Going green, growing greens: How the cannabis industry is addressing its energy problem


According to a nearly ubiquitously reported study, the cannabis industry has an energy problem. Indoor growing, the study authors write, contributes to greenhouse gas emissions in a “range, based on location, from 2,283 to 5,184 Kg CO2-equivalent per kg of dried flower.”

So, what does that mean? In short, it’s a lot of greenhouse gasses pumped into our already loaded skies, from Southern California (lowest emissions) to Hawaii (highest). The Colorado State University researchers added in a companion story to their study that an ounce of cannabis grown in Hawaii is like burning 16 gallons of gas.

Also, indoor-grown flower was nearly half of the $19 billion 2020 market. Indoor growing is widely expected to become the majority growing method as its light, climate and other quality controls make for much-desired, crystal-covered, high-THC buds. And, these indoor crops can be produced in multiple crops a year, regardless of what the weather outside is.

“It’s a good study,” said Shawn Cooney, an indoor farmer in Boston and founding member of the Sustainable Cannabis Coalition, emphasizing the Colorado study’s effort to document not only energy use but also how that energy is produced where the farm is located. If the energy grid in the region is coal-based, then the carbon footprint of the farm will be higher.

“It’s just the beginning of people looking at the business and not rationalizing (the issue) away but saying, ‘How can we make this a better industry?’ At that point you can start talking about where the industry is headed, as opposed to cringing every time some university professor writes a paper,” Cooney said.

While scientific studies looking at the impact of the still-emerging cannabis industry can motivate growers, consumers and policymakers to shape the market for a more sustainable future, growers are already motivated to reduce their energy use. Not only is energy expensive, Cooney points out, but growers know they need to establish best practices for their industry that regulators can follow, rather than regulators continuing to place demands on businesses at the behest of policymakers.

The circumstances around cannabis growing are also important to understand as scrutiny of the industry’s energy use grows. First, cannabis is illegal federally, so growers have to work within the energy grid and climate of the state they sell in. Each state and community has a matrix of rules unique to them and many of those rules make outdoor growing difficult if not impossible. While outdoor and greenhouse farms are where the majority of cannabis is grown, a lot of communities don’t want to see, smell or worry about kids getting into an outdoor cannabis patch.

“In contrast to other agricultural commodities in California,” writes the author of a 2020 San Jose State University study reviewing the latticework of policies around cannabis in that state, “the cannabis industry has not benefitted from publicly funded agricultural research on how to better optimize production in various cultivation settings.”

Yet, nationally, the illegal and legal markets in the U.S. are estimated to hit $66 billion by 2025, with only roughly half of that being legally grown.

“As the cannabis industry continues to grow, its negative externalities will continue to grow as well,” the study author concludes, “unless local governments develop regulatory policies that drive energy efficiencies and sustainability.”

So the race is on.

California may be first out of the gate to attempt a comprehensive review of energy use by growers by 2022, and establish standards for renewable energy by 2023, requiring growers to buy carbon offsets if they can’t meet these standards.

“Greenhouse and outdoor cultivation can drastically reduce (greenhouse gas) emissions by avoiding the practice of indoor cannabis cultivation altogether,” the Colorado study authors add.

“I see the future of cannabis being grown indoors all over the country, and that’s going to hurt,” said Dan Mcdonell owner of Maconha Farms in Mendocino County, Calif. “I think taking into account that the amount of energy consumed in a pound of indoor cannabis is significant, I don’t know, maybe it should be outlawed outright.”

Mcdonell runs 16 greenhouses and argues that outdoor and greenhouse-grown cannabis can fulfill consumer demands if allowed to grow wherever the climate works, like the wine industry, while acknowledging that water demands can be an issue for these growing platforms.

“This plant is meant to be in the sun, not inside under artificial lights,” Mcdonell said, adding that the quality of outdoor versus indoor buds is often marketed around THC levels associated with indoor growing. High THC, he said, “might not be as big a factor as people make of it now … terpenes and combinations of cannabinoids can produce a better high than just high THC.”

With 20,000 square feet of indoor and three acres of outdoor cultivation, Mackie Barch, co-founder and chief cannabis officer at CULTA in Maryland, has significant interest in both worlds.

“You guys out West have such a different perspective on things, because it’s been so normalized out there for so long,” Barch said. “This is like aliens have landed back East. We’re a very very very long way from cultural normalization of business practices.”

Barch agrees that encouraging or allowing outdoor and greenhouse growing is an important step in combating cannabis’s energy problem. Most marijuana products sold are oils or edibles of some sort and those don’t require perfect, consumer-enticing buds, he notes.

When CULTA moved some of its production indoors, Barch explained, they started with LED lights and built around those, after testing whether LED lights could grow high-quality buds.

“We started building everything in LEDs, that was the first stop, and then we started looking at our power bills and going, ‘Oh my god,’” Barch said.

Switching to LED lights — which are much cheaper to operate and let off much less heat than the standard high-pressure sodium lights — requires a lot less energy to control heat in a building, he said. But, that also means retrofitting a building already using the older-style lights, modifying its HVAC systems etc., is much more complex and expensive than simply twisting in new light bulbs.

Barch hopes CULTA’s growing production can become carbon neutral in a decade, through efficiency but also forms of co-generation such as solar panels or generating electricity with combined heat and power (CHP) that use a fuel source such as natural gas or biomass.

“The industry is really taking it upon itself to tackle this issue,” he said. “While you haven’t seen a major push yet, you’re going to see it. … This industry is going to be growing by double and triple digits for the next decade, and if we don’t get our hands around sustainability, we’re going to have a PR problem.”

On that front, Cooney from Sustainable Cannabis Coalition said his group is working to provide cannabis growers with tools and standards that help them to know and document their greenhouse gas position. They hope to have an app available for producers soon that can help them account for, track and report their carbon footprint.

“So they can talk sanely about what their sustainability position is,” he said. “They can say to their customers, their investors, the state of Massachusetts or Colorado or California, this is what we’re doing.”


Jake Ellison has been an award-winning journalist for 30 years in the Pacific Northwest (primarily at the Seattle Post-Intelligencer) covering science, higher education and cannabis legalization. 

Jake Ellison