Why is Google so interested in renewable energy? In 2006, non-hydro renewable energy sources supplied less than 2% of the world’s energy consumption, in part because of the relatively high cost of production. Renewable energy isn’t as cost-competitive or widely available as fossil fuels, so Google (and most of the rest of the world) must rely on carbon-based power sources of electricity.

A number of organizations are working to bring down the price of renewable energy to be cost-competitive with coal. Google wants to apply our capital and engineering skills to join this important endeavor.

Why the goal of 1 gigawatt of energy? Is that how much power Google needs? This initiative is not just about creating clean, affordable electricity for Google - though we are keenly interested in making our business as environmentally sustainable as possible. If successful, this effort would likely provide a path to replacing a substantial portion of the world’s electricity needs with renewable energy sources. We want to do our part, but that won’t be enough alone to thwart climate change; we need a worldwide green electricity revolution to do that.

Why is Google focusing its R&D on solar thermal technology? Solar thermal systems convert heat from the sun into steam that powers electric generators. And solar thermal plants are efficient – they naturally generate the most power during the peak electricity demand periods of the summer months. Google believes that solar thermal technology has strong potential to produce utility-scale power at low cost.

What has prompted your collaboration with eSolar? eSolar is working to develop solar thermal technology based on super-efficient design and a large enough scale to compete in the market with carbon-based electricity like coal. We believe that eSolar's approach has great potential to produce utility-scale power cheaper than coal. Read more about eSolar’s technology at http://www.esolar.com/.

What is high-altitude wind power all about? There is enough available wind energy to power the world's current energy needs. If we can tap into this vast energy source - particularly powerful high-altitude winds - we can power the globe.

What made you decide to invest in Makani Power? Makani Power is led by an incredible team which includes MacArthur award winner Saul Griffith, PhD and Don Montague, the “father of kite surfing.” We are pleased with the progress they have made and look forward to ongoing collaboration. Read more about Makani Power at http://www.makanipower.com/.

What is “enhanced” geothermal technology? The heat stored deep beneath the surface of the earth is potentially a vast resource of widely available renewable energy. Tapping the earth's heat through the use of "Enhanced Geothermal Systems" (EGS) is historically under-funded and only a handful of projects exist. Google plans to accelerate the development and adoption of this promising technology.

The earth's enormous resource of geologically stored heat is available anywhere. EGS uses advanced heat mining technology to extract energy from the earth's crust beyond the limitations of conventional geothermal systems. Since conventional geothermal systems require the pre-existing combination of high heat, steam or water, and permeable rock -- a combination limited in nature -- the potential for conventional geothermal energy to be a major portion of our energy mix is somewhat limited. EGS, however, overcomes the limitations of conventional geothermal systems by replicating the required conditions through geo-engineering. EGS would therefore unlock the much greater geothermal potential of heat stored in deep hot dry rocks.

Why geothermal? EGS has the potential to provide baseload power cheaper than coal, could conceivably be deployed almost anywhere, and is essentially limitless in supply. Most importantly, EGS has a relatively small footprint and virtually no greenhouse gas emissions. EGS development has been limited mostly by the lack of research interest and commercialization funding - not technology. According to a recent report from the Massachusetts Institute of Technology (MIT) while further advances are needed, none of the known technical and economic barriers limiting widespread development of EGS are considered to be insurmountable. For more information, please see http://geothermal.inel.gov/publications/future_of_geothermal_energy.pdf.