TR: You’re working on new drilling technology. How does this fit in?
JT: We feel that as part of a long-term view of the possibility of universal heat mining, we should also be thinking about revolutionary methods for cutting through rock and completing wells. Most of the drilling that’s done today is made by crushing and grinding our way using very, very hard materials to crush through and grind through minerals in the rock. And it’s been very successful. It’s evolved tremendously over the past century, and we can do it, certainly, routinely, to 10 kilometers. But it costs a lot. So we’re looking for a fundamental way to change the technology that would change the cost-depth relationship, and allow us to drill deeper in a much more cost-effective manner. It would open up the accessibility tremendously.
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.
TR: What are some environmental concerns with “heat mining?”
JT: Obviously in any system where you’re going underground, you need to think about are you disturbing the natural conditions in the earth that might cause bad things to happen. We have a pretty good history of knowing the effects of extraction. Nevertheless, it has to be monitored carefully and managed carefully.
In some natural systems you have to deal with the emissions – control of hydrogen sulfide and other gases. Environmental regulations insist on full re-injection of the fluid.
This is not a free lunch, but there’s virtually no carbon dioxide, so you’re producing baseload electric power without generating any carbon dioxide.
TR: How fast do you think artificial geothermal systems can be developed?
JT: With sufficient financing and a well-characterized field, you can go into existing areas right now and build a plant, getting it operational within a few years. But to get universal heat mining is going to take an investment which won’t be quite that quick. It might take 10 or 15 years of investment to get to the point where you have confidence that you can do this in virtually any site that you can go to. Once it gets in place, though, it can be replicated. I think it’s very reproducible and expandable. That’s the great hope at least.