The maps above, compiled with data from the US Energy Information Administration, document the growth of renewable energy over the last 10 years (without counting hydroelectric power). Yes, the darkening blue is thanks to widespread adoption of solar, wind, and, to a lesser extent, geothermal and biomass.
Those blue spots reveal some encouraging progress, especially when paired with news that coal-fired generation was down to a three decade-low in 2011. The southeast, however, has stayed mostly stagnant in terms of renewable energy production.
Nonetheless, there are some powerful success stories in there—particularly in states like Iowa and Texas, where there was scant clean energy before the 00s brought a boom in wind power. Indeed, wind accounted for the bulk of the growth in the renewable sector nationwide in the past decade.
And Maine, already a leader in renewables in 2001, now gets 27% of its power from renewables; the largest share in the nation.
Factor in hydro power, and the picture looks better yet:
So what drove the growth we see above? Smart policy, mostly—24 states, along with the District of Columbia, have enacted a renewable portfolio standard, which requires a certain percentage of electricity be generated from clean sources. Five more have non-binding renewable energy targets that guide policy. And as the EIA notes, "Federal production tax credits and grants also contributed to increases in renewable capacity and generation between 2001 and 2011."
Unfortunately, many of those production tax credits have either expired or face expiration, and some Republican governors are working to roll back the renewable energy standards that have driven the expansion.
Finally, it's worth noting that the pictured rate of growth will simply not be sufficient to reduce greenhouse gas emissions to the extent that scientists say is necessary to avoid the worst impacts of global warming. We're going to have to deploy wind, solar, and other alternatives at a much, much faster rate than the present—and those states are going to have to do a lot more than go navy blue if we're going to rein in carbon emissions to any meaningful effect.