The Top 3 by E3

The Present State of PV Solar Recycling

• E3 Consulting • Season 3 • Episode 1

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Join the conversation as we sit down with Francis Willberg, a Photovoltaic Analysis Engineer with E3, who discusses the challenge of solar panel retirement. As we approach a staggering 1 million metric tons of photovoltaic waste by 2030, discover how the industry is grappling with the financial and technological puzzles that come with recycling the complex "panini-like" layers of PV modules. In this episode, Frances and Al Rettenmaier, host of the Top 3 by E3 podcast, reveal how the development of bifacial modules and the reuse of still-functional panels can play pivotal roles in propelling us toward less waste.  Learn about the proactive measures that are being taken to design new modules that are easier to recycle and how efficiency, reuse, and advanced recycling methods are steps helping with this effort. 

Al Rettenmaier:

Welcome to the Top 3 by E3 podcast about the intersection between engineering and energy and project finance. I'm Al Rettenmeier, a managing director at E3, and I'll be your host today. Today, I'd like to introduce Francis Wilberg, a photovoltaic analysis engineer, here at E3, who will be providing an overview of the present state of photovoltaic recycling and end-of-life management. Welcome, F frances.

Frances Willberg:

Hi, A al, it's great to be here. Thanks for having me. This is one of the biggest topics of conversation in the solar energy world right now. Whenever I tell someone what I do for work, one of their first questions is always so what happens to solar panels when they're old or broken and can't be used anymore? I live in Arizona, and so we've become used to seeing solar panels on homes, businesses and utility scale installations, because we have some of the highest solar energy potential in the country, and a lot of people are wondering what's going to happen to them when they have to be removed and replaced.

Al Rettenmaier:

Absolutely. Yeah, that's a big topic. This is such an interesting time in the industry where you know, so many of the early photovoltaic or PV installations which were installed 10, 20, or even 30 years ago are coming to the end of their useful lifespan and they're either in need of being decommissioned and disassembled or in that process, and all that old equipment has to go somewhere.

Frances Willberg:

Absolutely. And we've seen such a huge increase in the utilization of solar energy installations in the United States in the last few decades, which is wonderful. But because of that, the US is expected to contain 1 million metric tons of PV waste by the year 2030 and up to 10 million metric tons by the year 2050. And aside from the issues of just plain landfill capacity to hold all of that waste, there are some concerns that certain forms of PV waste could contain harmful metals in trace amounts, such as cadmium and lead, and so some states may consider that hazardous waste which needs to be disposed of through proper measures. And I will mention, as we get started, that PV recycling and disposal processes differ significantly depending on the technology used in the PV modules. So for the purposes of this discussion, we're going to be focusing on crystal and silicon PV modules. These make up the vast majority of PV modules installed both in the United States and worldwide at the present time, and so, because of that, recycling efforts have mostly focused on those types of PV modules.

Al Rettenmaier:

Okay, great, great. Well, let's dive right in. So you know what are some of these challenges that we've kind of outlined, which you know would impede the development or implementation of PV recycling methods.

Frances Willberg:

At this point, the largest barrier to efficient PV recycling is its cost. Recycling can be up to 15 times as expensive as just sending modules to a landfill. The cost of sending modules to a landfill is between a dollar and five dollars per module, but the cost of recycling is between 15 and 45 dollars per module. And this doesn't include the cost of transportation and shipping to get solar modules from their point of use to their point of recycling. And at this point there's only a handful of recycling centers for PV modules within the United States. So if you're not located close to a recycling center, the cost of transporting the modules to a recycling center could be as much as the cost of recycling itself. And as much as we want to hope that our recycling efforts are motivated by altruism rather than just cost, the cost focus is obviously a huge issue and from the perspective of a site owner at this point, when the cost difference is that substantial, there's really not that much incentive to pay that exorbitant additional cost to recycle modules instead of sending them to a landfill.

Frances Willberg:

The united states does not presently have federal requirements for pb recycling and the only state with legislation currently mandating PB module recycling is the state of Washington.

Frances Willberg:

So Washington state has a law that will require module manufacturers to take the initiative to plan and pay for module recycling at the end of the module's useful lifespan.

Frances Willberg:

This law is expected to take effect in 2025, so that's next year as we're recording this podcast and the idea behind this law is that it would function similar to that of a carbon tax, where the producer of the product has to account for the cost to offset the issues caused by the product at the end of their useful lifespan. This means that the onus for module recycling is taken off of the purchaser and the user of that equipment, but it could then mean that there are higher startup costs, higher equipment costs on the front end to purchase and install modules, so that module manufacturers can recoup those costs that they'll need to spend to recycle the modules at the end of their lifespan. It is expected that other states will follow Washington's example in instituting requirements for PV module recycling, and it's expected that increased state and federal legislation will create more incentive for manufacturers and solar asset owners to recycle modules. But recycling costs have to drop dramatically before PV module recycling can become an economically sustainable practice.

