THE UNIVERSITY OF VERMONT
How Panels Prevail: New Solar Research Facility to Study Effects of Challenging VT Conditions

The new UVM Solar Research and Training Facility at McNeil Generating Station was unveiled today, energizing the study of the performance and durability of solar panels under often-challenging Vermont conditions: freezing temperatures, heat and humidity, cloud cover, hail, and having their surfaces covered in everything from bird droppings, snow and ice to dust from agriculture and dirt roads.

The facility - the result of a partnership between the University and the City of Burlington, the McNeil Joint Owners (Burlington Electric Department, Green Mountain Power and Vermont Public Power Supply Authority), Encore Renewable Energy, and Vermont Gas Systems - includes panels purchased as part of a Department of Energy (DOE)-funded UVM research project in the College of Engineering and Mathematical Sciences as well as a large number of panel donated by Sandia National Labs from the former DOE/Sandia National Lab solar test site in Williston. The array will serve as a core research facilty serving several new research projects and training opportunities and will support the long-term goal of identifying industry partners interested in testing new technologies.

The equipment for the facility was donated by the federal government with the assistance of Senator Bernie Sanders, who also directed $150,000 in Congressional funding to the U.S. Department of Energy to help make the project a reality.

"Our research and education related to sustainability and renewable energy rank among the most important work we do," UVM President Suresh Garimella said. "I am thankful for Senator Sanders and the rest of our partners on this project for their roles in relocating this array to the McNeil Generating Station, where it will be of great value to our research efforts and provide exciting opportunities for student projects."

"This partnership is an excellent example of how Vermonters work together to tackle the big issues of our time," Sen. Sanders said. "We must do all we can to fight climate change, and conducting solar research that will lead to the more effective use of energy from the sun to power our communities is a step in the right direction. I was glad to direct impactful funding to the Department of Energy to help move this important project forward."

As decarbonization policies continue to go into effect in Burlington as well as at UVM, the electrical grid must include more renewable energy sources - but these sources present challenges, according to UVM's Mads Almassalkhi, L. Richard Fisher professor of Electrical Engineering and Principal Investigator (PI) of the first major research project to leverage the facility.

 "We're very focused in our research groups on studying the impact of renewables and improving the reliability of the grid by leveraging the capabilities of a lot of distributed energy resources, like batteries, inverters, and responsive loads," Almassalkhi said.

While solar technologies are certainly not new, many questions remain about how to optimize their efficiency, especially in cold climates. Given that such research can take decades as panels degrade under years of snow, heat and dirt, the question, according to Almassalkhi, is, "how can we speed up our understanding of how solar photovoltaic panels degrade in cold climates?"

One way is to speed up the solar panel degradation process artificially, said UVM's Matthew White, a professor in the Department of Physics and co-PI of both the solar installation and research projects. "We want this facility to be what we call a quasi-accelerated lifetime test," White said. "We're trying to find a stepping stone between the rapid acceleration data from the lab - that really has no correlation to what happens outside - to putting a device outside and watching it for 30 years, which is a very slow process."

The McNeil facility provides an opportunity to leave the panels "fully exposed to all of the dust, rocks, birds, squirrels - everything that you might expect panels to be exposed to outside," White said. White and his colleagues plan to control one factor - freezing and thawing - because as White notes, "we think that that's a fairly critical element to how these technologies will survive in Vermont." The team is exploring ways of heating the panels above freezing on winter days, then letting them refreeze at night, repeatedly throughout the winter.

The researchers will then have plenty of data to work with, according to Almassalkhi. "We want to sensor the heck out of this facility," Almassalkhi said. "We want to measure everything, record everything and then study and analyze it and build models that predict lifetime performance."

In addition to sensors on the panels themselves, a weather station at the site records near-constant data on temperature, humidity, precipitation and solar irradiance - how much sunlight is hitting the panels in real time. The weather data will complement the sensors' data about the panels' performance and efficiency, and the researchers can see how weather conditions and energy efficiency correspond at any given moment.

At a lab on campus, meanwhile, White and his student research team will put some panels through a series of rapid freeze-thaw cycles in a purpose-built environmental test chamber that White describes as a "refrigerator-oven." The chamber also allows researchers to test panel coatings designed to help them shed ice and snow. This is important because solar panels can be more efficient in cold than in hot weather - if the sun can reach their photovoltaic cells. In Vermont, a cold, sunny winter day can mean fantastic solar energy production, provided the panels are not covered in snow.

"We're looking at passive, and in some cases even active, coatings where we can have a small electric field on the surface," White said. "The ice and the snow then fall off more easily."

A key aspect of the research is scale, Almassalkhi said. Using the extensive data they're collecting, the researchers are creating predictive models of the solar panels' performance, batteries, electrolyzers and inverters - as parts of a larger hybrid system.

"In scientific literature, there are a lot of experts on each of the components," Almassalkhi said, "but few experts have looked at the whole system. That's what's new here. How do we improve the economic performance and technical capabilities of such hybrid energy systems?"

The questions extend beyond the Solar Research and Training Facility and Vermont. Across cold climates worldwide, the long-term performance of solar panels is an important question as nations work to move past fossil fuel dependence.

The facility also opens doors for the next generation of renewable energy engineers and scientists, and between UVM and a slew of private energy entities surrounding, there are opportunities on campus and beyond. The first major research project enabled by the facility is a $4M Department of Energy research project led by Almassalkhi and a team of engineers and physicists, including White in physics, two new junior faculty in electrical engineering, and faculty in mechanical engineering. Vermont is well-positioned to play a role in renewable energy's future, Almassalkhi says.

"The reason I am excited to be in Vermont is because the ecosystem for energy innovation here is enormous, and it's enormous far beyond the footprint of the state," Almassalkhi says. "You don't even need to measure per capita to measure the energy innovation happening in Vermont - you have some of the most innovative energy companies in the country in Vermont." He hopes that the work at McNeil will lead to greater collaboration between UVM and energy industry entities across the state.

"I think that the biggest environmental problem that we have by several orders of magnitude is the warming that we're seeing as a result of CO2 emission," White said. "Finding ways to expediate the adoption of renewable energy technologies and energy storage and integration with modernizing the electrical grid in Vermont is going to be really important for us. It's something that we value as a research program." And, White says, he sees that this is a clear priority for students as well.

"They seem to universally view this as a priority problem that they want to address."

"As a UVM undergraduate student and researcher in electrical engineering and energy systems, I'm incredibly excited about the launch of the UVM Solar Research and Training Facility at McNeil," said Emily Ninestein 24, who is pursuing a bachelor's degree in electrical engineering and serves as president of the student chapter of the Green Mountain Section of the Institute of Electrical and Electronics Engineers (IEEE). "Being able to explore research questions and confirm models with real data is critical to making progress and pushing the envelope of energy technology - with real-world, Vermont data, we can ground engineering education in Vermont's rich and active history of energy innovation.

"This site will unite bright, inspired minds with the tools they need to solve problems, which makes me feel hopeful and excited about the future of energy research at UVM and the future of Vermont's energy industry as a whole."