I have a background in energy and I have studied these issues extensively, so I could write many pages, but I will try to be brief. We actually already have the technology to support 10 billion people at the US standard of living sustainably. It is good to think about the dynamics and embodied energy. But because typical renewable energy pays back the energy investment in about three years, if we just took the energy output of renewable energy and reinvested it, the amount of renewable energy production would grow at about 30% per year. Therefore, if we just reinvested our current renewable energy production, we would be at 100% renewable in a couple decades. The energy payback time of nuclear energy power plants (not mining) is more like one third of a year, so this is even more favorable.
The HANDY paper does not consider technological improvement, which is probably appropriate for the timescale of past collapses (but note that in the longer term, our carrying capacity has gone from millions as hunter gatherers to billions now even with higher consumption per capita, so technological change is key). However, now that we have markets and R&D, we don’t need the government to intervene to get to a sustainable solution quickly. The book “Limits to Growth” does consider technological improvement. But for some reason it estimates the carrying capacity of the earth is much below current consumption, perhaps because it does not recognize we can make nitrogen fertilizer with renewable hydrogen. I think the carrying capacity issue is why “Limits to Growth” nearly always predicts collapse.
It is conceivable that we will overreact to these slow problems much more so than we did in 2008, and this could turn into a catastrophe. But more likely these resource constraints could reduce our resilience slightly to actual catastrophes. From a food perspective, there is around a 10% chance of nuclear winter this century, and when you include lesser catastrophes like regional nuclear war, volcanic eruptions, abrupt climate change, pandemics disrupting food trade, etc., it is greater than even chance. So I am worried much more about these catastrophes than resource constraints.
But because typical renewable energy pays back the energy investment in about three years, if we just took the energy output of renewable energy and reinvested it, the amount of renewable energy production would grow at about 30% per year.
How many scarce materials would be needed? How much land area? How much toxic waste would be produced, e.g. from solar elecontronic components? Energy investment is not the only input needed for renewables.
(If you have a link that answers these and similar questions, that would be good.)
Thanks for the good questions. Wind power can use scarce materials, like rare earth permanent magnet generators. But it is possible just to use copper. Some photovoltaic technologies use scarce materials, but silicon is abundant.
US per person primary energy use is ~10 kW: Energy Information Administration. “Annual Energy Review 2007.” If we start with renewable electricity, we need less primary energy, 4-8 kW, so say 6 kW. So 10 billion people require 60 trillion watts (TW). Current wind technology could provide 72 TW: Archer, C. and M. Jacobson. “Evaluation of global wind power.” JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 110, D12110, doi:10.1029/2004JD005462, 2005. Solar maximum on land is ~6,000 TW, but practical ~600 TW: Lewis, N.S. “Powering the Planet” California Institute of Technology presentation. If solar is 10% efficient and average solar radiation is 200 W/square meter, this requires ~0.1 acre/person: 5% of ecological footprint quota, but could be in desert or on rooftops.
Of course we need to be careful with toxic waste, but landfills take up a negligible amount of land.
I have a background in energy and I have studied these issues extensively, so I could write many pages, but I will try to be brief. We actually already have the technology to support 10 billion people at the US standard of living sustainably. It is good to think about the dynamics and embodied energy. But because typical renewable energy pays back the energy investment in about three years, if we just took the energy output of renewable energy and reinvested it, the amount of renewable energy production would grow at about 30% per year. Therefore, if we just reinvested our current renewable energy production, we would be at 100% renewable in a couple decades. The energy payback time of nuclear energy power plants (not mining) is more like one third of a year, so this is even more favorable. The HANDY paper does not consider technological improvement, which is probably appropriate for the timescale of past collapses (but note that in the longer term, our carrying capacity has gone from millions as hunter gatherers to billions now even with higher consumption per capita, so technological change is key). However, now that we have markets and R&D, we don’t need the government to intervene to get to a sustainable solution quickly. The book “Limits to Growth” does consider technological improvement. But for some reason it estimates the carrying capacity of the earth is much below current consumption, perhaps because it does not recognize we can make nitrogen fertilizer with renewable hydrogen. I think the carrying capacity issue is why “Limits to Growth” nearly always predicts collapse. It is conceivable that we will overreact to these slow problems much more so than we did in 2008, and this could turn into a catastrophe. But more likely these resource constraints could reduce our resilience slightly to actual catastrophes. From a food perspective, there is around a 10% chance of nuclear winter this century, and when you include lesser catastrophes like regional nuclear war, volcanic eruptions, abrupt climate change, pandemics disrupting food trade, etc., it is greater than even chance. So I am worried much more about these catastrophes than resource constraints.
How many scarce materials would be needed? How much land area? How much toxic waste would be produced, e.g. from solar elecontronic components? Energy investment is not the only input needed for renewables.
(If you have a link that answers these and similar questions, that would be good.)
Thanks for the good questions. Wind power can use scarce materials, like rare earth permanent magnet generators. But it is possible just to use copper. Some photovoltaic technologies use scarce materials, but silicon is abundant. US per person primary energy use is ~10 kW: Energy Information Administration. “Annual Energy Review 2007.” If we start with renewable electricity, we need less primary energy, 4-8 kW, so say 6 kW. So 10 billion people require 60 trillion watts (TW). Current wind technology could provide 72 TW: Archer, C. and M. Jacobson. “Evaluation of global wind power.” JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 110, D12110, doi:10.1029/2004JD005462, 2005. Solar maximum on land is ~6,000 TW, but practical ~600 TW: Lewis, N.S. “Powering the Planet” California Institute of Technology presentation. If solar is 10% efficient and average solar radiation is 200 W/square meter, this requires ~0.1 acre/person: 5% of ecological footprint quota, but could be in desert or on rooftops. Of course we need to be careful with toxic waste, but landfills take up a negligible amount of land.