Global bioenergy capacity as constrained by observed biospheric productivity rates

Virtually all global energy forecasts include an expectation that bioenergy will be a substantial future energy source. However, the scale of this potential resource remains poorly understood because of uncertain land availability and yield expectations. Here, we used climate-constrained, satellite-derived net primary productivity data computed for 110 million square kilometers of terrestrial plant production as an upper-envelope constraint on primary bioenergy potential (PBP). We estimated the maximum PBP to realistically range from 12% to 35% of 2009 global primary energy consumption, with yield potential ranging from 6.6 to 18.8 megajoules per square meter per year-roughly four times lower than previous evaluations. Our results highlight many recent bioenergy evaluations as overoptimistic, which we attribute to a failure to adequately apply biophysical constraints in estimates of yield potential. We do not advocate bioenergy production at the levels reported in this analysis; instead, we simply report the ceiling for PBP based on current planetary productivity.