view counter

Donate to SolveClimate News

Once a day
Get Articles by e-mail:

Get Today's Climate by e-mail:

Climate Science Links

U.S. Government


Academic, Non-Governmental

AltaRock: Enhanced Geothermal Could Supply 20% of U.S. Electricity by 2043

By Matthew Dakotah

Feb 23, 2009

This fall, renewable energy startup plans to launch what could be the first U.S. demonstration of Enhanced Geothermal Systems (EGS). Though technical hurdles and the risk of induced earthquakes remain, experts say EGS promises to swiftly becoming a reliable, continuous source of carbon-neutral power around the globe.

America’s geothermal resource is “effectively unlimited,” according to U.S. Energy Secretary Steven Chu, and AltaRock Energy President and Chief Technology Officer Susan Petty is on a mission to tap it. With federal policy support and increased access to capital, Petty believes geothermal could supply 20 percent or more of the nation’s electricity by 2043.

EGS goes deeper than traditional geothermal, and Petty will first test its ability to work in tandem with conventional systems like those at in Northern California where rigs are set to arrive this spring to begin work on the demonstration project. Early AltaRock Energy investors – including technology giants Kleiner Perkins, Vinod Khosla, Paul Allen and Google – are sure to be watching.

I sat down with Petty to go beneath the surface for the latest on this emerging green technology.

Q. A 2007 MIT-led on the future of geothermal energy in which you were a contributor estimated that America’s total geothermal resource is 14 million exajoules, and that we use approximately 100 exajoules of energy annually in the U.S. That’s 140,000 years of carbon-neutral power, yes?

A. Yes. But then we did a more detailed calculation of what we thought was the recoverable resource and it’s more like 12 million megawatts for 30 years.

Q. But that is still a huge number, and the report states that geothermal could supply up to 10 percent of the country’s electricity needs by 2050. That might seem like a less than ambitious goal to some, given the vastness of the resource and the nation’s urgent need for clean, renewable energy. What will it take to achieve even that 10 percent?

A. That was based on economics – how quickly we thought you could bring the cost down and then looking at market penetration. Let’s put economics aside for a minute and just look at what it would take to get geothermal to 20 percent of U.S. energy supply – just electric power. I did an analysis and found that you don’t have to produce more than about 10 percent more a year in order to get to 20 percent of the total by about 2043.

Right now, there’s about 3,000 megawatts of conventional geothermal power online. And they are putting about 450 additional megawatts online a year. …There’s still plenty of supply of conventional geothermal out there, and by the time we get to the point where we’re running out of conventional geothermal to meet that demand, we’re already to the point where we should be having pretty mature technology for at least the best places to do EGS.

Q. It’s really about demand and financing to get it to scale in order to fast track it to the 20 percent by 2043 then?

A. That’s exactly right. It’s not an unrealistic goal, and I think you could possibly do it even faster than that if you were really motivated. It would only take, for instance, about 15 percent of the U.S. land rig count. Those guys are idle right now because the price of oil is down, so it’s not an unreasonable thing to expect that we could get 15 percent of the U.S. land rig count into geothermal over the next 20 years.

Q. What are the biggest remaining technological hurdles?

My dad is actually the CEO

My dad is actually the CEO of Altarock and it really is great. Unfortunatley a ny times artical that reported untruly has stopped Altarock from getting more funding


I think it is fantastic how the stimulus funds are making a difference. They are being taken advantage of all the time with the installation of geothermal heat pumps to replace high energy heating and cooling systems.

Post new comment

The content of this field is kept private and will not be shown publicly.
  • Allowed HTML tags: <p> <a> <em> <strong> <cite> <blockquote> <code> <ul> <ol> <li> <dl> <dt> <dd> <img> <h1> <h2> <h3> <ul> <li> <ol> <b> <i> <p> <br>
  • Lines and paragraphs break automatically.
  • Youtube and google video links are automatically converted into embedded videos.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Images can be added to this post.

More information about formatting options