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Aha. And that takes care of that pesky time component that I couldn't work out. Thanks. My neighbor had his house lifted to add another floor beneath it and it got me thinking: How much energy did it take to lift that house, and how much of it could you get back if it were to be lowered to its original position again? And could something like this be used as a decent mechanical battery? The answers, it seems, are "not that much" and "not really".

Thanks for the quick reply. Could you elaborate a bit further on the math? I am mostly trying to figure this out with the bare minimum of experience with physics. I looked up the definition of a Joule on wikipedia and the formula given was: 1J = 1Nm N = kg x m / s2 so J = kg x m2 / s2 (that was the time component that I didn't/don't get). In your formula, I don't understand what the term g represents. Also, why is U the term you use for Joules? What does that stand for? Sorry for all the basic questions but I have not had any physics since high school, and even that was a very long time ago. P.S. I would never think to disparage gravity. It's what keeps me grounded in my life

It appears that gravity is actually a pretty lousy mechanism for storing energy. Could someone check/correct my logic here? Assuming that an average house weighs about 110,000 kg (got this number from yahoo answers). This means that if you raised this house by 1 meter, you would be "storing" 110,000 Joules? (I get confused by the time element here). If that's the case, and if you were to allow the house to settle the 1 meter over the course of about 8 hours, you would get back roughly 30 Watt Hours during that time - or enough to power a single 100W bulb for the duration of the sinking house. That seems incredible to me. Did I do the calculations right? Just a thought experiment really. The idea of a house rising and sinking a full meter every day is absurd on the face of it anyway. Especially if the payback is so ludicrously small. Bet I'm not the first to consider the idea and not the first to be disappointed at the results.