Outside Delta, a one-stoplight town in the scrublands of central Utah, a giant battery is taking shape underground.
Two caverns, each as deep as the Empire State Building is tall, are being created from a geological salt formation, using water to dissolve and remove the salt. When completed next year, the caverns will be able to store a huge amount of energy, but in a form that is vastly different from the chemical batteries found in everything from flashlights to cars.
Here, the energy will be stored as hydrogen gas.
As the world seeks to fight climate change by burning less coal, oil and other fossil fuels, the spotlight is shifting to hydrogen as an alternative. Hydrogen produces no planet-warming emissions when burned, making it a potential replacement fuel in transportation, electricity generation and industries like the making of cement and steel.
But with this project and a second mammoth construction site across the street, developers are taking hydrogen’s potential to another level.
The developers, including Chevron, which bought a majority stake in one of the projects in September, plan to produce hydrogen using excess solar and wind power in spring and fall, when demand for electricity is low, and store it in the caverns. Then in the summer, when electricity demand is high, it would be burned in the second project, a power plant that would use a blend of hydrogen and natural gas.
That new plant would replace an aging facility that burns coal, the dirtiest of the fossil fuels, but would still emit some planet-warming gases depending on the mix of natural gas and hydrogen.
Using hydrogen as a battery is one of the more audacious concepts being developed as industries and governments work to wean the world from fossil fuels.
“It’s a little bit of a paradigm shift,” said John Ward, a spokesman for the Intermountain Power Agency, which is building the new power plant to replace an aging coal-fired one. “We’re making hydrogen as an energy storage carrier.”
Mr. Ward was speaking at the power plant construction site, which was swarming with crews working in the shadow of the old coal plant, its twin boilers still fired up and emitting large amounts of carbon dioxide and other greenhouse gases. Construction of the new plant is expected to be completed by 2025 at a cost of $2 billion.
At a nearby railroad siding, workers were using a crane to unload the first of 40 electrolyzers from a rail car. The 100-ton behemoths, each roughly the size of a large shipping container, will be used to generate the hydrogen by splitting water molecules. The process, electrolysis, has been used for decades, although not at this scale. The cost of this project is expected to be more than $1 billion.
Because the electricity would come from solar and wind power, this would be “green” hydrogen, produced with no planet-warming emissions. Currently almost all hydrogen is made by using natural gas. That’s far cheaper, but the process generates planet-warming carbon dioxide. (No matter how it’s made, hydrogen when burned produces mostly water vapor and no carbon dioxide.)
In any project involving hydrogen, there are questions about the potential climate effects of gas leaks during storage and transport. While hydrogen is not a greenhouse gas, its reactions with other chemicals can lead to greater warming.
And the Delta projects raise further questions about the cost and efficiency of using electricity to make hydrogen and then using the hydrogen to make electricity again, and about whether the new power plant can eventually become emissions-free by burning only hydrogen by 2045.
For the people of Delta, a farming community of about 3,000, it is unsettling to exchange the coal plant, a reliable, well-paying employer for nearly 40 years, for what is for now only a promise of a clean energy future focused on hydrogen.
“The immediate impact will definitely be hard,” said Nicholas Killpack, a City Council member, as the hydrogen storage project and the new power plant together will employ about 200 workers, far fewer than the 500 who worked at the coal plant at its peak. “But our best option going forward is to lean into this thing.”
If it works as planned, the hydrogen project will be an alternative to the utility-scale chemical storage batteries that have been installed to quickly provide energy to the nation’s power grid. Such “dispatchable” energy is considered critical to fill in gaps and keep the electricity supply consistent as more and more power is provided by intermittent sources like solar panels and wind turbines.
“You need more robust energy storage to have a reliable grid,” Mr. Ward said. “And that’s what this is about.”
The hydrogen project would contain a lot of dispatchable power. The two caverns are deep, and when full would hold far more energy in the form of hydrogen than all the chemical storage batteries installed in the United States so far.
“It’s a massive amount of storage,” said Jigar Shah, head of the Department of Energy’s loan program office, which issued a $504 million loan guarantee for the project. “And it comes at the exact right time” in the West, he said, where there are many new renewable energy projects that together can produce more electricity than needed in the spring and fall. “This is a great way to deal with all that excess supply.”
The scale of the hydrogen project will serve as a catalyst to help bring down the cost of electrolyzers so that green hydrogen eventually becomes less expensive, Mr. Shah said. “If someone doesn’t go first,” he said, “then we’ll never get to the cost reductions in the future.”
Chevron declined to make executives available for comment, but in a statement announcing it had bought a controlling interest in the hydrogen project, the company said that in addition to supplying the gas to the new power plant, it was developing “several other opportunities” to sell hydrogen to customers in the utility, transportation and industrial sectors in the West.
The storage project and new power plant have been in the planning stages for more than a decade, the result of a confluence of factors.
The coal-fired plant, which was dedicated in 1987 at a ceremony that featured the Mormon Tabernacle Choir, is due to shut down because it stands to lose its major customers, Los Angeles and other cities in Southern California, as that state has moved to sharply reduce greenhouse gas emissions from power generation.
But because the coal plant sends power to Southern California, there is a long-distance, high-voltage transmission line already in place. At a time when building new lines is costly and can take a decade or longer, an existing line is invaluable. It could carry electricity from the new natural gas-hydrogen plant and also could bring in renewable power for the hydrogen project.
And in what Mr. Ward called the “happiest of coincidences,” geology played a role, too. As it happens, the area is underlain by salt domes, underground columns of salt that can be dissolved with water, leaving impermeable caverns that are ideal for gas storage.
“You put that all together and it all points to the project we have under construction today,” said Greg Huynh, a manager with the Los Angeles Department of Water and Power, which, because it is a major electricity customer, is deeply involved in building the new power plant.
The caverns are created by a process called solution mining, in which a well is drilled into the salt and high-pressure water is pumped down. As the salt dissolves, the resulting brine comes to the surface and is stored in large containment ponds. The caverns are about 200 feet in diameter and 1,200 feet high, with their tops 3,000 to 4,000 feet below the surface.
Hydrogen molecules are especially small and can easily escape in storage and transport if care is not taken.
The Delta hydrogen project “is an example of the kinds of challenges that all these hubs are going to face,” said Beth Trask, an associate vice president at the Environmental Defense Fund who works on energy transition issues. “To get hydrogen right, that means you have to ensure that it’s produced cleanly, it’s managed carefully, it’s deployed and used responsibly. All these things really, really matter.”
Mr. Ward said the projects were being planned so that the production, storage and transportation of hydrogen, by a short pipeline to the power plant, would be safe and secure.
“We’re integrating mature technologies at utility scale,” he said. “This isn’t a science fair experiment.”
Because hydrogen contains less energy by volume than natural gas, the power plant is being designed with larger pipes and other features so that it can initially run a mix containing up to 30 percent hydrogen. There are few large natural gas plants around the world operating with any hydrogen at all, much less such a high percentage of the gas.
And utility-scale turbines that can burn only hydrogen have yet to be developed. So getting to 100 percent hydrogen in the next 20 years, if it can be achieved, would very likely require major upgrades, if not a complete rebuilding, of the Delta plant, said Ilissa Ocko, a scientist at the Environmental Defense Fund.
“The costs can very easily add up when you make the adjustments that you need to the infrastructure,” she said. “There are so many complicating factors here that can make it very easily turn into something that is not beneficial to the climate.”
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