Coal-burning power plants would not seem to have a bright future in a world worried about global warming.

In terms of climate change, they are a horror story, each plant dumping millions of tons of heat-trapping carbon dioxide into the atmosphere each. But if coal could be burned relatively cleanly, the industry’s carbon emissions could conceivably be reduced by hundreds of millions of tons a year.

That’s what makes the Wallula Energy Resource Center – a consortium led by a Gig Harbor company, United Power – so intriguing. Its goal is to make coal a much cleaner energy resource by extracting most of its carbon dioxide, compressing it into a liquid and pumping it into the deep, vast basalt formations underlying much of Eastern Washington.

WERC intends to do this as part of a planned 700 megawatt power plant in Wallula, Walla Walla County.

With 65 percent of the coal’s carbon being locked underground, the plant in theory would operate as cleanly as those burning natural gas, the cleanest fossil fuel. It would meet the state’s clean energy requirements – an astounding accomplishment for coal power.

While geologic “sequestration” has never been done before, the theory sounds distinctly promising. One part – pulling the CO2 out in the process of turning the coal into a synthetic gas fuel – is proven technology.

The unproven part lies underground. Small-scale tests at the Pacific Northwest National Laboratory in Richland have shown that, under the right conditions, liquid CO2 will combine chemically with basalt to produce calcium carbonate, a solid mineral. This would prevent the gas from ever turning up in the atmosphere to contribute to global warming.

Real-world tests at Wallula will begin this winter; if everything works, the plant could be up and running in 2014.

It would be great news if WERC’s $40 million gamble paid off. Underground sequestration will never turn coal into a genuinely clean power source, like hydroelectric dams. But it would make it much, much cleaner.

And for all the hand-wringing about it, coal isn’t going away anytime soon. It generates half the electricity in the United States. The burgeoning economies of India and China are heavily dependent on cheap – and very dirty – coal power.

Any measures that make some coal plants burn substantially cleaner could deliver a big net gain for the planet. Geologic sequestration might be one of those measures. It would be sweet indeed to see that technology proven in our own back yard.