Econometric models for distinguishing between market-driven and publicly-funded energy efficiency

Marvin J. Horowitz, Demand Research

Keywords

market effects, public programs, impact evaluation, econometric models, externalities, free ridership, spillover, rebound, gross impacts, net impacts

Abstract

Central to the problem of estimating energy program benefits is the necessity to differentiate between changes in energy use that would have occurred in the absence of public programs versus declines in energy use that would not have occurred but for public programs. The former changes are often referred to as naturally-occurring or market-driven effects. They occur due to a combination of one or more independent variables, such as changes in prices, incomes, weather, and technology. For a rigorous, scientifically-valid program evaluation, it is essential to first control for these variables before making statistical inferences related to public program effects.

This paper describes the economic and statistical issues surrounding quantitative studies of energy use, energy efficiency, and public programs. To illustrate the strengths and weaknesses of different impact evaluation approaches, this paper describes three new studies related to electricity use in the U. S. commercial buildings sector. Specification and estimation of time series and cross section econometric models are discussed, as are their capabilities for obtaining long-run estimates of the net impacts of energy efficiency programs.