NORTH CANTON, Ohio -- Wind and solar farms are generating clean power at lower and lower prices, but not always when it is needed.

Fuel cells, which generate electricity by combining hydrogen and oxygen, could change that equation, says a University of California researcher, eliminating the need for large coal and nuclear power plants and leading to a zero-emissions electric grid.

Jack Brouwer, a professor of mechanical and aerospace engineering and director of the National Fuel Cell Research Center at University of California-Irvine, made the claim to a group of fuel cell manufacturers gathered Wednesday at Stark State College for the 18th annual Ohio Fuel Cell Symposium.

It's an old idea, but one that looks increasingly promising because the costs of all three technologies (wind, solar and fuel cells) have steadily declined, leading to a glut of power at certain times of the day and not enough at other times. The imbalance occurs seasonally, too, said Brouwer.

Grid managers and utilities across the country have turned to massive lithium ion storage systems to even out the imbalances. But there is not enough lithium on earth to build the kind of storage needed to balance the nation's grid, Brouwer said. And what is built will be expensive.

Instead, that excess power, which is now not used when its availability exceeds demand, could be used in hydrolyzers, a kind of reverse fuel cell that pushes electricity through water to separate the oxygen and hydrogen (H2O) into separate gases. The technique was developed in the 19th Century. Many high school students get their first look at the process, hydrolysis, in physics class.

The hydrogen produced from water then could be stored, said Brouwer, either underground or in tanks for use by gas turbines or even more efficient fuel cells, he said. The hydrogen, in effect, becomes a kind of physical battery: available for use any time.

Alternatively, controlled quantities of the hydrogen could be fed immediately into existing natural gas pipelines and delivered to gas turbines.

UC-Irvine began testing a prototype system in 2015, injecting hydrogen created by green power into a campus gas line which fueled an on-site gas turbine, which burned both gases.

But fuel cells are not gas turbines. For years, some fuel cell developers have struggled to design a fuel cell that can pull the hydrogen out of natural gas on its own, a process that turned out to be more thorny than expected because pipeline natural gas shortens the life of the fuel cell.

One such company is LG Fuel Cell Systems, Inc., a joint venture between manufacturing giant LG, of Seoul, South Korea, and London-based power systems designer Rolls-Royce Holdings. The company appears to have solved the problem.

Rolls-Royce Holdings created Rolls-Royce Fuel Cell Systems in 2003 and came to Ohio in 2007 when it bought Ohio-based SOFCo-EFS Holdings LLC from McDermott International Inc., and put its North American headquarters on the campus in an $8 million fuel cell prototyping center built by the state.

LG bought a majority share of the company in 2012, creating the joint venture. The company employs about 130 people, most of them in North Canton.

Rolls and LG want to build fuel cell systems large enough for industrial customers and for utilities. The company a little more than a month ago began testing its first grid-connected, continuously operating 250,000 watt fuel cell on the Stark campus.

The fuel cell is using pipeline natural gas. The electricity it creates flows into a transformer and then directly into AEP Ohio's distribution grid.

The system sits in a parking lot at the rear of the laboratory. Though a bit noisy with the sound of compressed air, the fuel cell emits no air pollution because it combines the hydrogen from the natural gas (CH4) with oxygen from the air in an electro-chemical reaction that produces electrons and water. In other words, it does not burn the hydrogen. The process does produce carbon dioxide but none of the other pollutants associated with combustion.

In a presentation earlier in this week's symposium, Andrew Marsh, CEO of LG Fuel Cell Systems, told the group that the fuel cell was the first fully integrated unit, not a production unit.

"We are, at the moment, a development company. We don't have projects in the market. We are moving in that direction steadily, but we are not there yet," he said.

Edited by the author to explain that a direct methane fuel cell such as the LG fuel cell does create carbon dioxide, though no combustion products such nitrogen oxides (NOX) or volatile organic compounds (VOC) nor any of the pollutants associated with coal burning.