Heat Rises: Data center’s waste heat to power greenhouse

About 85 feet beneath the surface at Springfield Underground, Bluebird Underground LLC’s data center is the engine that helps power 5G mobile networks, digital medical services, the internet and cloud computing.

The industry is hot, figuratively speaking, with the International Energy Agency predicting the demand for data center services will rise dramatically over the next decade, driven in part by emerging technologies like blockchain, machine learning, the internet of things and the metaverse.

The data center also is hot, literally speaking.

“Data centers produce heat all the time – it’s just a byproduct of what we do,” said Todd Murren, Bluebird’s general manager for data centers, explaining the need for cooling exists year-round.

In one large chamber at Bluebird, a room-sized contraption called a plenum constantly processes and cleans the hot air before blowing it to the surface through a hole that is 13 feet in diameter.

It’s something to see, or more accurately, something to feel, like hot Saharan scirocco winds buffeting anyone standing beneath that limestone chimney.

Today, the thermal wind merely rises to the surface and dissipates into the outside air. But soon, if father and son Mike and John Chiles of development company Ozarks Renewal LLC have their way, that heat will be captured and put to work as energy to produce hydroponic lettuce.

It’s a symbiotic relationship that uses technology to meet the most visceral human need: food.

Hope’s Garden
John Chiles said the mission-driven for-profit Ozarks Renewal would lease land from Springfield Underground to build a 3-acre greenhouse above and slightly to the east of the Bluebird vent pipe, with a packing shed located nearby. He said the parties have arrived at a tentative, undisclosed price for the rental; he also declined to disclose the terms of the agreement with Bluebird for heat.

The developers are calling the project Hope’s Garden, which will start with a hydroponic greenhouse to produce leafy greens that can be sold in area grocery stores.

“One of the largest costs of running a hydroponic greenhouse is heating the greenhouse,” John said. “They typically use natural gas, but using waste heat mitigates the largest cost of running the greenhouse, and there’s a huge environmental benefit.”

Murren said the heat isn’t benefitting anyone at the moment.

“We’ve been here many years, and we’ve just exhausted the heat,” he said. “We never thought about it – it was just a byproduct, and we threw it away. You know what they say, though – one person’s trash is another person’s treasure.”

John noted using the excess heat also benefits the environment in multiple ways.

“Predominantly, most of the greens we get from the grocery store are grown in California or Arizona,” John said. “There’s a huge carbon impact from shipping that across the country.”

And transporting the food to Missouri takes time.

“This gives an added five days of shelf life,” Mike explained. “It takes about five days to get all the produce picked, shipped and unloaded.”

Growing hydroponic lettuce – an estimated 90,000 heads per week – is the beginning of the Chileses’ vision for the Hope’s Garden project, according to John. Like the Bluebird data center, humming away underground so a smart refrigerator can signal the milk is almost gone, there is much more beneath the surface.

Next phases
John Chiles said food service companies and distributors already have expressed an interest in large-scale production of Hope’s Garden lettuce, but there is a second stage: a food hub.

The food hub, to be located near the greenhouse, is a distribution center. John said through the hub, produce from local farmers can be aggregated, packed and shipped in trucks to grocery stores and other food service operations. John noted Ozarks Renewal has been in talks with Associated Wholesale Grocers Inc. as a possible market for Hope’s Garden goods.

“The challenge with that, we’ve talked to AWG, Cox, Mercy – every one of them really wants to buy food from local farmers, but it’s just too difficult to deal with lettuce or eggs from a hundred different farmers,” he said. “You can’t just show up with a pickup full of sweet corn.”

The food hub would bridge the gap between farmers and purchasers, he said, providing economies of scale and making sure the food is inspected, traceable and properly handled.

“Most farmers generally just want to grow food,” John said. “The food hub creates that space where that’s all the farmer has to do.”

There’s a third phase, too, John said – providing an accelerator for small farms. An increasing number of young people want to get involved in farming, he said, and the Ozarks Renewal project aims to create purposeful opportunities.

“This is an example of a really meaningful path for employment of growing leafy greens and creating infrastructure down the road to support small-scale farming,” he said.

Mike said agriculture is largely in the hands of a few conglomerates. The region’s meat industry is dominated by four companies, and the grain industry is dominated by four or five.

“They’ll turn around and export our grain to China, and multiglobal companies are making most of the money,” he said. “When you drive through the Ozarks, you see rundown farms because the money has been sucked out of the economy – yet consumers here want to buy local food.”

John noted Ozarks farmers have the know-how to produce food.

“It’s in the DNA of Ozarkers,” he said. “If we can show this can work here in the Ozarks with a systems-based approach, a lot of other people are going to want to do the same thing.”

Capturing heat energy may be in the Chileses’ DNA. Mike is past president of Watts Radiant, selling radiant floor heating systems. And John has a background in socially conscious investing, having overseen investor due diligence and deal screening for E8 Angels, a cleantech angel investment group. Both have MBA degrees.

Solving multiple problems
Murren said Bluebird has the goal of becoming carbon neutral by 2040, and it’s a challenge, as data centers use massive amounts of electricity and therefore produce large carbon emissions.

“We can make 1%-2% efficiency increases, and then you can have one customer come in here and double your megawatt load,” he said. “It’s like spitting into the Atlantic Ocean and thinking you can influence the volume.”

The International Energy Agency reports data centers and data transmission networks accounted for 0.9% of all energy-related greenhouse gas emissions in 2020. Data centers used 0.9%-1.3% of global electricity demand in 2021.

ACHR News, the trade magazine of the air conditioning, heating and refrigeration industry, reported in August that a typical large data center can generate 20 to 50 megawatts of heat, while a data center campus can generate up to 300 megawatts. The U.S. Nuclear Regulatory Commission reports a single megawatt can produce enough electricity to power 400 to 900 homes for a year, depending on where the homes are located.

The fact that Bluebird is underground and releases heat through a single shaft makes the thermal energy easy to collect, though Mike said it’s possible to carry heat over several miles by turning it to liquid and conveying it through pipes – a common means of heating homes in Iceland.

Murren said Bluebird will benefit from the proposed project by being able to offset its carbon footprint.

“If they can take our heat and do something good with that, that’s where it gets really interesting on the offset,” he said. “We’re not going to turn things off just to save carbon emissions, so if there’s anything we can do to offset, that’s where the magic is.”

Ozarks Renewal has interested investors, John said, and soon will be ready to raise capital. Early financial support was provided by Matt O’Reilly through Green Circle Projects, which funds projects that promote environmental stewardship.

The company prospectus lists its capital needs as $7 million in equity and $14 million in conventional or foundation-provided loans.

It received a $200,000 Urban Agriculture and Innovative Production Grant from the U.S. Department of Agriculture in 2021.

The Chileses plan to get the greenhouse off the ground in 2023 and begin producing year-round – then the rest might heat up from there.