This article discusses criteria for comparing the effectiveness of energy resources. It focuses on the interrelationship between the effectiveness of energy resources and movement from one technological stage to another. What emerges is the consistent pattern of change in existing technologies, and increasingly evident is that, at their current stage of development, neither nano- nor biotechnology will lead to an evolution from the current and fifth technological stage to a sixth. Of note is that at present oil remains the key energy resource, which means that in the near future peak oil will force us to confront an unprecedented event in industrial history: energy degradation, which can be viewed as a regressive movement in the existing technological stage.