(1) The department shall develop an emissions calculator to assist state agencies in estimating aggregate emissions as well as in estimating the relative emissions from different ways in carrying out activities.
(2) The department may use data such as totals of building space occupied, energy purchases and generation, motor vehicle fuel purchases and total mileage driven, and other reasonable sources of data to make these estimates. The estimates may be derived from a single methodology using these or other factors, except that for the top ten state agencies in occupied building space and vehicle miles driven, the estimates must be based upon the actual and projected operations of those agencies. The estimates may be adjusted, and reasonable estimates derived, when agencies have been created since 1990 or functions reorganized among state agencies since 1990. The estimates may incorporate projected emissions reductions that also affect state agencies under the program authorized in RCW
70A.45.020 and other existing policies that will result in emissions reductions.
(3) By December 31st of each even-numbered year beginning in 2010, the department shall report to the governor and to the appropriate committees of the senate and house of representatives the total state agencies' emissions of greenhouse gases for 2005 and the preceding two years and actions taken to meet the emissions reduction targets.