Introduction: The Ellen MacArthur Foundations says: “We need to talk about renewables. The need to integrate a circular economy approach into the renewable energy transition is clear. While there are barriers in the current system to overcome, a number of pioneering businesses and policymakers are forging ahead to create solutions. Their efforts, especially if bolstered by others, can lead to a renewable energy sector that not only produces cleaner energy but is delivered via infrastructure that, by design, eliminates waste and pollution, keeps the materials it needs in use, and regenerates nature. This model, a circular economy, will lead to greater benefits for the environment, people, and business.” [i]
Renewable energy enjoys public support because it is key to climate change mitigation and long-term energy security. In the US, large solar and wind power plants produce increasing shares of electricity demand, as do rooftop and community solar PV systems. Electricity storage and vehicle propulsion batteries connected to electricity transmission, distribution and building circuits, and paired with small, medium and large solar and wind generators, will proliferate.
What does it mean to “integrate a circular economy approach into the renewable energy transition”? All components and materials of would need to be recycled, remanufactured, reused or repurposed. For this to happen, leading national consumers of renewable energy, especially the US and China[ii] must lead the creation of circular renewable energy economies (CREs), starting with national plans.
The fact that lead from “dead” car batteries is routinely and near completely recovered, recycled, and reused validates the potential for effective CRE policy interventions. The figure identifies a few basic circular pathways; they include local “waste” recycling”. The details of specific CRE pathways are being worked out by PV, wind and battery manufacturers drawing on experience in the buildings sector and inspired by seminal “cradle to cradle” papers, books and follow-up advocacy.[iii]
Circular Economy for Energy Materials (Credit: NREL)
Early CRE experience: Solar PV and battery industries have experience applying CRE principles. For example, in 2005, First Solar implemented a prefunded collection and recycling program for cadmium telluride solar PV panels that are used in large “behind the fence” projects.[iv] That same year, California banned lithium Ion batteries (LIBs) from the regular trash stream while requiring some retailers to provide a battery-return option.[v] The ban enables circularity when the collected LIBs are recycled or repurposed; for example, end-of-life LIBs from electric vehicles can be reused and paired with solar PV installations.[vi]
Silicon solar PV panels remain productive for decades, are warrantied accordingly, and are sometimes reused and repurposed. In 2021, California reclassified solar panels from “hazardous” to “universal” waste, a less stringent hazardous waste classification with streamlined handling and reporting requirements that reduce management burdens and facilitate recycling.[vii]
CRE integration: Integration of renewable sources with existing and new energy transport infrastructure is essential to affordability, environmental stewardship, and adoption rates. Integration of renewable energy product supply and recovery chains will have comparable long-term benefits. So, effective CRE integration merits timely policy and industry attention. Fortunately, “cradle to cradle” (C2C) certification programs are now available to retailers, designers, and manufacturers, including those in solar PV and other renewable energy industries. The first C2C certification of a PV panel in the US was announced in 2014.[viii]
Critical review: The National Renewable Energy Laboratory (NREL) recently conducted a critical review of CRE research and publications for the Air and Waste Management Association.[ix] The AWMA hosted a panel discussion of the NREL findings at its 2022 annual meeting.[x]
The NREL review applied a conceptual CRE framework to solar PV and LIBs and resulted in a comprehensive inventory of research literature and public domain documents. The resulting NREL report is a window on renewable circularity research and practices to date for two specific renewable technologies, solar PV and LIBs. It is a valuable first step toward creation of a national CRE plan for all renewable technologies.
National CRE plan: Multi-decade national plans are needed to catalyze circularity in the global renewable energy market. A national CRE plan should:
1. Identify goals and strategic assumptions, including a preferred vision and key success factors;
2. Identify the expected range of system and material diversity as well as factors that can disrupt circular pathways;
3. Forecast market, industry and product evolution and implications for implementation;
4. Identify opportunities for international collaboration, enforceable obligations of state and local governments, and the status of standards development for project decommissioning, equipment disposition, and site restoration; and
5. Identify research and development needs and opportunities.
Strategic assumptions: CRE planning should anticipate economic integration of solar PV and LIBs. A preferred vision would be to not only to circularize material flows but to extend the trouble-free operating life of renewable energy equipment and projects, thus multiplying decarbonization benefits and avoiding congestion on CRE pathways. Enforceable obligations, state, national and global certification requirements, and research collaboration among industries, companies, and national laboratories are key success factors.
Systems and materials diversity: While PV panel and LIB manufacturing relies on familiar bulk materials, the range of materials in use will expand as panels and batteries are designed to meet new market requirements. Also, the solar PV market will continue to diversify as it grows and as panel and system designs evolve. Most solar PV panels are currently arrayed on rooftops and vast areas of low cost land. Increasingly, they are also found on parking structures, unshaded brownfields, parcels of abandoned agricultural land, the sides of new buildings, and even on floating arrays on lakes and ponds.
Factors that can disrupt circular pathways: At the current stage of the clean energy transition, all types and sizes of PV systems last longer than they may remain under the control of the original owner. The same will likely be true in a later stage of the LIB storage system market.
Project and equipment ownership and industry changes often occur before repairs, replacement, and decommissioning are required. Subsidized and tax-incentivized project financing can create incentives for ownership changes that make equipment warranties more costly to enforce. PV panels last much longer than some of the companies that make them, disrupting chains of responsibility.
The chain of responsibility for renewable energy system stewardship is more likely to break down for smaller on-site and community renewable projects where longer-term obligations are harder and more costly to enforce.
