Casting new light on solar

Search “clean energy” on the internet and it won’t be long until a solar panel basking in the sun appears on your screen. This iconic image may be one reason that solar panels have largely evaded scrutiny by sustainability researchers.

Photovoltaic (PV) energy, the technology behind solar panels, generates electricity directly from sunlight without emitting greenhouse gases. Yet, even if far less harmful to the environment and human health than a coal-powered power plant, the life of a solar panel still has impacts on the world that are not well understood.

This is where Annick Anctil's research comes in. Anctil is an associate professor of civil and environmental engineering at Michigan State University. Her work turns the “microscope” of scientific inquiry onto solar panels in order to better understand the material impacts of using and manufacturing them. It might seem counterintuitive to question the green credentials of solar.

But that’s not how Anctil sees it. Far from discrediting solar, she wants to strengthen the industry by finding the best ways to not only make and deploy solar panels, but to recapture their material value when they no longer work. She sees this as a fundamental part of a decarbonized, circular economy.

Anctil holds Rochester Institute of Technology’s first doctoral degree in sustainability, making her the first graduate of the Golisano Institute for Sustainability at RIT. We recently had the privilege to sit down with Anctil to learn more about her work and why she thinks it matters when it comes to accelerating decarbonization and circularity.

Q and A with Annick Anctil (Ph.D., ’11)

Associate Professor in Civil and Environmental Engineering

Michigan State University

Q: “Clean energy” is a broad category of technologies and strategies for generating energy without using fossil fuels. What makes solar—photovoltaic (PV)—unique from other forms of clean energy, especially in light of meeting the Paris Agreement climate target?

A: Solar is the only type of direct energy conversion. It converts light energy directly into electricity. By comparison, all other types of energy use a turbine to convert energy, whether wind or water, to produce electricity. Most people think solar energy is not very efficient because they heard about module efficiency being around 20 percent. But there is a lot of energy in the sun, and converting that energy into electricity directly can produce a large amount of electricity. What makes solar particularly attractive is resource availability, which is way higher than other renewables. Although not desirable because it would require a large amount of storage and having a mix of energy is better for reliability reasons, we could meet the world energy demand just with solar energy.

Q: Your work may seem counterintuitive to people who see the solar panel as an emblem of clean energy. What led you to investigate solar panels in this way? And why should we think about the availability and impacts of the materials used to manufacture them?

A: I originally started in the microsystems Ph.D. program at RIT. While working in the lab and talking to other solar researchers, the main goal of the research was always to improve efficiency. It often felt like the efficiency objective led to poor choices in material and design of solar modules. It’s the main reason I switched from microsystems to sustainability. I was more interested in evaluating solar's unintended consequences and ensuring we were not creating new environmental and social issues. My undergrad and master's were in materials science, so I was particularly interested in the resource depletion and resource need for large-scale solar deployment.

Working on the environmental impact of solar energy is tricky because some think we shouldn’t do it at all. After all, if we identify concerns, they could be used against solar energy. As a researcher, in particular, doing research funded by federal grants, it is my responsibility to investigate potential concerns, and it helps earn the general public trust. I don’t think doing this research will “kill” the solar industry, as some told me early in my career, but rather help it because it is much easier to change technology early than when it has reached maturity and full-scale production. It is also important to identify best practices and recognize that all modules are not the same—but they are all better than burning coal in terms of greenhouse gas emissions. Still, some manufacturers are better than others at using renewable energy for manufacturing, recycled material, and non-toxic chemicals, for example. We need to highlight the best manufacturers and encourage others to follow those practices.

Q: You are no doubt especially aware of public concerns over solar. What are some things you keep in mind when sifting through critiques? How do you decide whether a critique is worth addressing or if it should be dismissed?

A: I think they are all worth addressing. Some of the concerns can be addressed simply by better educating the public about what is solar energy and how it works. Dismissing concerns only leads to additional opposition to solar and longer permitting or even canceled projects. It’s normal to be scared about something new, and it’s part of my job as a professor to educate the public.

One of the concerns I heard that I didn’t understand at first was noise from solar farms. I had to talk to developers and other solar experts to figure out that they were probably referring to the sound of inverters. So, the concern wasn’t “dumb.” There was some truth to it, and it was worth exploring and understanding potential issues. Much of my toxicity work is based on public concern—it is the most boring research for my students who can’t find anything toxic, but it is essential to do to reassure the public. The best way to improve support for solar is by answering questions, not ignoring them.

Q: There is considerable variety within PV manufacturing when it comes to design, material choice, and technology. You have studied the evolution of solar-panel modules over the years to learn how shifts in these three areas, especially material intensity and design, could affect decisions about what to do with panels when they break or wear out. What are some of the easiest, near-term design or material-choice changes a manufacturer could make to improve the sustainability of its product? What changes do you think would require more time and resources beyond what a company has within its own walls?

