As someone working in the greenhouse lighting industry, I might have some insight on this: 1. there is an existing technology called energy screen/curtain, with the primary function of retaining heat, but can also reduce light pollution by an order of magnitude. 2. light that escapes is essentially money lost, however it alone does not justify the use of energy screens. 3. as long as farmers have access to (relativel…
> 4. for the time being, it's a regulatory issue, just like water use (a single plant use 2-2.5 l/day) Is the 'plant' there a, say, tree or is it referring to the whole building?
water use is necessary to manage internal climate. the greenhouse was designed to keep heat inside. the plants have to cool themselves (hence the environment) by evaporation. the farmer manages evaporation rate by watering, temperature and humidity. there are many feedback loops, both negative and positive, balancing it is a non-trivial task.
btw. there's an average of 1.2-1.3 plant/m2 in most tomato greenhouses I've seen.