Kentucky is stepping up research on storing harmful carbon dioxide emissions underground. Three private energy companies will put up additional funding and expertise to help carry out the carbon storage test. Included are Peabody and ConocoPhillips, which are in the preliminary stages of designing a plant that would convert coal into gas for electricity. That plant will be outfitted to capture carbon dioxide before it escapes into the atmosphere. But geologists must prove it can be stored efficiently, and near the plant. Survey head Dave Harris says the challenge will be the amount of CO2 underground chambers might need to handle.“Five million tons of CO2 per year is a good ballpark number for the amount of CO2 that a plant like that would produce. I mean that’s a lot of CO2 you’ve got to get rid of. Until we get this well drilled we really don’t know how many wells you’re going to have to drill, and how much each well can actually handle per year,” Harris said.To find out, geologists will drill a mile-and-a-half deep well in western Kentucky and then inject it with a small volume of carbon dioxide. Even if the well can hold a substantial volume and no leaks develop, Harris says commercial-scale carbon storage is still 5 to 10 years away.