A: The main concern for solar modules is certainly toxicity. Most of this toxicity concern is for lead and, more recently, PFAS. Both chemicals are not necessary for solar modules; there are other options. Lead is used for the electrical connector, like in most electronics, and there are alternative options, but they are more expensive. New module designs also allow for lead-free alternatives. PFAS (per- and polyfluoroalkyl substances) could be used in modules, but there is no clear indication that they are. Again, silicone-based products could play the same role. I think the manufacturers will keep using the cheapest option until customers request a safer one, which they will only know about if manufacturers have to disclose materials used in modules. Similar to other products, I think there should be some environmental declaration of modules to allow customers to choose. Some of the work I’ve done has been in the area of solar standards such as EPEAT and the additional ultra-low carbon criteria. Those certifications allow manufacturers to distinguish themselves from the competition since they demonstrate higher environmental standards. Certification can be expensive and complicated for manufacturers, so there needs to be a demand for it.

Q: In your research, you found that the biggest cost driver in a solar installment comes down to siting and planning—not the technology or modules. Why is this the case? And what are some ways you think this challenge can be overcome?

The United States (US) and the rest of the world have invested a lot in research in the last decade, leading to rapid technological improvement. However, we haven’t been as quick with answering the general public concerns or the process for solar farm approval, which has led to a very long interconnection queue everywhere in the US. I think this will get better only if we streamline the process and have answers to the general public concerns.

Q: Solar cells made with silicon, in the shape of monocrystalline (mono-Si) and multicrystalline (multi-Si) silicon, are the most common type of PV technology that gets installed today. Yet, silicon is just one material that is found in a single solar panel. Polymers, copper, and ethyl vinyl acetate are also used to manufacture a solar cell, while aluminum and glass make up most of what goes into the entire PV module. Which of these materials should we be most concerned about when it comes to questions about scarcity and supply in the US? Can circular economy alleviate that concern? Is silicon the best candidate for recycling? 

A: The US has a sufficient supply of quartz for silicon and glass production. However, transforming this material into a solar module requires a lot of energy, which is expensive. This is why most solar cells and glass for solar modules are produced in China. So, it’s not a scarcity issue; it's more of an issue with cost-competitiveness for material production. Still, the US is working on it, with many current efforts focusing on decarbonizing those industries (glass, aluminum, copper, steel, etc). A circular economy will help reduce costs in the long term, particularly for glass and aluminum, because recycled material has a much lower carbon and energy footprint than primary material. It is not so clear for silicon because we need high-efficiency cells to get that, and we need very high-purity material. Reusing silicon in high-purity solar modules might not be the best option, but we should investigate other applications that don’t have as high of a purity requirement.

In terms of recycling, silicon is tricky because most environmental impacts are associated with the electricity required to purify the material. I don’t think it is feasible without additional research to produce high-quality silicon at low cost. It is too risky for polysilicon producers to switch the process to recycled silicon rather than quartz without any incentive or recognition as a greener material.

Q: Life cycle assessment (LCA) and material flow analysis are important tools you use in your research. What are some ways you use them? What are their strengths and weaknesses, in your estimation?

A: I use materials flow to track both the primary material and the waste associated with producing energy materials, from mining to end of life. I use LCA to evaluate the impact of making a solar panel and calculate the carbon or energy payback, corresponding to how long the solar module needs to produce electricity to compensate for the energy and carbon necessary for manufacturing the solar module. What I like about using those methods is that they can be helpful to convey complex information about the impact of technology to the public. It quantifies environmental impact, and the results can often be used for policy decisions.

What I don’t like about LCA is that sometimes, the conclusions are misinterpreted, or people choose the results that fit the conclusion they want. For example, a particular study could show that electric vehicles (EVs) have a higher impact than combustion engines in places where the grid is mainly coal and be generalized to say that EVs are worse than combustion engines. There is a lot of misinformation in the energy sector based on picking specific LCA results and generalizing them when they shouldn’t.

Q: It has been wonderful learning more about your research—thank you. We’re especially proud that you are the first graduate of RIT’s doctoral program in sustainability, which is now offered by the Golisano Institute for Sustainability. What would you say was unique about the program’s approach? And has that influenced how and what you research today?  

A: It was pretty risky to be the first in the program because it was not clear that there was a need for people with that skillset, but I’m really glad I did. I think what was unique was to have students from many different disciplines and backgrounds in the program but with a common interest in sustainability. Compared to other Ph.D. programs, there were a lot of required classes during the first year or two because there was so much to learn, including industrial ecology, risk, LCA, sustainability ethics, and economics. These are all subjects you don’t learn about in a traditional engineering program. It pushed me out of my comfort zone compared to staying in a traditional Ph.D. program. The most beneficial aspect of the Ph.D., besides knowledge about sustainability, is the ability to work with people from other disciplines. I was even told by colleagues in social science that I was not a normal engineer because we were able to discuss and work together. If you want to tackle big problems like energy transition and climate change, you need to collaborate to find a solution. I credit my education in sustainability at RIT for that skill.