Do Energy Efficiency Investments Deliver? Evidence from the Weatherization Assistance Program*
Quarterly Journal of Economics · 2018 · Meredith Fowlie、Michael Greenstone、Catherine Wolfram
中文摘要
越来越多的政策和项目旨在增加能效投资，因为传统观点认为，尽管这类投资具有正的私人回报并能产生环境效益，人们却未能进行这些投资。针对这一能效缺口，已有许多解释，但令人意外的是，检验这一传统观点是否正确的实地研究却很少。本文报告了对美国最大的住宅能效项目——住宅防寒保温援助计划——开展实验评估的结果，评估样本涵盖密歇根州约3万户家庭。研究结果显示，前期投资成本约为实际节省的能源费用的两倍。此外，模型预测的能源费用节约额是实际节约额的三倍以上。这一差异或许可以归因于“反弹”效应，即效率提高导致能源终端用途需求增加，但本文未发现经过防寒保温改造的住宅室内温度在统计上显著更高的证据。即使将减排带来的更广泛社会效益考虑在内，成本仍大幅超过收益；平均年回报率约为−7.8%。
Abstract
A growing number of policies and programs aim to increase investment in energy efficiency, because conventional wisdom suggests that people fail to take up these investments even though they have positive private returns and generate environmental benefits. Many explanations for this energy efficiency gap have been put forward, but there has been surprisingly little field testing of whether the conventional wisdom is correct. This article reports on the results of an experimental evaluation of the nation’s largest residential energy efficiency program—the Weatherization Assistance Program—conducted on a sample of approximately 30,000 households in Michigan. The findings suggest that the upfront investment costs are about twice the actual energy savings. Furthermore, the model-projected savings are more than three times the actual savings. Although this might be attributed to the “rebound” effect—when demand for energy end uses increases as a result of greater efficiency—the article fails to find evidence of significantly higher indoor temperatures at weatherized homes. Even when accounting for the broader societal benefits derived from emissions reductions, the costs still substantially outweigh the benefits; the average rate of return is approximately −7.8% annually.