The indoor agriculture industry has seen explosive growth in recent years. Many people are choosing indoor cultivation to boost productivity and reduce the risk to yields resulting from unpredictable weather conditions. But indoor grow ops are far more energy-intensive compared to outdoor cultivation facilities.
Here are a few statistics for some context. The total energy use in an indoor cannabis grow room typically accounts for between 20%-50% of total operating costs. On the other hand, energy costs for a medium-to-large-sized brewery make up only 6%-12% of total operating costs. Experts also estimate that indoor cannabis grows require roughly 10 times more energy compared to standard office buildings.
In addition to contributing substantially to total operating costs, grow room energy consumption is also a challenge since the high energy demand can overburden utility infrastructure. As such, it’s crucial to address the high energy consumption from both planning and operational perspectives, especially now that indoor farming is becoming more prevalent. One effective way to do this involves assessing the two major factors that contribute to much of the energy consumption in grow rooms – HVAC and lighting.
Grow room HVAC systems and energy use
No matter where it’s applied, HVAC is generally responsible for a significant proportion of total building power consumption. However, the significant energy use is exacerbated in indoor grows. This is because indoor cultivation facilities have far more critical environmental control factors compared to other buildings since they have to mimic the natural outdoor environment to promote plant growth.
Conventional HVAC systems are just not specialized enough to cater to these environmental factors. For example, a lot of conventional commercial HVAC systems use brute force to manage grow room humidity and temperature. Unfortunately, this method disregards energy efficiency and it doesn’t help with lowering the grow room electric bill.
Grow room lighting and energy use
Unlike outdoor farming which uses sunlight, indoor growing relies on intensive specialized lighting to achieve optimal flower production and plant development. Although necessary, the specialized lighting results in higher power consumption, and therefore, higher energy costs. Take a standard compact fluorescent light (CFL) bulb and an LED grow light for example. On average, the CFL bulb is around 25 watts while the LED lamp is around 1200 watts. This means that the LED lamp’s energy consumption is 48 times higher than that of the standard lamp.
Moreover, grow rooms require more than a single lamp and the number of lights will have a compounding effect on energy consumption and costs. You also have to factor in the amount of heat these lights produce and how this results in higher energy costs. For most conventional HVAC systems that rely on brute force to cool and dehumidify the space, the more lights there are and the more heat that is produced, the higher the cost of running the HVAC system.
Another key factor that affects grow room energy consumption is how long the grow lights run per day. For instance, the lights will typically run for 18-24 hours every day during the vegetative stage of cannabis growth and they will usually run for 12 hours each day during the flowering stage. This requires a lot of energy and translates into high energy costs.
Now that we’ve looked at how HVAC systems and lighting affect energy usage, let’s look at what you can do to create a more energy-efficient grow room and lower your grow room electric bill.
Tips for achieving grow room energy efficiency
The biggest challenge with achieving energy efficiency in grow rooms is being able to do so while still providing all the various elements crops require to grow. The following are some actionable steps you can take to ensure that you are using energy in the most efficient way possible.
1. Audit your energy use
Before you can think about how to lower grow room electricity costs and energy expenses, you first need to determine how much energy you’re using to grow your crop. You can find an energy company to break down your energy bill or you can perform an energy audit by yourself using simple calculations.
With lighting, for example, you can multiply the total lighting wattage by the amount of time the lights are on each day to determine total energy use. The result will allow you to see how much lighting contributes to the total energy bill. You can also deduce the energy cost of HVAC and other environmental controls by determining how much each element contributes to the total bill. This will depend on the crop you are growing. For example, a study showed that for cannabis production, air conditioning typically accounts for 21% of total energy consumption while ventilation accounts for 30% and lighting 38%.
An audit will help you optimize each system’s energy usage, whether that’s lighting or HVAC. However, the audit is one part of the solution.
A critical step in reducing energy usage and achieving energy efficiency is to continuously track and measure power consumption in the grow facility. Similar to conducting an energy audit, measuring usage will determine the areas that need improvement and help optimize energy performance and efficiency. It’s a good idea to supplement the energy tracking with a comprehensive energy management plan for overall energy consumption and costs.
