A tourist asks an Irish old-timer, “How do I get to Dublin?”
The old-timer responds, “Well, you can’t get there from here.”
That’s what came to my mind when I read Michael Kelly’s brief paper “A Challenge for Renewable Energies,” at the Global Warming Policy Forum.
The gist: “In recent years the energy sector has accounted for about 9 per cent of global GDP, with the implication that the return on energy investment [ROEI] in the world economy is, approximately and as an average, about 11:1. … the narrowly defined energy returns on investment for individual fossil fuel technologies [which provide about 87 percent of total world energy] are far higher …, of the order of 50:1 for coal and gas plants and 70:1 for nuclear reactors.” So what drags it down from 50:1 or 70:1 to 11:1? “Only … the low values for traditional biomass and all the societal externalities ….”
What’s the ROEI for solar PV? About 2.5:1 now, and even if panels became free, only 3.7:1—2/3 lower than for the current total world energy mix, 92.6% lower than for coal and gas, and 94.6% lower than for nuclear. For wind? “… at most double that figure”—whether he means double of 2.5:1 or 3.7:1 isn’t clear, so let’s be generous and assume the latter, meaning wind’s ROEI would be 7.4:1 or 1/3 lower than the current world’s total energy mix, 85.2% lower than for coal and gas plants, and 89.4% lower than for nuclear.
Climate alarmists want us to get the world to 50% renewable (mainly wind and solar) energy by 2050 and 100% renewable by 2100.
Can we get there from here?
Suppose in the future much improved renewable technologies expand to meet 50 per cent of the world energy demand, while operating at a value of energy money returned on energy money invested of 5.5 (i.e. half that which applies today in the global economy), while the other 50 per cent of the energy supply is as it is today. In this scenario, the 11:1 ratio would decline to 8:1 in round figures, and we would have to reduce overall global economic activity by about 40 per cent. For the first 10 per cent cut that could be achieved by eliminating or severely curtailing high culture, tertiary education, advanced medicine, international travel and the internet. I will leave it to readers to make their own choices as to how to extend this list to deliver the full 40 per cent reduction. Clearly, this is not an attractive proposition that would win democratic support. …
Suppose instead we try to envision today’s global economy being run on the basis that the energy sector is 50 per cent of the total economy, with an implied energy return on investment of 2:1, as would be the case if current renewables become pervasive …. What would the economy look like? To support the rest of the current economy, a further 90 per cent increase in population to service the expanded energy industry, and an increase of 90 per cent in the world GDP would be required. To first order, both of these changes are impossible. Furthermore, the second order interaction effects would be enormous and serve to shrink the global economy rather further than described above to meet the population constraint.
Finally, if all the approximately 10.3 billion people likely to be on earth in 2065 were to live European lifestyles, energy demand would be over four times that which we use today, less the considerable saving expected from energy efficiency and conservation.
Punchline: Regardless whether we can or can’t, we won’t get there from here.