Agri-PV is one way of using the thermal budget (and a great one from a habitat-harm perspective as it causes a net reduction in human-occupied land).
The albedo problem is the opposite of what your are thinking as it is another source of radiative forcing from putting a mostly black thing in the sun.
A Shockley-Queisser limited solar panel mostly only reflects IR. So where your plants/dirt might have an albedo of 0.3, the solar panel absorbs 80-95% of the light (albedo 0.05 to 0.2). 20-30% becomes electricity (and later thermalises when used).
This gives you a net forcing on the order of 100-250W or so _somewhere_ on earth for every m^2 of pv. If you cover too much land the radiative forcing is on the same order as GHG, hence the ~1% limit. 200-300W of work for 100-250W of new heat is a pretty fantastic deal compared to other options though.
Putting it above existing asphalt or a similar surface is 'free' because albedo is already 0.1 there. Similarly wind is free from a radiative forcing perspective.
Putting the panel in existing (light coloured) desert is much worse because deserts have an albedo around 0.4-0.6 so you are making 400-550W of new heat for your 200-300W of work.
This also leads to the interesting thought of placing bifacial tracking modules sparsely on low albedo dead surfaces and painting the surface white for a net reduction in thermal forcing (is there a 1000km patch of volcanic rock somewhere? Gobi desert?)
In the same framework, every joule of nuclear energy is a new watt of heating, and if it is from a steam engine, it's more like 3W (or even 5W once you include post-reactor heat as well as xW of heat for every 1W of pre-reactor work inputs of mining, milling, and enriching low quality ore).
Of course these all only become relevant if we slash carbon intensity to under 2% of what it is today and continue trying to grow our energy usage exponentially.
> Putting the panel in existing (light coloured) desert is much worse because deserts have an albedo around 0.4-0.6 so you are making 400-550W of new heat for your 200-300W of work.
Yeah, but the heat doesn't penetrate to the ground any more, which should help with water retention?
You might make your desert nice, but you're still doing a climate change if you try to install more than a few hundred TW of solar panels.
Ideally you make the desert nice and then take a chill pill before covering all of the deserts and settle for somewhere in the range of 2-100kW per human as a steady state economy powered by a mix of wind, solar, geothermal, and maybe some nuclear.
Unenriched uranium will fission eventually, but you're talking trillions of years. In a fission reactor, the U238 atoms are placed close enough to a minority of U235 atoms and to each othekr that neutrons from one fission will trigger the next at a rate just short of running away exponentially.
There are some ore bodies that are concentrated enough to fission faster, but they are rare (and not the uranium that is typically mined for fuel).
The albedo problem is the opposite of what your are thinking as it is another source of radiative forcing from putting a mostly black thing in the sun.
A Shockley-Queisser limited solar panel mostly only reflects IR. So where your plants/dirt might have an albedo of 0.3, the solar panel absorbs 80-95% of the light (albedo 0.05 to 0.2). 20-30% becomes electricity (and later thermalises when used).
This gives you a net forcing on the order of 100-250W or so _somewhere_ on earth for every m^2 of pv. If you cover too much land the radiative forcing is on the same order as GHG, hence the ~1% limit. 200-300W of work for 100-250W of new heat is a pretty fantastic deal compared to other options though.
Putting it above existing asphalt or a similar surface is 'free' because albedo is already 0.1 there. Similarly wind is free from a radiative forcing perspective.
Putting the panel in existing (light coloured) desert is much worse because deserts have an albedo around 0.4-0.6 so you are making 400-550W of new heat for your 200-300W of work.
This also leads to the interesting thought of placing bifacial tracking modules sparsely on low albedo dead surfaces and painting the surface white for a net reduction in thermal forcing (is there a 1000km patch of volcanic rock somewhere? Gobi desert?)
In the same framework, every joule of nuclear energy is a new watt of heating, and if it is from a steam engine, it's more like 3W (or even 5W once you include post-reactor heat as well as xW of heat for every 1W of pre-reactor work inputs of mining, milling, and enriching low quality ore).
Of course these all only become relevant if we slash carbon intensity to under 2% of what it is today and continue trying to grow our energy usage exponentially.