The Cost of Lighting

From the outset, lighting has been a major issue for commercial indoor grow operations.

The standard incandescent bulbs still used in most households are more or less useless for growing cannabis, and many growers have turned to High-Intensity Discharge (HID) lamps to get the maximum yield from their plants.

However, metal-halide or high-pressure sodium HID lamps pose problems for many cannabis growers because of the strain they put on the electric bill. Issues with federal funding of utilities make it difficult to calculate the exact power usage of cannabis growing operations, but a study in 2011 estimated total industry power consumption at 1 percent of national electricity use.

Since then, more states have legalized marijuana use in one form or another, and recreational use has vastly expanded the industry. Kevin Oliver, a commercial grower in Spokane County, Washington, estimates that running conventional 1,000-watt bulbs costs about $50 a month for each bulb. “Some of these operations, the infrastructure is 2 to 3 million dollars before they turn the lights on,” Oliver said. “Large commercial operations can have power bills that run $50,000 to $100,000 a month.”

There are other ways of looking at it. Growing four plants draws about as much power as 29 refrigerators. A single HID bulb can produce between 200 and 300 grams of cannabis per year, at a cost of about $600. The percentage of the cost ranges depending on the retail price per gram, but energy costs can make up between 13 and 30 percent of the end product.

Juddy and Danielle Rosellison estimate that for their grow operation in Bellingham, Washington, Trail Blazin’ Productions, energy use is only about seven percent of their price. “Instead of wasting money on high-pressure sodium lighting, we just went straight to LEDs,” said Juddy.

They use solid-state LEDs that are spectrum controlled to help produce more of the wavelengths of light that the plants need, and fewer of the ones they don’t. LEDs use considerably less energy than HIDs and produce less heat in the bargain. That means their ventilation system doesn’t need to be as powerful, also saving the Rosellisons energy.

They helped fund the setup through a construction rebate with Puget Sound Energy, but not all utilities have a free hand in encouraging more efficient energy use at commercial grows. For instance, the Bonneville Power Administration, with offices across the Pacific Northwest, is federally-owned and restricted in how it can fund efficiency measures.

“Utilities don’t really do outreach at all, they’ve certainly never contacted us,” said Oliver, who is also on the board of the National Organization for the Reform of Marijuana Laws (NORML). “LEDs are coming on strong in the market right now. They don’t draw near the same energy, and for indoor growers, probably offer the most promise for energy savings.”

Some companies which sell LED grow lights will also check and see if local utilities have any rebate money for commercial cannabis cultivators. “As growing is becoming legalized and as utilities are starting to see intense energy use, they’re really trying to get on board,” said president of ForeverGreen Illumination, Kathleen Sullivan. “Our energy is not infinite, and these grows are using so much of it in a concentrated space.”

Even if every utility was free to fund whatever rebate it liked, there are some industry problems that need to be addressed as well. “Grow lights can’t be on EnergySTAR lists because they’re not measured in lumens,” said Sullivan. Rating horticulturally-focused lights in a way the utilities can understand is a necessary step, so they know what they’re paying for.

The Rosellisons got their first rebate check last year, for more than $150,000. They have 7,000 feet of plant canopy, lit by 140,000 watts, which has all been inspected by officials from Puget Sound Energy. “Growing under LED requires different techniques,” Juddy said, “People try and use their old techniques with newer LEDs and it doesn’t work for them.” There’s a learning curve to growing with LEDs, but the Rosellisons are learning fast.

Click here to add a comment

Leave a comment: