April 22, 2011 By Chad Vander Veen
Imagine driving on a road paved not with asphalt but with glass. And within this glass are photovoltaic cells that transform sunlight into electricity and send it directly to the homes lining the street. That’s the aim of an Idaho-based company called Solar Roadways. And before you dismiss the notion as impossible, you might be astonished to know that the company has federal funding and is currently leading the GE Ecomagination Powering Your Home Challenge, a program that promotes energy innovation.
“There’s 25,000 square miles of road surfaces, parking lots and driveways in the lower 48 states. If we covered that with solar panels with just 15 percent efficiency, we’d produce three times more electricity than this country uses on an annual basis, and it’s almost enough to power the entire world,” said Scott Brusaw, co-founder of Solar Roadways, in a segment of Your Environmental Road Trip, a new film that explores cutting-edge energy solutions.
Though many think driving on glass wouldn’t work, materials scientists beg to differ. Window glass is only one of countless forms glass can take. If specially manufactured, its strength can be that of steel and ideal for driving on.
“In dry conditions … there would be few surfaces better for a roadway than glass,” wrote the Pacific Northwest National Laboratory’s Joseph Ryan, a specialist in materials science, in a paper titled Energy Solutions from Glass Road Surfaces. This changes when water is introduced; however, that problem could be mitigated. “Molten glass can easily be molded into shapes specifically designed to maximize the run-off of water and maximize tire-roadway contact in wet conditions,” he said.
Solar Roadways has built a 12-foot-by-12-foot prototype. Not only does the panel generate energy, it also lights up, creating a safer nighttime driving experience.
It’s innovative solutions like Solar Roadways that many hope will serve as the foundation of our energy future. There won’t be a handful of energy sources — coal, oil, nuclear — like we have today. Rather, an entire ecosystem of energy technologies will work together to power our world.
As admirable as it is, it’s likely that Brusaw’s vision of the entire road grid covered in his panels won’t come to fruition. But even if some roads aren’t transformed by Solar Roadways, there are plenty of other ways to harvest energy from them.
Enter piezoelectricity. Piezoelectricity is the charge that’s generated by applying mechanical strain to materials. There are many devices we use every day that create piezoelectricity. Cigarette lighters and gas grills, for example, employ a small hammer that strikes a piezoelectric crystal — usually quartz — that creates sufficient current to spark a gas flame. Many other materials, such as cane sugar, topaz, bone, wood and certain ceramics exhibit piezoelectric properties. This fundamental electromechanical principle is being used by some companies that hope to transform our everyday movements into energy.
“There are several types of technologies in energy harvesting which converts kinetic movement into electricity,” said Farouk Balouchi, a technology analyst at IDTechEx, a research and analysis firm specializing in energy harvesting. “Kinetic energy can be transformed from movement into usable electricity for signage, low-power lighting, sensor systems and that type of thing.”
To do this, some companies are building piezoelectric energy devices that can be deployed in homes and offices. Germany-based EnOcean creates energy harvesters that generate a small amount of electricity when they sense motion, pressure, light, temperature change, rotation or vibration. For example, if these devices were installed in floors and on steps, every time people moved, electricity would be created and used to help power the facility. The electricity generated would supplant the energy that would normally come from the grid, allowing a home or office to power itself while helping to create a more efficient energy environment.
“[These] devices are being scaled down and made very small, and they allow a small movement or vibration to be used to power the electronics, which have become very small and only require micro watts of power,” Balouchi said. “It would be part of the kind of ecosystem of our living planet. The ‘Internet of Things’ comes to mind, where you have sensor in every part of your living environment in the buildings and in the floors in every part of your life.
“You can envision these systems powering themselves and being put into a building’s structure, so a truck driving by or a vibration on the actual wall of the building causes these devices to charge themselves,” Balouchi added.
Innowattech, based in Ra’anana, Israel, develops piezoelectric devices that are installed in roads and railways. The devices transform the kinetic energy of vehicles and trains into electricity, which is used to power lights, traffic signals, railroad crossings and red-light cameras along the road. Any excess electricity that’s generated is delivered into the grid for other uses.
In 2009, the Israeli government sponsored an experiment in which Innowattech installed its devices in a 10-yard stretch of highway. Each hour the small section of roadway generated 2,000 watt-hours of electricity. Innowattech calculated that if the devices were installed in a single lane one kilometer long, 200 kilowatt-hours of electricity could be produced — enough to power 200 to 300 homes.
“The energy is quite significant,” Balouchi said. “You’re talking about kilowatts of power and that could actually be put back into the grid system and used productively.”
Not all the energy solutions of tomorrow exist on the open road. Many promising technologies simply make existing energy generation better. At the 2011 Consumer Electronics Show in Las Vegas, Panasonic showed off its household fuel cell cogeneration system. The home fuel cell creates a chemical reaction using oxygen in the air and hydrogen, which in this case is extracted from a home gas connection. The reaction creates electricity and heat. The electricity helps power the home, while the heat is used to heat water and the home itself.
The household fuel cell has been available in Japan since 2009. There, the system has shown it can generate up to one-third of the energy used by an average Japanese household of four.
“You are literally generating on the site of your own home, your own electricity just as if it was a windmill generator or anything else,” said Peter Fannon, who manages Panasonic’s Corporate Environmental, Government & Public Affairs and Product Safety & Regulatory Compliance groups. “The goal is to reach a zero carbon dioxide emissions household, which we hope is doable within the next eight to 10 years.”
The systems aren’t cheap — Fannon said they retail at around $30,000. But like current home solar installations, he expects a combination of incentives and government programs to cut the price in half for homeowners.
As technology matures, the home fuel cell and other technologies like piezoelectric generation will help to address a fundamental problem with the electrical grid. Long-distance electricity transmission leads to line loss — the steady loss of electricity over distance. As more technologies develop that allow home and business owners to generate electricity on site, the line-loss problem starts to go away, making for a much more efficient energy environment.
“It’s 20 to 26 percent line loss in long distance, which is really painful,” Fannon said. “It’s because the lines are old and it’s [because of] the distance.”
Whether it’s a home fuel cell, a solar-powered road or a floor panel that creates electricity when you step on it, the future of energy is shaping up to be a diverse ecosystem of solutions that many hope will one day lead to true energy independence.
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