Those two blocks can power the average high-consumption American home -- one block can power the average European home. At least that's the claim being made by K.R. Sridhar, founder of Bloom Energy, on 60 Minutes last night. The original technology comes from an oxygen generator meant for a scrapped NASA Mars program that's been converted, with the help of an estimated $400 million in private funding, into a fuel cell. Bloom's design feeds oxygen into one side of a cell while fuel (natural gas, bio gas from landfill waste, solar, etc) is supplied to the other side to provide the chemical reaction required for power. The cells themselves are inexpensive ceramic disks painted with a secret green "ink" on one side and a black "ink" on the other. The disks are separated by a cheap metal alloy, in