You'd need to update your reasoning to take into account all the efficiencies lost in the fossil fuel creation and consumption in order to generate electricity.
The amount of energy hitting the surface of the earth is constant, assuming that the luminosity of the sun is constant. Photosynthesis as cyanobacteria/chloroplasts/chlorella perform it might be less efficient than a modern solar panel at converting the entirety of the spectrum to energy, but they did it and produced this fuel for hundreds of millions of years. Even if you get 10 times the efficiency gains on them, you reduce the amount of time it takes to produce the same energy to what, tens of thousands of years, at the same surface area as that of the oceans?
Now let's say the electricity generated is used in a way that is an order of magnitude more efficient than using fossil fuels. That takes us down to 1000-9000 years, let's say best case scenario 1000, a surface area the size of the ocean paved, to achieve the energy we have used in 100 years, and that doesn't account for the fact that we need the energy output we have now, not the output we had in 1920 which was orders of magnitude less. Constant output at current levels I would expect we would've used all that oil in under 50 years, but let's ignore that too.
Now, let's assume that that oil were to last us another hundred years at projected energy consumption rates, peak oil and all that. You'd need to pave an area of the earth, in my very rough sketch, the size of all the oceans, and process the entire earths crust for minerals for it, and keep it like this for 1000 years, to get enough energy to last humans 200 years.
I'm probably wrong about a lot of these numbers. Let's say I'm off (in your favor) by a whopping order of magnitude. You'd still have to pave an area the size of half the earths oceans to get 200 years worth of energy in 200 years. Exactly how much environmental damage do you think such a project would cause? Would you say that such a project would be more or less destructive than current climate change projections?
It's really pretty obvious, there are only 2 paths forward: get humans into space, where we can build solar panels to catch some of the unbelievably vast majority of solar energy that is not required by life on earth, out of material not currently underneath the ground life lives on, and use the lucky accident of these fuels to do it now before they run out, or take humanity down a few notches, kill three quarters of our population, somehow prevent the CO2 from our decomposition from entering the atmosphere, and start cooking with wood and cowdung again.
Or we can keep pretending that these pitches about carbon sequestration using solar and wind are actually viable and keep being frustrated that nothing is being done to stop it.
The Sahara desert is a great idea, probably our best bet. And if we can source all the material needed to pave it with panels right from underneath it, all the better. But that's unlikely, and still, that's 2% of the earths surface. Not enough surface area to cover our energy needs, despite what anyone says. If we really have reached peak oil, that is, used half or more of the oil available to us, in 100 years, that took 75% of the earths surface a billion years to produce, paving the Sahara desert won't make a dent. Even using energy from the sun 100 times more efficiently, that's still 50 times less energy than we need, 2% of what's needed, and that doesn't take into account increasing energy needs worldwide.
No, let's say that you are off by three or four orders of magnitude. Because your first estimate really is that bad, and without it, your entire "argument" falls apart.
