I show that the nature of the energy resources available to an economy qualitatively determines long-run growth outcomes. A harvested resource such as biomass drags on growth, a mined resource such as coal enables output per capita to hold constant, and both a tapped resource such as oil and a manufactured resource such as solar panels risk degrowth if energy return on energy invested (EROI) cannot stay above a threshold. The only energy resource that can fuel long-run growth is a manufactured resource such as solar panels. Either that resource must rely on substitutable energy inputs that have a sufficiently large EROI, or it must be produced by robots that are themselves produced from robots and energy. Even in these cases, coal and oil economies may have been necessary stages on the way from a biomass economy to a solar economy.