AS 13 ACTIVISTS DANGLED in the path of a Shell Oil ship last month, the hundreds of specatators amassed beneath the St. Johns Bridge could be forgiven for sparking up.

More than most protests, the massive demonstration on the eastern shore of the Willamette River had an air of celebration—it was the grandest moment in a recent flurry of fervent activism against fossil fuels in Portland. But there's something the protesters lighting up in solidarity probably didn't realize: That mellow comes at a harsh cost.

Oregon's emerging recreational cannabis market is poised to become the largest new drain on the power grid in years, churning out a product that's far less efficient to produce than nearly anything else you can buy. Existing estimates are shot through with caveats, but suggest the juice demanded by pot growth in the state could be enough to power more than 100,000 homes.

"These numbers are staggering," says State Representative Peter Buckley (D-Ashland) who, more than any other Oregon lawmaker, has addressed the energy-draining repercussions of legal pot. "The implication of that sort of energy use is truly something we need to be very, very careful about."

But pretty much no one is being careful. New innovations in indoor agriculture could slash pot's problematic energy demand, but suspicious growers have so far refused to adopt them. There are no state laws mandating efficiency for cannabis growers, and the federal government's stubborn insistence on outlawing marijuana can make it tough to qualify for common subsidies that help.

All of these factors, left unchecked, will lead the state in a very different direction than those pot-smoking activists beneath the St. Johns Bridge are hoping for.

"Oregon has two choices in this matter," Buckley staffer Andree Phelps told lawmakers at a legislative hearing in June. "Either we build a new power plant or we look at energy conservation."

TO STATE THE OBVIOUS: The climate situation is dire.

While Oregon stares down one of the worst droughts in a quarter century, new studies warn that the devastating acidification of the world's oceans will soon reach a point of no return. President Barack Obama just took the strongest stand against planet-warming carbon in the country's history, but that plan, if it survives, isn't enough to avoid catastrophe. Even the pope is preaching the evils of fossil fuels.

Through all this, Portland has been cashing in on its green reputation. In the last month alone, Mayor Charlie Hales took a climate meeting at the Vatican, came home to help that Shell Oil ship break through a line of protesters, then dashed off to Washington, DC, to talk greenhouse gases with Obama.

But even with increasing solar and wind energy and a rich history of hydropower, Oregon is more greenish-brown than green.

More than 45 percent of Oregon's electricity still comes from coal or natural gas, according to the Oregon Department of Energy. Most of the state is worse off than that. Portland General Electric and Pacific Power, which provide 66 percent of Oregon's electricity and are the sole providers in Portland, rely on fossil fuels for the bulk of their power. Pacific Power, in particular, has a taste for coal that accounts for nearly two-thirds of its Oregon power output, according to the state.

Even the scheduled closure of the state's only coal-fired power plant in 2020 doesn't mean we're ditching the dirtiest common source of electricity. Oregon utilities frequently source coal-based energy from Wyoming and Montana.

This is all an occasional point of smugness for Washington State, which uses hydropower for almost two-thirds of its energy (nearly 90 percent of Seattle's power comes from dams). Joel Myer, the government relations manager for a utility that serves Mason County, Washington, west of Tacoma, jokes that he's fond of comparing his district's fuel mix to Portland General Electric's, "just to make me feel better."

THIS POWER SYSTEM will have to chug along harder when Oregon's recreational pot industry is in full swing next year.

Professional indoor pot-growing operations draw as much energy per square foot as the infamous power-sucking "server farms" that Google and Apple are so fond of dropping in places like Prineville and the Dalles.

"There are very few other businesses that can use as much energy," says Ron Flax, a sustainability official in Boulder County, Colorado, which has led the nation in trying to curb growers' inefficient practices. "And there's certainly no other industry growing as fast as this is."

In Mason County, Washington, roughly 50 cannabis farms—0.1 percent of the county's electricity consumers—account for 2.5 percent of demand. Colorado has massive grows that demand enough juice to power more than 10,000 homes. According to a Denver Post report, pot production spurred 45 percent of Denver's unwelcome increase in power demand in 2014.

It's impossible to say what, exactly, this means for Oregon. The Oregon Liquor Control Commission is still in the process of carving out crucial details, like how many growers can be licensed in the state and how large their operations can be (right now it looks like indoor grows will be capped at 10,000 square feet).

That hasn't stopped people from guessing at how Oregon might fare. The Portland-based Northwest Power and Conservation Council, which has surveyed growers in Washington and tried to extrapolate what the same practices would lead to here, thinks demand for pot grows could reach as high as an average 100 million watts of power at any given moment, which could power nearly 70,000 Pacific Northwest homes.

Others expect Oregon growers' demand for energy could be even more ravenous. According to numbers compiled by Representative Buckley's office, the state could easily see a power demand of 150 million watts—enough to swallow the output of several small dams.

The problem is lighting. The 1,000-watt bulbs most indoor pot farmers string up throw off enough light to give you a tan, in the process draining prodigious amounts of power. Roughly a third of any indoor marijuana grow's energy use is estimated to come from lighting; an additional 45 percent is spent on dealing with the heat it gives off.

"Growers have been locked into technologies that were around in the '80s," says John Morris, a Portland-based energy consultant with the firm CLEAResult, which helps utilities work with cannabis farmers. "It is the kryptonite to efficiency."

