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EarthFix Conversations: Improving Renewable Energy Efficiency

Oct. 14, 2011 | Northwest Public Radio
CONTRIBUTED BY:
Courtney Flatt

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  • Pacific Northwest National Laboratory fellow Pete McGrail is working on a project to more efficiently heat and cool electric vehicles. This is a conceptual drawing of the heat pump he will help create. credit: PNNL - Pacific Northwest National Laboratory
  • Materials scientist Jun Cui is working to develop a manganese-based permenant magnet that will help power wind turbines and electric vehicles. These magnets will be created with inexpensive, abundant materials. credit: Courtney Flatt
  • Researcher Ewa Ronnebro is working to develop a new material that can store solar power at higher temperatures. They hope to develop a metal hydride that can store up to 10 times the amount more than traditional methods. credit: Flickr Creative Commons: Kincuri
Pacific Northwest National Laboratory fellow Pete McGrail is working on a project to more efficiently heat and cool electric vehicles. This is a conceptual drawing of the heat pump he will help create. | credit: PNNL - Pacific Northwest National Laboratory | rollover image for more

RICHLAND, Wash. – Three new projects at the Pacific Northwest National Laboratory are aimed at improving renewable energy efficiency and production. The projects recently received funding from the Department of Energy’s Advanced Research Projects Agency for Energy. They will look at replacing rare earth magnets in wind turbines and electric vehicles, storing solar power at high temperatures, and finding a new way to heat and cool electric vehicles.

In the latest round of funding (PDF), 60 projects received a total of $156 million.

In these EarthFix Conversations, Courtney Flatt talks with the lead scientists on each of the PNNL’s three new projects.

MORE EFFICIENT MAGNETS

Rare earth magnets are commonly used in green energy products like wind turbines or electric vehicle motors. They’re sometimes called permanent magnets. But researchers at the Pacific Northwest National Laboratory in Richland, Wash., are developing manganese-based magnets. The Department of Energy recently granted the lab $2.3 million to explore how manganese magnets could cut back on green energy production costs and possibly increase efficiency.

Materials scientist Jun Cui is working on the project.

Jun Cui

EarthFix Conversation with Jun Cui by courtneyflatt

EarthFix: First off, why are these types of magnets important?

Cui: Permanent magnets, especially now when we talk about green energy, one good way is to generate electricity. So for that you need a powerful motor. And there are two types of powerful motors: one is induction, the other is permanent magnet.

Permanent magnets – actually people don’t think about this – but, in a way, it is an energy source. So it does not do work to others like a battery does, but it does lend its energy to exert torque.

So the higher the permanent magnet is, the higher the efficiency. So that’s why if you see Priuses and high efficiency wind turbines, they actually all use high strength permanent magnets.

EarthFix: You’re looking at replacing rare-earth magnates with manganese alloys. What’s the difference?

Cui: Rare earth actually is the strongest permanent magnet. But the problem – why we do not want rare earth anymore – as the name sounds, rare earth actually is supposed to be rare. But that’s not entirely true. Rare earth is everywhere. You can find it everywhere on the earth’s crust. But it’s abundancy is low. So those rare earth elements help us sustain the high temperature performance.

EarthFix: And why is the high temperature performance important?

Cui: Rare earth permanent magnets are the strongest permanent magnets at room temperature. But it’s not so true when you move the temperature higher, like, 100 C. Unfortunately, if you have a Prius, by the time you’re operating it, it’s highly like that it’s about 80 C. If it’s a wind turbine, where you keep driving and moving and moving, then the temperature will go up.

So you actually have to implement a form of cooling mechanism to keep the temperature down.

EarthFix: And so it’s part of the hope too that with these manganese magnets they won’t have to have that cooling mechanism then?

Cui: Yes, this is actually what makes our proposal so unique. We plainly, plainly admit that we will not be able to compete with rare earth permanent magnets at room temperature. But we will be able to compete with them at a higher temperature, at 80 C to 200 C, around that range.

