New research uncovers carbon footprint of cannabis grown indoors

Posted at 6:47 PM, Apr 08, 2021

GYPSUM, Colo. -- On the western slope of the Rocky Mountains sits a cannabis farm 8,200 feet in elevation. Pot Zero is owned by Rob Trotter and his wife.

“The zero part of it is that we are zero carbon footprint and that’s kind of a big deal I think in the marijuana world these days because folks are going to find out that indoor growing and greenhouse growing are extremely energy consumptive,” Trotter said.

Pot Zero is a once-a-year outside grow. Vegetative growth is three inches per day in the middle of summer because of the sun’s high intensity at their elevation. However, cannabis grown indoors is a whole other world.

“You can control that indoor climate so well that you can really dictate the product,” graduate student Hailey Summers said.

Research on the environmental impact of cannabis grown indoors has been quite limited, but a new study led by Colorado State University graduate student Hailey Summers is uncovering the carbon footprint of the rapidly growing cannabis industry in the U.S.

“We found that generally your climate control systems – so your heating, air conditioning and ventilation – were the largest form of emissions," Summers said. "And then it was high-intensity grow lights, and then a material input of carbon dioxide. So carbon dioxide is actually pumped into indoor facilities to increase photosynthetic rates – so to get your plants to grow bigger faster and just generate more product.”

When mapping the regions with the highest greenhouse gas emissions, Summers says the Colorado Rockies and Midwest were more concentrated than coastal areas.

“The weather plays a big role because plants need a constant supply of fresh air and that fresh air comes from the outside," Summers said. "So if you’re in Colorado for example and it’s cold, you have to treat that air to get it to become comfortable for the plants and it takes a lot of energy.”

What if that energy came from a renewable source? Trotter says he's been powering his farm with a hydro-electric turbine since 1993.

“It drops 170 feet from a quarter mile up above to here," Trotter said. "So it’s as if you’re 170 feet down in the ocean right now and your pressure at that point would be about 70 pounds of pressure.”

He says the energy from the turbine has been powering all his lights and fans for 28 years for his home and six years for Pot Zero.

Trotter says he hopes other pot growers will follow his lead. Especially considering they would save money in the process.

“If you’re in an energy-consumptive business and you want to stay in business, reduce your energy costs," Trotter said. "If you reduce your energy costs, you reduce your carbon footprint and your pollution.”