Carbon Intensity

Carbon intensity, also called emission intensity, measures the rate at which carbon dioxide or another pollutant is released relative to a given activity, most often expressed for electricity as grams of carbon dioxide equivalent per kilowatt hour generated. The metric lets planners and regulators compare the climate impact of different ways of generating the same unit of electricity on a like for like basis. Lifecycle assessments that include construction and fuel supply as well as operation put coal generation at roughly 1,000 grams of carbon dioxide equivalent per kilowatt hour, against about 4 grams for hydroelectric power from a reservoir, an order of magnitude difference the raw fuel cost of either source does not by itself convey. The same measure scales up to compare whole economies or grids over time, tracking whether a country's or a region's electricity supply is becoming cleaner per unit generated even as total output grows.