“The defining challenge of our time is solving the climate crisis,” says Professor Jeffrey Bergthorson, William Dawson Scholar in the Department of Mechanical Engineering at McGill University.
He founded the Alternative Fuels Laboratory to focus on that goal. “This is research with purpose,” says Bergthorson. “We’re aiming to solve the problem of de-carbonizing society.”
Over the past 12 years, his team’s research has identified metal powders as the best alternative to carbon fuels. Metal powders are zero-emission, recyclable energy carriers. They can be stored and transported at large scales, generate electricity in remote areas beyond transmission lines, and even power heavy-duty vehicles. This makes metal fuels well-suited for communities across Canada, as well as for trading on the international clean energy market.
“This is the type of technology we need in Canada to get to the end of our de-carbonization mission,” says Bergthorson.
A not-so-novel approach
Burning metal powders for fuel is nothing new. They’ve been used for centuries in fireworks. The booster rockets in space shuttles burn aluminum as their main fuel.
“Our idea has been to take that rocket science and turn it into clean tech,” says Bergthorson, who holds a PhD in aeronautics from the California Institute of Technology. The combustion of metal powders creates only metal oxides and does not produce any greenhouse gases. This has the potential for a carbon-free transportation energy system, in which reactive metal powders are used as renewable energy carriers.
In his earlier research, Bergthorson explored biofuels. He quickly realized the main challenge was on the production side. “We can’t produce enough biofuels and at a low enough cost to offset carbon emissions at sufficient scales.”
His lab also explored hydrogen fuel for many years. “A lot of work on hydrogen is focused on how to safely transport and store it,” says Bergthorson. “It’s a great fuel to burn, but not great to move around and transport. So, what are the other options?”
This brought Bergthorson and his team to metals.
When iron is burned and turned into iron oxide, “you can bring that iron oxide back and electrolyze it or react it with hydrogen, pull the oxygen off it, and now you make iron fuel again,” says Bergthorson. “We first developed the science and then the technology to enable us to do that.”
Three of his former students have created a spin-off company, Altiro Energy. They’ve patented the first system that can burn pure iron fuel with air. “Since both the fuel and the recycling process have no carbon emissions, the process is carbon-free,” says Bergthorson, who serves as the company’s Chief Scientific Advisor.
Crucially, the same fuel can be used multiple times. “You produce it, you move it, you burn it, you bring it back and recycle it,” he says. “It stays inside the energy system without waste. It’s an infinitely recyclable fuel.”
Reacting with H20
Combustion isn’t the only way to tap the energy stored in metals. Another approach involves causing metals — particularly aluminum — to react chemically with water. That’s the second technology that Bergthorson’s lab is exploring.
In aluminum-water reactions, the water molecule is split apart. The released hydrogen gas is a fuel that can be burned in air or used in a fuel cell. The oxygen attaches to the metal atoms, forming an oxide, which can be recycled.
“The idea is to close the loop — to use that same bit of iron, or that same bit of aluminum, over and over again,” Bergthorson says. “That’s what enables this to be sustainable.”
Keeping it simple — and scalable
Bergthorson notes that both these technologies solve the problem of how to commoditize renewable energy.
Metals can be bulk transported by ground, rail, or ship — without needing to change the existing global transportation or manufacturing infrastructure. Iron burns at approximately the same temperature as coal, oil, and natural gas. So, it can be used as fuel in coal-fired power plants, for example.
To replace fossil fuels, the alternative must have high energy densities for convenient trade and storage. “If you look at the energy density that metals store by volume and mass, they beat batteries by orders of magnitude, and hydrogen storage systems by many times,” says Bergthorson.
As well, iron powder is non-explosive and environmentally safe. In fact, we have iron in our bodies — and our food.
“People are always looking for fancy new solutions. With metal fuels, we’re talking about the simplest and most scalable solution.”
A focus on the big picture
Bergthorson is collaborating with industry partners keen to explore this clean energy solution, including Hydro-Québec, Siemens Energy, Rio Tinto, Teck Resources, and AgnicoEagle. Another collaboration involves partnerships with major iron powder producers: Tata Steel, Hoeganaes Corporation, and Rio Tinto’s iron and titanium division.
“Our vision is for Canada to be a superpower in a renewable energy economy,” says Bergthorson of his Alternative Fuels Laboratory.
He believes this made-in-Canada technology will help solve many of the challenges we face today — such as transporting clean energy to remote communities beyond powerlines, increasing power storage capacity, and generating plentiful renewable energy for all.
He emphasizes it will take big ideas and big resources to make a quantum leap in tackling the climate crisis.
“That’s what we’re focused on — that bigger vision. Let’s not focus on getting the next 5 or 10 per cent there. Here’s how we can get all the way to a de-carbonized society.”