Arraya, back on topic (sort of). I think I remember this bit from CCiv about how history and wealth of civilizations can be measured by their ability to extract energy from their environment. I think this is what you’re getting at with the BTUs, and post above. I agree, there’s a profound connection.
But I think you’re being too pessimistic about what’s possible, not being able to replace energy found in fossil fuels. We’ll still have petrol, to be sure, but there is an enormous amount of energy present in our natural world. We have only begun to explore and develop next-generation technologies. I’m an optimist.
I suspect future energy supply technologies will trend from macro-generation to micro and be dramatically more decentralized. Such energy sources are harder for large corporations to control and profit from, so I expect the transition will be impeded by the existing energy industry looking to assert an ‘interest’ in next-generation energy supply models.
The public relations war being waged by established energy interests is a great example of this sort of anti-change activism, and their propaganda seems to have found its way into the clouded minds of a few adherents here on this list. Geology and physics will ultimately decide the day.