Legalization may be taking the business of cannabis out of the shadows, but there's an inescapable truth in the tangled mess of extension cords and intense lighting rigs used in clandestine basement grow-ops.

Pot requires power. A lot of it.

From lights and heating to pumps and ventilation fans, it's estimated that it takes about 2,000 kWh to make a pound of product using traditional growing methods. That's close to how much electricity an average Canadian household uses in two months.

The electricity it takes to create a pound of cannabis product is estimated to be around the same amount required to power an average Canadian home for two months. (Evan Mitsui/CBC) Medicinal and legalized recreational marijuana is projected to become a multibillion-dollar industry in Canada. As new cannabis businesses come online and existing medical growers scale up, the expectation is that there will be increased demands for power — but nobody knows precisely how much.

"We're not quite sure what the impacts of marijuana growth will be," says Chuck Farmer, director of stakeholder and public affairs at Ontario's Independent Electricity System Operator (IESO).

"We do predict that demand will go up slightly in the next 18 months."

At 47, Ontario has the most licensed cannabis producers and is currently in a good power supply situation, according to Farmer. The IESO forecasts the marijuana business will represent less than one per cent of Ontario's total electricity consumption.

Aphria, one of Canada's largest cannabis producers, operates a huge indoor production facility in Leamington, Ont. Growing pot is very energy-intensive. (Evan Mitsui/CBC) In comparison, Denver and Seattle also say under 1 per cent of their grid power goes to cannabis growers. Before California legalized recreational use, a 2012 report found three per cent of the state's power was used to grow pot.

While the Canadian grid should be able to absorb the extra load from the rising demand for cannabis products, electricity isn't cheap.

Commercial producers are looking for ways to drive their costs down, and that's fuelling a market for innovative scientific and engineering ideas to help soften the power demands of producing pot. And that research is delivering some interesting spin-off benefits, too.

Bright ideas

"[Cannabis] is traditionally done in this kind of guerilla horticultural style," says Brandon Newkirk, marketing communications manager at LumiGrow Inc. in Emeryville, Calif.

"Now everything is moving to very much enterprise-type, greenhouse-style horticulture. So the way that they were growing vegetables and flowers for a very long time is now being adopted to cannabis."

Brandon Newkirk (left) and Jake Holley work at LumiGrow's headquarters near San Francisco, Calif. The company tests LED lights and their effects on horticulture. (Sylvia Thomson/CBC) Lumigrow has spent years studying how artificial lighting affects plants. Its LED lighting systems are designed to reduce growing costs — as much as 50 per cent compared to traditional high-pressure sodium lights — while controlling certain plant properties.

"What we have here is a situation where you control different ratios of light," explains Melanie Yelton, LumiGrow's vice-president of research.

"And as you control those ratios, the plant will respond in a different way."

LumiGrow says its LED-based lighting systems can cut growing costs by as much as 50 per cent compared to traditional high-pressure sodium lights. (Sylvia Thomson/CBC) Yelton calls it precision agriculture. Her initial research shows it can change the potency of cannabis.

"I really stress that every single different variety can respond in a different way," she says.

"Generally speaking, if we reduce the blue and increase the red [light], we'll get a reduction of the THC. If I increase the blue, I'll get an increase."

Ideas to save the world

Besides light, cannabis plants hunger for water and nutrients.

Located not far away from LumiGrow, a tech startup called GrowX is researching aeroponics techniques that could make growing cannabis more efficient.

"Aeroponics allows you to grow without any medium, no soil," explains CEO and founder John Paul Martin.

At this AeroFarms aeroponics facility in Newark, N.J., plant roots are exposed during the vertical-farming process and are fed by a nutrient-dense mist sprayed directly on them. (Steven D'Souza/CBC) Martin's research has found that effectively suspending the roots in the air and channeling specific resources directly to the plant can reduce fertilizer consumption by roughly 40 per cent and water consumption by as much as 98 per cent.

Another benefit of aeroponics is that it can be done anywhere, including multi-storey buildings in cities.

This kind of "vertical farming" reduces the amount of land needed to grow cannabis, and potentially cuts the distance that the product needs to travel to market.

"This is really trying to move us towards a more regenerative food system," Marin says. "By moving high-impact crops inside, we can recycle more, we can do less damage to ecosystems."

Solving a world food crisis may seem a lofty goal to put on the shoulders of cannabis growers, but aeroponics research being undertaken for the pot industry holds the same promise of boosting efficiency for other types of agriculture.

Youbin Zheng, professor of environmental sciences, stands next to some Easter lilies growing under an LED light in a greenhouse at the University of Guelph. He says vertical farming technology holds the promise of boosting agricultural production efficiently. (CBC) "The technologies involved in cannabis production certainly can be used to help our vertical farming and indoor farming," explains Youbin Zheng, a professor of environmental sciences at the University of Guelph.

"Farmland … is getting smaller and smaller, cities [are] getting bigger and bigger. So if you could build a vertical farm in the middle of the city, a small area, you can produce many times more plant material than you could do outside of the city."

Old school, new tricks

It's not just new technology that's helping drive efficiency. Pot growers are also drawing on engineering brainpower and techniques from other fields.

Canopy Growth Corp. in Smiths Falls, Ont., is investing in technology to reduce the energy demands of its indoor cannabis-growing operations. (Canopy Growth Corp.) In Smiths Falls, Ont., home to one of the world's largest medical cannabis producers, good money has been spent on engineering solutions that save power and cut operating costs.

"Thanks to legality [of cannabis], you can get certified professionals to sit and think with you — to design, create, think and operate," says Bruce Linton, CEO of Canopy Growth. "The effect of that is that you get more efficient."

Linton describes one method that takes advantage of Canada's cold climate to cut electricity costs.

Heat created by high-pressure sodium grow-lamps is transferred to water, which is then piped outside. The outdoor temperature difference, combined with a glycol-based system, cools the water. Then it's run back into the building where the colder pipes sap excess humidity from the air before again pulling heat from the lights.

Bruce Linton, CEO of Canopy Growth, says the legalization of marijuana is attracting new investment in technology and engineering aimed at making commercial operations more energy- and cost-efficient. (CBC) "We sort of had to challenge ourselves to create this and manage our environment," says Linton, who also makes an economic argument.

"I'm doing it because I don't want to waste anything. It's a cost problem I'm solving."