Remember Solar Roadways? As a fresh reminder, Solar Roadways became massively viral a few years ago after claiming to be the end-all solution to the global energy crisis. The idea was to implement solar panels into the road to produce electricity. The panels allegedly were also going to light up the roads with different LED patterns replacing painted lines. For the winter, heating coils could melt snow and ice- all while generating electricity and requiring less maintenance. It seems too good to be true. And as it turns out, it is.
After years of development and millions of dollars (including government funding), all of the solar roadways installed today do not produce cost-effective energy production. The roads are expensive and produce far less electricity than what could be produced if the money was used on a solar farm- or by simply placing them by the side of the road. However, it is not the only flaw in turning roads into giant solar panels.
An Engineering Failure
With the global road network spanning an impressive 16.3 million kilometers, it seems reasonable that covering them with solar roadways could generate a substantial amount of electricity. Assuming the average road is 8 meters wide, the area accumulates a whopping 130,400,000 meters squared. Placing solar panels on a mere fraction, in theory, should generate enough to power the entire world. However, it is only achievable under the best of conditions- when the solar panels are in direct sunlight. The largest incentive of the project was its ability to pay itself off- or its return
The largest incentive of the project was its ability to pay itself off- or its return of investment (ROI). Though as of yet (and it has been almost 7 years in the making), no solar roadway has sustained a cash-flow positive income. Instead, the projects have caused a slew of problems which required extensive maintain. Although the technology has been in development for years, the idea is not yet viable. It makes sense, though.
Not enough light
On a tradition solar farm, solar panels are angled towards the Sun to maximize efficiency. On more advanced farms, the panels are made to track the Sun, further improving the amount of energy it can extract. Of the energy that the sun produces, a typical solar panel can only absorb about 20% of it. Optimizing the amount of light the panels are exposed to is imperative to run a cost efficient system.
On the other hand, solar roadways that lay flat minimize the panels’ exposure to direct sunlight- the optimal angle to absorb light. With the panels remaining non-parallel for most of the day, a significant amount of light is deflected resulting in major power losses. Laying a solar panel flat result will result in a 60 percent power loss in comparison to a tracking solar panel. The already small amount of energy that is available is further restricted by the environment around it. In the best of conditions, the panels are at a severe disadvantage, without the consideration of the constant wear and tear that it will be exposed to for its entire life.
[Image Souce: Thunderf00t via YouTube]
LED’s are difficult to see during the day
One of the features of the roads was to include LED’s that would replace the necessity to paint lines. However, a critical balance must be met by making the lights visible, yet not drawing too much power to make it an inefficient system. With current LED’s, the power consumption is still too high and the lights burn out too fast to make it an economically viable solution. LED’s in traffic lights use shielding to block out direct sunlight. On the road, solar roadway lights would be constantly exposed to direct sunlight. The lights would be incredibly difficult to see during the day. At night, they would be easily visible, but it causes an inherent problem. With no power being produced at night, the lights would be drawing electricity directly out of the grid. Without batteries, electricity acts as a use-it-or-lose-it system. The Solar roadways that are being used today face this significant issue.
Placing a blank sheet of paper reflects the majority of the light that hits it. The majority of the energy it is exposed to is used to generate light. In other words, the LED’s cannot produce more light than a blank sheet of paper on a bright day.
Considering that solar panels can only extract about 20% of the energy from the sun, the LED’s could only generate 20% of the light in comparison to the light that comes off of the piece of paper. Under the best of conditions, the light can only match that of 20% of the light that strikes the panels. At night, the lights work great. During the day, they were almost invisible.
However, determined to test the theory, a team did install a small section of solar roads in the US, but the results were rather unimpressive. Unfortunately, the small exhibition broke in a day, then caught fire sometime later. Also, the lights could hardly be seen at even direct angles to the road. Earlier this year, the panels did receive an upgrade, but the lights are still incredibly difficult to see without being at a high angle, the opposite of the angles drivers would view them as.
