We now have more insights into how the clean-tech economy is doing from this year's sixth annual US Clean Tech Leadership Index. The index, prepared by Clean Edge, a research and indexing firm founded in 2000, tracks and ranks clean-tech activities in all 50 states and the largest 50 metro areas in the US. It provides a powerful tool for regional comparative research, aggregating industry data, and deep, data-driven analysis of the American clean-energy market.

"The United States has seen a significant shift in its energy landscape since Clean Edge began publishing its clean tech leadership index five years ago," the report states.

"The transition to a clean tech and energy efficiency-based economy, based on the many indicators we track, is well underway. Solar and wind power, along with natural gas and energy efficiency, are now the mainstream choices for meeting the nation's electricity needs; coal-fired and nuclear power, the dominant choices of the 20th century, have become the marginalized 'alternatives.'"

Organizational structures of state and city indexes are shown here. More than 100 indicators comprise the entire index, which contains approximately 17,000 data cells. For a free downloadable summary report, click here. (Complete datasets are only available to Index subscribers.)

Key report findings:

Last year, utility-scale wind power (27%) and solar power (20%) combined to make up nearly half (47%)  of new U.S. generation capacity.

Eleven states now generate more than 10% of their electricity from non-hydro renewable energy sources.  In three of these states—Iowa, South Dakota, and Kansas—the proportion exceeds 20%.

Including hydropower and biomass use, four states—Idaho, Washington, Oregon, and South Dakota—now exceed 70% generation from renewables.

Last year, utility-scale solar began to take hold, with California deriving a full 5% of its electricity from utility solar plants.