The power of pot
<p>In this June photo, Johnnie Seitz moves a marijuana plant growing under lights at Sea of Green Farms, a recreational pot grower in Seattle.</p>
SEATTLE - As more marijuana producers move their plants indoors over the next two decades, the grow operations in Washington state are expected to need as much electricity each year as what a small Northwest city consumes, according to an energy forecast by regional power planners.
Demands on the Northwest electrical grid would grow further if Oregon voters pass a ballot initiative in November to legalize recreational pot use, the Northwest Power and Conservation Council said.
The council, which develops a long-term power plan for Washington, Oregon, Idaho and parts of Montana, has been studying the impacts of electricity needs for operations that grow legal marijuana indoors in Washington state.
New energy demand among growers of marijuana is estimated to expand to as much as 163 megawatts a year by 2035. That represents about 10 percent of what Seattle uses annually, or roughly what a small city such as McMinnville, Ore., uses, said Tom Eckman, the council's power planning director.
Still, it makes up less than 1 percent of overall regional electricity use.
"We're trying to ensure that we have adequate, affordable power supply," Eckman said. The analysis will be incorporated into long-term energy demand forecasts for the region, which is used by Bonneville Power Administration and regional utilities for planning.
Most producers grow pot outside, but they may start to move more operations into warehouses to get continuous harvests or have better control over the amount of light plants receive, Eckman said.
Indoor grow operations can be energy intensive, requiring electricity for grow lights or air conditioning systems to cool warehouses and control humidity.
Since Washington voters in 2012 approved an initiative to legalize recreational pot use by adults, the state Liquor Control Board has so far issued more than 200 licenses to marijuana growers from 2,500 who have applied.
Of the 217 licenses issued as of Wednesday, 93 indicated on their applications that they would grow pot indoors, while 37 said they would do it outdoors, said Mikhail Carpenter, a spokesman with the liquor control board. An additional 44 licenses include both indoor and outdoor production, and the rest use greenhouses or are not known, he said.
The power council is in the process of developing a 20-year regional power plan for electrical needs in the Northwest and pays close attention to new and emerging energy uses, such as indoor marijuana operations, new data centers and electric vehicle charging, Eckman said.