Over the last seven years, the electrical power sector has gone from being one of the most carbon-emitting sectors of the American economy per unit of fuel consumed to one of the least carbon-emitting sectors. From a report on ArsTechnica: That's according to new data from the US Energy Information Administration (EIA). Despite the good news, the EIA's numbers show that, since 1975, the carbon emissions of the US transportation sector per unit of fuel used has hardly changed at all. The EIA measured relative emissions across the US economy as "carbon intensity -- an average of the amount of carbon any sector gives off as it consumes different kinds of fuel. The measurements were applied to five sectors of the US economy: transportation, commercial, residential, electric, and industrial.