Some power generation facilities store energy during peak hours to later use during off peak hours (and vice versa). The best example of this is battery storage of energy from wind and solar generators. Wind and sun generate most of their power during the day, and in the case of solar, there is no energy generated in the evening. An example of how this process works both ways is in the case of hydroelectric power generation when water is pumped to higher elevations during off-peak hours. During peak hours the water pumped up is released, and extra power is available. This method is called “pumped storage.”
These processes result in some energy loss, but proponents say the cost to generate the electricity is minimal, so why not? For a small hit in efficiency, you get clean, carbon neutral power around the clock. For the most part, I agree. Wind, sun and water are in high abundance for power generation, and not an ounce of carbon is produced (though the added wear and tear on equipment eventually leads to shorter life spans, higher maintenance costs, etc…) This leads to more manufacturing and likely more carbon emissions. Regardless, these methods are all far better than popping up a new coal plant.
Now, add a “new” tool to the tool box. Compressed Air Energy Storage (“CAES”). I guess it’s been around for a while in Germany and Alabama, so it’s not so “new.” But it is possibly new to California! An article from the San Francisco Chronicle on August 27, 2009 details how PG&E is seeking a federal grant of $25 Million to design a facility in Kern County, CA using CAES. Kern County is about half-way between LA and San Francisco. The facility would use power generated by solar and wind to pump air into porous rock reservoirs.
Then, at night when the sun’s gone, or on a day when the wind won’t blow, the compressed air is released and generates electricity. The plant PG&E would like to see would provide 300 MW for 10 hours…that’s enough to power 750 homes.
The total cost of the facility would be about $300 Million over five years. That may seem like a lot, but when you realize that once it’s up and running there are no added costs for fuel, it starts to make sense.
By 2010, PG&E needs to generate 20% of it’s power from renewables. They’re not going to make it, but with efforts like this and the recent deal with BrightSource Energy (full disclaimer, BrightSource is a client of Bell, Rosenberg & Hughes, the workplace for the authors of this blog), no one can say PG&E isn’t trying. According to a recent article in the Sacramento Business Journal, Peter Darbee, CEO and Chairman of PG&E stated PG&E has contracts that will allow the utility to deliver up to 24 percent of its energy from renewable sources by 2013.
CAES doesn’t sound ideal, but creativity like this can only lead to better things. Also, with a carbon credit market likely around the corner, facilities like this may generate unforeseen dividends.
For the San Francisco Chronicle article that includes a great illustration of CAES, click here
For the Sacramento Business Times Article, click here
Steve Sacks
