The energy problem is mentioned almost in passing, but it could be a deal breaker for this type of farming.
Ventilation, heating and delivering light for photosynthesis require vast amounts of electrical energy, which, according to the article, comes mainly from diesel.
Averaged over a day, the sun provides > 12kWh per m^2 in farmable regions (estimated). It takes 70 days to grow cabbage, so for 1m^2 of cabbage that would amount to 168$ at 20cents/kWh.
> The energy problem is mentioned almost in passing, but it could be a deal breaker for this type of farming.
Indeed. Some harsh places do have lots of essentially free energy, though: 100% of Iceland's electricity comes from a combination of geothermal and hydropower; 99% of Norway's from hydro (source: Wikipedia). I've been wondering for a while if they could use that for this kind of agriculture. Looks like it might work.
It is expensive of course, else they would have been doing it for a long time.
But 12kWh/m^2 is for direct sunlight which cabbage etc. probably do not need, as they will have had some thoughts into that, also other hydroponic farms like in Singapore have the same problem. Also the light is tinted more violet and thus more efficiently usable for the plants. And I would not count with 20ct/kWh, as they probably pay industrial rates (though I have no idea how much that is over there).
You're right, industrial rates in Anchorage are around 11ct/kWh.
Also, it's possible to use LEDs tuned to the absorbtion spectra of chlorophyll, as you say.
If my back of the envelope calculations above are wrong by more than an order of magnitude, it might in fact be a commercially viable option for farming.
Is this [1] the Singaporean project you were refering to? They probably don't need heating, but nonetheless their quoted energy needs of 3$/month/structure are astonishingly low.
A 400W arc lamp plus losses (possibly bringing the total to 600W) was enough to grow 3x3ft. of plants in soil. Plenty of this light was in the green area so not absorbed by plants. I have never seen lima bean plants grow so big or be so productive (4th harvest of the year in december.) I don't want to plant anything outside anymore after this.
"Plenty of this light was in the green area so not absorbed by plants."
This isn't true. The majority of light from an HPS light is green, yet huge crops are grown using that light all the time. Plants utilize almost every visible wavelength (and some invisible wavelengths) to some extent. LEDs generally just focus on the wavelengths that have been determined to be efficiently utilized. It is all however still 100% crop-dependent. Some plants simply hate LED lighting because of the missing spectrum (like my orchids.)
Gotta remember photon physics - a photon gets absorbed and then another photon is re-emitted at a lower wavelength. That is just the nature of thermodynamics, second law specifically.
I think the most remarkable part of my basement garden was that I did not put all that much effort into it. I got a Lithonia "high bay" 400 HPS fixture, reasoning that the reflector on a lamp made to be mounted high would focus the light in a smaller area. I just put a cord on it and hung it from a chain.
Except for the lamp, it is just like growing plants in pots outside, except there are 90% less insects and no hungry critters to snack on your crops.
I did some experiments with adjusting the lamp timer and long days didn't keep my beans from producing. Some plants want "seasons" but mine didn't seem to mind.
Now I have a wife, and a basement again, and we are both interested in starting a small "farm." LEDs are viable now and I want to look into this.
"Space buckets" are probably the smallest scale you can easily do. With the red/blue grow LEDs you can get more usable light from a solar panel than straight sunlight can provide.
I've been looking for a change from outdoor gardening and a high density 1 m^2 indoor plot with 100W red/blue LED + 100W panel + automatic watering system sounds like a fun combination. Plus I can finally try growing tropical fruit and vegetables.
I guess I messed up the math the first time around because I'm getting something different this time.
* 45% of sunlight is in the photosynthetically active wavelength range
* Solar cells are 20% efficient
* Red LEDs are 39% efficient and blue LEDs are 35% efficient
So no, I was kind of off base there. Straight sunlight is still 6x more energy for plants. But it is close! 40% efficient panels exist and my LEDs efficiency numbers were from 2012 so the gap might be smaller. If you do this calculation yourself, remember to ignore lumens. They are a human perceptual unit and are completely meaningless for plants.
Now for human-visible light it is a little different. With the most efficient solar cells and white LEDs we can do better than the sun. (Straight sunlight is 93 lumens per watt. A 40% solar cell and 250 lumen/watt LED outperforms the sun.) Maybe this is what I was thinking of.
