Trees (plants in general) already do photosynthesis really well As I understand it, that's not exactly true; photosynthetic compounds are very efficient at har

Trees (plants in general) already do photosynthesis really well As I understand it, that's not exactly true; photosynthetic compounds are very efficient at harvesting light, but the chemical conversion to energy-carrying compunds is rather inefficient, I believe on the order of 1%. That said, those compounds are probably more valuable per joule than electricity since there is no storage problem, so it's hard to compare the two. The reason we can't simply genetically engineer an organism that converts sunlight into electricity (or fuels) is that at the moment, neither the photon harvesting process nor the chemical conversion process are well enough understood to try to replicate.