New routes to compressed air storage

Enough Northwest US wind energy to power about 85,000 homes each month could be stored in porous rocks deep underground for later use, according to a new study. Researchers at the Department of Energy’s Pacific Northwest National Laboratory and Bonneville Power Administration have identified two unique methods for this energy storage approach, and two eastern Washington locations to put them into practice.

The world’s two existing compressed air energy storage plants (one in Alabama, the other in Germany) use man-made salt caverns to store excess electricity. The study examined a different approach: using natural, porous rock reservoirs that are deep underground to store renewable energy. Analysis identified two particularly promising locations in eastern Washington.

One could access a nearby natural gas pipeline, making it a good fit for a conventional compressed air energy facility. The other, however, doesn’t have easy access to natural gas. So the research team devised a hybrid facility would extract geothermal heat from deep underground to power a chiller that would cool the facility’s air compressors, making them more efficient. Geothermal energy would re-heat the air as it returns to the surface.

Compressed air energy storage – for cars

We’ve all heard of CAES (compressed air energy storage). Normally, the expression brings grid-scale operations involving vast underground caverns to mind or, at the very least, a substantial plant such as LightSail’s headline-making design. But French automaker PSA, owner of both Peugeot and Citroen, thinks CAES can be used as a replacement for battery power in hybrid vehicles.

The proposed vehicle would have a conventional petrol engine, paired with a hydraulic motor, driven by air from a high-pressure tank and which would come into play during low speed urban driving. The first prototype is slated for 2016, with a combined economy of 117 mpg.

But this is not the first time that compressed air has been suggested for running vehicles. As an example, Tata’s MiniCAT (Compressed Air Technology) is a very lightweight car that was scheduled to flood the streets of India in the summer of 2011, then at the end of last year – and now this. It remains to be seen if France’s air-powered car will share the same fate.

More good funding news for compressed air

General Compression has secured a USD$60 million investment which will partly go towards funding the company’s first grid-scale energy storage demonstration project, reports Recharge News. The 2MW compressed air energy storage (CAES) project, which is already underway in Texas, is aimed at storing surplus energy generated from wind power and is being backed by ConcoPhillips Company.

General Compression has also secured investment from Northwater Intellectual Property Funds, US Renewables Group, Duke Energy, Serious Change and the Wellford Energy Group.

Bill Gates and Peter Thiel back energy storage

If you search for “energy storage” on Twitter you can count on a good dozen or so tweets being published every hour. But if you were online last night, you would have been getting several a minute.

The reason? Bill Gates and Peter Thiel (the co-founder of PayPal and the first outside investor smart enough to put money into Facebook) are putting USD$37.3 million into LightSail Energy, a three-year-old start-up helmed by Princeton graduate school dropout Danielle Fong, who could not attract government investment for the project.

The news was hot. Links to articles in the New York TimesWall Street Journal and Forbes were being posted left right and centre. LightSail has a variation on compressed air energy storage that overcomes several problems associated with the technology, particularly the fact that heat generated during compression is captured and not wasted, unlike with other systems.

In comments posted on a Wall Street Journalblog, Fong claims that the final product will be around 70% efficient. The investment is good news for energy storage, of course. But the high-profile nature of the investors is even better news. As well as generating a lot of short-term buzz, it could go some way from exorcising the ghost of solar firm Solyndra, which got through a billion dollars of investors’ money, as well as $500 million in public funds, before going under.

As we reported only last week, venture capital (VC) investors seem to have developed a real phobia about energy storage over the last 12 months. With Gates and Thiel on board, perhaps the VCs could fall in love with energy storage all over again.

Iberdrola’s NYSEG drops US CAES project

NYSEG, a subsidiary of Iberdrola USA, has told the US Department of Energy it will not move forward with a compressed air energy storage (CAES) project in the Town of Reading, Schuyler County. A number of site-specific issues, including the cost of site development, and energy market conditions, including the effects of inexpensive natural gas-fired generation on market prices, made the project uneconomical, NYSEG said.

PG&E wins CAES research grant

In the last issue of Energy Storage Report, we ran a story about Pacific Gas and Electric Company (PG&E) of California issuing an energy storage request for information (RFI), which we interpreted as the company dipping its toe into the energy storage pool. Well, it looks like we were right.The California Energy Commission (CEC) has announced that it has awarded PG&E a US$1m grant to demonstrate a compressed air energy storage (CAES) plant. San Francisco-based PG&E is planning to compress air into depleted natural gas reservoirs using excess wind energy. The air would then be released through a turbine to generate electricity for the grid, as required.The idea is that, should the results be promising, the CEC would sign up to a proportion of a further $50m needed to help see the project through to completion, with the remaining balance of the $50m provided by the US Department of Energy and other sources.

Underwater compressed air energy storage first for Canada

Working with the energy company Hydrostor, a team at the University of Windsor, Ontario, has been testing a unique CAES system that stores compressed 50 – 500 meters below the water’s surface in high-strength polyester bags when power supply outstrips demand.

When the grid demand increases, the weight of the water itself pushes the air back to the surface where it is then run through Hydrostor’s expander/generator system to generate the required electricity.

The team has already tested scale models of their system in the university’s swimming pool, plus a full-sized system in Lake Ontario. It is hoped that a commercial system could be online by the latter part of 2013.