In yesterday’s MIT Technology Review there’s an interview with Jefferson Tester, who claims that geothermal power is a potential game-changer in the energy world.
Technology Review: How much geothermal energy could be harvested?
Jefferson Tester: The figure for the whole world is on the order of 100 million exojoules or quads [a quad is one quadrillion BTUs]. This is the part that would be useable. We now use worldwide just over 400 exojoules per year. So you do the math, and you know you’ve got a very big source of energy.
How much of that massive resource base could we usefully extract? Imagine that only a fraction of a percent comes out. It’s still big. A tenth of a percent is 100,000 quads. You have access to a tremendous amount of stored energy. And assessment studies have shown that this is thousands of times in excess of the amount of energy we consume per-year in the country. The trick is to get it out of the ground economically and efficiently and to do it in an environmentally sustainable manner. That’s what a lot of the field efforts have focused on.
The idea is to break up super-hot rock way down in the earth, flood it with water that absorbs the heat, and bring the water back up, in effect mining the heat. Tester says the technology’s been successfully demonstrated and we could have commercial-scale plants up and running within 10 to 15 years.
The advantage over other renewables is that geothermal provides steady baseload power:
TR: What are the advantages compared with other renewable sources of energy?
JT: Geothermal has a couple of distinct differences. One, it is very scalable in baseload. Our coal-fired plants produce electricity 24 hours a day, 365 days a year. The nuclear power plants are the same way. Geothermal can meet that, without any need for auxiliary storage or a backup system. Solar would require some sort of storage if you wanted to run it when the sun’s not out. And wind can’t provide it without any backup at 100 percent reliability, because the typical availability factor of a wind system is about 30 percent or so, whereas the typical availability factor of a geothermal system is about 90 percent or better.
It sounds great, but as always, the proof will be in the pudding.
For more info, see this diary by Devilstower over on dKos. Also, another Kos diarist named Leading Edge Boomer says he’s seen a (as yet unpublished) draft of a technical paper Tester’s co-written on the subject. "IMHO," he says, "this is A Big Deal."