"Ventilation, heating and delivering light for photosynthesis require vast amounts of electrical energy, which, according to the article, comes mainly from diesel."
They must have forgotten about thermodynamics. Even with LED lighting, there's still a fair amount of generated heat to deal with. Also, with LED lighting, you reduce the amount of light actually required for growth as you focus on the more actively-utilized wavelengths of light.
As long as they use the diesel for controlling atmospherics, the rest of the place could easily be done on solar + sufficient battery bank. Arctic and Antarctic insolation is actually much higher than a good portion of the globe. [1]
To the various critics: A) As someone noted, this is a small town. B) It has a high unemployment rate and it is very remote, so there is both lack of capital and high up front costs. C) It is a tribal culture whose traditional diet is hunter-gatherer based local foods. D) It is so expensive to import produce that this project is already competitive with existing produce prices. The value lies in the fact that it is fresher. They hope to get costs down, this is why they are talking about wind power.
I will add that the article only briefly touches on the lack of roads in Alaska. Alaska has something like six times as many pilots per capita as any other state. Due to the extreme weather during the winter, flying is a common form of travel. This adds to the logistical challenges -- and expense -- involved in trying to import new technologies of this scale.
An economics professor and one of her students are walking down the street together. The student says “Hey, look, there’s a $20 bill on the sidewalk!” The professor replies by saying “That’s impossible- if it really were a $20 bill, it would have been picked up by now."
I found you point to be, because economists who have done many years of study are stupid and won't pick up $20 because of their many many years of study in the subject would for some reason ditch logic and not pick up a $20 bill.
They are stupid people who study at university who reduce brain capacity.
Maybe I'm stupid too but, if wind power worked there then that can be the project, no need to add the agriculture on top of it.Why the hell make it harder and use it on only a untested (For viability) growing machine that might make peoples lives better?
> By that reasoning, it makes no sense to install wind power anywhere, because surely in most other cases there were existing power plants, too.
The difference is installing wind power for general purpose use, vs installing it specifically for a single project.
Installing some new power source specially for one project is a red flag, exactly like he says. If it was a good idea it would be installed for general use.
So people who try new experiments should keep mum about it until they've proven complete and total success ? If we didn't combine our knowledge to improve on unsuccessful attempts we'd still be hunting and gathering.
He's saying that installing some new unproven power source at the same time that you are installing some new unproven hydroponics system is a red flag.
You don't do two risky things at the same time when you don't have to.
Wind makes sense in a big way too. If you have a building that's heated on the inside, and the air is still outside, it won't lose as much heat to the environment as it would if the wind was blowing at 30mph.
Much like how solar is super useful on bright hot summer days in the south... It gives the most power when you want the AC on the most
If it's efficient for the hydro setup to use wind for heating, why not the rest of the village? My point stands?
A better example 'might' be plants can take random times of darkness in their stride so random blackouts don't matter. But given the high cost of the setup I doubt you'd want to screw with efficiency.
Because there are other things to consider besides efficiency. You don't just swap out your stack on a whim, because you lose other things like experience. There are probably people up there who can fix a diesel generator in a snowstorm blindfolded using a part they had in their garage from 10 years back. They could probably fix a wind turbine.
But probably isn't the word you want when your whole town is dependent on that power source. So you start small, fix the problems that will arise, gain a knowledge base, and THEN move on to bigger things.
Up until very recently, fossil fuel was cheap and there was little incentive to invest in other resources such as wind or solar. Furthermore, there was relatively little political incentive to avoid fossil fuels.
Both of these things have changed and large amounts of money have subsequently been invested in renewable energy sources, making them cheaper (mass-produced) and more reliable (better technology).
If you were to re-build the town today, wind farms and battery storage may well be the most economic choice, but to switch to wind, it not only has to be cheaper (and more environmentally friendly) but also so much cheaper that the initial investment costs are returned in a reasonably timeframe.
Nobody said you can't use wind energy for more than one thing. In addition, demand isn't static (for a village). Whereas demand is static for the heating of the greenhouse, and only changes twice a day for the lighting. So wind energy could be utilized more efficiently.
Averaged over a day, the sun provides > 12kWh per m^2 in farmable regions (estimated). It takes 70 days to grow cabbage, so for 1m^2 of cabbage that would amount to 168$ at 20cents/kWh.