Solar roads are becoming a more popular topic of discussion. The concept has been around for decades, but only recently have countries started to seriously plan for solar roads. Solar roads are like traditional asphalt roads except the road is a series of panels that produce electricity. These solar strips could be placed in areas where a high volume of cars pass by daily such as highways and freeways, therefore providing clean energy to the grid.

This article discusses the concepts, constructions, pricing, and current and future developments of solar-powered highways. 

How do normal solar panels work?

Normal solar panels are made up of dozens (if not hundreds) of cells. These cells consist of a thin layer of silicon sandwiched between two conductive layers. The top layer is textured to increase the surface area exposed to sunlight and has a positive electrical charge. The bottom layer is flat and has a negative charge.

Solar panels work by using a series of photovoltaic cells to harness the sun’s energy. Each cell is made of a thin semiconductor material, usually silicon. When the photons from sunlight strike the surface of these cells, some of them are absorbed as energy. The solar panel then converts that energy into electricity and stores it in a battery for later use. The panels themselves are typically made up of several photovoltaic cells (also known as “solar cells”) wired together to create a module. The more modules you have in your system, the more energy you will be able to generate.

The amount of energy generated by 1 square meter of a solar panel depends on how much solar radiation reaches that one square meter. The average amount of solar radiation reaching the Earth’s surface is approximately 1000 watts per square meter, but this number can vary based on latitude, time of year, and weather conditions. Solar panels are designed to convert this energy into electrical energy. Most panels convert about 15%–20% of incoming solar radiation into usable energy.

If you were to compare the CO2 generated from 1 square meter of solar panel surface area to the same area of the coal-fired power plants, you’d find that the solar panel would only generate about 4 grams of CO2 per year. This is in contrast to a coal-fired power plant, which would generate about 19,800 grams of CO2 per year—that’s 4955 times more. The solar panel produces 0.02% of the emissions that a coal-fired power plant generates.

How do solar roads work?

Solar roads are roads with a glass surface that has solar cells embedded in it. The idea is to replace asphalt with this glass surface, so instead of using petroleum-based materials to build the road, you can use a renewable resource and produce energy along the way.

The idea of solar roads was first proposed in 1978 by a mechanical engineer named Scott Brusaw. He envisioned a system made up of hexagonal-shaped solar panels that cover the surface of the road and would be embedded with LEDs to display traffic information and lane markings. It was also designed to be durable enough to withstand the weight of cars driving on it, as well as strong enough to hold up against inclement weather.

The solar cells that are used in solar roads are actually the same as those used in solar panels—only stronger. That’s because glass roads have to be able to withstand more than just rain and sunlight. They have to be able to withstand cars and trucks driving over them, which means that they need to be tougher than regular solar panels. And they need to work even when covered in dirt or snow, which is another reason why the engineers opted for solar cells instead of thin-film solar cells, which don’t function if they get dirty or cold.

Asphalt is made up of sand and aggregate stones that are glued together by bitumen. This is then used as a foundation for roads that are paved over with more asphalt or concrete. In order for asphalt to become a solar road, an additional layer of silicon cells must be added on top of it before being coated with an ultra-violet resistant resin material which protects them from damage caused by sunlight exposure and wears & tear caused by vehicles driving on them regularly (or even occasionally).

How much do solar roads cost?

The biggest cost associated with solar roads is the installation process. This is because it’s necessary to remove the old road and install a new one. The panels themselves are not that expensive—less than $6,500 for a two-lane road, according to the New York Times—but it still costs a lot more than repaving a conventional road.

The cost of installation will vary based on where you live and how many solar roads you want to install. The city of San Francisco, for instance, has estimated that it would cost $11.3 million to build a one-mile stretch of solar roads in the city (and this includes parking spaces). That’s about $47,000 per lane-mile, which compares favorably with other major cities like New York (which spends about $50,000 per lane-mile) and Los Angeles (which spends about $2 million).

Why aren’t more solar roads being deployed?

There are many reasons why solar roads haven’t been deployed—at least not en masse. These obstacles include the high cost of solar roads, the logistical challenges of installing them, and the complexity of maintaining them.

Solar roads have a lot going for them. They’re an attractive green energy source, they help offset the cost of road maintenance, and they can also provide power to adjacent buildings. However, all of these benefits come with some pretty hefty costs. Solar roads can cost almost twice as much like traditional asphalt roads, and they don’t last as long either. Additionally, it’s more complicated to install solar panels on the road than it is to install them on a rooftop or another open surface, so that adds another layer of cost. And then there’s the issue of maintenance: because solar panels produce electricity when exposed to sunlight, you have to clear snow off of them in order for them to work during the winter months. That’s not an easy thing to do when roads are buried under feet of snow!

When you take all these issues together, it’s easy to see why solar roads haven’t been widely adopted yet—but that doesn’t mean they won’t be someday soon!

It’s estimated that if solar roads in the US alone could potentially power 80% of the populations energy needs

Solar road deployments

There are a growing number of companies that offer solar road technology.

The first company to come to mind is Solar Roadways, Inc. They got their start with a crowd-funding campaign, and as of March 2018, they have not yet been deployed in any places.

Another company is Wattway, a subsidiary of the French company Colas. They have had success with solar roads so far—as of March 2022, they have deployed one test project in France, and they have projects in development in China and India.

Another company is Pavegen. Instead of converting the sun’s light into energy, this company creates energy from the pressure created by people stepping on its pavement tiles. It has been used in London and Lagos for small-scale projects such as lighting up displays at bus stops or powering cell phone charging stations.

Conclusion

Solar roads are an ambitious, yet exciting application of solar technology. Simply put, solar roads are a more efficient alternative to traditional roads since they produce an alternative form of energy. While the concept of solar roads is nothing new, build costs still remain expensive on a large scale. So far, we haven’t seen a lot of them in action, but the future for solar roadways does indeed look bright. 

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