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 cell

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.