However, the distribution of wind power across states varied greatly, with some states well ahead of others.

The American Wind Energy Association (AEWA) said that figures from the Department of Energy's Energy Information Administration showed that wind power exceeded 25% of total electricity production in Iowa and South Dakota, while other states still have no installed capacity.

Over the past five years, wind power installations accounted for 30% of all new capacity added in the US, AWEA said.

Texas, the state with the largest installed wind capacity, generated the most electricity from wind energy, with more than 35.9 million megawatt hours fed into the grid.

After a lean year in 2013, with only 1.1GW installed, the wind energy industry started 2014 with a record 12GW of wind capacity under construction.

ST. PAUL, Minn. -- This year's solar energy incentive program is over-subscribed, providing more evidence of the state's strong interest in expanding solar energy, state Commerce Commissioner Mike Rothman said Friday.

The Made in Minnesota incentive program helps homeowners and businesses install solar energy systems manufactured in the state. The Legislature set up the program last year and established a $15 million annual budget for the next 10 years, funded by Minnesota's utilities.

Rothman said more people have signed up than what the program can support. Applications that the department received in January and February will be selected by lottery.

"It's a phenomenal success," Rothman told those gathered at the Solar Powering Minnesota  conference in St. Paul. "It just shows the increasing demand and sort of what's at the ready."

The solar incentive program is one piece of a new law that also requires large utilities to produce 1.5 percent of their electricity using solar by 2020. The state's overall goal is 10 percent by 2030.

Those are goals Minnesota is in a good position to reach, said Minh Le, director of the U.S. Department of Energy's solar technologies office.

"When I look out the window today it's overcast, but I'm often reminded that even though this is the northernmost state in the continental United States, you boast more sunlight than the country of Germany," he said. "Germany has installed more solar in the past decade than any other country in the world."

Le said the cost of solar energy to the consumer has dropped 40 percent in just a year, and he noted that Minnesota's solar industry has added hundreds of jobs in the past year.

Despite strong policies and dropping prices for the technology, Le says it will still be a challenge to integrate solar into an aging grid.

"Our nation's grid was designed 200 years ago," he said. Our grid "is straining under some of these technologies. But that doesn't mean it can't be done."

Le also said cities, states and other jurisdictions need to be more uniform in their approach to permitting solar electric systems for homeowners and businesses.

"More paperwork means higher costs, and there's no reason for that. We can reduce those costs," he said.

Solar by the numbers

4.7: The number of gigawatts of solar energy installed in the U.S. in 2013. That's 10 times more than were installed in 2009 and 15 times more than were installed in 2008.

142,000: The number of people in the U.S. working in the solar energy sector. Job growth in the industry has been 10 times faster than the overall economy.

73: The percentage growth in the past year of solar energy jobs in Minnesota. More than 1,000 in the state now work in the solar industry.

31: Minnesota's rank among the states for number of jobs in the solar sector. "It's sure to climb," Le said.

45: The number of gigawatts of solar energy to be sold globally this year.

75: The percentage by which the U.S. Department of Energy wants to reduce the cost of solar by the end of this decade.

$1.50: How much the U.S. Department of Energy wants one watt of solar-produced electricity to cost by 2020.

18,000: The number of jurisdictions in the U.S. that can permit electric systems. Le said they all have different rules and regulations when it comes to permitting solar systems, which can increase the cost.

99: The percent by which the cost of solar panels has dropped in 35 years.