Startup’s Carbon-Removal Technology Paves Path to Cleaner Future

Over more than a decade as an engineer, entrepreneur Keeton Ross has helped advance some of the most innovative clean energy technologies at companies large and small.

Nuclear energy. New battery storage. Electric vehicles.

"Taking a breakthrough technology from idea to industrial scale is enormously difficult, but tremendously exciting,” Ross said. "I like working on problems where if we get this to work, it has a massive positive impact on people’s lives and livelihoods."

These days, as president and co-founder of the Knoxville-based startup Holocene, he's helping pioneer groundbreaking technology that permanently removes carbon dioxide from the air.

It's known, fittingly, as direct air capture. Rather than eliminating or reducing emissions output – an aim of many technologies – it instead captures the atmosphere’s existing emissions.

Holocene aims to fill an important niche in the world’s suite of climate solutions.

And its technology could help Tennessee Valley Authority reach its aspiration to have net-zero carbon emissions by 2050.

Innovation leaders at TVA have thrown support and funding behind the company.

“At TVA we need clean technologies to transition to a low-carbon future,” Miles Biggs, TVA's manager of innovation partnerships, said. “We see it as our responsibility to help accelerate and develop the technologies we need to solve our future challenges.

“We saw Holocene pitch a few years ago," he said. That led to partnering with them. "We want their technology to become commercially available.’”

Keeton Ross, president and co-founder of Knoxville-based Holocene.

Scaling Up

With TVA’s sponsorship, Holocene participated in Innovation Crossroads, a two-year incubator program at the Department of Energy’s Oak Ridge National Laboratory. The University of Tennessee’s Spark Incubator Program also supported Holocene with lab space and mentoring.

As it graduates from the incubators, Holocene is now scaling up its technology, expecting to reach full commercial operation by 2030.

Customers are already lining up.  A consortium of large companies has signed contracts committing to purchase carbon removal credits from Holocene.

For TVA, supporting Holocene is all about building a path toward net-zero carbon aspiration, said Andrew Campbell, TVA’s senior manager for transformative innovation initiatives.

In 2023, TVA achieved a 53% reduction in carbon emissions intensity from a 2005 baseline.

It is currently deploying plans to add renewable generation, enhance clean nuclear and hydro generation, and shift from coal to natural gas. Pathways are being developed to get an approximate 80% reduction in carbon intensity by 2035.

Beyond that, new carbon-capture technology that can trap up to 95% of emissions in flue gas could be added to natural gas plants to bring the region even closer to net-zero carbon emissions.

And that’s where Holocene’s technology comes into play.

“How we address that last few percent of carbon emissions is really an important problem to solve,” Campbell said. “Direct air capture to offset those hard-to-capture emissions – that’s the place this technology fits to truly get to net zero.”

Holocene’s proprietary process involves specialized equipment such as this tank in which carbon dioxide is trapped into solid form, hoses and valves that transport carbon dioxide through a direct air capture machine, and a maze of pipes that forms a symphony of science for Holocene engineers.

Purification Process

The concentration of carbon dioxide in Earth’s atmosphere was stable for thousands of years. But it has gone up 50% in the past 200 years, since industrial technology brought widespread burning of fossil fuels.

Holocene’s technology extracts carbon from ambient air through a chemical process that turns the carbon into a white powder, which is then lightly heated to create a concentrated gas.

“We're purifying CO2 from the air,” Ross said. “We’re trying to grab that needle in the haystack and end up with a pure stream of CO2.”

That pure CO2 – carbon dioxide – is the waste being removed from the air, Ross said.

At that point, there are several options for what to do with it.

“You can either take that CO2 and turn it into products or take that CO2 and put it back underground where it first came from,” Ross said. “Just like garbage waste – some of it we store in landfills, some of it we recycle to use again. CO2 will be the same.”

Either way, it’s no longer building up in the air.

Holocene, named after the geological time period when atmospheric CO2 was stable, has licensed a patented discovery by Oak Ridge chemists to advance beyond direct air capture concepts first tested by Holocene's peers.

Holocene’s breakthrough is a system that can run continuously using low-temperature heat from renewable energy – features that Holocene expects will make its commercial-scale technology more affordable than other options.

Andrew Campbell, TVA senior manager for transformative innovation initiatives, talks to Ross about Holocene's technology.

Safety Valve

Building a new company – much less a new industry – comes with a lot of uncertainty, but Ross and his two cofounders are all in.

He, along with CEO Anca Timofte and chief technical officer Tobias Rueesch, moved to Knoxville to collaborate with the chemists at Oak Ridge as they were starting Holocene. Rueesch came all the way from Switzerland, where he had lived his entire life.

To all three, the risk seemed worth it because the potential payoff was so important – creating an affordable solution to the problem of excess CO2 in the atmosphere.

“There's no silver bullet to fix this problem, but the closest thing we have to a safety release valve in the system is direct air capture,” Ross said.

Other, better solutions may come along.

Ross hopes they do.

“I genuinely hope we get put out of business and there's no need for us to exist because the world fully decarbonizes,” he said. “But in fact the opposite is happening – the world isn’t decarbonizing fast enough and direct air capture is only becoming more critical.” 

TVA innovation leaders aren’t putting all their eggs in one basket.

Campbell’s group backs other clean energy innovations, including novel battery technologies, either directly or through TVA’s membership in the Electric Power Research Institute, a utility industry group.

“There are other companies that we look at in these incubator spaces,” Campbell said. “All these things coming through incubators let us see what new technologies might be possible.

“There are many horses in the race, and we hope several of them win.”

Photo Gallery

In a space of about 400 square feet, the Holocene pilot facility can capture carbon dioxide from ambient air.

Holocene chemical research associate Zeke Stoika, right, looks on as Charlie Little, head of chemistry, works in the research and development lab.

Charlie Little conducts research in the lab at the company’s Knoxville facility.

Holocene engineers Joe Geers and Finn Chilsen admire the product of their hard work.

Jim Biggs, of Knoxville Entrepreneurship Center, jots a celebratory note on equipment during Holocene’s pilot launch.

PHOTO AT TOP OF PAGE: The process rack at Holocene’s direct air capture pilot facility.