Earth Notes - Carbon Sequestration

Flagstaff, AZ – Earth Notes: Carbon Sequestration

Carbon sequestration is an optimistic but untested idea for controlling greenhouse gas emissions. The concept is simple. Carbon dioxide is a primary cause of climate change so why not bury it? Now a test of that idea is coming to northeast Arizona.

Starting soon, 2,000 tons of carbon dioxide gas will be trucked to Joseph City, a small community west of Holbrook. That's the site of the coal-fired Cholla Power Plant run by APS, Arizona's largest electricity utility.

The CO2 will be pumped 3,500 feet below the surface, and engineers hope it will stay there, instead of polluting the air. There's a deep saline formation under that stretch of the Painted Desert, and geologists think it might be able to hold the CO2 for a long time.

This is only a test. Engineers are a long way from removing and injecting carbon dioxide from the Cholla plant's actual emissions plume. In fact, nobody knows yet whether the sequestration technology will really work. But monitoring will be in place to check that the injected CO2 doesn't leak into nearby geological formations or groundwater.

If it does work, the Joseph City carbon sequestration project is a bare start for keeping carbon dioxide out of the air. The 2,000 tons of greenhouse gas it will contain would be emitted from a single coal-fired power plant in about two hours.

But it is a start, and geologists hope the area around the pilot site could contain more CO2 in the future.

-Anne Minard