The assumptions used in the LTPP evaluation are developed in conjunction with the Energy Commission (which provides the demand forecast) and the California Independent System Operator (which uses the same assumptions for transmission planning). The assumptions are revised every two years to incorporate changes in the resource mix and revisions to State policies (e.g. higher RPS targets). Current assumptions are hosted on the CPUC website.

The analysis that evaluates need compares demand with existing generation, new resources and also takes into account the retirements of resources. In addition to forecasting expected resource needs the proceeding develops information on alternative paths to meeting the state’s policy goals, such as increasing distributed generation, or energy efficiency expenditures. Each step of the process asks for and incorporates stakeholder feedback.