CO2 is Expensive for Greenhouses. And is getting more Expensive in Germany.

Updated: Jun 4, 2020

You may think that with CO2 levels in the atmosphere continually rising, that the molecule would be abundant and cheap. However, industrial CO2 for use in various industries is still relatively expensive. The price of industrial CO2 in a 1 MT tank is approximately US$250 per metric ton (MT) and that of a 100 lb tank is over US$1,500 per MT. CO2 gassing has been used in greenhouse and indoor cultivation for decades in order to supplement plants with more carbon for faster and greater growth. However, approximately half of the CO2 is lost through ventilation required to reduce heat, resulting in CO2 escaping to the atmosphere. 

HVAC cooling fans on a sealed greenhouse.

As an example, a 100,000 sq ft greenhouse uses approximately 180 MT of CO2 per year costing $45,000. Since greenhouses require cooling especially in the hot months, many use HVAC (heating, ventilation and air conditioning) systems that run on electricity or generators powered by fossil fuels such as gasoline or diesel. This is an added cost especially if the greenhouse is sealed in order to implement CO2 gassing.

A recent law passed in Germany has added to the cost of CO2. According to this recent Horticultural Daily article, German greenhouses will now have to pay an additional tax of between 10 to 25 euros (US$11 to US$28) per MT of CO2 generated by fossil fuel powered energy for heating and cooling. The costs can be quite significant as described in the article “Even with an entry-level price of 10 euros per tonne of CO2, medium-sized companies will incur costs of around 15,000 to 20,000 euros (US$17,000 to US$22,500). This would be a massive burden for the companies in view of the current market pressure and increasing requirements combined with necessary investments.

In order for greenhouses to save on both CO2 supplementation, energy for cooling and the related taxes from using fossil fuel powered generators, greenhouses must find ways to more efficiently utilize CO2 for their plants and find ways to allow maximum heat ventilation thus reducing the need for energy consuming HVAC systems.

CO2 Delivery Solutions™

Introducing CO2 Delivery Solutions™. By completely dissolving CO2 gas into water, CO2 Delivery Solutions™ creates an aqueous CO2 solution that is saturated at 80-100% with CO2 gas. The aqueous CO2 solution is then misted directly on to the plant leaves. The CO2 solution’s micro droplets create an aqueous film around the entire leaf surface, isolating the leaf from the atmosphere. This creates a diffusion gradient favoring CO2 transport into the leaf and other gases out of the leaf. Increased carbon availability enhances photosynthesis resulting in faster and larger plant growth. CO2 Delivery Solutions™ has been demonstrated on crops including cannabis, hemp, lettuce, kale, microgreens, peppers and flowers. 

This process makes 8-10 molecules out of every 10 gas molecules contacting the leaf’s surface CO2 in the aqueous solution versus only 1 in 2,500 gas molecules being CO2 contacting the leaf’s surface in a standard atmosphere environment.  Even when the atmosphere is supplemented with CO2, this number increases to only 2-3 in 2,500 molecules being CO2.  this is still far less efficient than 8-10 out of 10. Therefore, our aqueous CO2 application is much more efficient than traditional CO2 gassing, using only between 2% to 10% of the CO2 for equivalent results. Using 90% to 98% less CO2 means significant savings.

Since aqueous CO2 solution has very little off gassing and uses far less CO2 gas to begin with, greenhouses do not have to worry about containing CO2 gas in the rooms by sealing. This means they can have open ventilation to allow heat to escape thereby reducing the need for expensive energy consuming HVAC systems.

Open roof greenhouse for natural heat ventilation and no expensive HVAC system.

Another benefit of aqueous CO2 misting is a cooling effect on the plant thus requiring less energy to cool the greenhouse. According to this article the energy savings of keeping the greenhouse temperature closer to the outside temperature by 1 degree Celsius, is 5%. The temperature at the plants is what matters regardless of the temperature in the rest of the greenhouse.

Therefore as an example, if the temperature at the plant is 1 C lower due to aqueous CO2 misting versus a scenario of no misting, then the thermostat control for the entire greenhouse can be raised by 1 C in order to operate the cooling system less and save on cooling costs by 5%. The temperature at the plants with CO2 misting will remain 1 C lower than the rest of the greenhouse.

Less CO2 waste, less energy use for cooling and less fossil fuel use for generating the energy all save money for greenhouse growers while enabling CO2 supplementation resulting in faster and larger plant growth and greater profits.

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