In Finland, where the winters are extreme and energy efficiency is important, greenhouse farming is developing quickly when it comes to energy. Puutarha Timo Juntti Oy, a family-owned business specializing in cucumber and tomato production, focuses on how they can implement new solutions for energy systems inside their greenhouses. Spanning 20,000 square meters, the greenhouses operate year-round, using technology to achieve sustainability and improved production.
Founded in 1964, the company has always focused mainly on cucumbers, currently cultivating them across 15,000 square meters, with tomatoes grown on the remaining 5,000 square meters. Over the years, the company has adapted to surfacing challenges, including energy demands, climate control, and cost efficiency.
Tero Juntti, owner of Puutarha Timo Juntti Oy
From fossil fuels to heat recovery
Tero Juntti, the current owner, invested in high-capacity energy storage tanks, heat transfer systems, and advanced climate control technologies in order to make their operations more sustainable. This decision was driven by a desire to improve energy efficiency and move away from being dependent on fossil fuels.
"Normally, greenhouses ventilate huge amounts of energy out through hatches, even in winter," explains Tero. The new system addresses this inefficiency by capturing excess humidity and heat from the greenhouse and storing it in large water tanks via heat pumps. This stored energy is then reintroduced during cooler periods, significantly reducing the need for external energy.
One of the Novarbo's heat and humidity recovery units
Tero highlights that the investment has streamlined operations: "Our climate control has improved, enabling a higher CO2 level and more consistent conditions. Thanks to this, yield levels have increased."
According to Arttu Lammensalo, project engineer at Novarbo Oy, such innovations are transforming greenhouse farming. "Greenhouses are no longer just energy consumers. With the right technology, they can become energy producers," he states. He believes energy self-sufficiency is a realistic goal. "The amount of energy greenhouses collect from the sun annually can exceed their needs, but capturing and storing it economically remains a challenge." Arttu managed the project, overseeing sales, agreements, and design. He had to ensure that the system's calculations and overall operation were optimized.
Buffer tank and the heat pump
Cost savings and environmental benefits
The adoption of heat recovery technology has yielded significant economic and environmental benefits. With most thermal energy now generated by heat pumps, the system operates at a competitive cost, even during Finland's peak winter season. Moreover, the need for ventilation has been dramatically reduced, minimizing heat loss and maintaining optimal humidity levels.
Tero notes that this has had a direct impact on plant health. "High CO2 levels and stable climate conditions are reflected in better yields," he says. The system's ability to condense excess moisture and recycle it for irrigation further enhances efficiency. "Additionally, less ventilation means fewer temperature fluctuations, which is crucial during winter."
Challenges and adaptations
While implementing the new technology has been relatively straightforward, fine-tuning the system during extreme freezing temperatures required adjustments. Despite this, the overall cultivation strategy has remained unchanged.
Tero foresees further advancements in greenhouse climate control. "Mechanical climate control is increasing, and energy utilization is moving towards electrification. We need more energy-efficient ways to remove moisture than traditional heating and ventilation," he observes.
Despite the promising technological advancements, the industry faces challenges. Cost-push inflation over the past two years has strained consumer purchasing power, affecting sales. "In grocery stores, price is emphasized at the expense of healthiness," Tero says. However, he remains hopeful. "New nutritional guidelines recommend increasing vegetable consumption. I believe this trend will grow stronger."
Water "Energy" towers where all the heat collected from the greenhouse is stored for later use
Exploring energy self-sufficiency
In Finland, greenhouses collect twice as much solar radiation energy annually as needed for heating, according to the Finnish Natural Resources Agency. The challenge lies in economically viable energy storage for nights and winter.
Tero is optimistic about the possibilities but acknowledges current limitations. "It would be an interesting option to sell excess heat, but there are no potential buyers nearby," he says. However, he is exploring ways to use surplus heat during summer within the greenhouse area.
Arttu also believes that energy self-sufficiency in greenhouses is achievable. "The amount of energy collected from the sun can exceed what is used annually, but capturing it all is challenging," he explains.
For more information:
Novarbo Oy
Lauttakyläntie 570
27510 Eura
Finland
Mr. Arttu Lammensalo, Project Engineer
tel. +358 40 846 9086
[email protected]
www.novarbo.fi