Storing sun and wind power

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An initial CAES facility in Alabama is using the stored compressed air in conjunction with a traditional natural gas turbine. Gas turbines use about two-thirds of their fuel to compress air, according to the Electricity Storage Association. The CAES system pre-compresses the air, making the turbines more efficient.

A similar system is being tested at the Iowa Stored Energy Park, where a group of municipally owned utilities intend to store compressed air in porous sandstone. It will be released, as needed, to help turn a traditional gas turbine.

The Iowa project is expected to cost $200 million and operate by 2011 with the capacity to store 200 megawatts of power, enough for several days.

Both the Iowa and Alabama installations can draw air to make power within 15 minutes and make a gas turbine roughly 40 percent more efficient.

General Compression's plan is to combine underground storage with on-turbine air compression. Its product designs call for an air compressor to be built into the nacelle of the turbine, the container behind the blades at the top of the tower.

Rather than feed the air to a traditional gas turbine to make electricity, General Compression envisions using another device called an expander, which, when combined with heat, will be able to generate power.

The company plans to make a 1.5-megawatt "dispatchable wind turbine" the size of turbines typically used in large wind farms. It intends to have prototype systems operating in 2010 and commercial products by 2012, according to David Marcus, who spoke at the Conference on Clean Energy in Boston last month.

One obvious restraint on CAES is available geological formations to store the compressed air. But Marcus said there are enough locations, such as depleted gas fields in Texas, to last for several years. Wind farms could be located directly above underground storage or, potentially, the compressed air could be sent through existing natural gas pipelines.

"(CAES) is probably the most viable, large-scale energy storage potential on the market right now," Corey said. "It's looking really attractive because the volume of storage is definitely available already. There are a lot of salt domes that will handle 300 psi (pounds per inch) of compressed air."

Industrial-size batteries
In the absence of underground storage to provide on-demand renewable energy, truck-size battery packs can do the trick.

Smart Storage Pty of Australia is seeking to combine the high-energy density of a supercapacitor with well-understood lead-acid batteries to make a single unit capable of storing large amounts of electricity.

The company claims that its batteries will be able to charge up to 50 percent more power and will last three times longer than other lead-acid batteries. Cleantech Ventures chose to invest in the company because the technology can be commercialized relatively easily.

"Our technology development path is directed towards manufacturing in existing lead-acid battery plants," Andrew Pickering, a principal at Cleantech Ventures, said in a statement.

VRB Power Systems has been testing its "flow battery" for several years with utilities in the U.S., Ireland, and Australia, where its batteries have been used to shore up wind power.

The company's vanadium-based batteries use two tanks of an electrolyte, which flows over a stack of fuel cells to generate electricity. The system is capable of storing hours or even days of power and can last longer than traditional lead-acid batteries, it says.

Ohio-based utility American earlier this year said it is purchasing sodium sulfur (NAS) batteries from NGK Insulators of Japan. One of these multi-megawatt batteries--part of a plan to install 25 megawatts of storage this decade at the utility--will be attached to a wind farm next year.

[WheelerCub]

Testing

Testing the system to ensure it works.

[kadsanat]

cool

[suyts2]

This is some promising news.

I like the compressed air idea but it doesn't tell us about the energy trade-off so we don't really know if it is worth it or not. Batteries, 50% more or not, still aren't the answer. One loses so much in the power conversion that I'm not sure that we wouldn't have to have a wind turbine or solar panel every square mile in the US. I'm sure, sooner or later, someone will come up with the proper way to store AC power, until then, we are stuck with the traditional power sources. Coal, gas, and now atomic.

[frflyer]

We aren't stuck with coal gas nukes

Solar power plant companies already have other ways of storing power. Some use hot water or oil, while the most effective seems to be molten salt. The compressed air in caverns idea is the one in a proposal to convert the U.S. electric grid to 69% solar by 2050 using solar thermal and concentrating PV power plants in the southwest U.S.

Scientific American A Solar Grand Plan
http://www.sciam.com/article.cfm?id=a-solar-grand-plan

Green Wombat has a bunch of articles about progress in California with solar thermal power plants.

http://blogs.business2.com/greenwombat/

Wind and solar complement each other. Wind is stronger generally at night, while solar obviously works only in daytime. Solar is strong during peak hours.

Using 1% of our southwest deserts with solar power plants would power the whole country.
1% of the Sahara Desert would power the whole world. Here's what Ausra, a solar thermal company says:

"Solar thermal power plants such as Ausra's generate electricity by driving steam turbines with sunshine. Ausra's solar concentrators boil water with focused sunlight, and produce electricity at prices directly competitive with gas- and coal-fired electric power."

"Solar is one the most land-efficient sources of clean power we have, using a fraction of the area needed by hydro or wind projects of comparable output. All of America's needs for electric power ? the entire US grid, night and day ? can be generated with Ausra's current technology using a square parcel of land 92 miles on a side. For comparison, this is less than 1% of America's deserts, less land than currently in use in the U.S. for coal mines."

There is an enormous amount of dis-information out there, trying to convince us that alternative energy can't do the job. Don't believe it.

Besides wind and solar there is a big potential with biomass to methane like Environmental Power Corp is doing.

"Wild Rose Dairy in Webster Township, WI is home to an innovative renewable energy facility powered by cow manure and other organic waste. The farm is home to 900 dairy cows, and an on-site anaerobic digester creates methane-rich biogas from their waste, which is used to generate 750 kilowatts of electricity per hour?enough to power 600 local homes 24/7."

"Environmental Power?s Huckabay Ridge is the largest renewable natural gas plant in North America, if not the world. Huckabay Ridge generates methane-rich biogas from manure and other agricultural waste, conditions it to natural gas standards and distributes it through a commercial pipeline. The purified biogas, called RNG®, is generated by Environmental Power?s subsidiary, Microgy, and is a branded, renewable, pipeline quality methane product."

All the existing forms of energy get bigger subsidies than alternative clean energy, so don't be fooled by arguments about subsidizing them.
Nukes, coal, gas and oil are heavily subsidized.
In the case of oil hugely subsidized.

[parolespedia]

Will be

Will be that true?
It's nice but who knows...
Paroles - http://www.parolespedia.com/paroles/r/ray-price/index.php
Pedia - http://www.parolespedia.com/paroles/r/roger-daltrey/index.php

[c|net Reader]

Geological Stresses

I don't like the sound of the underground compressed air storage. What happens when the pressure increases underground to store energy and then the air is bled off to use the energy later? Any time you push against a rock and release the force, something gives, even if only a tiny amount. Now repeat that process hundreds or thousands of times. The result will be underground collapses. Would you want such things occurring beneath your house or office?

[oxtail01]

More like hot air

Nothing innovative here. Just another take on storing energy for later use much like water pump storage but with very low practicality. Imagine the volume of compressed air need to generate any meaningful MW of electricity.

[frflyer]

Hot air?

The people who drew up a proposal to convert the U.S. grid to 69% solar by 2050 seem to think the compressed air in caverns idea is viable.

Scientific American A Solar Grand Plan
http://www.sciam.com/article.cfm?id=a-solar-grand-plan

http://blogs.business2.com/greenwombat/
Green Wombat has several articles on current progress with solar thermal in California. Just scroll down to see all the stories.

[wylde brumby]

storage of the aeolian kinetic as hydro potential

The neighbourhood generation and storage system I call "Aeolian Hydro" uses a vertical wind turbine attached to an Archimedes screw to lift water into a storage cistern.

The storage cistern can release water to power microhydro generation when there is an unmet requirement for power.

This would convert intermittent wind energy into reliable microhydro power to provide energy when the sun isn't available.