The article's numbers are that 1m^2 of wheat needed 20m^2 of solar panels.
That implies a 5% efficiency in the "total solar captured area" of the solar panel + LED lights compared to just sticking the plats out in the sun, which is totally independent of the plants own efficiency in photosynthesis.
(I guess coming from a site about Low Tech, their slant on the numbers might be questioned, but they certainly hold up to initial scrutiny from here...)
That implies a 5% efficiency in the "total solar captured area" of the solar panel + LED lights compared to just sticking the plats out in the sun, which is totally independent of the plants own efficiency in photosynthesis.
(I guess coming from a site about Low Tech, their slant on the numbers might be questioned, but they certainly hold up to initial scrutiny from here...)