LED lighting is hardly visible during the day [Image Souce: Thunderf00t via YouTube]
Further restricting the roads ability to produce electricity arise from the properties of glass itself. Glass is incredibly soft in comparison to traditional road material. With a glass layer, dirt and rocks will accumulate on the surface and will act as an abrasive material that will scratch and wear the road quickly. The small glass fragments that are produced can also pose a health hazard if ingested.
Advanced polymers were considered to construct the roads, however, most polymers are expensive to manufacture in sufficient quantities to build a road capable of withstanding the constant force of traffic. The material is also typically made from fossil fuels, defeating the purpose of using solar panels to reduce the carbon footprint.
As the panels wear out, the glass material will become opaque. The clarity of the glass would significantly degrade the panels ability to collect light. The challenge is mounting. The cost of implementing the system could never exceed the efficiency and [racticallity of simply installing the solar panels in far more efficient arrangements.
The idea of replacing asphalt with a glass panel is even more absurd once the cost is considered. Currently, there is no coating available that can withstand the force of moving vehicles yet produce electricity at the same time.
It is absurdly expensive
Covering the southern 48 state roads with solar roads (about 6 billion square meters) would produce three times more electricity than the annual power consumption of the United States-a claim made by Solar Roadways. The figure is accurate, however, it does not factor in the cost of such an astronomical project. Calculating the cost of the raw materials for glass reveals that covering an area that extensive will cost in excess of 20 trillion dollars. Rather unfortunately, it is 10 times the federal budget. With the consideration of the cost of the solar panels, installation, and other materials, the price will be significantly higher.
The idea is fun to imagine. However, with the materials available today, the idea is not quite feasible. Significantly more research is required to develop a viable solution. Although, it may be a better idea to tailor the placement of the panels and put them places where the can be in the direct sunlight. Building a shelter over roads and layering the roof with solar panels is more practical and significantly more efficient. Perhaps introducing a roadway cover that extends above the road with solar panels on top could be a possible solution. However, for the time being, the cost still remains too high.
With today’s technology, the better solution may be to invest in current technologies that are already viable solutions. It would be significantly more efficient to run the solar panels alongside the road where they are not subject to harsh conditions, are easier to maintain, and are much more economically minded. Furthermore, the panels could be angled or made to track the sun, maximizing the power that is available to them.
What Progress has been made
So far, a few solar projects have been installed around the world. Some of them work better than others, but as a whole, they do not generate much electricity- far less than what could be expected if the money that funded the project was used on traditional solar farms.
With the unveiling of a solar roadway in the USA a few years back, the results were rather underwhelming. The lights were dim and it broke soon after. The LED’s did receive an upgrade, however, the results are still not great. Despite the economic and practical failures, one promise the company made did hold- its ability to melt snow. Which makes sense given how much energy the lights draw.
[Image Souce: Thunderf00t via YouTube]
As of yet, the company has yet to produce any information as to whether they can actually produce any electricity at all. As of now, it is a solar roadway that cannot generate power and cannot be driven on.
Technological advances are being made all the time. Modern humanity thrives on innovation. Though there are many great ideas, solar roadways designed for cars is not one of them.
The design is far too expensive, unreliable, and does not work. With the technology available today it is not feasible to design such a project. Instead of using the time and money to develop impractical science projects, real advances could be made like funding a functional solar farm that is proven to work.
Perhaps in the future, there will be such a material that can withstand the stresses of traffic and can produce electricity. That time, however, is not now. The idea is incredibly cool, but unfortunately, it is also entirely impractical.
Also, a big thank you goes out to those who are willing to constructively criticize extravagant claims. Without criticism, science cannot progress. It is great to think outside the box, however, it is also important to invest time into more practical solutions. Albeit a great idea, it is an idea that just cannot work- not yet that is.
For more information on the engineering blunder that is solar roadways, here are some fantastic videos to check out.