Huge (1 GWh) energy storage project announced for Utah using compressed air in salt caverns

Last week a massively huge energy storage project was announced in Utah. Details are scarce, but since the announcement included both Utah Governor Gary Herbert and US Secretary of Energy Rick Perry, the companies involved were able to draw on some heavy firepower and maybe there is some government funding involved. The Utah Advanced Clean Energy Storage Project is a joint venture by Mitsubishi Hitachi Power Systems and Magnum Development. It uses a salt dome owned by Magnum that will be used to store compressed air on a massive scale, along with a “flow battery”, a solid oxide fuel cell, and what’s being called “renewable hydrogen”.

From the press release: “The Utah Advanced Clean Energy Storage Project will generate enough power to meet the needs of 150,000 households. That’s the equivalent of about 21 percent of the total households in Utah,” Herbert said. “This investment shows that Utah is not only blessed with unique energy resources, but also benefits from wise policy and an ability to forge unprecedented partnerships that help drive innovation.”

That is – the project is slated to hold up to 1 gigaWatt-hours of energy. In the current market storage projects in the megaWatt-hour range are thought to be large, so this thing is massive. Moving forward in order for renewable energy systems to play any significant role on the electricity grid, the size of energy storage systems must be in the gigaWatt or even teraWatt range.

As we’ll see – the project might not reach that size, it depends on how the business develops.

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The pitch is that the system will store excess renewable energy by compressing air in a gigantic cavern in a salt dome. Solar and wind resources are being installed rapidly, outstripping the ability of the grid to accept such energy. Currently that means the solar and wind resources are asked to “curtail” output, meaning to waste the energy that’s being produced. Obviously we need that renewable electricity to go to use. What’s intended here is that compressed air pumps will turn on, pump the air underground, storing the energy as air pressure. Then later in the day when the grid needs energy, that compressed air can be released through a turbine to generate electricity.

This is an energy storage system that uses zero lithium. No battery pack is in sight, it’s all about compressed air.

Magnum Development owns a set of salt domes in Utah. Most of them are used for storing “liquid fuel” (crude oil?) and natural gas. The plan is to turn one of them into this energy storage project.

But the project is not just about compressed air, instead the key points are:

  • Renewable hydrogen.
  • Compressed air energy storage.
  • Large-scale flow batteries.
  • Solid oxide fuel cells.

“Renewable Hydrogen”? Does that specifically mean hydrogen stripped out of water? Not necessarily. The phrase refers to cases where the electrolysis is powered by renewable energy, that results in what is called “renewable hydrogen”. Which raises the specter that possibly the hydrogen will come from the natural gas Magnum is storing in other salt domes? And therefore “renewable hydrogen” is smoke and mirrors?

In the press release we see: “As a next step in decarbonization, MHPS has developed gas turbine technology that enables a mixture of renewable hydrogen and natural gas to produce power with even lower carbon emissions. The MHPS technology roadmap aims to use 100 percent renewable hydrogen as a fuel source, which will allow gas turbines to produce electricity with zero carbon emissions.”

MHPS refers to Mitsubishi Hitachi Power Systems. This describes a plan to start with natural gas enriched with so-called “renewable hydrogen”, and to eventually use only hydrogen.

The model for the Renewable Hydrogen energy system is a circular loop of clean energy production, supposedly.

Mitsubishi-Hitachi directed us to https://www.changeinpower.com/acgt/ to learn more about Renewable Hydrogen. That page discusses the Air-Cooled M501JAC Gas Turbine. Other than the massive size of the turbine, 600 megaWatts, this doesn’t help with knowing about Renewable Hydrogen, but at the bottom of the page is a link to a PDF brochure containing this image. Now we have something to try and grok.

The picture wants us to believe the turbine is powered by hydrogen, and the hydrogen is electrolyzed from some unnamed source where the electrolysis is powered by excess energy from solar and wind plants. But the image shows the electrolysis energy as coming from the electricity grid. And the image doesn’t say what is being electrolyzed. And the quote given earlier says that initially they’ll mix hydrogen with natural gas, promising to eventually get to pure hydrogen.

Where will the hydrogen come from? Utah is a very dry state, and “dry” in this case doesn’t mean liquor laws but the availability of water. It doesn’t make sense to rely on electrolyzing water in Utah to get the hydrogen to drive those fuel cells. When they get to 100% hydrogen in the turbines, will the hydrogen still be coming from natural gas?

How do we know whether this is an exercise in smoke and mirrors?

About David Herron

David Herron is a writer and software engineer living in Silicon Valley. He primarily writes about electric vehicles, clean energy systems, climate change, peak oil and related issues. When not writing he indulges in software projects and is sometimes employed as a software engineer. David has written for sites like PlugInCars and TorqueNews, and worked for companies like Sun Microsystems and Yahoo.

About David Herron

David Herron is a writer and software engineer living in Silicon Valley. He primarily writes about electric vehicles, clean energy systems, climate change, peak oil and related issues. When not writing he indulges in software projects and is sometimes employed as a software engineer. David has written for sites like PlugInCars and TorqueNews, and worked for companies like Sun Microsystems and Yahoo.

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