Cannabis is known for being very resource-intensive. In places where resources are becoming scarce, it is logical that growers and managers are starting to see regulations for their electricity, fuel, and water usage. "California is considered a pioneer in regards to these types of regulations with Title 24, and we foresee many, if not, all states across the country where Cannabis (medical or recreational) is legal, implementing similar kinds of energy standards and regulations," the Ceres Greenhouse Solutions team says.
Most new energy regulations address limitations on artificial lighting
Ceres explains that one of the most common ways that states are regulating energy usage is by limiting Lighting Power Density (LPD). LPD refers to how many Watts of electricity dedicated to lighting is used per square foot. For example, if you have a 1,000 Watts fixture used for lighting 10ft² , then the lighting power density is about 100 Watts/sq.ft (1,000 / 10). Illinois limits the lighting power density to 36 Watts/sqft. This type of regulation often pairs with another type that mandates growers use lighting fixtures with a minimum efficiency of 2.2 µmol/J – which basically eliminates the usage of High Pressure Sodium (HPS) and Metal Halide (MH) fixtures in these growing spaces. These fixtures are around 1.8 to 2.0 µmol/J (typically) while LED fixtures can get up to much higher efficiency and average out at about 2.7 µmol/J.
Before the introduction of these energy regulations, growers could disregard the amount of energy used by artificial lighting because the revenue from their yields would far outweigh the energy cost. These new lighting regulations will ensure that these growers are limited in the amount of energy they can use, and therefore how many light fixtures they can have.
Many indoor growers are concerned that this cap on light fixtures will hurt their yields, and make them less competitive in the market. The bottom line is that any indoor grower that simply wants the highest yields possible will have to reexamine their expectations or look into different methods of cultivation.
Capturing the sun – a free energy source
What about greenhouse cultivation? In a greenhouse with high light transmission, the quantity of artificial light required will only be to compensate for sunlight. This means you can achieve the Daily Light Integral (DLI) and the yields that you want using less light fixtures and energy.
For example, a typical indoor grow aims for a Photosynthetic Photon Flux Density (PPFD) of 1,000 µmol/m²/s which is the equivalent of a DLI of 43 mol/m²/day over the course of a 12 hour photoperiod (typical flowering cycle). Using LEDs, achieving the 1,000 µmol/m²/s would mean 400 Watts/m² of lighting power density, or approximately 40 Watts/sq.ft.
The lowest monthly average of DLI is between 5 to 13 mol/m²/day, depending on your location. This would mean, in a sunny location, the actual DLI level required from the supplemental lighting would be 33 instead of 43. This can be achieved with 30 Watts/sq.ft of lighting, and would be compliant with Illinois’ regulations for example. The graph below shows how much light is needed from supplemental lighting in a greenhouse versus indoor if you want to reach 40 mol/m²/day in Fresno, California.
Designing for compliance and success
"Regulations on energy and resources are getting more strict and commonplace throughout the country. And they don’t stop at lighting. Energy regulations also address the type of energy used, fossil fuel limitations, water efficiency, waste management, and photovoltaics installations," Ceres says. "Our facilities are already compliant with these regulations and requirements. For example, we have full HVACD systems that don’t burn fuel and run on electricity only. We design greenhouse solutions with the knowledge that the future of CEA has to be greener and more aware of the use of resources. We also know that this is just the beginning, and more regulations will be put in place nationwide as food and energy insecurity increases. If you are a CEA operator trying to navigate the strict regulations in your state, let us help you decide on a grow solution that will be both compliant and successful."
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Ceres Greenhouse Solutions