Bridgestone is aiming for carbon neutrality by 2050 as well as to advance circularity in the tire industry through a multipronged approach. In this Q&A, Bill Niaura, director of Sustainable Materials and Circular Economy, Bridgestone Americas Technology Center, discusses some of the plans, from replacing petrochemical-derived materials used in tire manufacturing to what some may consider an unorthodox partnership with competitor Michelin.

Waste360: What are the biggest challenges in trying to advance circularity of tires?

Niaura: Bridgestone is targeting carbon neutrality and tires made from 100 percent renewable materials by 2050. To achieve these goals, we are looking at a variety of solutions focused on the replacement of materials derived from petrochemicals such as synthetic rubber, carbon black, and silica. In many instances, the technology exists to develop and deliver renewable solutions such as bio-based synthetic rubber and recovered carbon black.

The challenge is creating a market large enough to support use of these materials at scale. It’s a bit of a chicken and egg scenario that will require deep collaboration across industries and stakeholders to build a sustainable economic model. We are engaging in conversations with several suppliers, partners, and even our competitors with the aim of advancing sustainability in our industry. It will take all of us collaborating to achieve our collective long-term sustainability goals.

Waste360: Tell us about your partnership with LanzaTech to use rubber to make new tires and biofuels.  How does this differ from burning tires for energy?

Niaura: We have a clear path, technically speaking, to convert rubber from end-of-life tires (ELTs) to sustainable ethanol by leveraging LanzaTech’s carbon capture and gas fermentation process. Conversion of ELTs to sustainable ethanol can capture as much as 93percent of the carbon in the tire versus 0percent for ELTs burned for energy.

Bridgestone and LanzaTech will also jointly explore opportunities to co-develop proprietary microbe technology to achieve more efficient pathways to produce butadiene, a key ingredient in synthetic rubber. We have a strong vision for scaling this process. If all goes as planned, we will look to introduce a scaled process within the next several years.

Waste360: How does Bridgestone Americas plan to use guayule, leveraging a DOE grant, as a source of natural rubber?

Niaura: Natural rubber is the tire industry’s most vital raw material. It’s critical to the proper functionality of tires as it provides unique capabilities that are yet to be replicated synthetically. In fact, certain tire performance, such as durability and resistance to heat and cuts in demanding applications, can only be achieved through natural rubber.

Currently, more than 90percent of the world’s natural rubber comes from the Hevea rubber tree, primarily grown in Southeast Asia. Rubber tree disease and climate change are threats to the future of natural rubber, and this is a problem Bridgestone is trying to help solve through the development of guayule.

Guayule is an alternative source of natural rubber. It’s a heat-tolerant, desert shrub, and we’ve been growing it in Arizona so we can study it and use it to produce rubber for tires. What makes guayule special is that it produces natural rubber that is chemically identical to the rubber from Hevea trees.

Utilizing guayule rubber reduces the risk of relying on a single source of natural rubber. It also gives us the opportunity to localize production of a key raw material, decrease emissions related to transporting natural rubber to the U.S., and reduce our carbon footprint. Guayule also requires less than half the water to grow compared to crops like cotton and alfalfa. This makes guayule an excellent choice for growers in areas with persistent drought conditions.

Bridgestone Americas was recently awarded a research grant by the U.S. Department of Energy (DOE) Joint Genome Institute that will help advance our efforts to produce a higher-yielding crop through our guayule breeding program. The grant will support sequencing and mapping genes of three guayule varieties. Field tests will be conducted at Bridgestone guayule research centers and farms in Arizona, California, New Mexico, and Italy.

Ultimately, our goal is to create a sustainable model for commercializing guayule natural rubber for tires by the end of the decade. To deliver this goal, we must develop a strong supply pipeline of the material. We are partnering with growers in the Southwestern U.S. to transition their fields to guayule and working to enhance the overall economic model.

Waste360: How are you preparing for the increased scale of electric vehicles (EVs) and, with that, opportunities to return EOL tires to the supply chain?

Niaura: In the near- to mid-term, the opportunity with EVs is to support their overall market appeal and utility in terms of efficiency and range. Bridgestone tire technologies such as oLogic and ENLITEN are built around this concept, reducing tire mass and/or lowering rolling resistance, which contributes to vehicle efficiency.

Longer-term, as EV powertrain technologies continue to advance and range becomes less of a challenge, the opportunity is to deliver other values such as extended mobility technologies like self-sealing tires that mitigate the need for a spare tire, lowering vehicle mass and opening up additional space for batteries and cargo.

In addition, renewable tire technologies, such as what we are exploring with LanzaTech, can contribute to the reduction of EV’s carbon footprint and reduce the use of raw materials in tires.

Waste360: What do you think will be key to Bridgestone reaching carbon neutrality and the manufacture of tires from 100 percent renewable materials by 2050?

Niaura: The most important near-term step is to work with our suppliers to start shifting their feedstocks away from petroleum to recycled and renewable oils like TPO, plastics pyrolysis oil, oil from waste biomass, and soybean oil. They can generally be used as substitutes for, or blends with, petroleum oil in existing manufacturing infrastructure.

Longer-term, new technologies will be required to achieve our sustainability commitments. We will need to work with our suppliers and other industry partners to de-risk the technology so that it becomes investable.

Waste360: How are you working with your competitors/peers and others along the supply chain to advance circularity?

Niaura: Last fall, Bridgestone launched a joint initiative with Michelin aimed at increasing utilization of recovered carbon black in tires. Today, less than one percent of all carbon black material used globally in new tire production comes from recycled ELTs due to a weak supply pipeline for the recovery and reuse of carbon black.

Bridgestone and Michelin recognized a need to collaborate with stakeholders across the tire and rubber industry value chain to accelerate progress. The two companies are currently establishing a coalition of stakeholders, including tire manufacturers, carbon black suppliers, pyrolysis partners, and emerging technology startups to drive discussion and ultimately identify ways to increase supply of recovered carbon black with speed and scale.

Recovered carbon black presents the opportunity to reduce the tire industry’s reliance on petrochemicals by replacing a portion of traditional carbon black with a sustainable and circular alternative without introducing performance tradeoffs. Additionally, using recovered carbon black in new tire production reduces CO2 emissions by up to 85 percent compared to virgin materials.

Waste360: Do you track where Bridgestone’s ELT’s go? If so, can you provide figures? If you don’t track this, can you say why?

Niaura: All the tires removed from service at Bridgestone’s 2,200+ company-owned retail stores are recycled and collected by an ELT management company. However, it is challenging to track and recover tires sold and/or removed from service through retail channels that are not owned by our company.

We continue to proactively explore opportunities to close the loop to ensure proper ELT recycling and material circularity. This is why partnerships, like the one Bridgestone is pursuing with LanzaTech, are so important. There’s huge potential to scale our LanzaTech initiative to provide a pathway and process that supports recycling and renewal of all tires at the end of life.

Waste360: What is most important for the solid waste management industry to know about the tire industry’s work to cut tire waste, find alternatives to burning for energy, and the search for more sustainable materials?

Niaura: The tire industry is incredibly innovative, and I believe, overall, very committed to minimizing our impact on the environment, but we need the help and partnership of companies and innovators in your field. It will take all of us working together to deliver a more sustainable mobility future. By working together, we will reach our goals faster and achieve our long-term sustainability commitments.

This article has been edited for length.