Analysis: Plastics-to-Fuel Gets High Marks
Previously published in Plastics Engineering and posted with permission from the Society of Plastics Engineers.
Plastics recycling has grown year-over-year in the United States for decades, along with recycling overall. But… the majority of our nation’s used materials continues to be buried in landfills, entombed for generations. This represents a waste of resources because that “garbage” we regularly place at the curb contains an enormous amount of energy that could provide a key to a more energy-efficient America.
Energy Recovery with Recycling
Especially the non-recycled plastics. Often thought to be simply garbage, these plastics actually are valuable “materials.” The molecules that make up plastic products are a powerful source of energy. Scientists at Columbia University found that if we were able to convert into energy all the non-recycled plastics produced in the United States in a year, we could power 5.7 million homes annually.
Beyond plastics, if all municipal solid waste headed to landfills each year could be converted to energy, we could produce enough electricity to power nearly 14 million households annually. That could be more than 12 percent of American households powered solely from garbage. In other words, we have a domestic source of energy that could power 14 million homes every year. And we’re burying it.
Some communities are, in fact, recovering this energy—their waste-to-energy facilities produce enough electricity to power two million homes annually, diverting approximately 12 percent of our nation’s garbage from landfills. Other nations are far ahead of us. For example, primarily through a combination of recycling and energy recovery, Germany landfills only one percent of its waste.
Promising New Fuel from Plastics
So… Instead of burying them in landfills, what could we do with plastics that aren’t being recycled? For example, could we capture the energy in non-recycled plastics?
There are promising technologies today that can turn used plastics into transportation fuels, chemical feedstocks, and other valuable materials such as waxes and lubricants. For example, numerous companies use a process called pyrolysis to thermally decompose and then convert non-recycled plastics into petroleum products that can be refined into fuel for autos and other purposes. The process varies but usually involves these steps:
- Plastics are collected and sorted for recycling, and then plastics that do not have commercial recycling markets are shipped to a pyrolysis facility;
- These non-recycled plastics are heated in an oxygen-free environment, where they melt into a liquid and then vaporize into gases; then
- The gases are cooled and condensed into a wide variety of useful products, such as diesel fuel for vehicles.
This technology holds enormous promise: If all the non-recycled plastics in the U.S. that are currently landfilled could be converted this way, we could fuel nine million cars for a whole year.
Sounds promising, indeed.
Comparing Fuels
But what about the environmental impact? How does the process of breaking down non-recycled plastics and reconstituting the molecules into diesel fuel compare to traditional fuel production?
Enter Argonne National Labs.
Part of the U.S. Department of Energy, Argonne National Labs (ANL) created and manages a database that can help answer these questions and more. ANL’s GREET® database (Greenhouse gases, Regulated Emissions and Energy use in Transportation) evaluates energy and emission impacts of transportation fuels, from fuel extraction through vehicle disposal. GREET contains more than 100 different fuel pathways and is used by the U.S. Environmental Protection Agency in implementing the Renewable Fuel Standard Program enacted by Congress. GREET allows researchers and analysts to evaluate diverse vehicle and fuel combinations.
To assess potential energy and environmental benefits, ANL researchers compiled pyrolysis data from five plastics-to-fuel companies. The researchers calculated the energy, water consumption, and greenhouse gas emissions of converting non-recycled plastics into ultra-low sulfur diesel, the primary diesel fuel used in today’s vehicles. Then they compared those calculations to the conventional process for making diesel fuel.
The results?
Diesel fuel made from non-recycled plastics results in significant energy and environmental advantages. These include reductions of up to:
• 14 percent in greenhouse gas emissions,
• 58 percent in water consumption, and
• a whopping 96 percent in traditional energy use when compared to diesel made from conventional crude oil.
The researchers’ peer-reviewed analysis, “Life-Cycle Analysis of Fuels from Post-use Non-recycled Plastics,” was published in the April 14, 2017, edition of the journal Fuel.
Plastics makers lauded the findings. “Argonne’s analysis clearly determines that plastics-to-fuel (PTF) technology is a viable and beneficial materials management option,” said Craig Cookson, senior director of recycling and energy recovery for the American Chemistry Council (ACC). “Not only does PTF reduce waste going to landfills, but these technologies can help reduce greenhouse gas emissions while conserving both water and energy.”
Obstacle: Public Policy
While ANL’s analysis shines a spotlight on the benefits of using pyrolysis to convert plastics to fuel, obstacles remain to the widespread use of this technology. One key obstacle: outdated public policy. Because the plastics used in the process typically would head to a waste facility such as a landfill, many states consider pyrolysis facilities to be “waste disposal” facilities. This is not only inaccurate—it also forces expensive, burdensome, and counter-productive regulations on the facilities and operators. These regulations discourage innovation and investment.
Plastics-to-fuel facilities are simply manufacturing facilities: raw materials are processed into products that are sold; so treating them as waste facilities is unwarranted. Fixing outdated regulations could unleash the huge potential of plastics-to-fuel in many communities around the nation.
Fortunately, some states are moving in the right direction. For example, the Florida legislature in May passed legislation ensuring that plastics-to-fuel manufacturing facilities are not wrongly classified as solid waste management facilities in the state. It also recognizes that the conversion of post-use plastics into valuable products can count as “recycling” and contribute to Florida’s 75 percent recycling goal. The upside is large: converting Florida’s non-recycled plastics into fuel could power more than 500,000 cars every year.
ACC’s Cookson commended the vote, saying that ACC “welcomes the unanimous passage of HB 335—first-of-its-kind legislation that will make Florida a welcoming environment for innovative businesses that convert post-use non-recycled plastics into fuels, chemicals, and chemical intermediates.”
Promising Path Forward
While traditional recycling of plastics continues to increase around the nation, there remain economic barriers to recycling 100 percent of plastics… or any material. But instead of needlessly burying these valuable materials in landfills, we instead should ask: what could we do with plastics that aren’t being recycled?
Given the results of ANL’s analysis and emerging changes in public policy, converting plastics into fuel or new petrochemicals using pyrolysis could answer that question.
