Solar Roadways: Unrealistic Dream or Future Reality?

January 19, 2024

Solar-powered roadways are an idea that has existed for many years but remains constantly in the spotlight thanks to ever-evolving technological developments. Driving on solar roadways and generating clean energy under the wheels – fantasy or a tangible possibility?

The United States has a keen interest in solar energy like no other. This is demonstrated by the World Energy Outlook infographic for the year 2023, confirming that America and the European Union are its primary importers and will remain so until 2030.

Solar Roadways: Unrealistic Dream or Future Reality

Source: World Energy Outlook

Will solar roadways be the way to a brighter future? It depends on the cost of the technology, government policies, public support, and other factors. Only time will tell if solar roadways become a reality, but they certainly have the potential to alter how humanity currently produces and consumes energy.

In this article, we’ll delve into the origins of solar-powered driveways, explore what they entail, outline potential advantages and disadvantages of solar roadways, and, most importantly, assess their fate: whether they’re worth it or not.

Popular Myths About Solar Panels Busted 5

Solar Panel Driveway: The Beginning

The history of solar roads began in 2006 in the city of Sandpoint, Idaho, USA, when Scott and Julie Brusaw contemplated the possibility of using solar panels to generate electricity on roads. They believed it would reduce dependence on fossil fuels and enhance infrastructure resilience effectively.

Within two years, the couple founded solar roadways to develop and implement their technology. They started with the prototype of the solar-powered road, consisting of individual modules containing solar panels, LEDs, and other components.

By 2014, the company turned to alternative funding through online crowdfunding and attracted more sponsors. In total, around $2.2 million was raised.

First Public Installations

#1 Public Installation #2 Public Installation
  • Location: J. Jones City Square in Sandpoint, Idaho.Year: 2016What was it? A pedestrian walkway project with 30 panels of the SR3 model, generating 36 watts.Estimated cost: $60,000
  • Location: Inner Harbor Tourist Center in Baltimore, Maryland.Year: 2019What was it? A public 36-panel display of the new SR4 model, generating 55 watts.Estimated cost: $72,000

The collected investments soon materialized into concrete plans, which were ambitious given the campaign’s fundraising success. Despite various reasons, these projects did not succeed and were soon closed. Nevertheless, the company continues to develop and improve the technology. Now, the firm puts effort into securing stable funding for the commercialization of solar roadways.

Features of Solar Panel Roads

Highways and solar panels, electricity, and various weather conditions – it seems like an unlikely combination. But the technology is simple: it involves using panels embedded in the road surface.

Each solar panel consists of three layers:

Layer Description Function
Top layer Durable glass surface. A hexagonal crystalline lattice of metals ensures the densest packing of atoms, and the tempered glass enhances mechanical strength. Providing an optimal trajectory for vehicles on solar roadways
Middle layer Photovoltaic elements. They are securely fastened in a sealed aluminum frame. Semiconductors on top are covered with a protective polymer film. Collecting solar energy
Bottom layer An integrated power supply system. On the back of the solar panel, there is a sealed distribution box where the energy transitions from photovoltaic elements to electrical wires leading to the controller. Efficient distribution of collected energy

The efficiency of panels for solar roads depends on the material they are made of.

  • Silicon panels are the most efficient and expensive.
  • Polycrystalline panels are less efficient but also less expensive.
  • Amorphous or thin-film panels are even less efficient but the most economical.
  • Organic or polymer panels are the least efficient but the lightest.

The next important feature to consider about solar roadways is the dependency on various factors like lighting or temperature. Therefore, the choice depends on specific needs and circumstances.

In addition, when developing the solar roadway project, attention should be given to panel configurations.

The most common configuration is monolithic, where solar panels are directly installed on the road surface. It’s a good choice for projects with limited space or high levels of sunlight.

Another configuration is modular. It’s more robust and resistant to wear. Solar panels are installed in modular blocks, which are then laid on the road. Unlike the previous type, they are flexible during replacement or regular maintenance.

The right choice will impact the project’s cost and, in the future, the performance of the panels on the road.

Prospects of Solar Roads

The technology of solar roadways is still in development. However, it certainly has the potential to revolutionize electricity generation.

