The costs of energy supply disruptions for industrialised economies go well beyond the economic measures of national accounts. According to different kinds of risks, physical shortages or price shocks, there are several categories of negative effects. Oil disruptions have both a direct and an indirect impact, (at global and local levels) and have a short- and a medium-term horizon. The economic effects of electricity shortages are also direct and indirect, but the temporal lag is shorter than for oil disruptions. In this paper, we summarise the different ways an economy is affected by an oil shock or a power black-out. Oil crises in the past produced high inflation rates, trade and payments imbalances, high unemployment, and weak business and consumer confidence. The social costs of electricity shortages have immediate negative results, and relatively small, indirect effects - depending on the extension of the disruption, the duration, the availability of advance warning and information. A specific assessment of the social costs of an electricity shortage remains a research task for the future.