Utility least cost planning and the Washington GAS integrated model

Washington GAS (WGAS) was ordered in 1988 by the District of Columbia Public Service Commission (DCPSC) to construct a least cost plan for the District of Columbia. As part of this order, WGAS was required to reduce natural gas consumption to specific target levels in Washington, DC by the year 2000. To comply, WGAS constructed a long-range planning model with supply and demand components to mimic the local energy marketplace. A selection algorithm was also constructed to pick the least costly combination of energy conservation programs to meet the gas reduction targets. This algorithm was incorporated into the long-range planning model. This article reviews the algorithms and the long-range planning model currently being used by WGAS. By using the energy conservation selection algorithm within the long-range planning model, WGAS can determine the least costly combination of energy conservation programs required to meet a particular reduction target, what level of program participation is required, and what are the estimated energy conservation costs.