How is the gas burn data calculated?
Our approach is based on power flow measurements at all our plants. We take into account the nuclear, coal and gas fired generation in an area – at the moment, we are only doing gas areas – and combine that with load in the same area. Where we don’t have an hourly load measurement, we use a population-weighted temperature index as a proxy. The gas figure is derived as a result of a multiple regression approach using those data inputs. In back-cast testing, we found our gas burn data for the east to be within 6% of the EPA continuous emissions monitoring (CEM) data on a monthly cumulative basis. For the west and producing areas, the error is 5% or less.
