When I was 10 years old, I got an electronic kit for Christmas. There was an instruction how to build radio receivers, radio transmitters and other electronic constructions that were most exciting to build. The one component attracting most of my interest was the photovoltaic cell. It was advertised to give an impressive 1% efficiency. The cell of some 2×5 cm should thus theoretically be able to produce about 1W. My home build radio transmitter could go on transmitting day after day without any external input of energy, except for the daylight. I was amazed.
In recent years the photovoltaic cells have progressed; they are more efficient and much less costly. Today, research has shown cost efficient solar cells of more than 10% efficiency. Research cells are close to 50% efficiency as recently reported by NRL .
Biomass is growing in the fields using photosynthesis with just a few pro-mill efficiency. If solar cells now have 50-100% more efficient land-use for energy harvesting one may challenge the established thought that sustainable energy should mainly come from wind mills and biomass.
100 x 100 m of solar cells equal the energy production of 1000 x 1000 m energy forest.
As I reported last summer, solar cells and motion sensors are utilized to light up bus stops in remote locations in the Swedish archipelago. I say, this is just the beginning of sane commercial use. Which exciting use of solar cells can you imagine to support public transports?