Al Rettenmaier:

Wow, yeah, this is really almost a whole new world that we're in. I guess one question is why is it that recycling is so much more expensive than just disposal?

Frances Willberg:

Part of it has to do with how crystal and silicon PV modules are constructed. So a silicon PV module is constructed the way that I had it described to me is similar to that of a panini, where you have multiple layers of the module that are pressed together and the pressure and the heat that is applied solidifies the layers of the module together, and so those layers include a polymer backsheet, a layer of ethylvinyl acetate or EVA encapsulant, then you have the silicon active layer of the module encapsulant. Then you have the silicon active layer of the module. It's covered with another layer of ethylvinyl acetate on top to fully encapsulate the active layer, and then a layer of timbered glass on top to protect everything. And the reason why it's layered in that way is to make sure that the silicon active layer, which is the layer that produces energy, is protected from moisture and damage.

Frances Willberg:

The silicon is very sensitive to breaks, and so that layered structure makes the solar module significantly more sturdy and able to stand up to physical and environmental damage. That makes it significantly more durable when it's being used, and we obviously want high durability in our equipment while we're using it. But because of the way that those layers are pressed together, it's very difficult to pull them apart at the end of their useful life. So if you think of again going back to the example of the panini, after you've pressed the ingredients for your sandwich together, it's difficult to pull them apart in the discrete layers that they were at the beginning, before you applied the pressure and the heat.

Al Rettenmaier:

So why would you want to? Because it's all hot and gooey and stuck together and just perfect. You're making me kind of hungry.

Frances Willberg:

Exactly, yeah, so think of you know you can't. It's very difficult, for example, to pull apart layers apart in ways that you then still have enough purity and quality of those materials to be able to recycle, Because recycling economically is based on whether you have an economic value of those constituent materials that you're pulling apart. And so if you can't pull apart the materials into a form that is then able to be resold and reused, recycling is incredibly difficult to make economically viable.

Al Rettenmaier:

Yeah, interesting yeah. So how do they do that?

Frances Willberg:

Hmm, yeah, interesting value. So if the modules aren't cracked or broken, if they can still produce power and are still safe to operate, even if they're not necessarily producing as much power as a brand new module, they can be sold on the resale market. So the first check when a lot of these modules are being received at a recycling center is checking to see if they are still operative, and if they are, that can be a great way for owners to recoup some of the costs of site decommissioning and PV module recycling. And then it also creates an affordable secondhand market for PV modules that keeps older modules both out of the landfill and out of a recycling center. If modules can't be reused in that way, they are disassembled, and so all of the components on the module that aren't the module itself are removed. So this includes the aluminum frame that's usually around the border of a PV module, and then the junction box and attached cables, which are the portion of the module that directs the produced electricity out to the circuit. Those are all removed from the module. So all you have remaining is the finished panini, if you will, the layers of the silicon PV module, and the next step for recycling depends on the desired end product that you want to get out of this PV module.

Frances Willberg:

So one of the most popular forms of PV module recycling at this point is to just simply grind up the module with all of those layers still stuck together. So they just send the module through a grinder and grind it all up into a material that's known as cullet, and so this is the mixture of glass, silicon and polymer that still contains all of those materials all together, and cullet is actually a very profitable end product. It has uses in areas like insulation, building material, it's used for sandblasting. Occasionally it's used as a component of concrete and cement, and the market for cullet is worth billions of dollars at this point and it's expected to grow even more significantly, as you have so much PV waste that can be repurposed into this form. So that has been the major end product of PV recycling up until the present time, just because it allows you to keep all of those layers of the PV module together and doesn't require them to have to be removed prior to recycling.

Frances Willberg:

But there are recycling centers that are trying to focus on extracting more valuable end products out of PV modules as they're recycled, and that does require engineering new ways of separating the module layers prior to processing.

Frances Willberg:

So there are some recycling centers that are trying to use robotic arms to pull the layers apart, which would allow the individual module components to be extracted and repurposed. One of the benefits of this is that silicon modules contain trace amounts of high value end products such as copper and silver in the electrical contacts within the modules which, if those can be filtered out, those can be resold for a significant amount of money. And then, using that robotic arm method to pull apart the layers, you have the possibility of extracting the high purity crystalline silicon that's used as the active layer in these modules. And if that silicon layer can be extracted without damaging the crystalline structure, that silicon can then be reused for other solar panels or other uses of high quality crystalline silicon. So this method is a lot newer and is still in development, but this definitely has the potential to increase the profitability of PV recycling efforts, which would hopefully create more incentive for module manufacturers and site owners to recycle modules instead of just sending them to a landfill.