According to an oft-cited 2012 study, this outdated system means the indoor pot industry trails every other sector in smart power use. Researcher Evan Mills found that emissions caused by one kilogram (2.2 pounds) of pot are roughly equal to driving across the country seven times in a fuel-efficient car. The lighting used for a grow area that can accommodate four plants—which, by the way, you can legally grow at home right now—sucks about the same power as 29 refrigerators.

All of this has Oregon environmentalists anxious.

"We're already seeing the impacts of climate change, and the simple reality is that we can't get to where we need to be by cutting emissions alone," says Andy Maggi, director of the Sierra Club's Oregon chapter. "We also have to increase energy-efficiency and reduce use."

One company in Washington is doing just that.

THE FUTURE OF SUSTAINABLE POT comes in a sealed yellow envelope, and can be purchased for $18 a gram just over the Columbia—a standard gouge under Washington's onerous and complicated tax structure.

It's got the crystal dusting and gnarled red hairs of other cannabis strains, and boasts potencies on the higher end of the spectrum, but the bud you can purchase from Battle Ground-based producer Agrijuana is probably the only indoor-grown sack on the menu that matches both your climate politics and your jones for a premium indica.

Agrijuana's massive facility is reminiscent of a Lisa Frank doodle, if Lisa Frank suddenly became obsessed with cannabis fields. Beyond looking cool, the trippy purple hues that bathe 30,000 square feet of pot canopy might make it the Northwest's most efficient indoor pot farm.

While other growers cling to wasteful bulbs, Agrijuana's thought to be the only big producer in Washington to have fully embraced red- and blue-hued light-emitting diodes (LEDs) to nurture its crops

"Our yields are fantastic, and this is really the only sustainable technology that makes sense," says Mike McElveny, the company's operations manager.

The numbers McElveny touts—all backed up by Agrijuana's power provider, Clark Public Utilities—are insane in the context of indoor marijuana operations. The company uses a fifth of the power of a typical grow its size, saving nearly $750 a day and nearly five million kilowatt hours of juice a year.

The versatile LED discs that Agrijuana slaps to magnetic rails above its plants are expected to last years, rather than months, and they require less power, and generate far less heat, than standard grow bulbs.

But no one's following Agrijuana's lead. Longtime pot farmers are largely dubious of LEDs, after years of experimentation with the technology resulted in lackluster grows or insufficient potencies.

"I've tried just about everything," says Bradey Day, the sales director for Camas-based EcoGrow Lighting, which supplies Agrijuana's LED system. Day says he's more likely to meet disdain than amazement when he shops his product around these days. "When I go to grow shops they say: 'LEDs. That's awesome. Let me show you what I've had in my back storage room for the past five years.'"

In the face of that skepticism, Day has to offer up an old plea: That his system is different. EcoGrow believes it's developed a "deep red" spectrum LED that's better suited to coaxing temperamental cannabis buds.

McElveny's enthusiasm and the success of Agrijuana—looked to by utilities across the Northwest as a model operation—would seem to back up that claim, but Day's had trouble attracting growers willing to experiment.

The case for LEDs isn't helped by the price tag. EcoGrow's setup costs roughly five times what a traditional high-intensity lighting system costs. That initial outlay is often too much for growers, who can struggle to secure loans from banks. They'd rather pay meteoric energy bills with the money they rake in from their cheaper lighting systems.

In this context, Agrijuana was lucky: Its power company was willing to kick in nearly $290,000 toward the cost of its efficient lights.

Such incentives are common in other industries, but can be hard to come by for pot growers in Washington, where the bulk of utilities rely on the federal Bonneville Power Administration for power. Since marijuana is still classified as the worst kind of drug under federal law, some utilities are wary of upsetting federal regulators by subsidizing pot.

Oregon's less reliant on the Bonneville Power Administration, though cities like Eugene and Ashland lean on federal power. For customers of private utilities—like Portland—the Energy Trust of Oregon has signaled that it's willing to help growers operate efficiently, but notes there hasn't been much demand for such help from the area's existing medical marijuana operations.

"I've gotten nothing but really good feedback down there," says Day. "I think everyone really wants LEDs to work."

And most industry watchers expect it will—eventually. That might be years off, though, when the cannabis market has matured and big players turn to LEDs to help their profit margins.

"Unless you're being efficient and can compete, you're going to be gone in two or three years," says McElveny. "There are a lot of people falling by the wayside."

ONE OF OREGON'S chief advantages in putting together a working pot market is that we can see what's happened elsewhere. The state's already cribbed lessons on taxation and dispensary organization from Colorado and Washington. But officials are doing very little to ensure that the enormous industry expected to take root here next year operates as efficiently as it can.

Oregon lawmakers this year created a "Task Force on Cannabis Environmental Best Practices," but it's not required to turn in findings for more than a year. By that time, producers will be up and running—using the same energy-draining systems that are straining power grids in Washington and Colorado.

Experts looking at the issue say that if Oregon's going to manage energy costs, front-end requirements are needed. CLEAResult's Morris has floated a policy that would get growers speedier permits if they submit a plan to keep their energy costs low. Massoud Jourabchi, an analyst with the Northwest Power and Conservation Council, says definitive state lighting standards "could be a very effective way of making sure our cannabis is produced more efficiently."

But with grower permitting slated to begin next year, there's no sign any of that is in the works. Like so many things involved with saving the planet, the matter's left to consumers, who can make the conscious decision to purchase pot grown outdoors or with efficient practices.

"The lion's share of people don't do that," says McElveny. "They say, 'I want that 24-percent Purple Kush and I don't give a shit. Let's put it in the pipe.'"