Personalizing Solar Power

Researchers are hoping to improve solar energy installations by coupling a solar panel to an efficient hydrolysis unit that splits water into oxygen and hydrogen. Daniel Nocera of MIT says the approach could lead to personal solar power units that could get many houses off the grid.

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IRA FLATOW, host:

You're listening to SCIENCE FRIDAY from NPR News. I'm Ira Flatow.

Next up, personal solar power station. But I'm not talking about it in a traditional way with a big bank of batteries or connection to the power company for rainy day or anything like that.

What if you had a solar panel on your roof that could easily make hydrogen from the sun, use the sun's rays to make hydrogen? And you power up your own personal fuel cell, you store that solar energy in the form of hydrogen over time and you just click a switch and use it when it's needed. Well, with the right chemistry and the right catalyst, it might be possible.

Joining me now is Daniel G. Nocera. He is the Dreyfus professor of energy and chemistry, and he's also a professor of chemistry at MIT in Cambridge. Welcome to SCIENCE FRIDAY.

Professor. DANIEL G. NOCERA (Energy and Chemistry, MIT): Thank you. Hi, Ira.

FLATOW: Hi, there. And now, you have - you guys have developed a new catalyst that can take the hydrogen out of the water more efficiently?

Prof. NOCERA: Yup, that's what it does. It actually splits water. And so, when you take water and you split it, you get hydrogen and oxygen. And you might remember even seeing that in grade school or high school where teacher put two electrodes in a beaker, and you saw the hydrogen and oxygen bubbling out. So we did the same thing, but we aren't using platinum. We're using a really inexpensive catalyst that operates under a whole bunch of variety of conditions that no existing catalyst could operate by, previously.

FLATOW: Mm-hmm. So you could take solar panel - are you saying that we can hook up to photovoltaic roof panels or you're going to have it work like using something else?

Prof. NOCERA: There's a bunch of ways we found this catalyst works and one way is exactly what you just said, just take the solar panel, put it up on your roof�

FLATOW: Right.

Prof. NOCERA: �and then, solar panels put out electricity, which you could use when the sun is shining. And if you wanted to, you could take some of that electricity, feed it to this catalyst, which then when it gets electrified from the photovoltaic, it splits water to hydrogen and oxygen. Another way you could do it is this catalyst forms directly on the PV material, which is a semiconductor.

And so, then you can just shine light right on the semi conductor, never really get the light to electricity directly, just use the energy of that supercharged photovoltaic to split water to hydrogen and oxygen, because the catalyst is coated on the semiconductor so it can basically take the energy from the photovoltaic directly.

FLATOW: Wow. And so, how close are you to making these kinds of devices?

Prof. NOCERA: We're really close. As a matter of fact, for the first one, where you would feed it electricity from a photovoltaic, we've been able to build - we've actually have built this out of polyvinyl chloride, PVC piping.

FLATOW: That white piping you get at the store.

Prof. NOCERA: Hmm?

FLATOW: That white piping�

Prof. NOCERA: That white piping, yup�

FLATOW: That plastic stuff.

Prof. NOCERA: �that stuck - that's in your basement maybe that's carrying all the water around your house.

FLATOW: Mm-hmm.

Prof. NOCERA: So it's really cheap. And the catalyst is very inexpensive. Because we're in water, we've been able to invent another catalyst that makes the hydrogen. So, this is important. Usually when you split water, the first thing you make is oxygen, and then you leave protons behind, which later are combined to make the hydrogen.

And the catalyst we invented splits the water, does the hard heavy lifting to make the oxygen. The hydrogen then is made now, not - it also - usually people use platinum. We've been able to use an inexpensive alloy of metals. And we have a plastic membrane. So, for 100-watt system, we're building these things for almost under $30 right now.

FLATOW: Wait a minute, you can build $30 photovoltaic system that makes 100 watts?

Prof. NOCERA: Not the photovoltaic. I still need to pay for the photovoltaic.

FLATOW: Right.

