Clearing the Air

There were many times that Christine Gabardo wondered if the project would ever get up and running.

For more than four years, Gabardo, a post-doctoral fellow in mechanical and industrial engineering at U of T, had been working on a machine designed to take carbon dioxide that would have ended up in the atmosphere and turn it into useful chemicals. She and a team of postdocs, students and faculty advisers scaled it up from a small lab process handling a few milligrams at a time to a truck-sized machine capable of converting hundreds of kilograms of CO2 per day. They hoped to win first place in the $7.5 million (U.S.) Carbon XPrize, a competition to reward the team with the best technology for converting carbon into a marketable product.

But first they had to get the machine, called an electrolyzer, installed at the test site in Calgary. Unfortunately, the day the machine was delivered in January 2020 the temperature had dropped to minus 30 Celsius, and when they opened the delivery door the building’s heaters were immediately overwhelmed. “It was just terrible to be out there,” Gabardo said. Even worse, the extreme cold damaged some plastic components of the electrolyzer, which they had to have manufactured again.

Despite the damage, and further challenges such as frozen pipes and technical difficulties – as well as a global pandemic – by the end of December the team had succeeded in running their unit for almost 2,500 hours and in converting carbon dioxide into chemical products. Now their plan is to bring the electrolyzer back to Toronto and use it to convert emissions from U of T buildings, while continuing to refine their process.

“In time, the technology could yield a new method for fighting climate change. And it’s an example of how U of T plans to harness on-campus ingenuity to fulfil a plan to make the St. George campus not just carbon neutral, but carbon negative by 2050. This means the campus would actually remove more carbon dioxide from the atmosphere than it generates.

The university won’t rely on any single strategy to achieve this, says Ron Saporta, U of T’s chief operating officer for property services and sustainability at St. George. “The plans we develop are going to include everything from carbon capture and renewable energy to fundamentally reducing the energy we consume,” he says. “There is no silver bullet that will address our carbon challenge.”

Greenhouse gases come from many sources, including power plants and industrial facilities, which burn fossil fuels and send the exhaust gases up the smokestack. Carbon capture removes the carbon dioxide from the stack before it makes its way into the atmosphere. But the process raises costs, so most companies won’t do it unless required. There is also the problem of what to do with all the CO2 you capture. At the moment, most of it is pumped underground, which further adds to the expense.

If that carbon dioxide could be converted into products and sold, carbon capture would be a lot more attractive for businesses. As long as the electricity used in the process is clean – produced with solar or wind, for example – no additional carbon dioxide enters the atmosphere. If the products made with the process can replace goods manufactured the traditional way (in which carbon dioxide is emitted), then there is an added environmental benefit.

THE U OF T XPRIZE TEAM was founded in 2016 by Alex Ip. At the time, he was the director of research and partnerships for the lab of engineering professor Ted Sargent. Sargent and fellow engineering professor Dave Sinton are advisers to the team, which has since expanded to 12 members. (Gabardo joined in 2019.) They named the team Carbon Electrocatalytic Recycling Toronto, or CERT.

About the time the team started, Canada’s Oil Sands Innovation Alliance and the U.S. power company NRG teamed up with the XPrize Foundation to run the competition in search of the best technology for converting carbon dioxide emissions into usable products. Although brand new, the team decided to enter the contest.

The process they developed is similar in principle to the high school chemistry experiment in which you use the energy from an electric current to split water (H2O) into its two components – hydrogen and oxygen. The U of T team’s technology breaks down CO2 into separate molecules of carbon and oxygen, says Ip, and goes a step further. It puts the pieces back together again, but adds hydrogen, which enables the team to create valuable materials, such as ethylene (a building block of plastic), ethanol (a solvent) or a mix of hydrogen and carbon monoxide called synthetic gas, which can be used as a fuel.

By adjusting the type of catalysts they use, the operating temperature and voltage, and many other variables, the team is able to “tune” the machine to create more of the chemical they want – say, lots of ethylene, but not much ethanol. But getting the process to work in the lab is only the first step. The Carbon XPrize rewards teams whose machinery is efficient, has been tested over a long period, is able to convert large amounts of carbon dioxide at a time, and has the potential to work at an industrial scale.

