So this accidentally made me go down a speculative rabbit hole... Cannabis is apparently a C3 plant[0]. It's also not a perennial. So while you have a point, there is still room for improving efficiency. I tried looking up what the current status with genetically modifying plants with high photosynthetic efficiency was. First thing I found was... tobacco[1]. Yeah, that's not all that useful.

More generally, I wonder if there might be some kind of "holy grail" easy-to-grow, easy to genetically modify plant out there that could be a perfect template for photosynthetic production of all kinds of organic compounds. I know people have been trying to modify algea and cyanobacteria to make synthetic biofuels directly for ages, for example. Sadly the Wiki page on photosynthetic efficiency remains fairly superficial[2], and the C3, C4 and CAM pathway articles, while a tempting rabbit hole, don't seem to help much either[3][4][5].

Also, we all know monocrop farming is not going to be sustainable: the simplicity of it makes it easier to "optimize" for farming machines, but at the cost of soil degradation, while also being more prone to diseases and weather disasters. Plus, with current improvements in automation the optimization advantage is shrinking rapidly. Could agroforestry, like the kind advocated by Geoff Lawton[6] or Willie Smits[7][8][9] be combined with this? The benefit/problem with agroforestry is that it has many different kinds of complex yields. All useful, but perhaps not so flexible. However, Smits suggests an economy based on the sugar palm as a source of bioethanol:

> And Smits said that he discovered that because of the [black sugar palm]'s special leaf structure, its year-round production and extremely efficient photosynthesis, the yield of ethanol from the sugar palm was far greater than the biofuel output from other feedstocks in use around the world. Smits says that his process can produce 19 tons (6,300 gallons/24,000 liters) of ethanol per hectare annually. That's a staggering output-to-land area ratio compared to corn, the favored ethanol crop of the United States, at 3.3 tons (1,100 gallons/4,200 liters) per hectare, by most recent U.S. Department of Agriculture yield figures. It also far outshines Brazil's sugarcane; output was assumed to be 4.5 tons (1,500 gallons/5,700 liters) per hectare in the U.S. Environmental Protection Agency's recent lifecycle analysis of renewable fuels. [A hectare is 2.5 acres.]

Keep in mind that once a tree has grown it requires less energy and material to maintain. Non-perennial plants have to grow every year, which comes with large energy and material overheads (both from the plants itself and from the labour involved). That makes the claim more plausable. (Cool little tangent: looking for more information on this Arenga Pinnata the first thing I came across was its listing as an invasive species on BioNET-EAFRINET, a knowledge database run by Kenyan and Ugandan research institutes[10]. This is the kind of work that never reaches the Western media, and I would guess it's partially because it does not fit our existing narrative biases that are still very much stuck in colonial times)

Now, bioethanol is a fuel source for cars, but sugar is a fuel source for living things. So why not use that as a form of "energy currency" for biohacking? It would have the benefit of increased flexibility. Imagine having a food forest centered around sugar palms, like Smits suggests, with a few genetic modifications for even higher energy yields, and with a lab nearby that can grow the more complex organic compounds with simpler but easier to genetically modify life-forms, like yeast. The sugar palm provides a steady source of biofuel, while the yeast (or whatever) being cultivated can be changed quickly to meet shifting market demands.

Anyway, this is all just speculation, and perhaps the losses of energy involved are so great it would not work out. OTOH, going the agroforestry route yields so many other integrated benefits like local climate control, CO2 sinks and a fresh water supply in the groundwater that I expect it will be a net win when viewed holistically.

[0] https://old.reddit.com/r/botany/comments/63ybgx/c3_and_c4_pl...

[1] http://science.sciencemag.org/content/363/6422/eaat9077

[2] https://en.wikipedia.org/wiki/Photosynthetic_efficiency

[3] https://en.wikipedia.org/wiki/C3_carbon_fixation

[4] https://en.wikipedia.org/wiki/C4_carbon_fixation

[5] https://en.wikipedia.org/wiki/Crassulacean_acid_metabolism

[6] https://www.discoverpermaculture.com/video-1-pdc-2019

[7] https://news.nationalgeographic.com/news/energy/2011/06/1106...

[8] https://vimeo.com/8724530

[9] https://www.ted.com/talks/willie_smits_restores_a_rainforest...

[10] https://keys.lucidcentral.org/keys/v3/eafrinet/weeds/key/wee...