If 9 billion humans consumed energy at USA per capita levels, the total annual energy consumption would be approximately 2,565 exajoules. This is more than four times the world’s current total annual energy consumption (around 604-620 exajoules in 2023).
2,565 exajoules of energy, provided by an 80% oil and 20% coal split, is equivalent to approximately 350.3 billion barrels of oil and 27.3 billion short tons of coal annually and growing with every new human added.
Annual energy from oil:(2565EJ times 0.80=2052EJ
Annual energy from coal:2565EJ times 0.20=513EJ
The technically recoverable resources of each at any cost would last at these consumption levels
Oil: 4.46 years
Coal: 50.1 years
You cannot have 9 billion living at USA levels on this planet using fossil fuels it is mathematically impossible in the long term.
Nukes could do it but you need to Henry Ford mass produce them.
Total annual energy requirement (2,565 EJ) by the annual energy output of a single 1.5 gigawatt reactor (0.047304EJ/year) = 54,225 1.5 gigawatt reactors would be needed to supply 2,565 exajoules of energy annually.
Solar absolutely can do it it’s the largest single source of primary energy by far on the planet.
The total solar energy striking the Earth’s land surface per year is approximately 3.4 to 3.85 million exajoules.
It would take 1.2% of the area of the Sahara to provide the 640EJ to provide 2565EJ is nearly exactly four times more. So 4.8% of the Sahara lifts all of humanity to USA levels of energy consumption. Of course you wouldn’t do it in one spot but every desert on war th between 30N and 30S has nearly identical insolation rates so really any land area of equal size spread out anywhere between 30-30 would work.
Engineered Geothermal could do it as well.
“A 2006 MIT report estimated that over 200 ZJ (200,000 EJ) would be extractable with existing technology (at that time) from enhanced geothermal systems (EGS) in the United States alone, with the potential to increase this to over 2,000 ZJ with technology improvements.”
This is the tech that unlocks the top 10km not 3km they are getting rates of penetration of 5 meters per hour in solid granite. 3000 metres is just 25 days of drilling. That’s shorter than a typical deep SWD well in the Permian basin.
https://interestingengineering.com/energy/us-firm-record-breaking-drill
EGS works everywhere on this planet the hydraulic stimulation aka fracking to make a EGS system is identical to shale wells it opens up tens of cubic MILES of rock for heat mining.
Solar, nukes, geothermal those are the only way to have 8-9-10+ billion humans at EU levels of energy consumption let alone USA levels.
Again it’s just math, which doesn’t have feelings, beliefs, politics, gut feelings or some other nonsense.
Math it’s universal.