Thursday, August 13, 2009

Energy Storage is EASY

I was astounded by another article I saw this morning talking about the problem of storing energy that photovoltaics, wind-power, etc. all face. The article went on to talk about truly massive (city-sized) electrical batteries, ultracapacitors (which'll be great for cars) and other devices. For small-scale use, the problem remains, but for broad-scale power production where energy is only produced during the day, but the amounts of energy being produced are massive, why hasn't anyone thought of digging a big basement and almost filling it with a massive concrete block? When you need to store power, you lift the block up to ground level, and when you want to draw power, you lower it. If you want your power I/O to be very sharp-edged, you use a simple pulley (or massive rotating beam serving as a pulley); multiple pulleys can be rigged for any level of I/O you want. Now, granted, conversion back and forth from mechanical to electrical energy will have losses, but given the non-linear response to compressing a gas (not to mention keeping a pressurized cavern airtight), friction losses from flywheels, etc., it can't be that bad.

But what really gets me is that no-one's mentioned it before even though potential energy is part of high-school physics -- could it be that hard? Really?

9 comments:

boxingalcibiades said...

Look up "flywheel capacitors." Mechanical storage of energy IS being looked at.

JimDesu said...

That's cool, but different: that's storing energy in momentum -- I'm talking about storing it by conversion to potential.

But that is cool...

Russ said...

So you're talking giant screwed/threaded pistons?

Mike said...

That sounds interesting. Good point on the simplicity of it too. This could fall under the "Its so stupid its brillant" category. I'm not saying its stupid, but many times you have something so simple, so "DUH", that people assume that it couldn't possibly be that easy and therefor must be dumb (somehow).

The phrase actually comes from a response to the "mole" escape technique in WWII.

Anonymous said...

I often find that if you look hard enough you'll find that if you've had an idea, at least 2-3 other people have as well. The trick is then to find out who did what with the idea.
I think the potential drawback to your idea is that I think you would have to keep putting energy into the system to keep that big of a block "up" to maintain its potential energy to let out later. You'll be constantly fighting gravity and the friction/thermal losses from such energy conversion back and forth plus the maintenance of the potential energy strikes me as the weak link in the system.
But it's not a bad idea. I'm just thinking out loud in engineering terms and some other technical considerations I believe would need to be addressed before this was practical over battery and ultracapacitor approaches; the latter I'm working on a little bit.

JimDesu said...

Yes, because you're a smarty-pants; as for me, I'm at the technology level of lifting a big-ass rock. :)

Anonymous said...

Smarty-pants? Why I think that's a compliment.

Convivialdingo said...

Just pump the water back up the river.... LOL

JimDesu said...

Yeah, exactly!

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