Electricity crises can spur improvements in electricity conservation that would be unachievable under normal circumstances. This paper investigates how businesses adapted to electricity shortages following the March 11, 2011, Great East Japan earthquake, tsunami, and nuclear disaster. In summer 2011, mandatory and voluntary electricity conservation measures affected nearly all of Japan, and peak hour electricity consumption was reduced by a remarkable 18% in the Tokyo region. Using statistical data from 14 business surveys conducted in 2011 and 2012, this paper identifies patterns with regard to type of adaptation, conservation requirements, economic sector, and timeframe. Results indicate that behavioral adaptations (e.g., reduction of illumination or air conditioning) were much more common than schedule adaptations (e.g., shifting production times) or hardware adaptations (e.g., installing energy-efficient devices or private generators). Adaptation patterns were very similar between mandatory and voluntary conservation areas. Manufacturing companies were more likely to implement schedule adaptations than other companies. Certain types of adaptations persisted into 2012, especially reduction of illumination and air conditioning, and installation of energy-efficient devices. These insights may be useful for informing electricity conservation policies in non-crisis contexts. (C) 2013 Elsevier Ltd. All rights reserved.