Scientists at Howard Hughes Medical Institute, LBNL, Kavli Energy Nanosciences Institute and UC Berkeley have reported on the ACS journal Nanoletters a way to use artificial photosynthesis to convert sunlight into chemical energy, similarly to what plants are doing (they produce carbohydrates).
Plants harvest 130 Terawatts to produce 115 billion tons of biomass each year (it is plenty of energy but the efficiency is also very high: for comparison in Italy we use yearly roughly 10 Terawatts to support our telecommunications need, 2 Terawatts by the Telecom Italia network, 4 Terawatts to power smartphones and domestic gateways attached to that network and the remaining 4 for other telecommunications Operators network active in Italy).
Technology has been used so far to convert sunlight into electricity (photovoltaic) not to convert sunlight into chemical energy, as plants do. One of the reason is the difficulty in creating an artificial photosynthesis process.
The team of scientists presented in their paper a way to do that by relying on the help of bacteria. They have created a photosynthesis cell with a photoanode made by an array of carbon nanotubes to harvest sunlight to produce H+ out of water H2O and combine it with CO2 using bacteria (xxx) to produce acetic acid. This is the basic organic component that can be further processed by another type of bacteria ( yyy) hosted over a cathode also made by carbon nanotube to produce complex substances like plastic and drugs.
The carbon nanotube are an essential component providing the big surface required to host the bacteria into a small volume thus providing sufficient density of molecules to a huge number of bacteria yielding significant production.
Amazing how we mix artificial with natural processes. Bacteria are used as very efficient chemical processes and the chip like artificial structure provides the overall chemical plant.