Electricity Cost per month:
I sat down yesterday and crunched the numbers to get an idea of what my power bill for running the system under lights will be. I called my power company and they charge $0.1143 cents per KW. It is a bit more pricey than some of the other places I have lived... but only by two cents or so. That being said... the power grid in my area is fed by endless fields of massive wind turbines and solar
panels. Probably why it costs more.
Each of my four light fixtures run four 15W LED T8 lights each (60W total). I really need to put a meter on them to see what they actually draw because most LED products use less wattage than what they claim. Anyways, this is the number I will use to get a base idea.
60W x 4fixtures = 240W total for the lights
240W x 12hrs per day = 2,880W per day = 2.88Kw
2.88KW x $0.1143 cents = $0.329 per day in cost
$0.329 x 365 days = $120.08 per year to run the lights @ 12hrs per day
The water and air pump
combined cost about $24 per year running 24/7. So $24 for those and another $25 for good fish feed (Or make your own for free) would be all your costs in a greenhouse
I conclude that if my system is able to produce much higher quality lettuce... year round in the shade of the garage under cool lights... this will be worth it. My wife spends Much More than $10 per month on low quality lettuce at the store.
Not to forget that the store lettuce has had who knows what sprayed on it... and lettuce looses 80% of it's nutrition within the first day of being picked.
That is not the whole picture either though. For classically farm grown lettuce at least the following things happen in order for the lettuce to make it into your belly.
1. The soil samples are taken via machine over the entire field and they map out nutrient deficiencies.
2. Then a series of things happen to prep. the soil for planting such as... plowing a couple of times... deploying oil and chem based fertilizers... or spreading manure based fertilizers... and then sowing the seed via machine. Each time the ground is plowed... even more carbon
is released into the air.
3. Next comes water and sun. Either natural rain or well water is sprayed. Runoff
waterways. Introducing soil from erosion and the fertilizer that was added to amend the soil.
4. As the plants grow they will begin to have pest/disease issues since they are planted in mass as a mono crop. Things like herbicides, pesticides, fungicides, and/or each plant gets a physical barrier such as insect netting (that was manufactured elsewhere and shipped across country). Then these chems.. if used are leached into the soil and into local waters.
5. The plants are harvested either by machine or by hand and loaded onto a machine that they are following.
6. The plants are processed/washed and placed into plastic containers (produced from oil and shipped across country before hand).
7. The plants are refrigerated (More energy
8. The plants then work their way through a network of shipping. Requiring more fuel/energy to both move them and keep them refrigerated the whole time.
9. They are placed on the shelf waiting for purchase. More refrigeration time.
10. You purchase the lettuce with your money (which took energy to make) and then drive home using more energy.
11. You throw it back into the fridge when you get home.
12. You wash it again to consume. Throwing your plastic into the garbage.
I don't know how you would calculate it all out, but I suspect that even if you go to this extreme path of growing aquaponics inside using a fake sun/lights. You and the environment are much better off for it. Classic gardening
done right would be best though. However, the windows for good quality lettuce are small in my area.
My wife eats an INSANE amount of lettuce too. lol Sooo many plastic packages will be kept out of the garbage. That alone will way more than make up for the materials used to build the system.
I built this system to be a little lettuce factory. I plan to grow only loose leaf lettuce that can be harvested from many times. Setting it up for a quick turn-over rate.
I just threw down some seed directly into the gravel to get her up and going. From here on out as soon as lettuce is removed from the gravel... a 4 week old started plant will immediately go into it's space. I should be able to harvest a head every 4 weeks per square foot doing this. HOWEVER, if I grow the cut/come again head types my yield per square foot should be higher and I will not have to plant out as many seedlings. Saving time.
In early Spring I plan to clone at least one Shangri-La Mulberry tree, about two Illinois Everbearing Mulberry, and at least 6 Violette De Bordeaux fig trees. That and all of the clones I have made so far should cover me for power costs for a few years.
I am attaching a pick of the clones I just pulled out of the system and the spectrometer results
of my lights. 4 Improved Meyer Lemon trees in 5gal pots (One is about to be traded for several batches of chicken
eggs and several large goldfish from a pond
), a goji berry, two Sages, and two Rosemary plants.