First "Nutrition" Label for Energy

A new California state law requires energy service providers to disclose the source of their power to help Californians choose an energy supplier. The "power content label" will be sent to customers along with quarterly information from electric service providers. The label indicates the energy sources used by their provider and compares them with the generic California system power mix. For Californians who choose to purchase green power, the label adds a strong measure of confidence that their energy dollars are flowing to renewable resources.
http://www.energy.ca.gov/consumer/power_content_label.html