Greece is one of the first countries in the EU to allow large scale pharmaceutical cannabis production by independent companies. Cannabis grown in high-tech, fully automated and climate controlled greenhouses or indoor facilities, capable of year-round cultivation, require significant amounts of energy and a high power load capability. Some studies done in the US, in states where medical and recreational cannabis are legal, show that energy usage from cultivation sites can reach up to 2% of total state energy consumption.
This is a significant amount of energy. As we face climate change and carcinogenic pollution brought on by burning petroleum and fossil fuels, Cogeneration Turbines powered by natural gas, bio-fuel, wind or solar power represent one of the only practical solutions to enable the expansion of year-round pharmaceutical grows.
A turbine is a generator which produces electricity through heating and compressing a mixture of air and fuel, causing it to combust and create a hot, pressurised gas which drives the rotation of the turbine blades, and this motion is harnessed to spin a magnet surrounded by copper coils, generating electricity. The concept of a “co-generation” or Combined Heat and Power (CHP) turbine, is to use the “waste” heat released by the combustion of the air and fuel to power another system. The heat can be harnessed directly for industrial heating or cooling applications, or used to power a steam turbine, generating more electricity.
“Tri-generation” turbines are co-generators often referred to as Combined Cooling, Heating and Power units (CCHP), which use the heat to directly power a heat pump or an absorption chiller, while simultaneously using it to heat water in a boiler and generate steam to drive a steam turbine. These turbines are even more efficient than traditional CHP. Recently, technology has been developed to “scrub” the exhaust gas produced by the initial combustion; after the heat has been harnessed from the gas, it is put through a catalytic converter, which through chemical reactions, reduces the hydrocarbons present to carbon dioxide and water, and further breaks down nitrogen oxide gases into inert N2. This CO2 rich gas is free of dangerous compounds, and can be further filtered to produce 99% pure Carbon Dioxide, or CO2.
This technology is called “quad-generation”. CO2 has valuable applications in the horticultural industry. Elevated levels of CO2 in your greenhouse will increase photosynthesis in plants, enhancing plant growth, shortening production time and appreciably increasing yields. CO2 is used prevalently in commercial-scale cannabis grows in Canada and the US. Using a quad-generator to produce CO2 gas for cultivation eliminates the need for a separate CO2 generator, consuming more energy, or for costly CO2 deliveries to the site.
With its carbon dioxide production capabilities, clearly quad-generation for indoor or greenhouse medical cannabis facilities presents the most cost-effective, and environmentally sound choice for a primary energy source. Lighting, irrigation, climate control, and lots of other cultivation and technical equipment require power in the form of electricity, supplied by the initial combustion, or by the steam turbine, while left-over waste heat can be used in its direct form to drive heating or cooling devices in the cultivation, extraction lab, and office areas. Quad generators come in a wide range of potential power outputs, from small 250 kW units to devices with a staggering 10.5 MW of power. A cultivation company can decide which size is best for their operation, based on production goals and facility design.
Another variation on co-generation units which are especially functional for cannabis production, are Combined Temperature and Humidity Control units (CTHC). These units can be run off natural gas, as well as alternatives such as bio-fuel and solar, similarly to the co-generation turbines. However, all the electrical energy generated is used by the unit to power its own rotary wheel “desiccant dehumidification” process, while the waste heat produced can be used directly to heat the grow environment, or to drive a heat pump or chiller. The heat is also used to reactivate the dehumidifying absorption wheel, by heating air to evaporate and evacuate the moisture absorbed by the wheel. Dehumidification is critical to cannabis cultivation, and the compact size of these devices make them easy to install in cultivation areas. Greenhouse design engineers will be able to recommend the appropriate size and amount of units for a given facility.
Compared to using grid electricity to supply the site’s needs, numerous benefits come from using quad-generation turbines and Combined Temperature and Humidity Control units. Fossil Fuel power plant efficiency is usually around 40%. Electrical energy is generated by a turbine with 45- 49% efficiency, however by utilising the thermal energy as well, the co-generator’s efficiency rises to around 85%! This is great news for overall cost savings, and also means your company’s carbon footprint is drastically reduced. Incentives exist for businesses to install clean energy solutions; for example, any excess electricity produced by your co-generator can be sold back to the main grid, for further cost savings and rapid Return on Investment (ROI). In addition, European Union subsidies are available to companies wishing to install energy production systems which eliminate carbon emissions and run on cleaner burning fuels, or solar or wind, such as tri- and quad- generators and CTHC units.
All of these factors make cogeneration the obvious choice for building a cost-effective business model. As the construction of large scale pharmaceutical cannabis cultivation facilities begins, those who can see the big picture related to energy consumption and costs will enjoy success, and can be proud knowing that they are employing environmentally friendly practices as part of the solution to our world’s pollution problems.