 A hotly debated carbon dioxide pipeline has been given the green light in Iowa, though the project still has a ways to go. Midwest regulators signing off on the CO2 pipeline project that would take emissions of climate-warming gas for storage underground. Summit Carbon Solutions has applied for a permit to build the $5.5 billion, 2,500-mile-long pipeline that would carry CO2 emissions from dozens of ethanol plants to be buried deep underground in North Dakota.