Can an Army of Mechanical Trees Save the Planet?

Imagine a tree that removes carbon dioxide from the atmosphere 1,000 times faster than a tree designed by Mother Nature. This tree also captures and stores that CO2, which eventually becomes liquid fuel. Sounds like a futuristic sci-fi story, doesn’t it?

It’s happening today. Klaus Lackner, Ph.D., director of the Center for Negative Carbon Emissions, and professor at the School of Sustainable Engineering at Arizona State University (ASU), invented the Mechanical Tree™. Lackner’s trees stand 30 feet tall and instead of leaves contain a stack of 150 discs, which operate in the same manner as leaves. Both rely on wind to collect and store CO2. 

Recycled CO2 has many uses from injecting it into oil wells to increase oil production, to hardening cement, to power cars, or to turn it into insulation foam for housing. “Carbon dioxide is a waste product we produce every time we drive our cars or turn on the lights in our homes,” Lackner says. “Our device can recycle it, bringing it out of the atmosphere to either bury it or use it as an industrial gas. The atmospheric carbon situation has become critical and we need to start doing something about it.” 

Lackner has been working on developing the Mechanical Tree™ since the early 1990s. Lackner was the first scientist to suggest CO2 could be captured from the air to combat global warming. “We have released so much CO2 into the atmosphere that it cannot disappear naturally,” Lackner says. “This technology can reduce carbon emissions, which is a leading cause of climate change.”

Good old-fashioned wind

“We are using passive Direct Air Capture technology,” Lackner explains. “A passive approach removes the need for fans and blowers that’s used in other Direct Air Capture systems. Our Mechanical Trees™ use ambient wind to deliver CO2.”

According to Lackner, the only energy that’s required is for processing the captured CO2. “This makes our passive approach much more cost effective,” he says. 

Partnerships and mass production

Lackner and ASU’s Center for Negative Carbon Emissions and the School of Sustainable Engineering have partnered with Carbon Collect Limited, an international climate tech company with headquarters in Europe and offices in the United States and Canada. Currently a handful of Lackner’s trees exist. An older and smaller model still sits on top of a building at ASU. Another is in London situated near a power plant, and one is on display at a science museum in Atlanta. 

Within the next decade, Carbon Collect expects to install Mechanical Tree™ farms globally. This large-scale plan will cover 0.8 to 1.2 square miles per farm. According to Lackner, “Two hundred and fifty large scale Mechanical Tree™ farms have the capacity to capture one gigaton (A gigaton equals one billion metric tons.) of CO2.” 

Planting trees by hand is a drop in the bucket. A study in the journal Science found we’d have to plant more than a half trillion trees to capture approximately 205 gigatons of carbon. 

That same study also found planting a billion hectares of trees by hand is a major operation that takes between one and two thousand years. Once those trees take root, some can take 100 years to reach maturity. 

“Constructing our trees is much faster and our technology has the potential to solve climate change,” Reyad Fezzani, vice chairperson and executive director at Carbon Collect, says. 

Lowering costs

Leaders at Carbon Collect are working with large corporations and governments to achieve this goal. The issue at hand is cost. “What we’re trying to do is reduce the cost per ton to the lowest level possible, ideally below $100,” Fezzani explains. “Today, carbon dioxide is manufactured at much higher prices.”

Lackner seems optimistic. “As with new technology, prices eventually drop,” he says. “Look at computers when they were first introduced. The carbon collected by this technology might drop down to $30 per ton.”

On their way

Carbon Collect is one of six carbon-capture companies that will receive funding from the Department of Energy (DOE) for $2.5 million. “We expect this project to be an important step for the commercialization of a technology that can be scaled to help balance the world’s carbon budget,” Pól Ó Móráin, Carbon Collect’s CEO and director says. “The award will demonstrate how this technology can contribute to the CO2 drawdown that will be needed to keep global warming in check.”

Looking to the future

Ó Móráin set a goal “to accelerate the global climate effect in the Paris Agreement to contribute to reversing global carbon emissions in the next 10 to 15 years,” he says. “Our passive process is the evolution of carbon capture technology, which has the ability to be both economically and technologically viable at scale in a reasonably short time frame.”

Lackner, Fezzani, and Móráin are fans of the trees. “If we, however, plant trees the traditional way, it takes years for them to mature,” Lackner explains. “This is a faster process and with CO2 emissions continuing to rise, we need a quick solution.”