The Circular Economy Can Renew Renewable Energy Technologies

By Bill Tumas, Associate Laboratory Director at the National Renewable Energy Laboratory

We all know that it’s much easier to not create problems in the first place than to have to fix them later.

Throughout my career, I’ve put that principle into practice tackling waste, waste treatment, pollution prevention, and chemistry as a whole. At DuPont, I spent a lot of time on advanced oxidation technologies, which is about getting pollutants out of water to clean it up. I also helped the Army dispose of its chemical weapons stockpile. At Los Alamos, I got much more interested in not making waste in the first place. I was one of the founding board members of the Green Chemistry Institute, which promotes the development of chemical processes and earth-friendly products that will prevent pollution generation.

While reducing environmental hazards is always important, there are increasing concerns about the world’s stewardship of material resources as a whole. The era of “take, make, and dispose” to create economies is rapidly coming to a close. Today, that linear economy model appears not only inefficient and unsustainable, but the scarcity of resources we face will make it impossible to maintain. We are even asking if there are enough of certain elements on Earth to meet our needs.

To ensure that we create the best system to meet our energy needs — terawatts of clean energy in an expanding global economy­­ — we must take lessons from the past. Prevent, not fix. We need a system with circularity — one that can reuse materials instead of simply dumping them. For example, the Ellen MacArthur Foundation, in partnership with the World Economic Forum, predicts that by 2050 plastic in the oceans will outweigh fish. That simply cannot be allowed to happen.

That’s why the National Renewable Energy Laboratory (NREL) is dedicating resources to research that will underpin a new energy system. To transform energy systems, we will design materials for renewable energy technologies by keeping reduction, reuse, and upcycling top of mind. As part of our 10-year vision for NREL, the Circular Economy for Energy Materials is one of the laboratory’s three key research areas.

Clearly, creating a circular economy isn’t easy; there are a number of scientific and technical barriers. But there are already efforts in that direction. Many industries support recycling items ranging from polymers to lithium batteries and silicon solar cells. But the crisis is real, time is running out, and it will take a global effort to address.

NREL is part of the solution. Our researchers are poised to tackle the challenge of polymer upcycling. Yet, let us be clear.

NREL has excellent capabilities and expertise to upgrade polymer waste, but also to design new polymers so that they can be readily recycled or biodegradable. Fascinatingly, if we think about what a polymer waste stream looks like to an enzyme, we realize that such a stream may not look that different from heterogeneous cellulosic waste materials. NREL scientists have already worked for decades on converting plant waste to cellulosic ethanol, and now drop-in fuels. This has been done with major advances in engineering and science, including synthetic biology. Today, we can apply our know-how to redirecting polymer waste.

It turns out that polymers are in almost all energy technologies, from the back sheets of photovoltaics to the membranes in fuel cells, electrolyzers, and battery systems. As we transform our energy system, we need to know how to be sure we include the concept of circularity early on. All of us have to ask probing questions from the beginning. For battery manufacturing, for example, we must ask just how much cobalt in the world will we need? Where will it come from, and how will it impact the environment? As part of our efforts, NREL is a partner in the U.S. Department of Energy’s ReCell Center based at Argonne National Laboratory. That collaboration has the most complete suite of battery life cycle R&D facilities in the nation. But it’s only one step.

The list of challenges to consider in building a circular economy goes on.

Looking at basic elements in renewable energy technologies, such as lithium, we have to make sure there’s enough lithium because the scarcity of lithium or rare earth materials cannot be brushed aside. If anything belongs in a dump, it is our worn-out assumption that we can dig up more resources. Instead, we will need to be thoughtful as we:

• Assess emerging critical materials and better understand when they will become critical if deployed at scale

• Explore the design of products to allow for use of lower purity materials (recovered materials), as well as the possible trade-offs

• Determine how we can design for modularity, upgrades, and deconstruction as well as how to create a longer-lasting product by designing it for upgrades, reparability, and yes, recycle.

Due to our extensive expertise in energy technology development from fundamental science to analysis and deployment, those paths mesh well with NREL’s vast work on reliability and durability of current and emerging technologies. Our laboratory is a leader in expanding the durability and reliability of photovoltaics, fuel cells, and batteries. Additionally, we have many partners with similar goals.

Going forward, we’ll need adaptive materials for energy systems. At NREL, we’re learning from natural systems to develop energy technologies that are cheaper, lighter weight, more flexible, more resilient, and more adaptable to their environment. It is an evolution of thought. With that mindset, we will:

• Design and develop new materials, innovative concepts, and next-generation technologies for sustainable energy generation, storage, and use

• Develop new tools, data, analytics, and science for lifetime prediction of new, recyclable, or upcycled materials, components, and systems

• Establish new concepts and processes for the upcycling, reclamation, re-processing, and re-manufacture of elements, materials, components, devices, and systems.

On the pathway to a circular economy, we will ensure that new energy technologies have the right lifetime. We will insist that there is a way to recycle and reuse elements. And we will be disciplined in ensuring that our system is not putting too many critical materials in the equation.

Of course, all of these steps — and more — will be required to provide the terawatts of renewable energy generation and storage we need for the future. More than that, we have to learn from the past. As someone who has wrestled with these problems for decades, I know that we must not create new legacy problems for people in the future to try to fix. Instead, we must be strategic — and avoid them with forethought.