Al Rettenmaier:

Okay, interesting. Well, you mentioned the robotic arms. What are some other technological advancements that you could apply that would you know, make this a less costly and maybe more productive module recycling process?

Frances Willberg:

The biggest push at the moment is actually to focus on ways to redesign how PV modules are constructed to make them a lot easier to recycle at the end of their lives. So in cases like that, there are new ways of quote-unquote unzipping the layers to make the layers of the silicon module themselves easier to strip off and extract the layers individually themselves easier to strip off and extract the layers individually. There are some people that are focusing on methods of screen printing the electrical contacts onto the silicon layer instead of having them soldered on, which makes the extraction of the silicon significantly easier than with the present method of soldering electrical contacts directly onto the silicon significantly easier than with the present method of soldering electrical contacts directly onto the silicon layer. So there are a lot of people that are researching new methods of pv construction that would make recycling significantly easier and less expensive. There are other advancements in the pv industry that seem unrelated to recycling but actually have a huge impact in how much PV waste is going to be generated in the future. So if you think of the old adage that we've all been told reduce, reuse and recycle those adages are listed in order of effectiveness, so it's always going to be more effective to reduce the amount of waste you have to begin with. Then try to reuse what waste you have after that, and then to recycle whatever waste is remaining. So to start with reducing.

Frances Willberg:

Obviously, we don't want to reduce the amount of solar energy that we're producing, but we want to reduce the amount of waste that is generated for the amount of power that we want to produce, and so the biggest way to do that is to develop more efficient PV modules that can produce more power for less surface area and less material.

Frances Willberg:

A way that a lot of manufacturers are focusing on doing this is by making modules that are bifacial, which means that they have a silicon energy producing layer on both sides of the module, which can potentially increase power output by up to 50 percent, and then increasing the power output of PV modules reduces the number of PV modules that you need to meet your energy production goals, and so by manufacturers focusing on creating higher power, more efficient modules that will reduce the amount of PV waste that those sites will generate when they are decommissioned.

Frances Willberg:

We already discussed how the first step in PV recycling processes is to see what modules that are being removed from a site can be reused. So whatever modules that are still functioning that a client may no longer have need for. Those modules that are still perfectly functional, safe to use and still productive can be sold on the resale market and be able to continue to be used for as long as they have a reasonable lifespan, but then removing them from either needing to be recycled or being sent to the landfill. So if we can reduce the number of PV modules that we need by using PV modules of greater efficiency and power capacity and then reuse modules that are still functioning but maybe a little bit older, then we can focus on recycling the modules that can't be reduced or reused in that way, and that will make PV module recycling and disposal significantly less impactful and significantly less expensive.

Al Rettenmaier:

Great, great, well, very interesting. This has really been a fascinating topic. You know, our podcast is called the Top Three by E3, so we always try to sum up the top three takeaways from the subject. And so what would you say?

Frances Willberg:

your top three takeaways would be so my top three takeaways on this topic would be number one, that efficient and cost-effective pv module recycling is going to be one of the linchpins of ensuring that solar energy remains sustainable for generations to come.

Frances Willberg:

This is an issue that we're starting to face now and that we'll continue to face for the next few decades, as we start to see the first generation of PV modules be disassembled and disposed of, and so it's something that we need to have solidified how we're going to approach this in order to make sure that our industry continues to remain sustainable.

Frances Willberg:

Number two adopting module designs that can be more easily disassembled is going to be the key to enable cheaper and easier PV recycling. It's always more efficient to focus on making sure that your product is easy to recycle rather than needing to necessarily reinvent the wheel and create complex, expensive recycling processes for an existing piece of equipment. So the work that's being done to try to focus on making sure that newer modules are easier to disassemble and recycle is going to be one of the key tasks for this effort. And then, number three, reducing the amount of PV waste by embracing more efficient modules and reusing older modules when possible is going to be just as important as developing better methods of PV recycling in order to reduce the amount of PV waste that we are generating and needing to send to the landfills.

Al Rettenmaier:

Great, yeah, that that really sums it up. Well, thank you very much, Frances. It's it's a fascinating podcast. I'm sure folks will get a lot of good information out of this and to those who are listening, if you have any questions for Francis or the rest of the E3 team, or if you have a suggestion for a future podcast, please feel free to reach out to us via email at E3co@e3co. com . Yeah, and we look forward to hearing from you. Thanks again, Frances.

Frances Willberg:

Thanks Al, thanks everyone.