As the global power industry adds clean energy technologies such as renewables and energy storage to meet decarbonization goals, there will be an increasing number of wind turbines, solar photovoltaic (PV) modules, and battery systems dotting our landscapes. As the earliest deployed systems reach their mid-life, key questions are being asked, such as: What happens when they are taken out of service? Energy companies, local and regional governments, and various other agencies around the world are seeking more information on what to do with the equipment, how much can be recycled, and other key questions.
It’s a very topical issue, as just last week, the U.S. Department of Energy issued an action plan to enable the safe and responsible handling of solar PV end-of-life materials. For more than a decade, EPRI has been studying end-of-life considerations for solar, wind, and storage equipment. For solar modules, expected lifetimes are anticipated to be 30 years or more, although some are taken out of service early due to damage, underperformance, or safety issues. Wind turbines have an expected service life of around 25 years. Lifetimes of individual battery modules are about 10 years, although full energy storage systems could last 10-30 years.
Most clean energy deployments today are relatively new and have many years of useful life remaining. For example, 96 percent of solar PV capacity was built in the past decade. Therefore, experience with decommissioning large-scale clean energy facilities is limited. In the absence of experience and policies in many countries, high-perceived risk may result in project development delays, prescriptive decommissioning requirements, and higher-cost performance guarantees.
Decommissioning Guidance
EPRI is developing guidance around planning for decommissioning. Robust decommissioning plans can reduce uncertainties around end-of-life requirements, minimize environmental impacts, and avoid unexpected costs. Related work includes developing cost estimates for plant decommissioning, creating decommissioning plans, and conducting case studies. Repowering existing facilities with higher-performance equipment is an emerging option that extends the lifetime of the facility and may reduce liabilities, investments, and environmental impacts associated with full decommissioning. Continued use of sites for energy production and storage maintains jobs, tax revenue, and environmental improvements in local areas. EPRI is also conducting techno-economic modeling and exploring technical due diligence activities, like performance degradation studies and physical asset inspection work, to evaluate repowering scenarios.
While solar and wind energy are gaining in popularity throughout the U.S., Europe has been using these renewable resources for much longer and as a result, has established uniform PV panel and wind blade recycling regulations. Additionally, the European Union just completed the first stages of passing new batteries regulation to govern sustainability characteristics of an entire product life cycle, from the design phase to end-of-life.
Currently, there are no U.S. federal policies involving decommissioning unless the project is located on Bureau of Land Management property, nor is there a federal regulatory framework to promote recycling or landfill diversion of the associated equipment. Consistent regulatory approaches among states can be challenging to navigate for companies operating over broad regions.
EPRI has been quite active in this space, focused on research and development related to environmental issues across the lifecycle of wind, solar, and energy storage plants. Dedicated research programs on environmental aspects of wind, solar, and energy storage proactively address end-of-life management considerations, in addition to siting and permitting, public acceptance, land use, vegetation options, and wildlife issues. The storage program additionally addresses fire safety and subsequent environmental and health impacts.
These research programs provide: 1) information and best practices to manage environmental risks and compliance goals, and 2) technologies and techniques to improve sustainability and biodiversity. This year, EPRI added a Circular Economy Interest Group, focused on educating utilities and other industry stakeholders on how to implement actions to increase sustainability across the entire lifecycle of energy technologies. As deployment of clean energy technologies accelerates, a circular economy approach can enhance environmental stewardship, incorporate responsible economics, and provide a clear path for recycling and reuse.
Toxicity Testing
Specifically, EPRI is collaborating with a handful of our stakeholders, such as the National Renewable Energy Laboratory, the DOE ReCell Center, Sandia National Laboratories, and Arizona State University (ASU), on end-of-life projects. For example, EPRI worked with ASU to develop a standard operating procedure for sampling solar PV modules for toxicity testing. In December 2021, the American Society for Testing and Materials (ASTM) published ASTM-E3325 Standard Practice for Sampling of Solar Photovoltaic Modules for Toxicity Testing, based on this procedure. EPRI and ASU are applying the ASTM standard to develop a comprehensive database of toxicity test results for a wide range of commercial modules. The results will provide insights on whether use of lead and other heavy metals is prevalent in PV modules and whether leaching concentrations exceed the EPA threshold.
