Der Spiegel has an article on an idea that has been kicking around for a while now - the "solar road" - Electric Avenue: Solar Road Panels Offer Asphalt Alternative.

A lot of thought is put into how much energy we use to drive from point A to B. But what if the road itself could generate energy? Julie and Scott Brusaw, a married couple from Sandpoint, Idaho, have taken on just such a concept, which they hope will make the auto transport of the future cleaner and safer.

The idea is as simple as it is ingenious. Wherever roads are laid, solar panels could go instead. They would generate electricity, which would in turn be fed into the grid. Thus, oil is conserved twice: Electric cars could be charged with the energy produced by the panels, and the panels would replace the use of asphalt, the production of which requires petroleum. Moreover, Solar Roadways, as the Brusaws have dubbed their invention, are heated and equipped with integrated LED screens, which act not only as street markings, but can also show warnings directly on the road.

The Brusaws are aware that their vision cannot be realized in a day. They've decided to start small: with pedestrian and bicycle paths or large parking lots at supermarkets. As they see it, every square meter of asphalt that gets replaced with Solar Roadway is a small step on the path toward independence from fossil fuels. The giant leap would be to take on urban roads and highways on a global scale.

Renewable Energy World has a post on a German solar highway project that is almost finished - 2.8-MW A3 Highway Solar System Nears Completion.

Evergreen Solar Inc. announced that the first phase of construction of an installation placing more than 16,000 solar panels on the roof of the tunnel of Germany's A3 highway using Evergreen Solar panels is nearing completion. When finished, the 2.8-megawatt solar installation will be one of Germany's largest and first to be located on a public highway.

The installation, located near Aschaffenburg, Germany, occupies 2.7 kilometers of the A3 tunnel roof. German-based solar installer Ralos is overseeing the construction and Goldbach-Hoesbach, which purchased the land from the German government, will oversee the projects interconnectivity to the power grid. The €11 million investment in the project is expected to be paid back through cost savings over 16 years.

Inhabitat has a post on an unusual project in Victoria to mount solar panels along the freeways as a combined power generation and noise barrier option. I'm not sure this is a good use of solar panels compared to mounting them at the optimal angle on rooftops, but the more PV installed out there the better - Could solar freeways power our cities ?.

In the search for a solar solution to power our cities, one of our biggest obstacles is the massive acreage required by conventional arrays. Photovoltaic panels are flat and expansive, and urban centers are at a serious loss for free space. Now Australian renewable energy retailer Going Solar has conceived of a clever strategy that infuses urban transit systems with energy producing potential - install solar panels in highways as sound barriers!

Going Solar’s first highway installation was completed on the Tullamarine Calder Interchange in Australia. The solar sound barrier comprises 500 meters of photovoltaic panels that are attached to a public display showing the project’s power output. As the highway is located near some residential areas, energy doesn’t have to travel far to reach its destination, and the massive solar panels provide much needed soundproofing to the houses nearby.

It is expected that the installation will produce 18.7 megawatts per year, which is enough to cover its cost in about 15 years. The innovative application has netted Going Solar the ATRAA’s award for best grid-connected system.

EcoGeek has a post on using the heat collection capacity of roads as a way of capturing solar energy- Hot Asphalt as Better Energy Collector than Solar Panels?.

Researchers in Massachusetts are working on a technique to turn heat gathered by asphalt into useable energy via water pipes. Their paper, released this week at the International Symposium on Asphalt Pavements and Environment in Zurich, posits that asphalt roads could be better than solar panels in gathering energy.

They say that all the parking lots and roads that sit there baking in the sun all day are basically already solar energy collectors, and that the sheer amount of useable asphalt offsets the lower efficiency factor. We just need a way to transfer that heat into energy on a large scale. The researchers point out how asphalt stays hot even after the sun goes down, which anyone in the Southwest can attest to, and so could continue to generate energy when solar panels can’t. A system of heat exchangers could become part of road construction projects and improvements, and the system could help out the issue of heat islands.

While my mind instantly goes to a slew of issues that could exist for places with cold winters, the Netherlands, an unarguably arguably cold place in winter, has already done something like this on a very small scale and it has been a success. The idea sounds viable, but I have a hard time thinking that it would surpass solar panels as energy collectors; however, I’d love to see it tried out in a place like Phoenix, where the heat gathered could be used to run homes’ AC units. How’s that for a loop?

REA has an article on Idaho company Solar Roadways and their endeavours to make road building materials that generate solar power. I'm pretty dubious about the practicality of this idea - putting solar panels on rooftops seems a lot cheaper and easier than embedding them within roads - but hey, its an interesting idea anyway.

The concept of using road surfaces to generate clean solar power is moving beyond the idea stage. Roads absorb heat from the sun every day and are usually free of sightline obstructions that could otherwise block the transmission of light rays. And if the roads built for cars and driving are partly to blame for global warming, why not make them part of the solution too?

Idaho-based Solar Roadways is one of the trailblazers. Electrical engineer Scott Brusaw was inspired to start the company when he heard Caltech solar energy expert Nate Lewis suggest that covering just 1.7 percent of continental U.S. land surface with photovoltaic (PV) solar collectors could produce enough power to meet the nation's total energy demand.

Brusaw put two and two together when he realized that the interstate highway system already covers about that much of the nation's land surface, so he got to work designing a system that combines a durable and translucent glass road surface with PV solar collectors that could be wired directly into the electricity grid.

The heart of the solar roadway concept is the solar road panel. Each individual panel consists of three basic layers, the road surface layer, which is translucent and high-strength yet rough enough to provide traction. The surface layer is capable of handling today's heaviest loads under the worst of conditions and protect the electronics layer beneath it.

Next is the electronics layer, which contains a large array of cells, the bulk of which contain solar collecting cells with LEDs for "painting" the road surface. These cells also contain the "Super" or "Ultra" caps that store the sun's energy for later use. Batteries are not used in the solar roadway. Since each solar road panel manages its own electricity generation, storage, and distribution, they can heat themselves in northern climates to eliminate snow and ice accumulation.

The third layer is the base plate layer, which distributes power (collected from the electronics layer) and data signals (phone, TV, internet, etc.) "downline" to all homes and businesses connected to the solar roadway. The power and data signals are passed through each of the four sides of the base plate layer.

Overseas, Europeans are also pioneering ways to use the sun's rays to work as they beat down on roadways. The British firm Astucia has developed a road stud that contains small solar panels and emits LED light to illuminate dark roadways. On the 120 U.K. roads where the new studs have been installed, night-time accidents are down 70 percent.

And the Dutch firm Ooms Avenhorn Holding BV has developed a way to siphon solar heat from asphalt road surfaces and use it to de-ice roads and help power nearby buildings. A latticework of pipes under the road surface allows water to heat up during warm weather. The water is then pumped deep under ground where it maintains its higher temperatures and can be retrieved months later to keep road surfaces ice-free during winter months. Apartment buildings, industrial parks and an air force base have benefited from the innovation, and the firm is working on exporting its system to other countries in the coming years.