Saturday, June 14, 2014

The energy storage that gets Hawai`i to 100% renewable--just around the corner.

We’re not quite there yet, but there’s lots of progress toward the battery that will change the energy world.

That, of course, is the energy storage system that will store cheap solar power cheaply, deliver It efficiently, use non-toxic materials, and keep working long enough to make economic sense.

For Hawai`i, it’s the battery that turns solar and wind power into firm power, and it may be the ultimate key to getting to 100 percent renewable energy in the Islands.

Existing batteries haven’t gotten us there. 

The old standby lead-acid has its applications, but it’s not cheap, the lead toxicity is an issue, and while your solar panel might last 20 years, a lead-acid battery is lucky to last a third of that in daily cycling.

Lithium-ion is interesting, and last many more cycles, but it’s still not cheap.

Lithium-air has tantalizing qualities—it’s very energy dense—but they’re having trouble getting it to survive enough cycles to be economically feasible. It’s discussed deep in this article in The Economist.

Here’s a report from the blog The Engineering Economist on a graphene battery that may be running on nothing but the heat in the room. If you read the article, you’ll see that there are still some questions about it, but it’s an intriguing concept. 

There has been lots of discussion of heat-based energy storage. Most of it, though, has involved converting the stored heat (in molten salts or rock) into electricity with old-school steam engines. And thus far, the economics haven’t been great.

But researchers are working on it, and hard. One team has developed what it hopes will be a cheap form of energy storage using a heat transfer mechanism that doesn’t uses a steam engine. Rather, it stores heat in crushed rock surrounded by argon gas. As the argon moves between a hot chamber and a cold chamber, it runs through a pump hooked up to a generator.

In this article in The Economist, engineer Jonathan Howes figures he can store and then generate energy at less than five cents per kilowatt-hour. They call their system Pumped Heat Electrical Storage (PHES), and their company is Isentropic.

Of course, they haven’t built the thing yet.

Nature magazine wrote last month about Michael Aziz and his cheap quinone battery, a flow battery. It shows great promise, although it’s still in testing and has some toxicity problems. I’ve met Aziz, and his work is taken very seriously by his colleagues in the field. 

There’s lots going on in energy storage technology.

The breakthrough, as they say, is just around the corner.

But nobody’s predicting just when we get to that corner.

© Jan TenBruggencate 2014

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