Adoption of energy-efficient technologies could reap both private and social rewards, in the form of economic, environmental, and other social benefits from reduced energy consumption. Social benefits include improvements in air quality, reduced greenhouse-gas emissions, and increased energy security. In response, governments around the world have adopted policies to increase energy efficiency. Still, there is a broadly held view that various barriers to the adoption of energy-efficient technologies have prevented the realization of a substantial portion of these benefits.
For some thirty years, there have been discussions and debates among researchers and others in academia, government, non-profits, and private industry regarding the so-called “energy efficiency gap” (or “energy paradox”) — the apparent reality that many energy-efficiency technologies are not adopted even when it makes sense for consumers and businesses to do so, based on their private costs and benefits. That is, decision makers appear to “under-invest” in energy-efficient technologies, relative to the predictions of some engineering and economic models.
What causes this gap? The answer to that question could presumably help inform the development of better public policy in this realm.
Possible Explanations for the Energy-Efficiency Gap
Potential explanations for the energy efficiency gap tend to fall into three broad categories: (1) market failures, such as lack of information or misplaced incentives; (2) behavioral effects, such as inattentiveness to future energy savings when purchasing energy-consuming products; and (3) modeling flaws, such as assumptions that understate the costs or overstate the benefits of energy efficiency. In this essay, I simply want to outline the types of hypothetical explanations of the gap that have been posited within these three broad categories.
First, various Innovation Market Failures have been posited, including: research and development (R&D) and learning-by-doing spillovers; inefficient product quality and differentiation due to market power; and inefficient introduction of new products due to consumer taste spillovers (for example, consumers becoming comfortable with a new technology).
Second, another set of potential market-failure explanations for the gap may be characterized as Information Problems. These include: lack of information on the part of consumers (learning-by-using or so-called experience goods; energy prices; energy consumption of products; and available substitutes); asymmetric information (the “lemons problem”); and split incentives and principal-agent issues (such as the frequently-discussed renter/owner dichotomy).
Third, there are Capital Market Failures and Liquidity Constraints, which may be a particularly significant issue in developing-country contexts.
Fourth, there are Energy Market Failures, including various externalities (environmental, energy security, congestion, and accident risk), as well as average-cost pricing of electricity.
The rise of behavioral economics has brought to the fore another well-defined set of potential explanations of the energy efficiency gap. A variety of alternative taxonomies could be employed to separate these explanations, but one such taxonomy would categorize the explanations as:
Model and Measurement Explanations
The third category of possible explanations of the energy efficiency gap consists essentially of a set of reasons why observed levels of diffusion of energy-efficiency technologies may actually be privately optimal.
First, there is the possibility of unobserved or understated adoption costs, including unaccounted for product characteristics.
Second, there may be overstated benefits of adoption, due to inferior project execution relative to assumptions, and/or poor policy design.
Third, an incorrect discount rate may be employed in an analysis, when the correct consumer and firm discount rates should vary with:
- opportunity cost of and access to capital
- buying versus retrofitting equipment
- systematic risk
- option value (see below)
Fourth, there is frequently heterogeneity across end users in the benefits and costs of employing energy-efficiency technologies, so that what is privately optimal on average will not be privately optimal for all. This can refer either to static (cross-sectional) heterogeneity or to dynamic (intertemporal) heterogeneity, that is, technology improvements over time, which raises two possibilities: the reality of some potential adopters being short of the frontier, and the presence of option value to waiting.
Fifth and finally, there is the possibility of uncertainty (real, not informational, as above), irreversibility, and option value. This could be due to uncertainty regarding future energy prices, or can be linked with option value that arises for delaying investments that have only minimal if any salvage value.
Public Policy and Next Steps
Determining the validity of each of these possible explanations — and the degree to which each contributes to the energy efficiency gap — are crucial steps in crafting the most appropriate public policy responses.
To inform future research and policy, Professor Richard Newell of Duke University and I have launched an initiative – sponsored by the Alfred P. Sloan Foundation — to synthesize past work on these potential explanations of the energy paradox and identify key gaps in knowledge. We are conducting a comprehensive review and assessment of published and ongoing social-science research on the adoption of energy-efficient technologies, including scholarly literature, industry case studies, reports from national and sub-national governments, and, to the extent possible, consulting reports evaluating specific programs.
We are working with leading social scientists — including scholars from economics, psychology, and other disciplines — to examine the various possible explanations of the energy paradox and thereby to help identify the frontiers of knowledge on the diffusion of energy-efficient technologies. We hope the products of this initiative will help decision makers in industry and government better understand the energy efficiency gap, and will thereby contribute to decisions that maximize the potential economic, environmental, and other social benefits associated with optimal adoption of energy-efficient technologies. As materials become available, we will post them at the project’s Harvard website and the project’s Duke website, and I will alert readers of this blog. In the meantime, please stay tuned.