In the US, renewable electricity deployment depends primarily on imported equipment, resulting in long circular pathways, problematic enforcement of agreements and warranties, and lack of visibility to manufacturer decisions impacting circularity.
Solar and battery project finance models discount the value of long, trouble-free inverter and battery life.
Opportunities for international collaboration and renewable energy materials stewardship: Order of magnitude increases in solar and wind capacity in the past decade are matched by order of magnitude increases in cloud computing that is transforming the renewable energy industry.[xi] Thanks to the digital revolution, renewable systems and components can be tracked through system life cycles and beyond.
All countries have an economic and environmental interest in establishing and collaborating in such tracking. China and the US, as leading renewable energy consumers, are well positioned to provide leadership, especially if they agree to collaborate. Industry scale economies in the US and China create economic flexibility to implement CRE principles. Global product distribution networks can be bi-directional, delivering products and collecting them for recycling, repurposing, etc.
State and local standards. In the US, states set standards for recycling and diversion of certain materials and equipment. Solar PV and LIB materials and equipment need such attention now.
Standards are enforced by local governments that provide waste collection and recycling services. Local governments will need to determine and enforce decommissioning obligations of renewable energy system and equipment owners. They will need to intervene in the case of abandoned systems and facilitate land use circularity by making brownfield sites available for local renewable energy projects.
Research and development: Once circular pathways are open, R&D can identify opportunities to reduce material recovery and equipment repurposing costs. Research, development and demonstration (RD&D) projects can evaluate circular pathways for components used by C2C-certified solar, wind and battery storage companies. National laboratories can pilot technologies used in material recovery processes and develop circularity metrics and databases.
Integration. Increased integration of solar PV, wind, battery storage, solar thermal power, and thermal storage into the U.S. energy generation sector will result in more cost- efficient resilience and decarbonization. Increasing industry profitability will open wider economic windows for circularity investments.
In parallel, as the renewable electricity economy continues to expand, a renewable gas economy will likely emerge, will synergize with the renewable electricity economy, and will require circular pathways for fuel cells and electrolyzers.
Renewable gas deployment is currently organized around deeply carbon-negative projects that produce biogas or electricity for on-site use (e. g., at wastewater treatment plants) and projects that convert animal waste to pipeline quality bio-methane. Going forward, renewable hydrogen production and advanced incineration will enable the circular renewable electricity economy by meeting the need for affordable storage of zero carbon fuel.
New Frontiers. Renewable integration attention to date has focused on the need for regional electricity generation systems to accommodate higher percentages of variable solar and wind electricity production. The rapidly emerging frontier of renewable integration will span building, vehicle and community electricity systems. The ultimate frontier is the integration of design and manufacturing with materials recovery and reuse.
Summary. Just as the atmosphere’s capacity to absorb GHGs without affecting climate is limited, so is the earth’s capacity to supply materials to replace those that are used only once. In a renewable energy context, there are two basic solutions. First, there is no technical reason renewable energy equipment cannot be built to last decades longer than it otherwise might. How can renewable energy markets and policies reward durability and long, low maintenance project and system operation even as major supply chain industries continue to thrive on planned obsolescence? Second, renewable energy material and component recovery and reuse is feasible but not generally either mandatory or economically rewarding. Will publicly financed renewable energy waste recovery be necessary, and which governments will take the lead in making it work fairly and efficiently?
Conclusion. National plans must answer these and many other questions. It is not too late to rein in raw material sourcing for renewable power that would otherwise harm communities and ecosystems.
[i] https://ellenmacarthurfoundation.org/articles/we-need-to-talk-about-renewables-part-2 See also https://ellenmacarthurfoundation.org/we-need-to-talk-about-renewables/part-1
[ii] https://www.statista.com/statistics/237090/renewable-energy-consumption-of-the-top-15-countries/
[iii] C2C-Center (2022a) The Hannover Principles Design for Sustainability. http://www.c2c-centre.com/library-item/hannover-principles
[iv] Field, K. (2018) First Solar Breaks Down Its Plans For Solar Module Recycling #SPI2018. Clean Technica. https://cleantechnica.com/2018/12/04/first-solar-breaks-down-its-plans-for-solar-module-recycling-spi2018/
[v] Rischar, H. (2020) New California rule will facilitate the recycling of solar panels. Waste today. https://www.wastetodaymagazine.com/news/new-california-rule-will-facilitate-the-recycling-of-solar-panels/
[vi] Pyper, J. (2020) Second Life: Carmakers and Storage Startups Get Serious About Reusing Batteries. Green Tech Media. https://www.greentechmedia.com/articles/read/car-makers-and-startups-get-serious-about-reusing-batteries.
[vii] Rishchar, H. op. cit.
[viii] Ref: https://www.c2ccertified.org/news/article/sunpower-solar-panels-awarded-cradle-to-cradle-certification-for-sustainabl
[ix] Heath, G. et al. A Critical Review Of The Circular Economy For Lithium-Ion Batteries And Photovoltaic Modules – Status, Challenges, And Opportunities, https://www.tandfonline.com/doi/full/10.1080/10962247.2022.2068878
[x] Schichtel, B. et al. Circular economy for lithium-ion batteries and photovoltaic modules—status, challenges, and opportunities, https://www.tandfonline.com/doi/full/10.1080/10962247.2022.2118473
[xi] Ref: https://ratedpower.com/blog/cloud-computing-renewable/