Back in October of last year, I blogged about the toll a certain brand of very lucrative “homegrown” agriculture is taking on the environment in Northern California’s Emerald Triangle — Mendocino, Trinity, and Humboldt counties. Yessir, I’m talking about the energy-intensive indoor cultivation of what’s considered to be America’s largest cash crop: Marijuana.

In that post, I mentioned that along with an increasing number of home invasion-style robberies and residential fires, household energy use in those areas has spiked dramatically. According to a study conducted by Schatz Energy Research Center at Humboldt State University, electrical use per household in urban areas of Humboldt County has shot up 50 percent since 1996, while in Arcata and more rural areas, household electricity use has jumped 60 percent.

Opening with a question that you needn't be stoned out of your mind to answer — “what kind of facility has lighting as intense as that found in an operating room (500 times more than needed for reading), six times the air-change rate of a biotech laboratory and 60 times that of a home, and the electric power intensity of a datacenter?” — a newly published study examines the massive impact that California's indoor pot growing industry has on energy consumption on a national scale.

Dr. Evan Mills, a staff scientist at Lawrence Berkeley National Laboratory and the author of the study, titled Energy up in Smoke: The Carbon Footprint of Indoor Cannabis Production, estimates that indoor pot-growing accounts for a whopping $5 billion worth of electricity annually which is about 1 percent of national power consumption. That’s enough juice to power about 2 million average American homes.

The study finds that in California, the top producer among the 17 states where it's legal to cultivate marijuana for medical purposes, not-so-green growing operations account for about 3 percent of all electricity use or about 8 percent of household use. However, because of California’s progressive use of clean fuels to generate electricity, the state only contributed to 20 percent of national CO2 emissions with incurring 70 percent of national energy costs.

The study, which aims to “to quantify a previously undocumented component of energy demand in the United States, to understand the underlying technical drivers, and to establish baseline impacts in terms of energy use, costs, and greenhouse-gas emissions,” also points out that a single joint represents 2 pounds of CO2 emissions (!) which is equivalent to running a 100-watt incandescent light bulb for 17 hours (or about 30 hours in California). Additionally, a single four-by-four production module found in growing rooms can double the electricity use of the average American home (triple that of an average Californian home). This increased energy use is equivalent to plugging in about 30 refrigerators. For growers who decide to go off the grid, 70 gallons of diesel fuel is required to produce one indoor plant. That figured is doubled if a less-efficient gasoline generator is being used.

The moral of the story? Whether you live in California or elsewhere and and want to save energy at home and lower your carbon footprint, don’t start growing pot in your garage. Simple as that.

Read a summary and the entire study here where Mills throws out some other staggering statistics, answers some interesting questions — “is Cannabis production intrinsically polluting?” and “wouldn’t just ‘going solar’ solve this problem?” — and solutions.

Via [The New York Times]

Matt Hickman ( @mattyhick ) reports on design, architecture and the intersection between the natural world and the built environment.