I can believe that oil accounts for something like 24% of the energy required to produce energy for non-oil sources of energy, since oil represents about 33% of total energy consumption according to BP. It would be hard for other energy products to escape using oil.
I can believe that oil is becoming too expensive for consumers to afford–that is the way I think about the situation. That could come from too much human energy going into production, or it could come from too much being spent on leasing the land, or it could come for a variety of other things, including too much oil being used in oil extraction. - Gail Tverberg