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.
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.