Experts say President Biden’s plan to get 40% of the country’s electricity from solar power by 2035 hinges on developing a device that would replace fossil-fuel power plants in the heartbeat of grids electric.
Called a grid-forming inverter, the tool is a combination of electronics and software and could also allow solar panels in millions of homes to help restore a cut-off power grid like the one left in Louisiana and Mississippi after the hurricane. Ida. Today, solar panels can no longer fulfill this role.
Inverters are electronic devices that convert the direct flow of direct current from wind and solar generation, and batteries, into the tightly controlled rising and falling waves of alternating current that provide power to the grid. Solar and wind units are currently built with inverters with “smart” digital capabilities to support grid reliability. But they “follow” or adapt to the AC conditions of the existing network and do not have the “network formation” capabilities envisaged by the researchers.
At the end of last month, the Department of Energy awarded $ 25 million to a research consortium to create a standard inverter forming a network. Separately last week, the Biden administration released the Solar future study calling for doubling and then doubling the 2020 record solar installations by 2035 (Energy wire, September 9).
“The study sheds light on the fact that solar power, our cheapest and fastest growing clean energy source, could produce enough electricity to power every home in the United States by 2035 and employ up to 1.5 million people in the process, ”the Energy Secretary said. Jennifer Granholm said in a statement.
Today, the alternating current of the grid is defined by the generators of conventional power stations – coal and natural gas units, nuclear reactors and hydropower. However, as their presence diminishes, wind and solar resources must be able to play this role as the grid approaches the high levels of solar energy demanded by Biden, said Ben Kroposki, director of the Center for Engineering of Solar Energy. electrical systems at National Renewable Energy. Laboratory (NREL), leader of the consortium supported by the DOE.
An inverter forming a grid would go beyond existing smart versions and have additional software controls that would allow it to “go first, not follow” existing grid conditions, helping to establish and maintain a stable flow of AC power. at precise voltage and frequency levels across the nation’s three vast synchronized power grids, like a conductor beating the tempo of an ensemble.
One of the key innovations needed to meet carbon-free energy commitments is the development of standardized and fail-safe advanced grid training inverters that utility engineers trust, the researchers say.
“The challenge really comes when you start to get much higher levels. [of renewable power] – no more than 50 percent of power based on the inverter. You don’t know if you have enough… conventional power plants left ”to maintain grid stability, Kroposki said.
The new inverters must be able to create the conditions on their own, Kroposki said.
“We need a significant portion of inverter-based devices to have this network training capability to maintain stable operations,” Kroposki said in an interview.
“We’re probably only about five years ahead of where we need to be,” he added, assuming solar power growth comes close to the Biden administration’s plan.
Advanced inverters could also allow solar or wind units of any size to help restart parts of the power grid shut down by natural disasters or cyber attacks, Kroposki said.
“Unfortunately, if you have solar power on your roof and inverters following the grid, but the grid is down, you won’t be drawing power from those panels,” he said. “Some of the newer inverters… may provide enough power to charge a cell phone, but it won’t power your home.
Other members of the new consortium include the University of Washington and the Electric Power Research Institute (EPRI), and it has support from other national laboratories, universities and industry researchers. Its aim is to create a standard for controls that all manufacturers will follow and to show the economic value of the technology to network operators.
“It is a unique piece that we are in the process of developing. We hope this will set the rules of the road, ”Kroposki said.
A senior official from a grid equipment manufacturer, who agreed to speak on the merits, questioned the potential of grid-forming inverters to maintain stable energy flows when renewable energy levels exceed 70 percent of production. “We have been experimenting with it for several years,” said the official. “This is just a start. I don’t know if there is a way to do this in a purely renewable system.”
The job of the new consortium is to answer these questions, said Daniel Brooks, vice president for integrated grid and energy systems at EPRI.
The initial grant from DOE is seed money to get the project started, he said. It will go towards testing and evaluation to determine how advanced inverters would perform in operation, so that large grids remain in sync and reliable, he added.
“After five years, the consortium is intended to be a stand-alone research entity that provides a centralized source of truth about inverters,” said Brooks.