GROWING UP IN ENGLAND after World War II, "all the youngsters like me were obsessed with aircraft," says Rodney Allam. "I had a picture on my wall of Chuck Yeager when he broke the sound barrier in the Bell X-1, the earliest turbine-driven aircraft." Those high-powered machines were inspirational. Allam became a chemical engineer and went to work at the U.K. division of Air Products & Chemicals, based in Allentown, Pennsylvania. There in the 1970s, he became obsessed with an idea: how to capture the carbon-dioxide emissions from the U.K.'s giant coal-burning power plants? He already knew where to put the CO2. BP and Royal Dutch Shell would jump at the chance to inject it into their vast oilfields in the North Sea. Injecting the gas (which acts as a solvent to free up stubborn crude oil) has long been a common practice in West Texas fields, where oil companies tap naturally occurring reservoirs of CO2. But there were none of those in England.