April 13, 2024

Indoor farms are energy-intensive, a test of their climate credentials

No one would argue that the climate in North Texas is ideal for growing lettuce, a crop that thrives when the air is cool. But the region’s scorching summers don’t worry Eddy Badrina, chief executive of Eden Green Technology, a vertical hydroponic greenhouse company outside Dallas.

The company, which sells its leafy greens to Walmart, controls every aspect of a plant’s life. In their 82,500-square-foot facility, cool air is pumped in to create the ideal microclimate around each head of lettuce and romaine. Seven miles of pipes provide nutrient-rich water. Although natural light floods the space – differentiating it from vertical farms that block the sun in favor of controlled lighting – additional LED lights obey a programmed algorithm that directs them to illuminate the right amount of light on each plant.

“We are pretty agnostic about the external environment,” Badrina said.

As the effects of climate change intensify, bringing more severe droughts, floods and pest infestations, some producers are wresting control of their crops from nature. Huge high-tech greenhouses and small vertical farms — windowless warehouses that typically grow plants stacked on trays — promise to allow farmers to grow crops almost anywhere.

But all this control comes at an environmental cost. Within these facilities, farmers are creating the perfect growing conditions with energy generated mainly by burning fossil fuels, and in large quantities.

“It’s a lot of the same technologies you would see in a building for human comfort, but being used for plants,” said Jennifer Amann, senior fellow in the buildings program at the American Council for an Energy-Efficient Economy, a nonprofit organization focused on in reducing energy waste. “There is extraordinary water efficiency in these facilities, but energy is really the Achilles heel.”

In colder climates, indoor agricultural operators heat their greenhouses with natural gas or propane, as these fossil fuels are often the cheapest option. Vertical farms represent a smaller share of the market, but they typically consume much more electricity than greenhouses to replace natural sunlight and to power refrigeration and dehumidification systems.

Across the country, the industry is on the rise. Between 2017 and 2022, land used to grow vegetables and herbs in greenhouses increased by more than 20 million square feet, an 18 percent jump, according to the federal government’s latest agricultural census, released last month. Although crops grown on indoor farms still make up a small percentage of what’s on supermarket shelves, they are making inroads in certain parts of the country. Today in New England, about 20% of leafy greens for sale come from controlled-environment agricultural businesses.

Energy use in industry varies widely depending on the size of the greenhouse and the crops being grown. A study of 12 indoor farms by the nonprofit Resource Innovation Institute found that five of them used as much energy per square foot as a hospital. A vertical farm, an exception, consumed as much energy per square meter as a data center.

These companies advertise their products as safer, more nutritious and fresher than field-grown produce, as their operations typically do not use pesticides and are within a few hours’ drive of major cities. They pride themselves on using one-tenth of the water, a claim backed by independent research. But they don’t often talk about energy use; most states do not require them to report this, and researchers said many are reluctant to share this data.

With the difficulty of obtaining detailed information about energy use, quantifying the carbon footprint of indoor agriculture is complicated. Researchers studying greenhouse gas emissions from industry have reached contradictory conclusions.

A comparison of studies accounting for emissions from greenhouse-grown and field-grown tomatoes suggests that those grown indoors had a carbon footprint six times larger. But a paper summarizing research into lettuce growers’ emissions came to a different conclusion: carbon pollution from indoor farms was lower than that from traditional farms because they were closer to their buyers and didn’t have to transport their produce. salad greens hundreds or thousands of kilometers away. diesel trucks.

But that debate aside, experts said indoor farms in the United States could be more efficient.

Gretchen Schimelpfenig, a civil engineer who has worked to monitor energy use on indoor farms, said many American greenhouses could cut their energy consumption by half. Dutch greenhouse technology has proven this is possible, she said, but in the United States there is little pressure on indoor food producers to do things differently.

“We have enjoyed very low natural gas prices for some time now, which is why we are seeing controlled agricultural facilities being built in Montana, Wyoming and Texas,” Schimelpfenig said.

Other states want to participate. At a time when consumers are looking for more vegetables and berries year-round, and many still have dark memories of the pandemic’s supply chain crises, states are courting indoor farms that can be built wherever there is a market for produce. fresh.

Pennsylvania Secretary of Agriculture Russell Redding said the state has created a “concierge service” to facilitate the permitting process and help indoor agricultural operators with site selection. His agency is focusing on locations in the Lehigh Valley and South Central region where there is proximity to key energy infrastructure and desirable markets in New York, New Jersey and DC. Some of the state’s top universities are working on technology to speed automation within vertical farms and greenhouses, he said, while their colleges train workers for jobs in those facilities.

One of Pennsylvania’s selling points is its abundance of energy, most of which is generated by burning natural gas.

“These facilities consume a lot of energy,” Redding said, “but Pennsylvania is the second largest net supplier of energy in the country and we think that’s a differentiator for us.”

Virginia also eagerly awaits a boom in indoor agriculture. According to state officials, the industry has grown about 25% in the past five years and more companies are expected to set up shop. Plenty Unlimited, a California-based vertical farming company, is building what it claims is the largest indoor plant in the world. agricultural campus on 120 acres of land outside Richmond, where it plans to grow strawberries for Driscoll’s.

Some companies have committed to using clean electricity in their operations.

In Westbrook, Maine, Vertical Harvest is building a four-story, 52,000-square-foot vertical farm and negotiating a deal to power it with renewable energy. However, company leaders said they cannot apply the same strategy to their next project in Detroit, where the state’s energy mix is ​​heavy on fossil fuels and the company cannot choose its electricity supplier.

Little Leaf Farms, the dominant producer of controlled-environment packaged greens in New England, uses natural gas to heat its greenhouses. To get around this problem, CEO Paul Sellew said the company buys renewable energy certificates, each of which corresponds to a certain amount of energy generated by cleaner sources such as wind or solar. Little Leaf is also planning to build a large solar array on its 180-acre site in McAdoo, Pennsylvania, and Sellew said he is interested in eventually switching to geothermal energy, which is already being used in the Netherlands to heat greenhouses but has not yet caught on. in the United States.

Sellew said operators exaggerate the environmental benefits of vertical farms and describe them as a smaller but “unsustainable” part of the indoor farming world. “We don’t understand these alternative farming methods that don’t use the sun,” he said.

Some vertical farming companies, like Texas-based Eden Green, have responded to the dirty energy problem by focusing on efficiency. Eden Green’s hybrid model uses natural light, and the company reduces the load on its refrigeration system by using timed openings to control heat and humidity. Badrina estimated that his two farms use about a quarter of the electricity consumed by a typical vertical farm that grows leafy greens, which has allowed the company to plant other crops, such as herbs, that consume more energy.

Badrina said he noticed other growers starting to pay more attention to energy use after a series of high-profile failures in the vertical farming industry last year. Still, the upfront costs of energy-efficient technology sometimes outweigh the incentive of lower utility bills.

And as some companies look to build vertical farms in the swampy Southeast, Badrina said they will likely face even higher energy bills with all the energy needed to combat the region’s heat and humidity.

“People are coming up with more creative solutions for energy sources, but I think they will always struggle with energy use,” he said.

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