4 ms·

Wouldn’t 99% be good? Why are we celebrating shitty efficiency?

• detaro 4y ago
  200% would be even better!
• thombat 4y ago
  So a panel that looks like Vanta Black, but also at non-optical wavelengths? Better efficiency is being pursued but the engineering behind real products will always be the result of balancing design constraints: https://en.m.wikipedia.org/wiki/Solar-cell_efficiency https://en.m.wikipedia.org/wiki/Solar-cell_efficiency
• azalemeth 4y ago
  There are a bunch of physical reasons why you can't have a ~100% efficient solar cell – obviously thermodynamics chief among them, but also effects like the fact that the bandgap is finite (yet the sun's black-body spectrum has energy radiated below it) and the fact that solar cells themselves will heat up and re-radiate photons they absorb. For a long time, solar cell efficiency was around ~10-20%. There's actually a theoretical upper limit, the Shockley–Queisser limit, of a bit less than 34% for a single p-n junction photocell. [1] This is a tandem cell – for which higher efficiencies are possible but costs go up. The thermodynamic limit is reached if you have an infinite number of layers. Obligatory plot of progress vs time: https://upload.wikimedia.org/wikipedia/commons/2/25/Best-research-cell-efficiencies-rev220126_pages-to-jpg-0001.jpg https://upload.wikimedia.org/wikipedia/commons/2/25/Best-res... [1] https://en.wikipedia.org/wiki/Shockley%E2%80%93Queisser_limit https://en.wikipedia.org/wiki/Shockley%E2%80%93Queisser_limi...
• _ph_ 4y ago
  Shitty efficiencies[1] haven't stopped us from using combustion engines in cars for a century. But while combustion engines use expensive fuel, these solar cells use sunlight, which is free. So which technology should we celebrate? [1]: 20% is already quite a good efficiency for a car in mixed traffic. That doesn't even account for all the energy used to provide the fuel.