All magnets, their performance drops exponentially down. We are using a unique property of this manganese-based alloy. It actually increases with a function of temperature.

EarthFix: Is there no worry about manganese poisoning?

Cui: The application of this magnet, if you use it, is highly like not going to be really close to your refrigerator. Or even in the refrigerator it would have a pre-packaged seal. There’s no way for the regular consumer to touch it. For anyone who actually opens it and touches it, he probably should know what he’s doing. So poisoning is not likely to happen in a big, giant wind turbine up in the air, or in your car. It’s pretty far away from your food source, so it should be okay.

EarthFix: What’s your ultimate goal for the project?

Cui: The goal is, I don’t think we can create a world record based on our magnet, but one thing I hope we can do is create a world record in terms of cost and performance. If you look at cost-ratio at a certain temperature. I think we’ve got a very good chance to do that.

EarthFix: So do you think this will increase green energy production in the future?

Cui: That’s the point, actually. Green energy right now is really green, in terms of gasoline price and those kinds of things. But there is a break-even point. In order to make green energy as widespread as possible, your basic system costs has to be as low as possible so that people can easily adopt it. Right now it really is pretty efficient. It’s really the cost that prevents it from being more widespread.

Jun Cui is a materials scientist at the Pacific Northwest National Laboratory in Richland, Wash.

STORING SOLAR

In moving toward a more renewable energy generation, storage becomes increasingly important. Researchers at Pacific Northwest National Laboratory in Richland, Wash., recently received $700,000 from the Department of Energy to find a way to more efficiently store energy at higher temperatures. To do this, researchers will develop a metal hydride material.

Ewa Ronnebro is the lead researcher on the project.

Ewa Ronnebro

EarthFix Conversation with Ewa Ronnebro by courtneyflatt

EarthFix: First off, how is solar power generally stored now? And how will your project change that?

Ronnebro: There’s different applications. One is the solar towers, when they’re utilizing molten salts as heat storage, and there’s some really big installments in Spain, and there are also some prototypes in California at this point. However, these materials, although they are very efficient, they don’t store as much heat as we need for bringing the cost down and making it more efficient in the future.

So we have a new material that we believe can store energy about 10 times more than the conventional technique, and we believe that we can bring the cost down because it’s a very simple technology. It has not really been tried before.

EarthFix: You’re talking about the metal hydride material. What’s the difference between what’s being used now – the molten salt – and metal hydride material that you will be developing?

Ronnebro: The current technique is a molten salt technique. It’s basically salts that are melted. And they can contain a lot of heat. But the so-called metal hydride, that’s a class of material that can store more energy than molten salt. And it’s based on a simple material. Basically it’s consisting of metals. And then you have hydrogen – that’s the lightest atom we have. And as the hydrogen is diffusing in and out of this metal, you can reverse the heat and reversibly store the heat.

EarthFix: What’s the importance of storing head in a large capacity like that?

Ronnebro: Heat storage is important because, let’s say you have your house, and you have your solar cell panels on top of your roof. And the sun is shining on it and heating your roof. You can directly use it in the daytime. But at nighttime you don’t have a way to use it, so then you need to store it somehow. You need some kind of material that can keep it in storage for later use.

EarthFix: And do you think this will help with the adoption of renewable energies – because storage is one of the main humps to get over?

Ronnebro: Absolutely, as we are moving into the future and using solar power, wind power, water power, we need means of storing heat. We hope that this will help in the future.

EarthFix: Where are some places where this could eventually be applied?

Ronnebro: There’s many potential scenarios. One is residential homes. One is in communities with homes, so you store heat to use them later for appliances. You’re storing heat and later you’ll use it for power generation. Another is large installments like the similar one in Spain, and that is to power bigger communities based on solar power plants.

EarthFix: How much power do you anticipate this system providing?

