A number of people made some really interesting comments on my recent CleanTechnicaarticle, “Mark Z. Jacobson & The 100% Renewable Energy Naysayers.” Some of these had to do with the problem of getting the last 20% of our energy from renewable sources, after we got to the 80% mark.
The problem is that some applications seem to need combustion, and they seem to make that last 20% daunting. Two examples are manufacturing cement and powering large passenger aircraft. I decided to make up a list of sources of renewable energy that might have some bearing on the discussion.
