Abstract A study of the economic, social-political, and environmental consequences of using renewable energy technologies (RETs, e.g., photovoltaics, wind, solar thermal, biofuels) as compared to those of conventional energy technologies (CETs, e.g., oil, coal, gas) would show that RETs are singularly consistent with a whole ethic that is implicit in the concept of sustainability. This paper argues for sustainability as an ethical, as well as a pragmatic, imperative and for RETs as an integral part of this imperative. It brings to the fore some of the specific current economic, political, and environmental assumptions and practices that are inconsistent with both sustainability and with a rapid deployment of RETs. Reflecting an emerging planetary awareness and a pressing need to come to terms with intra- and intergenerational equity, the concept of sustainability explicitly entails the right of future generations to the same opportunity of access to a healthy ecological future and the finite endowment of the Earth's resources as that of the present generation.