“If we cut the numbers in half three times, the emissions of cannabis facilities would still be higher than other buildings.” In a recent webinar, the Cannabis Research Center (CRC) offered some research results on the environmental impact of indoor cannabis production, with the aim of raising awareness about these challenges. The researchers have studied what the biggest contributors to the emissions are, as well as the ineffectiveness of some seemingly helpful solutions. See the video below to watch the full webinar.
The biggest contributors
Hailey Summers, Director of Technology & Modeling at Soil Metrics, focused on understanding the greenhouse gas emissions of growing cannabis indoors, at a typical commercial scale indoor facility. With a research team of mechanical engineers, they built a model that calculates the energy and materials needed to grow in a typical indoor setting. At the end of this, the model tells you all of the energy and material for the entire facility to grow indoors. “I also do lifecycle assessment, which zooms out and takes that material and energy and overlays emissions. In order to do that, you have to look upstream, at the emission of the manufacturing of the fertilizer you use, as well as downstream, at the emission caused by the waste you produce.”
According to Summers, the results showed that there is about up to 2,5 times difference in emissions depending on where in the US you are growing, largely an effect of the weather. They made a breakdown of the contributing categories of the total emissions in ten different cities. In all locations, the largest source of greenhouse gas emissions is HVAC (heating, ventilation and air conditioning). “On second and third places (the position of which varied per location) are the grow lights and how much bottled CO2 you are providing to increase your growth rates.”
Ineffective solutions
Evan Mills, Energy & Climate Scientist at Lawrence Berkeley National Laboratory, explains that energy intensity of indoor cannabis cultivation specifically is off the charts. “Indoor cannabis growers use 10-100 times more energy than other types of buildings. This means that energy efficiency as we know it won’t suffice. You could cut this number in half three times and cannabis growers would still be more energy and carbon intensive than hospitals and restaurants, for example.” However, some of the seemingly helpful solutions are actually more ineffective than people may think. “Finding a solution is much harder than it seems. For example, we naturally think about solar energy. However, for large cannabis cultivators it is impossible to achieve net zero energy by using solar power. This is because the energy necessary is so intensive that you would need roughly 25 times the roof area in panels to offset that energy use.”
For more information:
Berkeley Cannabis Research Center 
crc.berkeley.edu