Greenhouses Can Produce Crops and Energy With New Solar Film

A new kind of solar film makes it possible for farmers to generate energy with their greenhouses while still allowing enough light to reach their plants for photosynthesis. 

The film, developed by the manufacturer 3M and the Swiss technology company Voltiris, can help greenhouse farmers reduce energy costs and carbon emissions while boosting crop yields, which could advance the development of more sustainable food systems. 

“It’s a way to produce energy in a space where it was not possible before,” Nicholas Weber, co-founder and CEO of Voltiris, told TriplePundit.

Generating solar energy this way is possible now thanks to a spectral filtering process. Light travels at different wavelengths, and the film uses spectral filtering to allow certain wavelengths of light to pass through to the plants while absorbing other wavelengths to use to produce energy.

Initially, the companies received a lot of questions about the economic impact of spectral filtering, Weber said. 

“That’s something that we had to clarify, and we had to work with growers and with research centers to validate the fact that we didn’t have any negative impact on crop yield,” Weber said. “But the other part of the equation that’s also what makes us special — and why the partnership with 3M is valuable — is that we managed to crack the equation of also producing energy efficiently.”

 

 

 

 

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Greenhouses can be used to extend the growing season of a wide variety of fruits, vegetables and herbs, or cultivate them year-round. But keeping the ideal plant-growing environment in the greenhouse requires controlling things like the lighting, temperature and moisture levels, which can be energy-intensive. Tomatoes, for example, grow best at a temperature of around 70 to 75 degrees Fahrenheit, leading to increased energy consumption when growing them in cooler months. 

If the energy used for the greenhouse comes from fossil fuels, increased consumption means producing more greenhouse gases and raising energy bills. Having a way to generate and use renewable energy instead, like solar film, can reduce those impacts. 

A 10-acre greenhouse, which is relatively small by commercial standards, can use up to $2 million in electricity a year for artificial lighting and HVAC, said John Morrow, insights lead of corporate research and development at 3M. 

“With the Voltiris [film], they can dramatically reduce their need for electricity coming in, and basically produce the majority of the electricity they need,” Morrow said. “I think our solution is the gateway toward the electrification of the greenhouses that will be a clean and stable supply of energy.”

Retrofitting greenhouses with solar film also has the potential to advance agrivoltaics, the practice of using the same plot of land for agriculture and solar energy generation. Agrivoltaics is often cited as a way to address concerns about land use in solar energy development, an important factor when up to 40 percent of the United States’ electricity could come from solar power by 2035. 

In the European Union, installing agrivoltaic systems on 1 percent of agricultural land would help surpass 2030 solar energy goals, according to a report by the European Commission’s Joint Research Center.

Voltiris and 3M demonstrated that their solar film works from both the economical and energy generation standpoints, Weber said. 

“Now, we’re in the last phase of our demonstration,” Weber said. “We’re scaling up the size of the projects that we’re doing. To some extent, we could already be doing some small-to medium-sized projects, but our ambition is to really leverage all the greenhouses that are available.”