SANDPOINT — You may have noticed the Christmas trees over the Solar Roadways pilot project in the town square. And you may have noticed the power monitoring link on the city’s website for the project reads zero.
Signs the project has failed? Far from it, say the company’s co-founders, Scott and Julie Brusaw. It’s simply a sign the pilot project has been temporarily shut down until the company can replace existing panels with the newest model this coming spring — at no cost to the city.
“The whole goal of a pilot project is to allow you to work out problems to get to mass production,” Julie Brusaw said. “These things were all things we needed to know before we get into mass production.”
“We are grateful to the city of Sandpoint and all residents and visitors who served as our testers on this pilot project,” added Scott Brusaw. “This ‘real life’ test gave us the information we needed to make important improvements to the design of SR4.”
The city of Sandpoint performed a key role in their efforts to get the panels ready for mass production, serving as a guinea pig of sorts so they could see how the panels worked in a variety of conditions and circumstances.
“It’s how you learn,” Julie Brusaw said.
The two years since the panels were installed at Jeff Jones Town Square saw a number of challenges and delivered a lot of data — all of which went into making the panels production ready.
The biggest challenge they faced was in the manufacturing process, the couple said. While each individual part worked fine on its own, putting everything together and running them through the manufacturing process created some problems and a huge learning curve. Those fundamental parts of the company’s panels — LED functionality, surface heating, and solar harvesting — all need to work independently as well as cohesively.
The panels at the square — version SR3 — were always a test product and were installed at the square to gather needed data to see how they would perform in a real-world setting. That data, combined with an array of civil engineering tests at Marquette University, has been used to tweak the panels to make them ready for mass production, the Brusaws said.
Did they have problems or not work as hoped? Sure, but as with any pilot project, those problems were expected — and needed so real-world results could be factored in to improve the overall design.
What did they learn from the Sandpoint pilot project? A lot, said the Brusaws.
An example: The panels’ diverse spectrum of LED lights allow for a dizzying array of situations and design options, from a picture of the planet on Earth Day, to crosswalks and traffic. However, after leaving the Earth design up for several weeks, they noticed something unusual — the blue LED lights were fading. Experimenting with other patterns, they noticed the same thing happening with the white and yellow LEDs lights. The only LEDs not affected were the red and green lights.
After many conversations with the LED manufacturer, they learned the different colored LED lights were made differently — and after a number of tests, realized the protective epoxy was causing a chemical reaction with the LED lights. Ironically, the sun was the catalyst.
That’s been corrected with the SR4 design so that protective epoxies are no longer needed, Scott Brusaw said.
Another example: This one relating to the panels’ heating elements. While the SR3 panels could keep up with the snow in most situations, they used anodized aluminum panel retainers between the individual panels. Because there was no heating between the gaps in the panels, the metal took on the ambient temperature around them. That caused the potential for ice bridges when the weather was extremely cold with heavy snowfall.
The SR4 replaces that with rubber, which also simplifies installation and maintenance. Another hard lesson learned: cables used with the SR3 panels had a plastic jacket, which over time became brittle and cracked, allowing water into the cable and causing the panels to fail over time. The water caused corrosion, which caused resistance, which in turn robbed the panels of power.
“This means that the microprocessor, the LEDs, and the heating elements are not receiving the power that they need to function properly,” Scott Brusaw said.
They learned the individual components of the panels have to not only hold up to the outside elements, but withstand the heat and pressure of the lamination machine. That’s why the pilot project has been so important — it’s allowed the company to learn what they needed to know so they can begin production of the first commercial version — the SR4 — in 2019.
“There’s so many moving parts, everything has to work, nothing can fail,” added Julie Brusaw. “We’ve been through a lot to get to the point where we’re just about ready for production.”
However, the most disappointing aspect of the pilot project was a lower-than-hoped-for energy collection from the panels — something critics pointed to, claiming it showed the concept was a failure and would never work. However, the Brusaws said that’s far from the case, instead the problem was traced to the use in the SR3 panels of a parallel/series combination of cell connections. What they learned through that was while, technically you can parallel solar power, the pilot project showed it to be a bad idea.
“What we found was this: every panel produced power, but we couldn’t get them to combine properly to meet the input requirements of the micro-inverters,” Scott Brusaw said. “We were never able to see more than one-third of the power being produced.”
The pilot project also showed that extra laminate used in the SR3 panels interfered with solar gain. Both of those problems have been corrected in the new SR4 design. The new design features a maximized solar cell area with a series connected system with increased wattage.
That means the panels will be more efficient and Solar Roadways will be able to increase the solar gain over time as the industry itself continues to advance, resulting in better products to incorporate into the panels.
As part of the company’s third contract with the U.S. Department of Transportation, the panels underwent a variety of tests at Marquette University’s civil engineering department. The tests, which included everything from shear testing to moisture conditioning to accelerated load testing — simulating 15 years of truck abuse in a three-month period, went so well that Marquette scientists are co-authoring a journal paper with Scott Brusaw about the overall test program.
While they are disappointed the SR4 panels weren’t ready in time for installation before winter, and frustrated internet trolls will point to problems with the SR3 panels as proof the panels don’t work, the Brusaws say it was the right move and that Solar Roadways panels are closer than ever to being available for customers at all levels.
And, they note the hiatus is temporary, installing the panels now would mean rushing and they want to do the job right. To keep folks updated on what’s going on at the company, the Brusaws are providing content for the kiosk at town square. Scott Brusaw has written a blog outlining the technical details of the pilot project and the panels, which can be found online at http://bit.ly/2zOaWtw. Also, a few of the SR4 panels are being installed by the company’s front doors so the community can see them in action.
Other things on the horizon? Some of the panels will be on display at the Treefort/Hackfort music festival in Boise this March and others will be part of a temporary exhibit at the Smithsonian in New York for four months, the SR4s will be installed in Baltimore, Md., in the coming year, and visitors continue to visit the community to see what’s up with the company, the Brusaws said.
“We decided from the very beginning of our Solar Roadways journey to be as transparent as possible,” Scott Brusaw said. “We realize that this is not the way startups usually operate, but we wanted to be different. We are doing this work for the world and we wanted to allow our fanbase to come along with us on the journey. Most people have realized that problems are part and parcel of the learning curve with inventing.”
Information: Solar Roadways, facebook.com/solarroadways, twitter.com/SolarRoadways or instagram.com/official_solar_roadways/
Caroline Lobsinger can be reached by email at firstname.lastname@example.org and follow her on Twitter @CarolDailyBee.