Posted on May 21, 2020
Solar Road
Two Roads Diverged in a Wood, and I— I Took the One Made Up of Photovoltaic Cells…
By: Megan Paonessa│map6150@psu.edu│May 14, 2020
Installment of the Solaroad in Krommenie, Netherlands. (Courtesy Solaroad)
I can remember when I was a small child watching science fiction movies with my father. So many of these movies and shows showcased advanced societies that were completely sustainable. These sci-fi fabricated worlds, where air-taxis zipped around and had mothers that sure do know how to rehydrate a pizza, inspired my imagination growing up. Now, as an adult, my dreams are of a more energy sustainable society. I recently came across an article that brings a sustainable dream into fruition through the application of solar paths. The article, “Harvesting Roadway Solar Energy—Performance of the Installed Infrastructure Integrated PV Bike Path,” is posted in the IEEE Journal of Photovoltaics. This article specifically focuses on the bike path implemented in Krommenie, Netherlands in 2015 by a company known as SolaRoad. This bike path is incredibly unobtrusive that “…riders hardly seem to notice anything different about the path’s surface” (TriplePundit).
Theoretical Predictions for Dutch Solar Bike Path
Out of all of the solar paths in the world, the Dutch pathway has been viewed around the world as a success. Compared to other solar paths, the path is nearly meeting its expectations for energy output. “The path is already producing more than 3,000 kilowatt-hours, or enough to power a home for a year” (John Wenz). Aside from energy generation, many factors must be taken into account to create a “successful” solar path. The designers had to account for annual traffic and temperature; both play significant roles in the deterioration of the system. Be aware that a theoretical model cannot accurately predict annual cloud coverage and rainfall that can affect solar systems. Aditya Shekhar et al. did admit that there were factors that were not taken into consideration when calculating the theoretical energy yield. These factors included dirt accumulation and dynamic shadows due to the movement of bikes. From the article, the study concluded that the actual energy yield was lower than the predicted energy yield. Many people may surmise that this path is a failure because it did not live up to theoretical yield, but the actual yield was not much lower than the theoretical yield. In my opinion, the results are still desirable because most implementations of photovoltaic cells do not live up to their theoretical yield. In many other cases, outside factors affect systems like this so negatively that the system itself was not worth the money and effort to install them in the first place. I would say, in this case, that the solar bike path does appear to be worth the time and effort.
Structure of Bike Path
Inner layers of the solar bike path structure are shown as workers install the path. (Courtesy Solaroad)
The structure of the bike path had to be very well thought out to be used as a path function. It is one thing to install solar cells on a roof and another to be walking or riding on top of them every day. The topmost layer of the path is composed of an anti-skid layer to provide friction for the bikes. This anti-skid layer does affect the irradiance the photovoltaic cell underneath receives; it also affects the temperature. Notice this structure does not contain any sort of cooling system (as one would see in other photovoltaic systems). In this structure, the ground below the cell is behaving like a heatsink. But using the ground as a cooling system is a risk, as it cannot indefinitely provide cooling. And the photovoltaic cells can only operate within its thermal limits.
Controversy Over Effectiveness of Solar Paths
As not all countries have been able to achieve a working photovoltaic pathway, this has become a controversial topic. In Normandy, France, the solar path was a major failure. The path deteriorated and therefore did not produce anywhere near the theoretical yield. I think this specific case is a poor example of the implementations of photovoltaic cells. Not that the road designers did not have good intentions, but these intentions were, perhaps, idealistic. A road that is going to be driven over with such volume of traffic and weight is not practical for photovoltaic cells. I do not blame the photovoltaic cells for their disappointing performance, but rather the designers for putting them there.
Solar roads are paving a brighter outlook on sustainable energy generation for the future. Although solar paths have seen success and blunders, this is only the beginning of where we can implement photovoltaic cells. I anxiously await the day that we can inconspicuously incorporate renewable energy methods in our daily environments such as the solar bike path seen in the Netherlands.
… and That has Made All the Difference.
Megan, your blog is so well constructed! You do a wonderful job of catching the audience’s eye with your visuals and your titles. If there was one takeaway from reading your blog, I’d say it’d have to be the topic of the structure behind the bike pathway. (Being a civil engineering major, I may just be a little biased towards enjoying this section more, haha!) I’ve been a part of different projects involving moving our society into the eco-friendly path, but this idea has never crossed my mind until now! You have a really deep understanding concerning this topic and I can see how much you genuinely care for the environment. I wish you the best in your future endeavors and I know you’ll do amazing things!
I thought that your blog was interesting, and I enjoyed reading it. I did not know that the ground could be used as a heat sink for photovoltaic cells. I thought that you would have to have a cooling system. I read an article about the possibility of turning the less-populated highways in Arizona to a solar road, but when you mentioned the French’s failure, I am not sure that this is such a good idea. I know that you will figure out a way to incorporate renewable energy sources into our everyday lives. I hope to read about all of your successes in the future.
I am a proponent for renewable energy, so I really enjoyed reading your blog post and the great work the Dutch accomplished with their bike path. My prior knowledge of solar panels is quite limited, so it was nice to learn the factors that affect the photovoltaic cells, like the important anti-skid layer. I hope that you will be able to work on projects that have meaning for you, like this one that pushes for a cleaner and energy sustainable society.
I have heard of solar roads in passing and sometimes in the news as “the next big thing”, and I am finally glad to learn about a successful iteration of one. Your article was a great read as it illustrates science working towards a better and a more tech-integrated world. It is a bit sad to learn about France’s failed implementation of a solar road, and as a nuclear engineer, I know how one failure can lead to decades of doubt, but I think that this solar voltaic roads are the future. Hopefully down the line we will be reading your name on the team of engineers who helped implement these roads in the United States!