Research from LUT University and 14 additional leading international universities suggest that the new system would be based largely on solar and wind energy, energy storage, sector coupling, and direct and indirect electrification of almost all energy demand. An energy system that is 100% based on renewables has emerged to become scientific mainstream.
I haven’t looked at this study yet in detail (but I will when I have time), however I’m suspecting they’ve missed or ignored some huge sectors.
There is at least one study that suggests effectively the opposite for just Australia, and Aus is a particularly good example because it actually has relatively low industrial energy use.
https://theconversation.com/itll-be-impossible-to-replace-fossil-fuels-with-renewables-by-2050-unless-we-cut-our-energy-consumption-189131
Compare Australia’s energy flow graph with that of China and the USA and then try to work out the numbers to show just how much new solar+wind+storage will need to be built to fill in the difficult-to-electrify but major sectors and you’ll see just how big the problem is:
https://flowcharts.llnl.gov/commodities/energy
I think the world might be able to largely electrify ground and sea transport, and maybe home heating, together with a net-zero electrical grid, all by 2050. However that’s just a small portion of the total energy use in the world.
It is also important to realize that there will be no peaks or valleys in the electricity demand graphs once all things are electrified (or even once just ground transport is electrified). This means all intermittent power generation has to include sufficient storage and or other backing for when it isn’t working.
From my own back-of-the-envelope calculations I find that renewables (other than hydro-electric) are at least one order of magnitude, and probably two orders of magnitude too far behind the fossil-fuel powered sector, while storage is at least three orders of magnitude too far behind. I think nuclear power will have to play a much larger part, but it can just barely make it to the table in large enough amounts by 2050, and it also requires some re-engineering to have a closed fuel cycle and use new fuels like thorium, and much of this is still research (though CANDU reactors have already been demonstrated to burn thorium efficiently).
There is also quite a lot of speculation in just exactly how some huge sectors can be electrified. Cement and steel being two. Sure there’s green steel being produced now, but China is also still building and planning to build numerous new coal-fired blast furnaces and smelters that may have to all continue running until after 2050. Also there are as yet no 100% net-zero commercial airline flights to book, and none on the near horizon either.
Add politics and capitalism to the matter, especially in the USA and China, and it seems very unlikely that the world will achieve net-zero emissions by 2050.