Attention, Pot Smokers: Weed Is Not Green

Energy Grow operations consume vast amounts of power “Cannabis use could cancel out” your “low-carbon footprint”

At a Denver warehouse, growers wear sunglasses as they check on 150 topheavy flowering plants. The 4-foot-tall bushes are flourishing under dozens of blazing 1,000-watt bulbs. “All these things consume too much power,” says Paul Isenbergh, a commercial real estate broker and co-owner of the 3,100-square-foot medical marijuana operation called Sense of Healing. He gestures at equipment surrounding varieties with names like Grape Crush. “The air conditioning, the lighting, the fans, the scrubber, the humidifier.”

The $3.5 billion U.S. cannabis market is emerging as one of the nation’s most powerhungry industries, with the 24-hour demands of thousands of indoor growing sites taxing aging electricity grids and unraveling hardearned gains in energy conservation. Without design standards or efficient equipment, the facilities in the 23 states where marijuana is legal are responsible for greenhouse gas emissions almost equal to those of every car, home, and business in New Hampshire. “Consumers seeking a green lifestyle are likely unaware that their cannabis use could cancel out their otherwise low-carbon footprint,” Evan Mills, a senior scientist at California’s Lawrence Berkeley National Laboratory, wrote in an e-mail.

Some operations have blown out transformers, resulting in fires. Others rely on pollution-belching diesel generators to avoid hooking into the electric power grid. And demand could intensify in 2017 if advocates succeed in legalizing the drug for recreational use in several states, including California and Nevada. State regulators are grappling with how to address the growth, says Pennsylvania Public Utility Commissioner Pam Witmer. “We are at the edge of this,” Witmer says. “We are looking all across the country for examples and best practices.”

Indoor pot-growing operations in 2012 racked up at least $6 billion in energy costs, compared with $1 billion for U.S. pharmaceutical companies, Mills found in a study he did independent of Lawrence Berkeley. Published in 2012, before the industry exploded following legalization in almost half the states and the District of Columbia, his report remains the best gauge of power use in the pot industry.

Some larger facilities consume as much as $1 million in power a month. In Colorado, more than 1,200 licensed grow facilities are responsible for almost half of total new demand for power. In 2014, two years after residents voted overwhelmingly to legalize the drug for recreational use, growing sites consumed as much power as 35,000 households. In California, the nation’s oldest legal medical pot market, indoor production consumed 9 percent of household power, the amount used in 1 million homes, Mills found.

At indoor operations such as Sense of Healing, the atmosphere is calibrated to allow growers to reap multiple harvests a year. The intense heat from the lights requires air conditioning and fans to keep grow rooms at 75F, a dehumidifier to prevent mold, and a carbon dioxide injection system. The electric bill for all this: as high as $5,000 a month. That represents

as much as 50 percent of an operator’s overhead, yet profits far outweigh costs, with a pound of medical marijuana fetching about $2,500 on the wholesale market, Isenbergh says. His costs to grow it are only $600 a pound.

Some cities where growing operations are legal have seen power consumption soar even as communities nearby made gains in meeting conservation goals. The disparity prompted several municipalities to tax growers who strain the grid. In Arcata, Calif., the local government is taking in $300,000 a year from an “excessive energy use tax” that went into effect in October 2013. Voters approved the levy in 2012 after police and fire departments spent as much as 20 percent of their time responding to calls at growing operations.

The city council placed the measure on the ballot after Pacific Gas & Electric found that 10 percent, or 663, of Arcata’s households were being used for large-scale marijuana cultivation. Many were receiving subsidized electricity rates based on low reported income, Mayor Michael Winkler says. “Instead of having our electricity use going down, we had roughly a 30 percent increase in electricity use in five years prior to the tax,” Winkler says. The tax caused the number of large home-grow operations to fall 90 percent, he says.

In Boulder County, Colo., commissioners levied an energy usage fee on pot facilities after discovering that a 5,000-square-foot operation consumed 29,000 kilowatt-hours a month, about five times more than a typical commercial customer, says Ron Flax, the county’s sustainability examiner. Such operations send about 30,334 pounds of carbon dioxide per month to the atmosphere, county statistics show. The fee will be used in part to pay advisers to help growers become more efficient. It will go into full effect next year. “We were aware there would be an increase in the carbon footprint because of this industry,” Flax says. “We are trying to get out ahead of it.” The bottom line In Colorado, more than 1,200 licensed indoor pot-growing sites consume as much power as 35,000 households.

Byrne