The cost of wind and solar power have fallen dramatically in recent years. Still, renewables only account for a fraction of the energy produced in the United States.

That is one of the challenges facing the new director of the National Renewable Energy Laboratory in Golden. Martin Keller took over following the retirement of Dan Arvizu late last year. Keller comes to NREL from the Oak Ridge National Lab in Tennessee, where he served as Associate Laboratory Director for Energy and Environmental Sciences.

Keller, who originally hails from Germany, sat down recently to discuss his new job.

Here are a few takeaways from the interview:

• A lot more innovation is needed if we’re ever going to get most of our electricity from renewables.

Keller describes the mission of the nation’s premier renewables research laboratory as one of filling in the innovation gaps in science and technology. Using wind energy as an example, he said much bigger towers and longer blades are needed to take advantage of wind resources in Southern states. These towers and blades would be too large to be transported, and would thus need to be manufactured on site.

“There is no technology out there, you cannot do this right now. This is where innovation comes in,” Keller said.

• Partnering with the private sector is critical.

The U.S. has a strong reputation as the world’s innovation leader in renewables, Keller said, owing to the country’s deep foundation in science through universities and the national lab system.

“Coupling this with U.S. companies gives the U.S. a tremendous edge,” he added.

• Storage and transmission remain two of the biggest hurdles.

The sun isn’t always shining and the wind isn’t always blowing. This intermittency has long been a principle argument against the wider expansion of these distributed energy sources. Despite the excitement generated by the announcement of Tesla’s Powerwall, battery technology has been very slow to advance.

“There are these two elements,” Keller said: “Number one is storage, number two is also the distribution system.”

Many of the country’s best renewable resources – take Wyoming’s wind – are located far from the largest populations in places like California. Working through the complex and often-controversial process of stringing high voltage transmission lines hundreds of miles, across many different property designations, can take decades.

• Scientists must do a better job explaining the science behind climate change.

NREL is a federal facility, owned by the Department of Energy. Its money comes from Congress, where polarized opinions on human-caused climate change are the order of the day. Keller lamented that climate change is too often talked about in terms of whether someone “believes” in it or not, which pushes it out of the realm of science and into a sort of religion.

“We are not creating religions, we are creating science and engineering,” he said. “On climate change, on the renewables side, we as scientists have to do a better job to explain what the driver is for the science and engineering that we’re doing.”

Inside Energy is a collaborative journalism initiative among public media with roots in Colorado, Wyoming and North Dakota.