One question I have had on my mind is about solar powered LED lighting.<p>Solar cells capture a wider spectrum than plants (plants are green ergo not green eaters).<p>At what levels of efficiency do solar cells and LEDs have to be before you receive a net gain by having the solar cells in the sun instead of the plants. How far away from that are we now?<p>Underground farming in arid regions seems like the best scope for something like this.
The Economist had some related content in this week's Technology Quarterly (<a href="http://www.economist.com/technology-quarterly/2016-06-09/factory-fresh#section-2" rel="nofollow">http://www.economist.com/technology-quarterly/2016-06-09/fac...</a>) - I made note of the 2 LED producers they mentioned: <a href="http://www.valoya.com/" rel="nofollow">http://www.valoya.com/</a> and <a href="https://www.heliospectra.com/" rel="nofollow">https://www.heliospectra.com/</a>
The next step is optimizing the plants to grow better in these greenhouse conditions - currently the plants waste lots of energy. For example my company, TAXA Biotechnologies[1], has identified a gene that doubles the rate of growth of lettuce per unit light energy. It wouldn't work in the wild as the cost is reduced pest-resistance but growing indoors there are other ways to control that.
[1]www.taxa.com
Link to the paper <a href="http://arxiv.org/abs/1406.3016" rel="nofollow">http://arxiv.org/abs/1406.3016</a>.<p>They do not seem to have accounted for the fact that the "waste" heat from current solutions reduces the overall heating bill. Of course, electrical heating is not usually as cost effective as other methods.
Greenhouse farming really could be a good way to help tackle the waste/runoff problem. I think Greenhouse farms could easily be closed systems with no need to push polluted water back into the world. The dead zone in the gulf of Mexico (all ocean dead zones actually) HAS to be dealt with pretty damn soon as I understand it...
Ceramic Metal Halide bulbs, at much lower wattage than HPS, but with more power than LED seems to be the immediate compromise. A 315w Phillips Ceramic MH will deliver a huge spectrum to the plants with less than half of the heat of a comparable 600w HPS/MH. The cost is getting very close to traditional HPS lights. LEDs do work, but they still use plenty of power, and are largely unproven. Try to find a greenhouse/grow store that stocks ANY led fixures. They have been cheap China crap for so long, that the better ones cost quite a bit of $.
It's already revolutionizing in India <a href="http://www.ujala.gov.in/" rel="nofollow">http://www.ujala.gov.in/</a>