The following list is not a direct comparison because the definition of renewable power varies by state. Comparisons may not be proportional. For instance, New York requires 24 percent renewables by 2013, including large hydropower generation, which currently accounts for 19 percent of power consumed in the state, while California's 20 percent standard by 2010 does not count large hydropower projects in place now. Large US hydropower projects are considered a mature source of energy and are not significantly expanding.
The following table shows states with renewable energy portfolio standards, compiled by the North Carolina State University's Solar Center.
| STATE |
STANDARD |
BY YEAR |
|
|
|
|
|
| Iowa |
105 megawatts |
1983 |
|
|
|
|
|
| Maine |
1% more annually to 10% by 2017 |
|
|
|
|
| Massachusetts |
4% |
2009 |
|
|
|
|
|
| California |
20% |
2010 |
|
|
|
|
|
| Connecticut |
10% |
2010 |
|
|
|
|
|
| New Mexico |
10% |
2011 |
|
|
|
|
|
| * Vermont |
10% |
2013 |
|
|
|
|
|
| New York |
24% |
2013 |
|
|
|
|
|
| * Illinois |
8% |
2013 |
|
|
|
|
|
| Nevada |
20% |
2015 |
|
|
|
|
|
| Montana |
15% |
2015 |
|
|
|
|
|
| Colorado |
10% |
2015 |
|
|
|
|
|
| Wisconsin |
10% |
2015 |
|
|
|
|
|
| Texas |
5,880 new MW by 2015 |
|
|
|
|
| Delaware |
10% |
2019 |
|
|
|
|
|
| Maryland |
7.50% |
2019 |
|
|
|
|
|
| Hawaii |
20% |
2020 |
|
|
|
|
|
| Pennsylvania |
18% |
2020 |
|
|
|
|
|
| Rhode Island |
15% |
2020 |
|
|
|
|
|
| Washington |
15% |
2020 |
|
|
|
|
|
| New Jersey |
22.50% |
2021 |
|
|
|
|
|
| Washington,D.C. |
11% |
2022 |
|
|
|
|
|
| Minnesota |
25% |
2025 |
|
|
|
|
|
| Arizona |
15% |
2025 |
|
* A renewable portfolio goal, which is voluntary, as opposed to a renewable portfolio standard, which is generally enforced by a state regulatory agency.
Maine has goal to increase the share of renewable power by 10 percent by 2017.
A megawatt, by US average, can power about 800 homes, but the number is lower for areas with high air-conditioning use, such as Arizona and Florida, where a megawatt can power about 400 homes.