Ken is presenting at Benchmark World Tour, Sydney, Melbourne, Perth next week, page-57

Talking about efficiencies, and purely from an extraction stand point;

The world has to spend about 6% of the energy it produces on the energy required to just extract that energy. With fossil fuels, extraction is forever. With wind/solar they are upfront cost technologies, as y-o-y "extraction" is just wind and sun. This would be obvious to most, recycling that 6% cost of FF extraction would be more than sufficient to build out renewable generation, compounding the decline of FF use by 6% pa, all done and dusted in 12 years.