Tulane professor sees wasted carbon as an untapped resource in the energy transition

Plastic headed for a landfill and natural gas burned off at an oil field may seem like two different environmental problems.

But to Tulane chemical engineering professor Dan Shantz, they also represent something else: wasted carbon that could potentially offer alternative energy sources.

Shantz, associate dean for research and PhD programs in Tulane's School of Science and Engineering, is studying ways to turn discarded or underused carbon sources into fuels and other valuable materials. His work reflects a broader sustainability challenge facing the energy industry - how to make better use of resources already in circulation while reducing the need to extract new ones.

"The idea is, in the case of waste plastics, you convert them into molecules you could blend into the transportation fuel pool whether it's diesel or gasoline," said Shantz, the Entergy Chair in Clean Energy Engineering. "It certainly seems better to do this than to put it in a landfill."

Mechanical recycling can extend the life of some plastics - recycled plastic water bottles, for example - but it has limits. And while researchers and companies have explored ways to chemically break plastics back into their original building blocks, those processes are not always technically or economically practical.

A key focus of Shantz's lab is exploring whether the large quantities of waste plastic that can't easily be recycled can be used as a feedstock to produce fuel. Plastics are rich in carbon and chemically resemble many products made from petroleum.

"There are huge quantities of plastics produced," Shantz said. "More than 100 million tons of polyethylene, which is used in products such as milk jugs and shopping bags, are produced globally each year, and total plastics production was over 400 million tons last year. While not all may be amenable to such processing, this clearly represents a large carbon source. To give a sense of scale, if you could convert half of that 100 million tons of polyethylene to fuel, you would generate the amount of fuel that comes from roughly 500 million barrels of oil. This is approximately the amount of oil produced globally over five days. Not to mention you are no longer landfilling that 50 million tons of waste plastic."

Turning waste plastic into fuel would not eliminate carbon dioxide emissions, which would still occur when the fuel is burned for energy. But Shantz argues that sustainability in the energy space requires more nuanced understandings of how increased use of one fuel source can cut down on another.

In an energy system operating on a global scale, even relatively small reductions can have substantial effects.

"Everybody thinks you're going to have this magic bullet, and then oil consumption will go to zero," Shantz said. "That's probably not how this is going to work. It's probably not how carbon dioxide emission reductions are going to work. You're going to have to take tranches - 5% here, 10% there."

That same philosophy underlies another area of Shantz's research: finding a better use for natural gas that might otherwise be burned off or flared.

Methane is the primary component of natural gas. At some oil and gas production sites, producers may lack adequate pipeline or storage capacity to move all the gas they recover. Rather than release methane directly into the atmosphere, where it is a potent greenhouse gas, operators burn it in a flare, converting it into carbon dioxide.

The practice generates emissions and also "is a waste of perfectly good natural gas," Shantz said.

For years, his lab has studied whether methane could be converted directly into methanol, a liquid chemical that can be used as a building block for fuels. The challenge is finding a way to achieve that conversion at the wellhead without the need for large, expensive facilities.

"If I could make it into something that's easy to move from the wellhead, then I've got a new carbon source," Shantz said. "That would be a big deal."

Both research areas - waste plastics and flared natural gas - illustrate a broader way of thinking about sustainability.

Rather than viewing every environmental challenge solely as a question of replacement, Shantz looks for opportunities to recover value from materials already present in the system.

That does not remove the need for renewable energy and other low-carbon technologies. But Shantz argues that reducing waste, avoiding unnecessary extraction and finding productive uses for existing carbon can all be part of a more sustainable energy system.

The challenge is making those ideas work economically.

Petroleum refining and plastics manufacturing have been optimized over decades and operate at enormous scale. Any alternative must compete against mature technologies, existing infrastructure and commodity markets in which even small price differences matter.

"Everybody would like to have clean fuels, but if I tell you you're going to pay $4 a gallon instead of $3, people are less enthusiastic, right?" Shantz said. "It's not an easy problem to solve."

This article is part of a series highlighting Tulane University energy experts and energy industry professionals ahead of 2026 Tulane Future of Energy Forum, which will take place Sept. 28-30. Learn more about the Future of Energy Forum or register for the free event .