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This IEEE article makes some questionable extrapolations in my opinion. First, they start with 2017's global primary energy consumption of 600 PJ, and then round it up (by 66%!) to 1000 PJ ("for simplicity"). Then, 1000 PJ is used as the baseline that we would need to replace with zero carbon sources, leading to scary-sounding propositions like "covering roughly 1.6 percent of the world’s land area with (solar) panels". But that's misleading. Up to two thirds of the primary energy we "consume" each year is wasted: it is used to pump, refine, distribute, combust, or otherwise perform work and/or create heat that is not directly needed or wanted for the desired "energy service", e.g. moving a vehicle or lighting a home. Electricity generated from fossil fuel combustion has an immediate primary energy loss of 40-70% due to the inefficiency of heat engines. Wind and solar power plants do not. For example, if a solar plant produces 1GWh of electricity in a day, the full 1GWh is considered "primary energy production", while a natural gas plant that produced 1GWh of electricity in a day may have consumed 2-3GWh of natural gas "primary energy" in order to do so. Similarly, electric vehicles are much more efficient than combustion engine vehicles at converting "intermediate energy" into useful work (a charged battery or refined gasoline into motion). Heat pumps are often more efficient at heating spaces and water than burning gas. So, if we are able to generate most of our electricity from renewable sources, and electrify all ground transport, space/water heating, and many industrial processes, our primary energy use will be significantly lower in the future than it is today! That's not to say there aren't major technical and political challenges ahead to mitigating climate change, but oversimplifications that make the problem seem harder to overcome are of limited usefulness. Further reading: IEA underreports contribution solar and wind by a factor of three compared to fossil fuels
http://energypost.eu/iea-underreports-contribution-solar-win... Energy flow charts:
https://flowcharts.llnl.gov/commodities/energy |