Well there is a proven electric supercharger on the market now. It's made by a guy who's been in the turbo business for years. I think the website is www.boosthead.com. I've been thinking about looking into this for small kicks of power. It's not meant to replace the belt driven supercharger or turbos, instead it's meant to be used like nitrous. I agree, there is no free power, however you can store electrical power in hi capacity batteries. One's like the Hawker Odysee can unload quite a bit of current very quickly. IIRC, the electric supercharger utilizes an Eaton supercharger mounted to three electric starter moters via a proprietary plate. It's real science and it really works, you just can't drive it directly off of the alternator.