The latest efficiency for current technology solar panels is only about 25% under the best conditions.....................
Correct those calculations used 23% photons to electrons not 25% it would be less if it was 25% and the modern dual band gap and bifacial panels are hitting 30% today.
So yeah fully aware of 25% PVOUT is the number you are looking for.
You could use 12% efficient but ultra cheap Perovskite solar cell in the wild and the land area would only double to 2.4% for 640EJ still not a lot on a species level.
Perovskite solar cell efficiency has reached over 26% for single-junction cells and nearly 35% for perovskite-silicon tandem cells in laboratory settings. These newer cells open up the dual band gap market at sub 10 cent per watt of PVOUT. It’s when not if. Bifacial panels of silicon can be had today whole sale for 9 cents per watt of capacity by the pallet of them delivered. Again it’s not the 1990s anymore this is 2025 and the 21st century is fundamentally different form the 20th. Old folks struggle to grasp that fact. It’s not the same world that’s just facts.