Duke to study how high volume of renewables affects grid

Source: Kristi E. Swartz, E&E News reporter • Posted: Monday, March 4, 2019

CHAPEL HILL, N.C. — What happens to a large electric utility grid if half of the generation on it comes from renewable sources? That’s what Duke Energy Corp. aims to find out.

Charlotte, N.C.-based Duke is partnering with the National Renewable Energy Laboratory to learn how its grid would function if the amount of solar, wind, storage and other renewables was as high as 50 percent.

The utility giant wants to understand its system better, especially as it continues to add more solar to it, said Ken Jennings, Duke’s director of renewable strategy and policy.

“We’re going to look at multiple scenarios, multiple resource mixes,” Jennings said in an interview with reporters at the UNC Clean Tech Summit held here.

Duke hopes to complete Phase I of the study by July or August, Jennings said. Phase 2 will be finished next year.

The study will model a combination of renewable resources. Jennings said yesterday that he sees wind as a complementary resource for solar, and it will be key to the company having a carbon-free system by 2050.

Duke wants to cut carbon emissions by 40 percent from 2005 levels by 2030.

“It seems like the next step is 2050, what does that look like,” Jennings said.

Flat electricity demand and the falling cost of renewables continue to drive a nationwide industry shift away from large power plants toward more distributed energy sources.

The Southeast has lagged other states in adding wind and solar to the grid, but that is changing as those resources have become as cost-competitive as natural gas in some instances.

N.C. solar boom

North Carolina is an exception and ranks No. 2 in the country for solar development, largely because of how the state interprets a federal energy law known as the Public Utility Regulatory Policies Act.

The state is also the only one in the Southeast with renewable energy requirements.

Duke, which operates in the Carolinas, Florida and parts of the Midwest, has its own goals to shutter its remaining coal-fired power plants over the next three decades. What’s more, North Carolina Gov. Roy Cooper (D) reiterated his own plans for the Tar Heel State to cut carbon emissions 40 percent by 2025.

“It will boost our economy by creating more clean energy jobs,” Cooper said, addressing the Legislature on Monday night during an annual State of the State address.

The rapid growth of solar across North Carolina has created a wide range of challenges, a chief one being that much of the utility-scale growth has not been in densely populated areas where electricity demand is higher. Secondly, solar developers have been frustrated with the lag time in connecting their projects to the grid.

“We’ve got a lot of integration issues,” Jennings said after a panel discussion on solar and moving toward dispatchable power. “The more solar you get, the more upgrades you have, and the cost to upgrade continues to go up.”

The challenges rise with the more projects in the queue. What’s more, as the cost of storage continues to drop, the pressure is rising on Duke to incorporate that into the power grid more quickly.

Panelists said storage — either by itself or coupled with solar — is a key to electric companies getting intermittent renewable energy when they actually need it. The possibilities are more than just batteries.

“We have more than enough solar in North Carolina to power everything we do, how do we get it to where we actually need it?” said Joel Olsen, CEO of O2 EMC. Olsen gave an example of storing several weeks’ worth of solar during the summer and then using it during the winter during long stretches of dark and rainy days.

“It’s not shifting from one hour to another, it’s shifting from one season to another,” he said.

Duke is working on a new version of a robust, multibillion-dollar grid modernization plan. Previous drafts have hit roadblocks with the Legislature and state utilities’ commissions for various reasons.

The company also must give the North Carolina Utilities Commission plans for a range of customer rates that will align with a new “smart” grid and corresponding meters by April 1.

The steps are all part of overhauling a decades-old business model to correspond with an ever-changing power grid. The work becomes more challenging because some of the regulatory policies are decades old, as well.

“I don’t think the technology is the big challenge for us, it’s the market policy that drives the behaviors of the companies out there,” said Brian O’Hara, senior vice president for strategy and government affairs for Strata Solar LLC, based in Durham.

Developing better policies requires everyone to get in a room and work out the issues, he said.

“It cannot be an us versus them, ‘big, bad utility versus big bad solar,'” O’Hara told a packed room yesterday.