The prize organizers brought five finalists to a site in Calgary next to a natural-gas-burning power plant. Each team was provided with a small lot with hookups for water, gas and electricity, as well as a supply of carbon from the power plant. And that was it. In the space of a year, the team had to have a pilot-sized version of their machinery built. They put in 12-hour shifts to keep their device running. Six of the team members ended up sharing a house in Calgary throughout the competition. “It was not an easy few months,” says Gabardo. “We worked together, we lived together. We were the only people we saw in 2020. But for me, it was an interesting and exciting experience – scaling something up from the lab. We learned a lot of different skills that aren’t necessarily associated with academic research.”

The results of the Carbon XPrize competition were announced in April, and the U of T team did not win. But Ip and Gabardo consider the project a success so far. Theirs is the largest CO2 electrolyzer in the world that functions at a low temperature. (Most operate at relatively high temperatures or at a smaller scale.) An analysis showed that the current process could produce ethylene competitively at an energy cost of five cents per kilowatt-hour. This is lower than the average industrial price of electricity in Ontario, but will be within reach as the price of renewable energy comes down, Gabardo says. “We definitely have a lot of work to do,” Ip adds. “We’re hopeful that in the next few years we can have some of these units operating.”

THE TEAM’S PROJECT FITS IN perfectly with U of T’s plans, says Ron Saporta. The university is committed to making the St. George campus carbon negative – or, as Saporta prefers, “climate positive” – by the year 2050. “Most people are talking about net zero for 2050. We want to go beyond net zero so that our campus becomes a carbon sink and creates a net benefit for our community,” he says.

In 2019, U of T adopted a plan for the St. George campus that called for a 37 per cent reduction in emissions below 1990 levels and included a number of ambitious measures. These include Canada’s largest urban geoexchange project, being built on the front campus, which will use an underground heat-pump system to add heat to the buildings around King’s College Circle in winter and remove heat in summer. Similar geoexchange projects are already in place at U of T Mississauga and U of T Scarborough.

Other measures include retrofitting buildings to be more energy efficient, installing more solar panels, and upgrading the 120-year-old St. George heating system. Right now, it uses natural gas to create steam, which is piped to buildings around campus. Converting it to a system that uses electricity to create hot water will be more energy efficient and will significantly reduce carbon emissions, says Saporta.

U of T Mississauga and U of T Scarborough share the university’s overall greenhouse-gas reduction goal, but each campus is formulating its own plans. For instance, UTM envisions creating a culture of sustainability. “We believe the larger campus community, including students and visitors, could play a role,” says Ahmed Azhari, UTM’s director of utilities and sustainability.

Even taking all of these measures together, though, the university will still be emitting about 74,000 tonnes of greenhouse gases a year in 2030. Under the “climate positive” plan, the St. George campus will cut its remaining emissions by 2050 through additional efficiency improvements. But there will be some greenhouse gas emissions that can’t be completely eliminated on campus. Those emissions will be offset with reductions off campus, says Saporta. For instance, the university may invest in building off-campus solar farms that would provide clean energy to the power grid. By replacing electricity produced from higher-carbon sources with renewable energy, the university will become an overall carbon sink, Saporta says.

Most people are talking about net zero for 2050. We want to go beyond net zero so the St. George campus becomes a carbon sink and creates a benefit for our community.”

The new climate positive plan also envisions developing new technologies that could help reduce carbon emissions further. Many of the gains will come from research that is being conducted on campus, says John Robinson, U of T’s presidential adviser on the environment, climate change and sustainability. Robinson, who is also a professor in the Munk School of Global Affairs and Public Policy and the School of the Environment, advocates turning the university into a “living lab” – using the research and talents of faculty and students to come up with new ways to improve sustainability on campus. “Part of the answer is uncovering the richness that’s already out there, and finding ways to connect it,” he says. “This is about universities stepping up. They need to engage.”

The carbon conversion project is exactly that kind of engagement. Although the machine is still in Calgary, the team planned to bring it to U of T sometime this spring. They are working with Saporta to find a good site – ideally, one that can make use of the carbon dioxide generated by a gas boiler that heats a campus building.

“We’re very excited to bring the team and their technology home to advance this critical research on climate change mitigation,” says Saporta. “And to start capturing carbon right here on the St. George campus.”

Where St. George’s CO2 Cuts Will Come From

Total carbon reduction by 2050: 138,000 tonnes/year

• 35% new building design
• 30% utility renewal and electrification
• 20% renewable energy
• 10% building retrofits
• 5% geoexchange fields