Wednesday, January 9, 2008

Energy Storage

Today I read about energy all day.  I was thinking about potential and kinetic energy a lot while on the bike Monday, and today I was reviewing energy.  As you may know, energy storage is a big problem today.  It's one area that has only improved slightly while most others have had explosive growth.  Chemical batteries aren't going to be improved much, we need to find a new technology, but so far fuel cells have only minor success.

One really interesting form of power generation (not really storage, but technically and effectively it is [odd that it would be technically and effectively true, yet not really in common usage]), is radioisotope thermoelectric generator (RTG).  Since I never know what to assume you know, my policy is just to review everything.  RTGs use a little chunk of radioactive material, and as it decays uses the heat it generates to create power.  Pretty simple really, and they have great qualities.  They are often used for space exploration.  They have a high power/size ratio, run practically forever, and are very low maintenance.  They are pretty much the promised nuclear batteries that run forever.  Since people are terrified of the word nuclear you'll only find them in the most exotic of applications.

Another form of storage though, that I had only slightly herd of before (mainly from Slashdot talking about it in UPS in data centers) is the flywheel energy storage (FES).  These are also pretty simple, yet have some interesting qualities.  It's just a wheel that spins very fast, and when you need power you use the spinning motion to power a generator.  At first this would seem absurd, but they work quite well.  They run in a vacuum with magnetic bearings so there is virtually no friction, the article claims they can hold a charge (keep spinning) for years.  It also claims they are over 90% efficient (the power you get out is 90% what it takes to spin it up). Also they are very low weight (for the amount of energy stored), long life, low maintenance, no memory effect, and they can be charged up are drained very fast (which is a big problem in chemical batteries).

I suppose there are some downsides, something about a metal wheel spinning over 50k rpm in your laptop (sitting on your genitals) could be frowned upon.

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