BrightSource offered $10 million to build the Palen Solar Power Project as part of Solar Trust’s bankruptcy auction. Has that deal closed?

A The deal closed Aug. 15. Palen is currently permitted by the California Energy Commission as a solar thermal plant using parabolic trough (a long, curved mirror); we will convert it to a solar thermal plant using our power tower technology. The Palen site is in a good spot, with good transmission.

Q In April, BrightSource shelved its plans for an IPO at the final hour. I’m trying to imagine what it was like to be there: You’re in New York, with investors who are ready to ring the NASDAQ bell.

A We have a very thoughtful board, and we realized that it was not the right move. The macro factors were against us: The market had two terrible weeks, and solar stocks were even worse. But it was a unanimous decision, and the decision was made in about an hour. In many ways, you have more degrees of freedom as a private company.


The company’s pioneering solar thermal technology uses 173,500 motor-driven "heliostats," each with two mirrors, to reflect the sun onto "power towers." The company’s flagship project is the 377-megawatt Ivanpah Solar Electric Generating System under construction on federal land in California’s Mojave Desert.


When completed early next year, Ivanpah will be the largest solar thermal power plant in the world, generating enough electricity for about 140,000 California homes. The electricity will be sold to Pacific Gas & Electric and Southern California Edison.

This newspaper recently talked with BrightSource CEO John Woolard at his Oakland office; the interview has been edited for length and clarity.

Q A lot of people say that renewable sources of energy like solar are facing increasing pressure from natural gas, which is falling in price and displacing many coal plants. Do you see natural gas as BrightSource’s biggest competition?

A There’s a lot of natural gas, but natural gas still isn’t a renewable resource. Utilities are trying to meet their targets under state renewable portfolio standards, and natural gas doesn’t count.


The main component of natural gas is methane, and methane emissions contribute to global warming. But utilities and grid operators want a source of energy that is "dispatchable" — easily ramped up or down — as well as reliable. At Ivanpah, we can fire up natural gas as a back-up system if we need to. You’re starting to see hybrid plants that combine natural gas with solar or wind.