Highest Lighting Energy on the Block

A version of this article appears in the Winter 2018 issue of Home Energy Magazine.

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Beginning with Colorado in 2012, nine states and the District of Columbia have legalized recreational marijuana use, and eight of these have also legalized home cultivation of cannabis. Legislation varies across each state but generally allows home growers to grow between four and six plants either indoors, outdoors, or in a greenhouse. The residential grow market poses a unique challenge to utilities because there is no formal tracking process for home growers, and they may consume more energy than their local infrastructure is equipped to handle. For example, one Oregon utility noted seven outages in the first three months of legalized home growing in 2015, that occurred because growers overloaded the local power grid equipment. Most of this energy consumption stems from using traditional energy-intensive fluorescent and high-intensity discharge grow lighting—including high-pressure sodium lamps and metal halides —between 12 and 24 hours a day throughout the growth cycle. The heating by-product from these energy-intensive lights also increases cooling and venting requirements for some growers.

To address these problems, utilities and other proponents of energy efficiency are looking for strategies to promote increased use of energy-efficient technologies, such as LEDs. Previous research conducted by Evergreen Economics found that while several utilities in states with recreational legalization offer some types of general commercial LED rebates for qualifying commercial growers, there are no cannabis-specific utility incentive programs for residential growers interested in higher-priced efficient lighting equipment.

Cannabis female plant under LED lighting.

The research on which this article is based looked to identify the need and/or the opportunity to incentivize and further promote energy-efficient technologies for home growers in Oregon and California by exploring the types of home growers in both states, the types of equipment they currently use, their decision-making processes and purchasing behaviors, their awareness and acceptance of energy-efficient growing equipment, and the ways in which utilities might promote the adoption of energy-efficient equipment going forward.

Research Topics

This research explored a variety of questions regarding energy use in the cannabis home grower market and the potential for integrating more energy-efficient practices into that market. Research questions varied somewhat between research conducted in Oregon and research conducted in California, but they generally fell into five categories. These categories focused (1) on characterizing the home grower market, (2) on characterizing the cannabis lighting market, (3) on identifying ancillary products that might affect energy use, and (4) on understanding home grower awareness of utility incentives. Here are some examples of specific questions:

• Where in the home are grows located (e.g., closet, basement) and how are lights configured (e.g., number of lights, are timers used, proximity to plants)?
• What grow light features are most important to customers and how well do products in each lighting category deliver these features?
• What lighting products are currently being sold for home grows, and is there a distinct class of products that is appropriate for the four-plant limit and not for large-scale grow operations? What is the market share for each lighting product type (e.g., LED, high-pressure sodium)?
• What are the channels through which lighting products are sold (e.g., specialty retailers, big-box/DIY stores, online), and what is the market share for each channel?
• Are there ancillary products (such as cooling equipment or fans) that affect the expected energy consumption of home growing operations?
• What types of energy efficiency program and incentive are best suited for home growers?
• How aware are home growers of the types of incentive that currently exist in Oregon and California?

Traditional metal halides lighting. (Plantlady223/Wikimedia Commons)

Research Methods

Research for this paper was conducted across two studies between May 2017 and January 2018. One study focused on the Oregon home grower market and one focused on a portion of the California grower market. While the scopes of these two studies varied somewhat, both focused on characterizing the home grower market and identifying the potential for incentivizing and promoting more energy-efficient technologies, such as LEDs, in the cannabis market. Research for this paper comprises methods and findings from both studies, and highlights commonalities and differences between the Oregon and California home grower markets. Findings stem from a variety of primary and secondary research tasks, including

• anonymous web surveys;
• market actor in-depth interviews;
• lighting sales data analysis;
• a grower workshop; and
• secondary research on legislative updates.
• Recommendations for Utilities and Future Research Opportunities

Based on our research, we make the following recommendations as to what type of energy-efficiency program may best help home growers to reduce their energy consumption and deliver cost-effective energy savings based on the key findings.

At least half of web survey respondents use at least one LED in their home grow operation. About half of these growers also use other lighting, suggesting that any program that incentivizes LEDs needs to account for the fact that growers may be using LEDs for only some of their plants or for only a portion of the growing cycle. This may change as LED technology advances to allow users to change the spectrum of lighting across the grow cycle.

Allowing growers to use LEDs alongside other lighting would enable them to test and trust the technology before using it exclusively in their home grow operations.

Over the course of our research, specialty retailers told us that they often offer ceramic metal halides (CMHs) as an energy-efficient alternative to LEDs. While our web survey asked respondents about metal halides, we did not specifically inquire about ceramic metal halides. Given the finding that these are being recommended in specialty retail shops and are rebated through some utility energy efficiency programs, we suggest that further research be done to learn whether CMHs are a viable energy-efficient lighting option for residential growers.

Any program design should consider that most LEDs are purchased online, not in specialty retail stores, and that these LEDs may lack independent quality verifications. Most non-energy-efficient lighting is purchased in retail stores. A program that focuses on the specialty retail channel may have a better chance of reaching growers who would not otherwise purchase LEDs. Programs could also work to increase the stocking of LEDs in specialty retail stores.

For utilities and energy efficiency groups looking to incentivize home growers, we recommend that they consider the distinction between residential growing for recreational use and residential growing for medical use. Oregon regulation allows medical growers to grow cannabis for other medical patients as well, thus using additional energy to light additional plants. Our web survey results show that respondents who grew for medical use were more likely to report growing more than four plants; medical growers can legally grow more than four plants in certain settings. These growers may offer a greater potential for energy savings, and we recommend that any program design include medical growers. Programs should be careful not to limit the number of incentives per household to a number that only considers the recreational limit—four for Oregon and six for California.

Workshop attendees in California noted that one problem in getting involved with utility programs is that it is hard to learn what the programs offer, or how program incentives can be applied to cannabis grows. We suggest that energy efficiency programs provide online case studies depicting various types of cannabis operation. These case studies could provide resources to potential growers that would help to answer these questions.

Joe Clark is a senior analyst and Martha Wudka is a consultant at Evergreen Economics.

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