Growing Green: Cannabis’ Environmental Impact

What uses four times more energy than a hospital, eight times more energy than a commercial building, and 20 times more energy than a church? If you guessed an indoor marijuana grow, you would win. For the same square foot of space, marijuana leaves a huge environmental footprint according to a study by Lewis and Clark College.

In fact, a few studies—one by New Frontier—have found that the budding marijuana industry already uses one percent of the total electricity in the US, or enough energy to power 1.7 million American homes. The problem is that the cannabis industry is growing so quickly that the research and regulation of energy, water and pesticide use when cultivating marijuana hasn’t been able to keep up.

Part of the reason that marijuana uses so much energy is because of the light needed to grow effective and high-flowering plants. In many grows, 1,000-watt lamps are used to bathe the plants in sun-like conditions. These lights provide 500-times the illumination recommended for reading and produce a lot of heat, which means more air conditioning is needed. Growing rooms must be keep a fine balance of both temperature and humidity. Too much humidity and the plants will mold; too little carbon dioxide and the plants will stagnate. On top of all of that, fans are required to simulate a breeze while irrigation systems deliver water.

“The sad irony is that legalization is probably the only avenue for solving the problem, if only policymakers would confront it…”

In the end, producing a few pounds of weed has the same environmental impact as driving across America seven times.

Evan Mills, a Ph.D. who works at Lawrence Berkeley National Labs and alumni from U.C. Berkeley’s Energy and Resources Group, said last year, “The sad irony is that legalization is probably the only avenue for solving the problem, if only policymakers would confront it. Until then, some of the nation’s hard-earned progress towards climate change solutions is on the chopping block as regulators continue to ignore this industry’s mushrooming carbon footprint.”

So, what is the cannabis industry doing to cut back on its environmental footprint?

Already, cities have capped the number of commercial cannabis growing licenses—Colorado has limited it to 350—to keep energy use down. Still, even then, growers face many energy challenges when trying to grow cannabis at a large volume.

One Denver area dispensary, L’Eagle, which sells recreational cannabis and has a 2,000 plant growing facility, has switched over to partial LEDs, saving the company around $1,800 a month, according to National Geographic. It was also the first dispensary in Denver to get the city’s green stamp of approval.

Unfortunately, LED lights are not the end-all solution to the industry’s problem. Though they can increase energy efficiency, they just don’t have the horsepower to get the job done.

Marijuana can take longer to mature under LED lights, which results in not much energy being saved. Still, horticultural lighting companies like Heliospectra and P.L. Light Systems have started offering sophisticated LEDs, which can generate more light intensity as well as the color spectrum that plants need to thrive. This means that cannabis growers can use bluer lights for seedlings and shift to higher intensity and more red lights as they mature.

Rodger Rutter, the owner of Evergrow Northwest, an indoor pot-farming business in the Pacific Northwest, told the New York Times that from utility rebates he only ended up paying $72,000 for LED lights instead of the $162,000 they normally cost.

“We wanted to find a way to save energy; that was important to us,” he said.


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