A massive underground battery is coming to a small town in Utah
Outside Delta, a one-stoplight town in the thickets of central Utah, a giant battery is taking shape underground.
Two caves, each as deep as the Empire State Building is tall, are created from a geological salt formation, using water to dissolve and remove the salt. When completed next year, the caves will be able to store a huge amount of energy, but in a form very different from the chemical batteries found in everything from flashlights to cars.
Here the energy is stored as hydrogen gas.
As the world tries to combat climate change by burning less coal, oil and other fossil fuels, the spotlight is shifting to hydrogen as an alternative. Hydrogen does not produce planet-warming emissions when burned, making it a potential replacement fuel in transportation, electricity generation and industries such as cement and steel production.
But with this project and a second massive 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 energy in the spring and fall, when electricity demand is low, and use it store in the caves. In the summer, when demand for electricity is high, it would be burned in the second project, a power plant that would use a mixture of hydrogen and natural gas.
That new plant would replace an aging plant that burns coal, the dirtiest of 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 boldest 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 a new power plant to replace an aging coal plant. “We make hydrogen as an energy storage carrier.”
Mr Ward was speaking at the power station construction site, which was teeming with crews working in the shadows of the old coal-fired power station, its twin boilers still burning and emitting large amounts of carbon dioxide and other greenhouse gases. Construction of the new factory is expected to be completed in 2025 at a cost of $2 billion.
On a nearby railroad track, workers used a crane to unload the first of 40 electrolyzers from a train car. The 100-ton giants, each about the size of a large shipping container, will be used to generate hydrogen by splitting water molecules. The process, electrolysis, has been used for decades, although not on this scale. The cost of this project is expected to be more than $1 billion.
Because the electricity would come from solar and wind energy, this would be ‘green’ hydrogen, produced without planet-warming emissions. Currently, almost all hydrogen is made using natural gas. That’s much cheaper, but the process generates carbon dioxide that warms the planet. (Regardless of how it is made, hydrogen produces mainly water vapor and not carbon dioxide when burned.)
With any project involving hydrogen, questions arise about the potential climate impacts of gas leaks during storage and transport. Although 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 costs and efficiency of using electricity to make hydrogen and then using the hydrogen to make electricity again, and whether the new power plant can ultimately become emission-free by 2045 alone to burn hydrogen.
For the residents of Delta, a farming community of about 3,000 residents, it is disturbing to exchange the coal-fired power plant, a reliable, well-paid employer for almost 40 years, for what is for now only a promise of a clean energy future focused on hydrogen. .
“The immediate impact will certainly be severe,” said City Council member Nicholas Killpack, as the hydrogen storage project and new power plant together will employ about 200 workers, far fewer than the 500 employed at the coal plant’s peak. . “But our best option for the future is to respond to this.”
If it works as planned, the hydrogen project will provide an alternative to the large-scale chemical storage batteries installed to quickly supply energy to the national grid. Such ‘dispatchable’ energy is considered crucial to fill gaps and keep electricity supplies consistent, as more and more power is supplied by intermittent sources such as solar panels and wind turbines.
“You need more robust energy storage to have a reliable electricity grid,” Mr Ward said. “And that’s what this is about.”
The hydrogen project would contain a lot of switchable electricity. The two caves are deep and, when full, could hold much more energy in the form of hydrogen than any chemical storage battery installed in the United States to date.
“It’s a huge amount of storage space,” said Jigar Shah, head of the Department of Energy’s loan program office, which has issued a $504 million loan guarantee for the project. “And it’s coming at just the right time” in the West, he said, where there are many new renewable energy projects that together could 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 drive down the cost of electrolyzers, ultimately making green hydrogen cheaper, Mr Shah said. “If someone doesn’t go first,” he said, “we’ll never get to the cost savings in the future.”
Chevron declined to make executives available for comment, but in a statement announcing it had purchased a majority stake in the hydrogen project, the company said that in addition to supplying gas to the new power plant, it was developing “several other options” 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 power station, which was inaugurated in 1987 during a ceremony attended by the Mormon Tabernacle Choir, will be closed as it risks losing its major customers, Los Angeles and other Southern California cities, as that state has taken steps to sharply reduce greenhouse gas emissions from energy generation .
But because the coal plant sends power to Southern California, a long-distance high-voltage transmission line is already in place. At a time when new lines are expensive to build and can take ten years or more, an existing line is invaluable. It could transport electricity from the new natural gas-hydrogen plant and also supply renewable energy for the hydrogen project.
And in what Mr Ward called the “luckiest coincidence”, geology also played a role. Coincidentally, the area is under salt domes, underground columns of salt that can be dissolved with water, leaving impermeable caverns ideal for gas storage.
“When you put it all together, it all points to the project we have under construction today,” said Greg Huynh, manager at the Los Angeles Department of Water and Power, which, because it is a major electricity buyer, is heavily involved during the construction of the new power station.
The caves are created through a process called solution mining, in which a well is drilled into the salt and water is pumped down at high pressure. As the salt dissolves, the resulting brine rises to the surface and is stored in large retention ponds. The caves have a diameter of about 60 meters and a height of 1200 meters, with their peaks 900 to 1200 meters below the surface.
Hydrogen molecules are extremely small and can easily escape during storage and transportation if care is not taken.
The Delta hydrogen project “is an example of the kinds of challenges that all of these hubs will face,” said Beth Trask, associate vice president at the Environmental Defense Fund, who works on energy transition issues. “Getting hydrogen right means making sure it is produced cleanly, carefully managed, deployed and used responsibly. All these things really matter.”
Mr Ward said the projects were planned so that the production, storage and transport of hydrogen, via a short pipeline to the power plant, would be safe.
“We are integrating mature technologies at utility scale,” he said. “This is not a scientifically fair experiment.”
Because hydrogen contains less energy by volume than natural gas, the power plant is being designed with larger pipes and other facilities so that it can initially run a mixture containing up to 30 percent hydrogen. There are few large natural gas power plants in the entire world that operate with hydrogen, let alone with such a high percentage of the gas.
And utility-scale turbines that can burn only hydrogen have yet to be developed. So reaching 100 percent hydrogen in the next 20 years, if feasible, would most likely require major upgrades, if not a complete rebuild, of the Delta plant, said Ilissa Ocko, a scientist at the Environmental Defense Fund.
“The costs can very easily increase if you make the infrastructure changes that are necessary,” she says. “There are so many complicating factors here that could very easily turn it into something that is not beneficial for the climate.”