Prof. NOCERA: But in terms of feeding the electricity from the photovoltaic into this little system, yeah, we can build that very cheaply. And so I'm hoping we were fortunate enough to get what's called an ARPA-E. I just heard Norm Augustine mentioned in the last segment. Norm was one of the people who championed for the Department of Energy to get a program to take science innovation to a technology. And we were lucky we were able to get one of those. And we're planning, with under a year and a half, to have prototypes built and working.

FLATOW: Is it possible to mimic photosynthesis at all and make - split the water instead of making wood out of it?

Prof. NOCERA: Yup. You've basically nailed the essence of the discovery, because what happens in a plant, when sunlight hits the leaves, an elaborate reaction starts. But what the - what it's really doing is taking the sunlight. And you have to, of course, give the plant water. And what it's doing is it's splitting water to oxygen and hydrogen. It's stored as solid hydrogen though. It's called NADPH. But that's exactly what the plant is doing.

Then what it does is it needs to then take the hydrogen and it needs a carrier. It just stores the hydrogen and stores it with Co2. And that's where it makes wood, and that's what the plant needs to do to stand up. But if it were just an energy machine, you wouldn't have it do that. You would just take the water splitting reaction upfront to store the energy, and then that's exactly what we've done.

FLATOW: Wow. It's like a (unintelligible)

Prof. NOCERA: The catalyst is even great because it even have the same type of structure as what's in a plant. So it really looks a lot like what's happening inside a plant.

FLATOW: That's interesting. So I guess in your home then, you would have a tank to store the hydrogen and someplace to go into a fuel cell.

Prof. NOCERA: That's right. So at the end of the day, after this catalyst does its job and makes the hydrogen and oxygen, put a tank and just bury it outside. You don't have the problems you do in transportation, because of course if you're moving a car you wanted those tanks to be pretty tiny. You can live with a, you know, a pretty big tank. You just put it underground. And then at night, like you said, you flip the switch and just let the hydrogen go in the fuel cell and you power your house.

FLATOW: Now, is this, is this catalyst something you patented over there and you license it, or how would it get into the mainstream?

Prof. NOCERA: Yeah. That's moving very quickly. As a matter of fact, I just left a meeting with a very, very large photovoltaic company who - we're now working and negotiating with them to actually make an integrated device.

FLATOW: Is it American or foreign?

Prof. NOCERA: And - it's half and half. It's American and it's foreign. I will say, the foreign countries tend to be a little further ahead of us in solar energy, so they've been, they've been the first to jump on it. But American companies - at the end of the day, you're going to need a lot of pieces. I have a catalyst I can split water cheaply.

I can even use the Charles River and dirty water. But if you start thinking about all the components we're talking about, it's going to involve lots of partnerships. And there's a lot of American and foreign companies involved.

But at any rate, this thing is moving pretty quickly. There's IT. MIT owns it, and they've licensed it. And the licensee is helping me make this a technology.

FLATOW: So give us a ballpark on when we might see it on someone's roof. Is there - you got a roof at MIT where it's working?

Prof. NOCERA: Actually, I was just talking to with - this PV company is building a house. And we're - and they're - in terms of making an integrated module, and we would like to do that fairly soon. But I'm going to give you one number. It's 8.1254 years. And�

FLATOW: I thought it was 253. I - in my calculation�

Prof. NOCERA: The reason I said that is once I was on CNN, and the first call-in was, how come scientists always say 10 years? And if you say 8.1254, people think, wow, that guy has really thought this out carefully.

FLATOW: Well, I was off just by a little on my�

(Soundbite of laughter)

FLATOW: �calculation. 1-800-989-8255. Let's see if someone's got a question. Yeah, we do. Anne(ph) in Barring - is it Barrington, Rhode Island?

ANNE (Caller): Yes.

FLATOW: Hi there.

ANNE: It is. Hi. Are you there?

FLATOW: Yes. Go ahead.

