"We here at Science Friday are constantly on the lookout for cool, innovative, renewable energy ideas. And when we came across these next two, we knew - I just knew I had to share them with you."
"Our first one, we go to a dormant volcano in Oregon. It's the site of a renewable energy project that involves hot rocks, millions of gallons of cold water and cutting edge geothermal technology. Susan Petty is the president and chief technology officer for AltaRock Energy, one of the collaborators on this project. She joins us from Seattle."
"Our first one, we go to a dormant volcano in Oregon. It's the site of a renewable energy project that involves hot rocks, millions of gallons of cold water and cutting edge geothermal technology. Susan Petty is the president and chief technology officer for AltaRock Energy, one of the collaborators on this project. She joins us from Seattle."
Welcome to Science Friday.
SUSAN PETTY: Hi, Ira. Good to get to talk to you.
FLATOW: Hope you're weathering the storm out there.
PETTY: Well, I had to stay home today, because we have 10 inches of snow out here and the road hasn't been plowed yet. But...
FLATOW: Well, what better way than to share your phone call with us then today?
PETTY: Absolutely. And we can talk about heat, which is a good thing.
FLATOW: Well, let's talk - so how do - how are you going to use this volcano? Tell us about this. Dormant volcano in Oregon. You're going to use it to generate power.
PETTY: OK. Well, we were very fortunate. AltaRock Energy is a company that's been focused on advance technology for using geothermal energy since 2007. And we found that the - some folks, Davenport Energy, our partners, had drilled two wells at Newberry Volcano, looking for conventional geothermal resources. And they didn't find it.
What they found, though, was a lot of heat really close to the surface. And so we came to them and said, Look, we've developed this advanced technology that should let us get this heat out, even though you don't have the normal cracks and hot water that would be in place for a conventional geothermal resource.
FLATOW: So instead of - so you made lemonade out of lemons when you got there and decided to try something new.
PETTY: Something new. And it really is new. I mean, there have been other projects where people have drilled down, gotten into hot rock and made fractures and then circulated cold water down one well and produced it hot out of another well. There're two projects like that - one in Germany and one in France. And they're generating electricity now.
The problem is that it's only economic to do this in some very special places or if you have the kinds of price incentives that they have in Europe to get people to do that.
FLATOW: So what you're aiming to do is to do what? You have the rocks – have the hot rocks there. You will send cold water down, heat it up, bring it back up to the surface?
PETTY: That's right. And what we are going to do at this particular experiment is we already have a well. That's great. And it's very hot. So what we'll do is we'll put this cold water down. And the combination of the cold and a little bit of extra pressure allows the rock to start to fracture. And then we can extend those fractures out from that first place.
And as they extend out, they will bifurcate and new little fractures will open up. That makes little snapping and popping sounds, which we can use to map where the fractures are going. And we do that from the surface using sensitive seismic instruments.
Then when we finish making one set of fractures, the new thing is that we then pump a suspension of little plastic bits into the crack we've made. That stops that crack going, allows us to let the pressure come up a little bit more in the well. And then the cold water can move out and down, and extend out another set of fractures in the well.
And we can then put the plastic bits in that set of fractures. We can do that again and again until we're happy with what we got. And then when we stop pumping in cold water - this plastic is a biodegradable type of plastic that will then as it heats up break apart into little tiny components of the polymer. That will be completely soluble in water. And we can then produce them out.
FLATOW: So you're making sort of a pool or a reservoir of hot water underground?
PETTY: That's right. A reservoir in little cracks. I don't want you to think of it as an underground lake. It's a reservoir in that it's a bunch of tiny little cracks. And the more tiny cracks we can make, the better we can get at that heat that's in that volcano.
FLATOW: This is not like fracking for natural gas is it?
PETTY: No. Because in fracking for natural they want a great, big, huge crack, which they then hold open with proppant, with sand. And we don't want that, because that wouldn't get us access to that rock that we want to contact with our cold water to get it to heat up.
FLATOW: How hot does the water get?
PETTY: Well, we're very lucky. Because this is a volcano, it gets quite hot. So the temperatures in this well are higher than 600 degrees F. They're above 320 C.
FLATOW: Wow. So does the water - that's superheated water then?
PETTY: Well, yeah. So the water will get that hot, and it will then come out of the production wells at that temperature. And we'll be able to - we have two options then as it comes out of the well. We can either take the steam part - it'll boil - and we then can separate the steam and the water and put the steam through a steam turbine, which is probably what we'll do.
But we have another option. And that is that we can take the full stream of hot water and put it into heat exchangers and boil another fluid. And that will vaporize and that can go through a turbine.
Either way, it's a closed loop. We take all of this water that comes out, pick the heat out of it to make the electricity, and then we put it right back in the ground.
FLATOW: So it's sort of like a boiling water nuclear reactor, but without the nuclear reactor.
PETTY: Well, you know what? At this place, it's without the nuclear reactor. But everywhere you go on Earth, the deeper you go, the hotter it gets. And that actually is kind of a nuclear reactor, because that heat comes largely from radioactive decay or radioactive isotopes that are in the crust of the Earth. So it's kind of a very diffused and controlled nuclear reactor there under us.
FLATOW: Yeah. So when does this all happen?
PETTY: Well, OK. So the schedule is that we're just now - we've just completed our environmental permitting work. The Bureau of Land Management has released our environmental study for public comment. We have got that public comment period almost done. The BLM will then say go ahead.
And we also have a grant from the Department of Energy to help us do this experiment. So they'll say go ahead. And we have to put in some more sensitive seismic instruments. And that will be happening in the spring. We will then rig up and start the stimulation experiment probably at the end of July, beginning of August.
FLATOW: Is this - so you're saying it's technologically feasible, but you have to discover whether it makes economic sense, right?
PETTY: This is the big part of this, Ira. Right now, we could do this pretty much anywhere. We have the technical capability to generate power from this type of method, anyplace that you would want to try and do it. The problem is it's just not economic. The wells are deep and expensive. And we don't get that much power out of each one, so it wouldn't be justified.
We're hoping that this new method, where we can get a lot more of the hot rock contacted and therefore produce more hot water out of each production well, will make this much more economic. And so then we can move off the flanks of dormant volcanoes, where it's really hot close to the surface and go to places where we would find more normal levels of heat at depth and use this technology to make power a lot of places. That's the goal.
FLATOW: Well, we wish luck. And we'll be watching to see how this turns out.
PETTY: Well, that's great. And we'll let you know what happens.
FLATOW: All right. We'll be watching. Thank you for taking time to be with us today.
PETTY: Thank you.
FLATOW: Susan Petty is president and chief technology officer for AltaRock Energy, one of the collaborators on this project.
