Editor’s note: This question was asked in response to Electronics Cooling’s recent webinar by Roger Stout. To view the webinar, click here.
Question: You suggested that we are already using as much total energy as we could harvest from all solar sources combined. Aren’t you being a tad pessimistic?
Answer: Yes and no. I listed my assumptions: using only 1% of Earth’s land surface for collectors, collectors are only 16% efficient, you only get 1/3 of the available hours of sunlight. Obviously some of these are high, some are low, and some are certainly outright swags. For instance, my own 5 kW array occupies only 0.9% of the property my dome house sits on, but the entire dome and garage represents 8% of the property area, all of which, in principle, could be used for solar collectors. Clearly, depending on location, using only 1% of the available land area of Earth might be ridiculously high or low; we’ve also got 3x more oceans than land, so utilizing even a small fraction of ocean surface for energy harvesting has huge leverage. Further, collector efficiency is bound to improve. On the other hand, cloud cover diminishes that 33% utilization number. All in all, I’d say I’m lucky if I’m within an order of magnitude of what’s feasible. Still, my real point is that within my own lifetime, humanity has reached the precipice of transitioning from environmentally insignificant, to environmentally dominant. That’s the main message. We can’t afford to continue to “inject” energy into the environment beyond what the sun is already delivering. That means, ironically to me in particular, that even working, clean, affordable nuclear fusion is no answer, because it injects energy not naturally found in the environment. In that sense, it’s every bit as bad a choice as burning fossil fuels. I’m now looking at fusion as a just another stop-gap to at least wean us off fossil fuels, conserving them as long as possible for needs they can uniquely fill at the present time (for instance, fuel for air transport). But we’ve got to accelerate our development of renewable energy sources, because long-term, that’s the only way we’re going to preserve our biosphere for continued civilized human occupation. And even that is asking a lot. Renewability – sustainability – those are the watchwords for the next two or three generations, or we have to move to Mars.
-Roger Stout