High-Value Recycling
As EPRI research has shown, there is a need for high-value recycling that recovers PV module materials like silicon and silver to offset recycling costs. In the past few years, recycling facilities with processes customized for PV modules have begun to be built. Veolia commissioned a recycling facility in France in 2018 that claims a 95 percent recovery rate using mechanical processes, including recovery of silicon. A new facility developed by France’s ROSI Solar is scheduled to be commissioned this year, with the capability to recover high-purity silicon and silver.
In the U.S., there are more than 20 facilities that advertise they accept PV modules, but high-value materials are often not recovered. The exception is Arizona-based First Solar, which has a dedicated recycling facility for the PV modules it produces and reports 90-95 percent material recovery. The current low supply of end-of-life module volumes provides little incentive for recyclers to invest in developing customized recycling processes for PV modules. Additionally, manufacturers are exploring options that would minimize the use of high-value components to reduce the upfront cost, posing additional challenges to the economics of recycling.
Wind turbines are made of 80-90 percent easily recyclable materials like steel and concrete. Wind turbine blades, made of fiber composites, are a part of the 10-20 percent that is challenging to recycle. Commercially available end-of-life options for composite materials include landfilling and co-processing in portland cement production. Emerging end-of-life options range from pyrolysis and solvolysis processes that use heat or chemicals to separate the reinforcing fibers from the composite resin to second life uses in structures like electrical transmission towers. Emerging technologies to enable recycling, such as alternative resins, are also being explored. The ability of emerging options to recover the full value of the reinforcing fibers and resins that makeup the blades varies widely.
The market for commercially viable composite material recycling options is still developing. Options will depend on the development of supply chains that both provide sufficient quantities and qualities of waste composite products for recycling and demand enough recycled fibers and resins. Â Since wind energy is only about 30 percent of the composite materials market, developing these supply chains will require coordination with the other major composite market segment including construction, electronics, transportation, and industry.
Current End-of-Life Costs Significant
For example, energy storage system decommissioning and end-of-life costs can be significant in part because few utility-scale systems have reached this stage, and the battery module collection and recycling industry is still developing. Specifically, a recent EPRI estimate for decommissioning a 20MWh/10MWh nickel manganese cobalt system was nearly $1.2 million; about 70 percent of that cost is battery module removal, transportation, and recycling. Reuse of EV battery modules in stationary or other applications is an active area of research to take advantage of remaining capacity in both grid support and customer-side applications. In fact, the topic is being studied through EPRI’s IncubatEnergy Labs program, providing an opportunity for startups and utilities to collaboratively work on power system challenges.
It can be difficult for aging modules to complete on performance and economics when the costs of new modules continue to drop, putting heavy emphasis on efficient management of the logistics around refurbishing, testing and recertification before reuse. Recent focus on the creation of domestic supply chains, such as through the Infrastructure Investment and Jobs Act in the United States, are rapidly spurring development in this area. EPRI is working with recycling companies to understand the costs and environmental benefits of their developing processes.
As more clean energy projects age and equipment and components reach their end of life, there will be greater need for coordinated research and development across numerous organizations to test, demonstrate and commercialize recycling and reuse approaches. This will increase recovery rate of key materials and components, and aid in developing systems that can cost-effectively collect, sort, and disassemble retired components.
Additional support could be enhanced with the support of federal research and development and demonstration funds, as well as consistent incentives and regulatory policies supporting the development of circular economy strategies in the marketplace.
Learn more here on EPRI’s wind, solar and battery end-of-life research issues.