Comment by standeven
2 hours ago
Comparing primary energy is VERY misleading. From Marc Jacobson:
The use of primary energy on the vertical axis is an old trick by the fossil fuel industry to mislead people into thinking that one unit of fossils = one unit of renewables. In fact, one unit of primary energy for wind or solar electricity is the equivalent of three units of fossil fuel electricity.
Another trick is to pretend we need all those fossils if we switched to renewables. In fact, if we switch to renewables, 12% of the fossil fuel energy disappears because that is how much energy is used to mine-transport-refine fossil fuels+uranium for energy, and we wouldn't need to do that anymore
A third trick is to pretend we need so much energy if we go to all electricity powered by renewables. In that case, because EVs use 75% less energy than gasoline/diesel vehicles, heat pumps use 75% less energy than combustion heating, etc., energy demand goes down another 42%.
In sum, this plot illustrates the real story of where we are and where we need to go. The proper metric is end-use energy, not primary energy.
and here's the paper
Making one unit of primary energy for wind or solar electricity equivalent to three units of fossil fuel electricity is an old trick of renewable energy advocates to argue that in future we will need less primary energy.
They base this on the efficiency of older gasoline engines, which is about 25%. They ignore future improvement in fuel efficiency and disregard all current combustion engines with higher efficiency.
High-tech gasoline engines have a maximum thermal efficiency of more than 50%.
https://www.formula1.com/en/latest/article/how-f1-technology...
Very fuel efficient diesel engines have been developed for large ships because fuel costs are large part of operating costs of big ships. Low speed diesel engines like the MAN S80ME-C7 have achieved an overall energy conversion efficiency of 54.4%, which is the highest conversion of fuel into power by any single-cycle internal or external combustion engine.
https://en.wikipedia.org/wiki/Engine_efficiency#Diesel_engin...
Renewable energy advocates also like to disregard efficiency of gas turbines. Latest generation gas turbine engines have achieved an efficiency of 46% in simple cycle and 61% when used in combined cycle. And still some of the waste heat can also be used for cogeneration.
Another trick is to pretend that renewables need almost no mining-transportation-refining. According to International Energy Agency.
"The special report, part of the IEA’s flagship World Energy Outlook series, underscores that the mineral requirements of an energy system powered by clean energy technologies differ profoundly from one that runs on fossil fuels. A typical electric car requires six times the mineral inputs of a conventional car, and an onshore wind plant requires nine times more mineral resources than a similarly sized gas-fired power plant."
https://www.iea.org/news/clean-energy-demand-for-critical-mi...