Thursday, April 03, 2008

Event Review: Electricity –Use it or Lose it?

On the first Tuesday of every month The Ballston Science and Technology Alliance hosts Café Scientifique. It's a talk about some scientific point of interest. This week they had Dr. Imre Gyuk from the Department of Energy talk about energy storage systems.

The talk started with a history of energy storage and generation systems. Starting with a pot to hold grain through today. There was an interesting battery of sorts found in Baghdad dating from between 200BC and 250AD. The best anyone can figure is that they used it for electro plating.

Things got more interesting when he started talking about huge batteries for storing energy.
In electronics you can use capacitors to smooth out irregularities.
For smoothing out quick rapid spikes in power consumption the cycles of the electrical system can be slowed from 60 cycles per second to something less. A cycle refers to how often the power reverses directions in an Alternating Current (AC) supply.
For larger spikes, like a clumsy squirrel on the power lines, you can get a UPC for your computer or a massive battery in the case of a whole building. This is used more in factories where that hiccup can cause the system to gum up and require several hours to clean and restart.
For whole towns there's hefty multi-megawatt batteries that are sometimes installed along side the older power relay stations. This is for when the town is growing faster than transmission capacity. You don't want to wait through 3 years of brownouts while another relay station gets built.
In huge cases, like Fairbanks, Alaska, the power is all sent several hundred miles from Anchorage. With all the towns and the distance between points A and B power in Fairbanks is pretty iffy. So they installed the world's biggest battery (40 MW I think) to keep things on more of an even keel.

What the speaker was proposing was that more of these sort of systems get built. As demand in the mornings and evenings is greater than the middle of the night these batteries could be charged at night, during the 25% lowest demand, and used during the day, during the 25% greatest demand. Individual factories could save money by storing the night power for use during the peak hours. But whole cities could also benefit. And, of course, this would solve the common complaint that solar power doesn't work at night and wind power doesn't work when it's still.

For $1 million dollars I can get a 1MW wind turbine at the farm. For $1 million more I can get a 1 MW battery so that it generates electricity at a constant rate all day long. Do you have $2 million I can borrow?

Then there's other storage systems. We can use extra power to pump water behind a dam and then use it to run turbines when the demand is greater. Or pump air into an underground reservoir and then let the pressure drive turbines.

The purpose for all this is to make renewable energy more useful as well as make our power grid more reliable. In the age of computers power flow can't take even little twinges.

Me? I want to build a 20 story dippy bird drinking from a lake. Just harness the power of the liquid running up and down the neck and put a generator on the pivot point.

If you want to get on the mailing list for future Cafe events I'd suggest e-mailing kbreen at arlingtonva dot us. I don't think that's how I did it, but it's the best idea I can find at the moment.

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