How much water does pasta really need?

An article in the New York Times today talks about cooking pasta in less water, thus saving both water and energy...

"After some experiments, I’ve found that we can indeed make pasta in just a few cups of water and save a good deal of energy. Not that much in your kitchen or mine — just the amount needed to keep a burner on high for a few more minutes. But Americans cook something like a billion pounds of pasta a year, so those minutes could add up."