Those of us that grew up with the Back to the Future series of movies generally feel a little short-changed when it comes to the innovations promised and not delivered. But GM's doing its best to remedy that by teaming up with Coskata, Inc., a company that has found a way to turn garbage into ethanol. Looks like that Mr. Fusion garbage-powered generator isn't so far-fetched after all! And the best part: it turns out it's cost-effective, too.

Growing bacteria on trash sounds simple enough, although its surely more complex a process than it seems. The result is ethanol made from scrap tires, wood chips, foam, rubber - anything you'd find in your local garbage dump - that costs about half what corn ethanol costs to produce in the U.S. That could translate into prices at the pump as low as $2 per gallon (€0.77/L) - a serious savings over both corn ethanol and petroleum-derived fuels.

The fuel is not just cheaper, either - it's higher quality, so it burns cleaner, and the process is more efficient and environmentally friendly than corn ethanol production. Coskata's process requires less than one gallon of water to produce a gallon of ethanol, whereas corn ethanol production requires 3-4 gallons of water.

A pilot program will be operational by the end of 2008, with a plan for production to scale up to 100 million gallons annually by 2011.