Solar Roadways: Unrealistic Dream or Future Reality

Source: ResearchGate

Wondering what’s wrong with regular asphalt covering? Asphalt is indeed an effective way to protect the road surface from wear and tear. But compared to solar roadways technology, it falls short in some aspects:

  • Asphalt also absorbs sunlight but doesn’t convert it into electricity.
  • Asphalt cannot fulfill other purposes besides protecting the surface, leading to reduced expenses on repair services.

For instance, a solar highway covers the need for lighting, heating, and charging vehicles. Let’s explore these and other advantages.

1. Renewable Energy Generation

Ecology and the sustainability of natural resources are on everyone’s lips. Humanity faces the problem of reducing dependence on fossil fuels, which have become an integral part of life. We are powering household devices, transportation, heating homes, etc. Fossil fuels are one of the main sources of greenhouse gasses, contributing to global warming.

Producing and using “green” energy is a decisive step in this matter. Claims that solar roadways will completely solve the issue are speculative, as more research is required to confirm the efficiency of these roads.

Nevertheless, solar roadways could potentially become a renewable energy source, as sunlight is a free and unlimited resource.

2. Powering Road Infrastructure

Typically, roads, especially highways, are equipped with traditional lighting (lanterns with incandescent bulbs), surveillance cameras, illuminated road signs, etc. Maintaining all this in working order requires careful and systematic maintenance, which is not cheap.

In this case, solar roadways present an alternative for street-side lighting with lower financial costs. What does such a road offer?

  • Use of LED streetlights on the sidelines
  • Variations in different types of lighting, from dim for pedestrian paths to brighter for main roads and intersections

Uninterrupted lighting in dark hours is a reason for a driver’s peace of mind, as they become more confident and protected from accidents on the road.

3. Possibility of Generating More Power

Solar roadways have the potential to generate a significant amount of energy, even more than traditional household solar panels (scaled accordingly).

Statistics for 2022 demonstrate that global electricity production amounted to nearly 0.7 trillion kWh. Experts’ calculations show that solar roads could produce over 14.5 trillion kWh of electricity per year, three times more than the annual energy consumption. However, this is contingent on the existing road network transforming into solar roadways.

4. Wireless Charging for Electric Vehicles

You might argue that there are significantly more fuel-powered vehicles. Yes, you’re right. However, the trend of having an electric vehicle is growing continuously. In the United States alone, over 910,000 electric cars were sold in 2022. According to the IEA, the number of such vehicles worldwide will increase tenfold by 2030.

Therefore, having an electric vehicle with solar panels on the road means you don’t have to worry about its power supply. The inductive charging system offers charging without stops or connection to a special cable. You simply drive on solar pavement, simultaneously powering your vehicle. Agreeably, it’s a convenient and effective scheme.

5. Automatic Road Heating

Winter driving on icy roads can be unpleasant for any driver. However, solar roadways provide a solution. Each solar panel has heating elements that activate when sensors detect low road temperatures. This heating melts snow and ice, and the panels can even help dry the road during humid conditions. This is especially beneficial for people who park on the road, as their cars won’t be covered in precipitation when they return.

Automatic road heating is a promising technology. Primarily, it ensures safety and comfort for drivers. Gitnux reports that over 70% of roads in America are located in regions where snow or ice is common, and over 75,000 people are injured in accidents every year. Road heating from panels can change this grim statistic.

6. Versatility

It’s already clear that the development of a solar panel highway can be geared towards various goals, e.g., powering, lighting, heating, and more. Moreover, solar roads with panels can be applicable in parking lots, bike and electric scooter lanes, pedestrian walkways, specific areas of public spaces, or any other location.

7. Additional Uses

Solar roadways can be used for other purposes, such as:

  • Aesthetic enhancement — transforming dull roadways into more modern and attractive spaces through potentially interesting design elements
  • Impact on the economic situation — creating new jobs in the fields of energy, construction, and engineering
  • Possibility of use for different locations — generating energy for areas where access to the power grid is limited or intermittent

Solar Highways: Drawbacks and Controversies

The more buzz around a topic, the less likely everything is as rosy in reality. Solar roadways are no exception. On the one hand, they can address several important issues, such as climate change, energy security, and solar roads safety. But on the other hand, there are several challenges to overcome before solar roadways can become widespread.

Challenge #1: Cost

On the surface, cost doesn’t seem to be a problem. Firstly, over time, the roads should pay off through reduced expenses for repairs, maintenance, etc. Secondly, according to IRENA, in the U.S., the normalized cost of electricity has decreased in recent years, and accordingly, the price for one solar panel has also decreased – in 2022, the average cost was $876 per kW.

