If life hands you a data centre, grow tomatoes

People everywhere are protesting AI data centres, with good reason. They use a lot of water and energy, and they create a lot of noise. They create relatively few ongoing jobs after construction is complete.

Electricity used to power servers at AI centres creates heat. To keep running they must be cooled. More electricity is used to power chillers to cool the computers. In summer, chillers evaporate water and dissipate heat to the atmosphere. Lots of it. A few Olympic-size swimming pools worth, even in our cold climate.

A 100 MW (100,000 kW) data centre uses enough power to heat about 10,000 homes with electric baseboard heat or an electric furnace. Or about enough to heat 80 acres of greenhouse on the coldest days of January. To put that in perspective, the recently completed Keeyask dam produces about 695 MW of power. A 100 MW data centre uses about 14 per cent of the power produced by the Keeyask dam.

In Finland, a data centre was built under downtown Helsinki. Waste heat from the data centre is recycled to heat the buildings above it.

Here’s where it gets interesting. A data centre doesn’t quit working when summer arrives. It keeps chugging out the heat regardless of the weather. People keep the servers busy asking questions, and the servers still need cooling. If you had somewhere to store all that heat, you could heat about four times as much … 40,000 homes or 320 acres of greenhouse. Well, the ground under the data centre can store a lot of heat, and it can be pulled out of the ground next winter when it can be used.

This works. I’ve been storing heat from solar thermal panels in my ground heat exchanger for the last 10 years. All summer, when it’s not covered with snow, the solar panel dumps heat to the ground-heat exchanger in our front yard. The heat pump in the house extracts the heat in January and February to improve the efficiency of the heat pump. A 2.5-by-4 metre solar panel increases the temperature of the ground by about 4 to 5 C.

So how many tomatoes can you grow in a 320-acre greenhouse? A climate-controlled greenhouse can produce up to 160 tonnes of tomatoes per acre every year. About 51,000 tonnes from 320 acres. About 2,000 truckloads of tomatoes that don’t have to be imported from California or Mexico. About $5-million worth of tomatoes. That’s about 80 per cent of the tomatoes we import into Manitoba every year. Eliminating the diesel fuel needed to ship the tomatoes reduces carbon dioxide emissions by about 13,000 tonnes per year.

It gets even better. Tomato plants produce more fruit when their environment is enriched with CO2. Gas turbines used to produce electricity can increase the CO2 concentration in the greenhouses and the tomatoes in a 320-acre greenhouse can absorb about 87,000 tonnes annually.

A commercial greenhouse employs about three workers per acre. That’s close to 1,000 full-time employees created by the waste heat from a 100 MW data farm.

Tomatoes allowed to ripen on the vine are more nutritious and have better flavour than tomatoes picked green and shipped across the continent.

Storing “waste” heat from a data farm eliminates the need for water to cool the computers. Heat produced by the servers keeps the greenhouse warm all year. Recycling the waste heat creates jobs and helps make Manitoba less reliant on imported food.

In the last few weeks Prime Minister Carney outlined two strategies:

A food security strategy — a $3-billion plan to boost domestic production, increase market choice and modernize regulations over the next 10 years. And also an artificial intelligence strategy for sovereign autonomy, increased adoption and trust and safety.

Integrating these two strategies could help us increase our food security and data sovereignty.

Ed Lohrenz is founder of GEOptimize Inc., a Winnipeg based engineering firm, and has worked in the geothermal heat pump industry for over four decades.