Source : Mouser Electronics
In the world of engineering, innovation has always been the driving force behind progress. Looking to the past, the ancient Romans proved to be masters of engineering and innovation. In fact, many of their roads are still in existence and in use today. I’m sure you’ve heard the expression that all roads lead to Rome. Well, one day that may change to all roads lead to the sun.
Today, we’re on the verge of a literal trailblazing revolution—the dawn of solar roads. Imagine a world where the very streets we drive not only transport us from point A to B, but also generate clean, renewable energy. No, this isn’t the stuff of science fiction; rather, it’s the future of sustainable infrastructure.
In this blog, we’ll examine the smart road concept and its potential to offer lighting, heating for ice and snow on surfaces, and other smart road functionality.
Roads that Harness the Power of the Sun
Unfamiliar with the concept of solar roads? Solar roads, by definition, are simply roads embedded with a series of solar panels, transforming them into energy-generating surfaces. What’s different is that these photovoltaic panels are specifically designed to withstand the weight of most vehicles and offer a safe, drivable surface while capturing sunlight to produce electricity. (They’re not the same slick, glassy panels you see on rooftops and on solar farms.) However, that’s only quickly covering the surface.
Digging deeper, solar roadways consist of three layers: a photovoltaic, electronic, and power transmission layer. The topmost layer is constructed of robust, high-traction photovoltaic cells to harness solar energy and offer an impermeable, waterproof surface to shield the underlying layers. The subsequent electronics layer consists of the microprocessor, sensors, and accompanying circuitry. This layer has the built-in capability to detect snow accumulation, measure traffic loads, and manage the heating system for snow removal or control lighting, all while relaying current road conditions. The foundational layer serves dual purposes: it stores energy and transmits it to the grid, plus it can simultaneously accommodate a charging strip for EVs to replenish their batteries when they travel over it.
In essence, solar roads represent a brilliant, forward-thinking solution that combines transportation and green energy production, offering a glimpse into a future where our infrastructure works in harmony with the environment, instead of against it.
A Road of Open Possibilities
Our sun offers an energy source that is renewable, inexhaustible, and reaches the entire planet. In fact, current estimates state that we need to capture 6 percent of our solar energy to cover all of humanity’s energy needs.[1] Solar roads offer a pathway towards meeting that need by generating electricity during the day, and with the right storage solutions, capturing that energy for use at night or on cloudy days.
Another factor to consider in this equation is the world’s aging infrastructure, specifically our highways and city streets. Roads are critical for moving an ever-increasing number of people and goods. The fact is our roads and transport systems have been around for too many decades and, for the most part, need to be repaired or replaced. Just in Japan, for example, about 60 percent of road bridges and 40 percent of its roadways and tunnels will be at least 50 years old by 2033,[2] which is the age widely recognized as the end of infrastructure’s normal life span. On the other hand, the EU has one of the densest transport infrastructure networks in the world, and a large part of it is now aging and coming under increasing pressure due to a rise in traffic. One thing is certain: all around the globe, our existing roads and streets have reached a point where a substantial upgrade is needed.
We must also think about how the automotive industry’s future is trending. As automakers quickly shift their development efforts to EVs, the electrification of vehicles and commercial trucks is reshaping our perspective on transportation and its associated infrastructure. EVs are the key technology to decarbonize road transport, a sector that accounts for over 15 percent of global energy-related emissions.[3] According to the International Energy Agency (IEA), worldwide EV sales are estimated to reach 31 million vehicles by 2030.[4] This acceleration in EV adoption is also driving demand for increased EV charging infrastructure coverage. The electricity generated by solar roads could help fuel EV charging stations or even serve as a possible fast charging solution.
As a result, solar roads offer a promising route forward in rebuilding our aging infrastructure, answering the world’s growing EV charging infrastructure demands, reducing our dependence on fossil fuels, and mitigating climate change.
Streets Paved with Pluses and Minuses
What’s the potential? According to the Transportation and the Belt and Road Initiative, there are a total of 64,285,009km of roads in the world, with 411,853km being made up of expressways and the remaining 63,873,156km being normal roads (paved and not paved).[5] Globally, roughly 35 percent of the roads are paved, based on recent GRIP global road maps.[6] Therein lies a huge upside, with a large natural surface area for solar panels helping conserve valuable land use required by large solar farms.
Beyond conserving land and the previously mentioned capability for how solar roads to charge EVs with clean energy on the go, numerous other advantages exist. Some pros worth noting include the fact that solar roads don’t soften at high temperatures and are impervious to potholes, can power LED lights for lines and signage, remain snow and ice free, and have a greater lifespan than normal asphalt roads.
Of course, like any innovative technology solution, solar roads are not without their challenges. A few of the present roadblocks engineers are working to address include durability, cost-effectiveness, and energy conversion efficiency. But with advancements in materials and technology, these hurdles are gradually being overcome, paving the way for improved designs and performance.
Outside of solar panel manufacturers, technology partnerships, and road construction companies, there are some dedicated companies actively working to overcome these challenges and deliver a real-world solution. Solar Roadways, Inc. is one of the latest companies developing technologies using solar energy to convert into electric power. Some major companies like PAVenergy, Colas, WattWay, and several others have developed photovoltaic panels that can generate 410kW hours per day but realize even higher power generation gains are needed going forward. China has built an entire solar expressway, the Netherlands recently pioneered a solar bike path to test feasibility, and AIT and German partners announced in 2020 a solar road canopy project.
Currently, companies are working toward generating 800kW hours per day. However, there are several variables that must be factored in, such as panel thickness, optimum tilt angle, and shading, which, with just 5 percent surface coverage, can reduce power generation by 50 percent.[7] Other elements to be considered include dirt, dust, traffic, and heat. For every 1°C over the optimum temperature, a solar road loses 0.5 percent of its energy efficiency.
As you can see, we remain miles away—or should I say kilometers away—from reaching desired results.
Inspiration for Engineers
For engineers, the development of solar roads represents an inspiring frontier and an open opportunity going forward. It’s a clear road sign that engineers have the power to reshape the world in which we live, making it more sustainable and energy efficient.
In short, the concept of solar roads is more than just a road; it’s a defined path to a future where our infrastructure is a source of clean energy, where sustainability and efficiency can coexist. But more than that, it’s a waypoint or an end destination where engineers can inspire the world with their groundbreaking creations, just like the Romans did centuries before us.
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