ANNE: I was wondering if the - the hydrogen ion is really acidic, right? So will it start to eat through the materials it's stored in?

Prof. NOCERA: Yup. So Anne, that's an absolutely beautiful and wonderful question.

ANNE: Oh, thank you.

(Soundbite of laughter)

Prof. NOCERA: When you take water and you split it, you actually make protons and it becomes acidic. And that's why people haven't been able to do this before. You should know that people have been - you can buy commercial electrolyzers. And they work really well, but they're super-expensive. And an electrolyzer splits water. And they're expensive because you start making the acid, so you have to run the electrolyzer in very concentrated base, like lye.

ANNE: Mm-hmm.

Prof. NOCERA: And that keeps the acidity down. But then it brings a whole bunch of extra cost to the system, and it makes it expensive. And our catalyst - the one special thing we did is that when you do build up the acid, it actually can start eating the catalyst a little bit. But as it does, we put in - and this is the first time a scientist has ever been able to do this - is my students were able to figure out how to make it self-heal itself.

ANNE: Huh.

Prof. NOCERA: So after the protons and the acid starts getting to the catalyst, the catalyst actually rejuvenates and fixes itself. And that was one of the big key discoveries�

ANNE: Wow.

Prof. NOCERA: �this catalyst�

ANNE: That's amazing. Oh, thank you very much.

FLATOW: It's good, Anne, that he gave his students some credit, didn't he?

ANNE: Yes, it is. And it's really interesting because I think when I took chemistry years ago, I was trying to figure out something like that. But that's about as far as my chemistry goes, being able to know a tiny bit about the water molecule. But this is really fascinating. And I love your show.

FLATOW: Thank you.

ANNE: So thank you very much.

FLATOW: Bye-bye.

ANNE: Bye.

FLATOW: People are thinking about this.

Prof. NOCERA: Oh, yeah. You want to know why? This is the world, and there is no question, the world of the future is you will own your - generate your own energy and be in control of your own energy. And that really captures your imagination, because that's how you like to live. Most people like to live in control of their world. The energy (unintelligible) scary, because we're always getting energy from someplace over there and things aren't too happy or stable. So it really makes - at least I've noticed, because a lot of the public will contact me by email, the one theme I see from them is they find comfort in thinking that someday they'll just use the sun, the sun that's just shinning on their face, to be able to generate their own energy and live�

FLATOW: Hmm.

Prof. NOCERA: �live basically in an autonomous world.

FLATOW: So your solar power device might come online just about the same time a plug-in electric car?

Prof. NOCERA: Yup.

FLATOW: You got enough power to plug it in, charge it up at night from that?

Prof. NOCERA: You could do that. There - so you could use the electricity from the fuel cell and charge the battery. The other interesting thing, this is a little further up, but you know, I'm in academics, so we can always - we aren't so tied by a product next year, even though now I am, as I try to develop the technology - but one of the things that keeps fuel cell - fuel cell cars are really wonderful machines. If you see the Mercedes F series, Toyota, Honda, they use hydrogen and then there's a fuel cell car - a fuel cell in the car. They're much, much better than the battery cars. The all-battery cars are very heavy with lots and lots of battery�

FLATOW: So I see where you're heading with this. Just hit those hydrogen right into your car.

Prof. NOCERA: No, this - that's what's hurt the fuel cell industry, is you have to distribute hydrogen. And it's hard to think about how will you have hydrogen gas stations - all of a sudden your house just became a gas station too.

FLATOW: Wow. Quite fascinating. I want to thank you very much for taking time to be with us. What did you say, 8.2134?

Prof. NOCERA: 8.1254 years.

FLATOW: Okay.

Prof. NOCERA: 8.1254. I'll be there.

FLATOW: All right, we'll be there with you. Thanks a lot.

(Soundbite of laughter)

Prof. NOCERA: All right, Ira.

FLATOW: Dan Nocera is the Henry Dreyfus professor of energy and professor of chemistry at MIT in Cambridge. They know how to get things done over there.

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