A half century of long-range energy forecasts: Errors made, lessons learned, and implications for forecasting

This paper assesses the major U. S. long-range energy forecasting studies conducted over the past half century, identifies the errors made and lessons learned in energy forecasting, and discusses the implications for current and future attempts to accurately forecast energy consumption, production, and prices. Over the past several decades, long-range energy forecasting has been extremely difficult and the accuracy of the major forecasts has, in retrospect, often been found wanting. Although, in hindsight, a large portion of the forecasts and associated policy recommendations turned out to be inaccurate and mistaken, here we conduct a careful review of 50 years of energy forecasting to determine how some of the major pitfalls can be avoided in future efforts. We identify: (1) lessons that can be learned from these past forecasting exercises that may improve our track record in the future; (2) basic trends and truisms that may be discerned that may allow us to more accurately forecast energy technologies and variables; (3) insights for doing the job better in the future; (4) the most egregious forecasting errors made in the past that can help us avoid making similar errors in the future; (5) assumptions that may aid us in better predicting the long-run energy future; and (6) how this review can assist policymakers in formulating energy policies and technology and R&D priorities for the future.