To give you an idea, a good management plan will include a set of metrics that help you track and measure energy usage and costs over time, e.g. total electricity consumption per pound of crop. Not having a way to track energy consumption can be a costly omission, especially as a grow facility expands.
2. Focus on energy efficiency right from the start
It’s good to establish your grow op quickly so you can go to market as fast as possible. Nonetheless, thinking through every detail is equally important. Sometimes ensuring that energy efficiency is on your side is as simple as choosing better build quality right from the start instead of trying to cut costs and only thinking about efficiency after everything is set up. For example, an integrated climate control system may require a high initial investment, but it has the potential to offset this with cost savings resulting from more efficient energy use.
Additionally, focusing on the details from the outset is important because although opportunities exist for cost-effective retrofit improvements, some details make more business sense when implemented during the initial setup of an operation.
3. Plan your space
Planning your facility layout carefully is important if you’re going to improve energy efficiency. Many times, growers will overestimate how much grow space they need, which leads to unnecessary energy use and costs. So when trying to figure out how to lower grow room electricity costs, considering exactly how much space your plants and growing team needs will help you achieve more efficiency.
4. Opt for the right solutions
The right solutions will make your indoor grow space more energy-efficient and cost-effective. As an example, the Harvest Wheel limits the amount of heat and moisture the compressors need to remove from the grow space. This reduces the amount of energy needed for cooling and dehumidifying the space and saves up to 75% of annual operating costs.
The Harvest Wheel is a rotary heat exchanger used for indirect air-to-air economization
5. Collaborate with the right people
If you’re after the right solutions, you need to work with the right people. Specialized indoor growing solutions are still uncommon and not everyone will offer the correct solutions. This is why it’s important to work with experienced teams that understand what indoor grows require. The right people will know how to optimize your energy usage and they will provide tailored solutions that offer superior efficiency.
Check out how the Harvest Integrated team helped an operator in the vertical farming space to design and set up a cooling and dehumidification system that is as energy efficient as possible.
6. Consider the efficiency of your grow’s CEA controls
The main elements of CEA control affect energy efficiency since they have a direct impact on HVAC systems and lighting, the two factors that contribute to much of grow room energy consumption. Ensuring the efficiency of each critical element will go a long way in ensuring energy efficiency in a grow facility.
Lighting
There are many grow room lighting options, with some being better at promoting energy efficiency than others. High-efficiency LEDs and CMHs are two examples of grow lights that can help you achieve more efficiency. You have to look at the merits and drawbacks of each lighting option to determine what works best for your setup and what will ultimately improve efficiency. For instance, LED lights provide powerful light with a superior spectrum, plus they require less energy, run cooler and are long-lasting. However, they can cost more upfront compared to other grow lights. CMH lights, on the other hand, can reduce energy consumption, but they have a high heat output.
Temperature and humidity
Out-of-control humidity and temperature can result in excess energy costs. Let’s say you use poorly sized, energy-inefficient dehumidifiers to address humidity levels. This can end up overworking your HVAC system and creating unnecessary energy usage. Similarly, poor insulation can make the HVAC system continuously heat and cool areas that would otherwise not need any heating or cooling, thus causing the system to work harder than necessary to maintain the correct grow room temperature.
Airflow
Maintaining optimal airflow in a grow room is important, but some growers are guilty of using too many fans than necessary or using the wrong fans. These mistakes result in unnecessary power consumption in grow rooms and end up significantly increasing energy costs. Considering airflow efficiency is a good way to lower energy expenses and achieve more energy efficiency.
7. Stay on top of your maintenance schedule
Without proper maintenance, your grow room systems may develop a whole host of performance problems that decrease energy efficiency. Make sure to stay on top of your maintenance schedule to ensure that your system performs at its best. One way to streamline your maintenance is to have robust maintenance plans for all elements of your grow room systems.
If you don’t already have any maintenance plans, get started with this article on HVAC maintenance plans.
The importance of grow room energy efficiency
Exorbitant grow room electric bills and energy expenses are at the top of many growers’ problem lists. Achieving energy efficiency in grow rooms is a great way to take care of this issue. But beyond that, an energy-efficient facility demonstrates the ability to operate strategically, something that can help enhance your operation’s success and sustainability (think scaling). Put simply, energy efficiency in grow rooms is key to getting good returns on your investment and ensuring the longevity of your business.