Statistical recoupling: A new way to break the link between electric-utility sales and revenues.

摘要

In 1991, US electric utilities spent almost $1.8 billion on demand-side management (DSM) programs. These programs cut peak demands 5% and reduced electricity sales 1% that year. Utility projections suggest that these reductions will increase to 9% and 3%, respectively, by the year 2001. However, utility DSM efforts vary enormously across the country, concentrated in a few states along the east and west coasts and the upper midwest. To some extent, this concentration is a function of regulatory reforms that remove disincentives to utility shareholders for investments in DSM programs. A key component of these reforms is recovery of the net lost revenues caused by utility DSM programs. These lost revenues occur between rate cases when a utility encourages its customers to improve energy efficiency and cut demand. The reduction in sales means that the utility has less revenue to cover its fixed costs. This report describes a new method, statistical recoupling (SR), that addresses this net-lost-revenue problem. Like other decoupling approaches, SR breaks the link between electric-utility revenues and sales. Unlike other approaches, SR minimizes changes from traditional regulation. In particular, the risks of revenue swings associated with year-to-year changes in weather and the economy remain with the utility under SR. Statistical recoupling uses statistical models, based on historical data, that explain retail electricity sales as functions of the number of utility customers, winter and summer weather, the condition of the local economy, electricity price, and perhaps a few other key variables. These models, along with the actual values of the explanatory variables, are then used to estimate ''allowed'' electricity sales and revenues in future years.