In face of the likely doubling of the world population and perhaps tripling of the power demand over the next 50 years, this paper (1) presents some thoughts on the possible ways to meet the power demands under the constraints of increased population and land use while holding the environmental impact to a tolerable one, and (2) outlines the ways exergy analysis may be effectively used in the conception and development of such processes. To effectively develop the innovative power generation systems needed in the 21st century, irreversibility and exergy analysis should be much more focused on the intrinsic process details.