PG&E Wants DOE Dollars for Underground Air Energy Storage

By Jeff St. John

Pacific Gas & Electric (PCG) will seek $25 million in Department of Energy stimulus funds to help pump lots of air underground, then release it to help generate cheap electricity at peak demand times.

That's the plan the utility outlined on its Next100 blog on Wednesday for a 300-megawatt energy storage project in western Kern County. It's the second publicly announced utility project seeking funds for grid-sized energy storage from DOE's $615 million smart grid demonstration grant program, which sees its first application deadline expire today.

PG&E envisions using cheaper electricity – mostly from wind turbines – to pump air into an underground reservoir when electricity is cheap. The compressed air can then be released to boost a gas turbine, helping to generate up to 300 megawatts of stored energy for up to 10 hours.

Such systems have some drawbacks compared to batteries, including the limited availability of underground caverns or geologic structures to store the air, as well as its limitation to boosting natural gas-fired generation rather than providing power directly.

Fellow utility Southern California Edison said Tuesday that it would seek $25 million in smart grid demonstration grant funds to install a 32-megawatt-hour lithium-ion battery, to be built by A123 Systems (AONE), to help incorporate more wind energy into its grid (see SoCal Edison Wants A123's Biggest Grid Battery Ever).

Utilities including American Electric Power (AEP), Xcel Energy (XEL) and Tokyo Electric Power Co. have installed megawatts of sodium sulfur batteries for grid storage, and General Electric (GE) is among the companies working on improving grid battery technologies to bring down costs (see GE Aims at Energy Storage for Trains, Grid).

But batteries – whether the more expensive lithium ion or cheaper sodium sulfur and flow batteries – are still far more expensive than compressed air energy storage, or CAES (see What Is the Cheapest Energy Storage Idea of Them All?).

In fact, according to the Electric Power Research Institute, it's among the cheapest, besides pumping water uphill and letting it flow to spin a turbine – another technology limited by the availability of water and reservoirs to hold it. PG&E's Helms Pumped Storage Facility is one such "pumped hydro" storage project.

Still, backers of grid batteries – as well as systems like flywheels and fuel cells – say they could lower prices as more systems get deployed (see Batteries for the Grid and GridPoint to Manage Wind Power Battery Storage).

It's led some market watchers to predict a big boom in the grid storage market in the years to come (see Grid Storage Batteries and Ultracaps: An $8.3B Market by 2016).

But so far, most of the smart grid stimulus applications have shied away from storage as a focus, looking instead to accelerate smart meter deployments or grid automation and control systems (see Green Light post).

Beyond stimulus funding, a bill proposed by Sen. Ron Wyden (D.-Ore.) could offer grid storage some tax incentives equivalent to those now enjoyed by solar and wind power investors (see Energy Bill Could Boost Storage Technologies).

PG&E is also asking the DOE for $42.5 million to install energy monitoring and control systems at about 75,000 of its commercial and industrial customers. The request is for DOE's $3.4 billion smart grid investment grant program, which is aimed at commercial-scale projects (see PG&E Seeks $42.5M in Stimulus Grants).

Comments

[john s. gordon:]

there has been significant use of CAES in europe.
> jack

Aug 28 11:04 AM

[samirsamir:]

There was one CAES plant built in Germany in 1978, but that is the only full-scale system installed to date (a few demonstration systems were built but are no longer in operation). Europe does have extensive experience with bulk storage in the form of pumped hydro however.

I looked at some of the issues around wind and storage on my blog yesterday

switchboard.nrdc.org/b...

I also published an in-depth report last year looking at CAES specifically

www.princeton.edu/~ssuccar/caesReport.html

Aug 28 01:00 PM

[crtoca:]

How can you say that CAES is less expensive than advanced batteries? Have you included the cost of fuel for CAES? Remember, the compressed air is used to run natural gas turbines. And what about the efficiency loss? Compressors take wind power and force it into the ground - requiring energy. How many btu's are burned to run the compressor and natural gas turbines? Subtract that from the wind energy. And include the transformer losses at the facility. And have you included O&M costs to run the compressor and gas turbines? There are "2" CAES projects in the world and experts can say with authority that CAES is cheaper - on what volume of data?

I work with an advanced energy storage system, the vanadium redox flow battery, and I know the costs, I know the efficiencies, I know that I can build one within 12 months without major political turmoil. Give me the 10 years it will take for the Iowa project and I can have more than 300 MW at distributed locations where the energy is needed, without more transmission lines. And, the distributed batteries will provide back-up power, grid security, improved power quality, savings in distribution upgrades and demand response - what is the value for that? The PG&E CAES project is just another opportunity to spend lots of ratepayer money on a huge R&D project with uncertain political and environmental problems that may never get built.

More information on the vanadium redox flow battery - VRB-ESS - is at Utility-Savings.com.

Aug 28 01:34 PM

[flipdog1:]

Lets see here boys.
California is not allowing drilling for oil or gas.
Soon,refiners will be history and huge gas and petroleum pipelines will be idle.
Rent the pipe lines and fill them with air.
A permit to build anything will take years anyway.
Saves a lot of CO2 pollution.
(I hope you see the humor in this)

Aug 29 08:39 AM