Several of us in the health professions have battled exhaustively to make efficiency changes and all too often found ourselves blocked by decrepit management structures.
Overall efficiency of the system is extremely low currently, thanks to a low concentration of those photon-catching structures, but individually they capture about 40 percent of the light's energy, meaning a higher concentration could make for very hearty soup indeed.
In the previous approaches so far, the systems have had complex structures such as organic complexes or plural photo-electrodes, which makes it difficult to improve their efficiency in response to the light.