Ronnebro: The prototype that we are building for this proof-of-concept project is a 3 kilowatt hour (kWh) prototype, which is fairly small. But to put it in context, an average American home uses about 24 kWh per day. And if you take one of your appliances you have in your home – coffeemaker, vacuum cleaner, so on – that’s about 1 kWh. So we’re building a 3 kWh prototype.

This project will hopefully one day result in an enormous installation, which produces megawatt heat storage. Ideally you would like to supply a large community, such as the Tri-Cities.

Ewa Ronnebro is a senior research scientist at Pacific Northwest National Laboratory in Richland, Wash.

DRIVING HEAT

Engines use heat generated from running a car to heat it in the winter. While this system works well for gas-fueled cars, it’s not as efficient in electric vehicles. In fact, heating an electric vehicle this way could cause it to lose up to 40 percent of its driving range in the winter. Researchers at Pacific Northwest National Laboratory in Richland, Wash., recently received a grand from the Department of Energy to develop a new material that will heat and cool an electric vehicle more efficiently – without any moving parts. The material is called an electrical metal-organic framework – or EMOF for short.

Pete McGrail is the lead researcher on the project.

Pete McGrail

EarthFix Conversation with Pete McGrail by courtneyflatt

EarthFix: So, Pete, what is the electrical metal organic framework? And how will it help more efficiently heat electric vehicles?

McGrail: Well, the conventional way to think about heating – think about your toaster. You supply power to a coil, it gets hot, and so that provides the heat. But that’s very inefficient, and that’s whe the range on an electric vehicle would go down so much.

So what we’re trying to do here is develop a device, which is essentially like a new kind of pump, a molecular pump.

EarthFix: And how would that pump work?

McGrail: The air conditioner in your car, for example, what it’s doing is it’s turning a compressor. And the engine works great for that because the pistons are moving, and things are rotating, and so it can run that compressor.

But what we want to do is try to use a new technique. Make a molecular kind of pump, where it takes much less energy to compress the refrigerant and move it around in the electric vehicle, compared to the same amount of power that would be required to turn a compressor. And we’re going to do that electrically. With no moving parts. So it’s just really, really cool. It’s just amazing.

EarthFix: Could this be used in non-electric vehicles as well?

McGrail: Yeah, so that’s the beauty of something like this. You could use it anywhere you’ve got electricity to run a cycle more efficiently. If you had a solar panel that was providing some current, for example, you could hook this up and run it off a solar panel.

Who knows. When you have a material that can function in a completely new way, compared to anything that’s available today… Things that we haven’t even thought about yet.

EarthFix: The sky’s the limit. So how do you develop the new materials?

McGrail: We try to design these materials on the computer as much as we can. And then, once we’ve designed the materials, and we think it’s gonna function like we’d like, we can synthesize it – hopefully – in the lab, do the tests, and see how it works.

EarthFix: How big would this new system have to be inside an engine?

McGrail: We calculated this. It was something we had to do as part of the proposal writing process. To cool a vehicle, it takes about 2.5 kilowatts. That’s what you wanna supply for a heating or cooling load. So to deliver that kind of power density, it turns out we need like a 2-liter sodapop bottle of a container that would hold the EMOF.

And then everything else on a vehicle would be virtually conventional stuff. You’d just have a condenser, and evaporator and some piping that would connect it. The only unique part is that you would have electrical connections to the EMOF molecular pump that would come from the battery.

EarthFix: What about maintenance for people? Like how you sometimes have to add, say, Freon to your car?

McGrail: It’d be very similar. So if you had refrigerant that leaked, you’d have to replace that because it’s still using refrigerant, still running around in a cycle. But in theory, the maintenance should go down because there’s nothing moving. So in theory, the devices should be more reliable and less maintenance and less cost for the vehicle owner.

Pete McGrail is a laboratory fellow at Pacific Northwest National Laboratory in Richland, Wash.

© 2011 Northwest Public Radio
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