A fundamental requirement that any energy supply system must satisfy for economic viability is a sufficiently high energy return on energy investment (EROI) for manufacturing, installing, operating and maintaining the system over its operating life. The question of what constitutes a sufficient return depends on the nature of the economy and society that the energy supply system is intended to support—while an EROI <1 implies a net energy sink, an EROI >1 does not automatically entail viability. Consider the limiting case in which net energy supply is zero, i.e. EROI =1. This would entail an economy consisting entirely of an energy supply sector that supported itself, but allowed for no economic activity beyond this. It’s certainly possible to imagine a functional economy along such lines, but it implies that every person living in such a society must dedicate their life to and focus all of their attention and effort on providing for the subsistence energy needs of their economic system. Such an economic system would serve no purpose beyond its own perpetuation; citizens of such a society might very well consider their lives to constitute a form of slavery to their economy. Continue reading →