Solar Roadways: Unrealistic Dream or Future Reality

Source: IRENA

But on the other hand, it’s worth considering the peculiarities of the U.S. road network, which is considered the most extensive. Statista informs that the total length of the network is approximately 22,017 million feet.

Derek Kuldinow, a Ph.D. from Stanford University in the USA, concluded that based on today’s technologies, a solar road project on the scale of the Interstate Highway System (IHS) with inductive charging devices would not meet the needs of travelers. Therefore, solar roadway costs are a significant hurdle in advancing the project, starting from the initial development stage.

Challenge #2: Efficiency

This challenge is directly related to the previous one. Solar roadways must be quite efficient and generate enough energy to compensate for the cost. Experts still need to figure out how to achieve this.

For example, the company of the Brusaw couple reported efficiency test results of the SR4 model solar panels at 23,7%. Were you expecting 100%? We understand, but the road to perfection is long and challenging.

Don’t overlook the impact of daylight on-road efficiency. Insufficient light equals zero expected result. While you can tweak panel settings or angles at home, on the road, it’s out of your hands. Nature rules and concerns persist about how solar roadways perform at night or in extreme conditions like darkness or excessive heat.

Challenge #3: Durability

On average, the weight of a regular car is not less than 1.5 tons. During peak hours, the road is crowded with numerous vehicles, adding to the overall weight and traffic. Can solar roads withstand such loads? We believe additional research is necessary.

In reality, panel coverings are quite “delicate” – too heavy vehicles or impacts from various objects can damage them. The option of making the panels thicker, for example, is not suitable because it will disrupt their transparency coefficient and, consequently, their permeability.

Making a solar panel road function correctly and precisely is not easy. Scott and Julie Brusaw have dedicated over 18 years to advancing the engineering of solar roads, and they’re making progress. Yet, the question of whether the results align with the time, effort, and investments invested in the projects remains open.

Mini-Projects of Solar Power Roads Worldwide

Equipping an extensive and long highway with solar panels is a complex process. However, experts don’t give up and find ways to get closer to the dream goal of creating solar roadways. While large projects are still in the development stage, there have been implementations of the concept on a smaller scale.

Netherlands, Krommenie
  • A 70-meter-long bike pathConsists of silicon elements covered with toughened glassOperational since 2014Provides enough energy for three households
France, Normandy Region
  • A 1 km-long highwayTotal panel area is 2800 km².Operational period: 2016–2019Provides enough energy for street lighting for over 3000 residents
China, Shandong Province
  • An almost 1 km-long highwayTotal panel area is over 5500 km².Operational period: 2017–2018Powers around 800 residential houses

For instance, here’s the description of the first solar road in a French town:

Solar Roadways: Unrealistic Dream or Future Reality

Source: Arab News

Regrettably, not all projects are ongoing. In France, solar roads failed to meet expectations by not generating the desired amount of energy. To be fair, all mentioned projects were not merely test endeavors but were implemented in real-life situations.

Driving Towards the Future: Exploring the Potential and Pitfalls of Solar Roadways

Recapping our investigation into whether solar-powered roadways will become commonplace, we can only say that it will take many more years for this to happen. So, if you hear about solar roadways, stay realistic! It really depends on us. Are we willing to invest in technology and overcome the challenges?

However, there’s another way to contribute to the eco-community. Consider installing solar panels on the roof or walls of your home. This way, you’ll save on electricity and make a contribution to conserving natural resources.

Frequently Asked Questions

How does a solar driveway work?

Its working principle is similar to regular solar panels. Solar roads absorb sunlight, converting it into electrical energy. This energy can be used to power homes, businesses, and more.

Does climate affect the functionality of solar roads equipped with panels?

Although solar panel roads can function in various climates, they will be more efficient in areas with longer sunlight exposure.

How do solar roadways impact driving?

These solar roads do not have a significant impact on driving, as they essentially have the same surface as traditional roads. You can drive on solar pavement with all types of vehicles, provided there are no weight restrictions.

Andy Worford
Andy Worford

Andy is a Founder, Chief Content Officer, regular contributor, and idea generator behind Solar Power Systems. He is well-versed in various aspects of solar energy, including photovoltaic systems, solar policy trends, and green technology innovations.