So what exactly is this new “Advanced Clean Energy Storage” project that was announced at the Governor’s Energy Summit last week?

It sounds promising, but it’s hard to tell from the hyped rollout it received.

It seems simple enough: store energy by pressurizing salt caverns in Utah’s west desert, and then use that pressurized air to drive generators when electric power is needed. In other words, it’s a giant battery, and batteries have never been more important. Storage allows us to use solar and wind energy when there’s no sun or wind.

But there is apparently a lot more than that going on here. Gov. Gary Herbert said the project would include hydrogen and solid oxide fuel cells and large-flow batteries.

The company behind the technology — a joint effort of Japanese industrial heavyweights Mitsubishi and Hitachi — has made its name in building and selling natural gas turbines. Electrical utilities across the globe have been closing coal-fired power plants and using natural gas turbines, which are more efficient and produce less than half the carbon of coal.

“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 company’s press release on the project says.

In other words, this isn’t just about storing renewable power. It’s also about generating power, and — at least over the short term — it appears to be generating it by burning a fossil fuel — natural gas.

That is progress from coal, to be sure, but it is still a carbon-producing way to make electricity. Cleaner, but not quite clean.

This is in keeping with the history of Herbert’s annual energy summits. Every year much gets said about renewables, but a closer look shows that most of the focus still is on maximizing the state’s fossil fuel deposits.

Despite having one of the highest solar energy potentials in the nation, Utah still relies more on coal for its electricity than all but a few states. And the argument for that — that it’s cheaper than cleaner alternatives — is literally collapsing. The cost of building solar generation has fallen dramatically, and the fuel is free. After years of bargain rates, Utah’s power costs are getting closer to the rest of the nation.

Is the Advanced Clean Energy Storage project a step in the right direction? Probably, but it remains to be seen how big of a step. The real summit is still to be climbed.