The Big Missing Piece to the Wind-Solar Puzzle Is...

A massive energy storage system that can guarantee uninterrupted power delivery.

Meaning: clean electricity all the time, even when the winds aren’t blowing and the sun isn’t shining.

And now there’s a battery unit being produced in Japan that claims it can provide just that.

They’re called sodium-sulfur systems. And they offer a way to store power from the sun and wind, and then dispatch it to the grid when demand is greatest.

It's welcome news if they can pull it off. Because without that missing piece, solar and wind will continue to play second fiddle to fossil fuels.

Bloomberg has the full story on the sodium-sulfur batteries -- and their Japanese maker too, NGK Insulators Ltd.

In Japan, the NAS storage units -- as NGK calls them -- have been a hit. They're used at over 30 sites already, totaling 28 megawatts. But in the US they're still an anomaly with just two customers.

American Electric Company is one of them. The coal giant has been testing a 1.2 megawatt NAS system since mid-2006 but not in connection with renewables at all. And Xcel Energy is the other.

It will be the first American utility to use NAS for wind energy storage beginning in October, when it starts testing a one-megawatt system in Minnesota.

The demo site will sit adjacent to an 11-megawatt wind farm and be able to power 500 homes for around 7 hours. When the wind blows, the batteries will get charged. And when the wind dies down, the batteries will be used to feed energy to the grid.

Dick Kelly, Xcel Energy chairman, president and CEO explains why he chose NAS:

Energy storage is key to expanding the use of renewable energy. This technology has the potential to reduce the impact caused by the variability and limited predictability of wind energy generation.

He's right about energy storage. And NGK would be happy with his pitch. They think their technology can give wind energy an entree into the electric power big league.

But NGK is small potatoes in the US. And at least one publication -- the Energy Tribune -- sees it going nowhere fast, as explained in this piece. The article gives the NSK technology a big thumbs down. Too bulky, too expensive, and too hot -- literally -- since the systems run at temperatures over 500 degrees. The author’s solution?

I suggest that we offer $1 billion to the inventor of a super-high-capacity system that is compact, affordable, and capable of storing multiple kilowatt-hours of electricity. Offer $10 billion to the inventor of a system with all of those attributes that can store multiple megawatt-hours of electricity.

The prize money and judging for The Super Battery Prize could be provided by the Department of Energy, or better yet, by a group of private foundations.

Not a bad idea. Especially given the uniform belief of many experts that electricity storage is the #1 Achilles heel of the renewable energy industry, as the American Institute of Chemical Engineers (AIChE) put it in this useful policy brief (pdf).

Take solar.

AIChE explains that to compete with fossil fuels as a primary source of continuous power, solar will need a massive electricity storage system (MES). It argues for 100 gigawatts, or 100,000 megawatts, of storage capacity, at minimum. That's about 10% of the total installed capacity of the US grid, which stands at 1,076 gigawatts.

And without MES, solar simply can't be a baseload provider. Apparently, that’s been a point lost on many, argues AIChE:

The public understanding and perception of solar power seems to be that, to displace fossil and other fuels in power generation, all that is needed for renewable sources to be the principal supplier is to install more wind farms, solar cells, or thermal conversion systems. Such perception is incomplete and oversimplified, and must be remedied.

And it’s not just the public who's failed to "get it." It's the DOE too.

AIChE reports that the agency is spending a piddly $2 million a year on energy storage technologies. That could change though, and rather soon.

The energy bill signed by the president into law in December 2007 includes a title on "Energy Storage and Competitiveness." It earmarks tens of millions of dollars a year for ten years for developing energy storage.

But it’s a mere authorization of funding, not the real thing. And unless those dollars begin to flow, America will be putting the cart before the horse.

Why?

Because R&D funding is being poured into improving the conversion efficiency of solar energy -- and other sources -- into electricity. And that's great. But it could be for naught if we haven't a clue how to dispatch the power for utility-scale use.

Best to flesh out the big missing piece of energy storage right now, before we get even further behind the renewable energy curve.

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