Wind and solar power are growing fast in Colorado. Wind capacity has quadrupled in the past 18 month and Xcel has become the largest provider of wind power in the US. Federal investment tax credits have helped to grow renewable energies.

In 2004, Colorado passed state law mandating 10% of electricity sales come from renewable sources by 2015. Xcel Energy met the requirement eight years ahead of schedule so government doubled the target, to 20 percent by 2020.

Colorado's aims to become a leader in clean, modern energy technology. Xcel Energy is a partner in the proposed Solar Technology Acceleration Centre, in Aurora, Colorado. It will be one of the world's largest solar test and evaluation facilities.