SolaRoad

Would it not be nice if our roads acted as solar panels? And vehicles could drive on the electricity produced by these roads? A key step towards this future has been taken by the development of the SolaRoad: a road surface that generates electricity.

Client:
TNO, Province of Noord-Holland, Imtech and Ooms Civiel Consortium
Location:
Krommenie
Status:
Self initiated
Country:
Netherlands
Element SolaRoad_Pro
Fietsen op Solaroad_Pro
Plaatsen elementen SolaRoad_Pro

Concept

Sunlight that strikes the road surface is absorbed by the solar cells and converted into electricity. The electricity can be used to power roadway lighting, traffic installations, households and – further into the future – to charge electric vehicles driving on the road.

Double Function

The SolaRoad means that roads will serve a double function: in addition to a mobility function they will also have a (sustainable) energy function. This prevents green areas from being used for the installation of solar panels. Sustainable energy consequently does not have to compete with food production or nature. The road surface that can be used for generating solar energy in the Netherlands is 450 km2. The potential that can be used for this purpose in the rest of North Europe is of course much greater.

Tripartite Collaboration

A special aspect of the SolaRoad is its development by the ‘golden triangle’. Knowledge institutes, government and the market join forces to create innovation. A Dutch feat of co-creation. The Netherlands Organization for Applied Scientific Research (TNO), the Province of Noord-Holland, Imtech and Ooms Civiel (part of Strukton Civiel) jointly make up the consortium that is developing SolaRoad.

Technology

SolaRoad consists of 2.5 x 3.5 metre concrete modules with a hardened glass translucent top layer that is approximately 1 cm thick. The surface has been roughened using a (transparent) coating system derived from the metalling applied in various areas such as bridges.

Protective Layers

The solar cells are located below the top layer. In the current version ‘ordinary’ silicon solar cells are used that are also used in the solar panels installed on roofs. The solar cells are located between the protective layers in modules specifically developed for this application. This protects the vulnerable silicon against mechanical loads, road salt and the Dutch weather.

Electronics

SolaRoad contains special electronics designed to extract optimal yield from the solar cells. In addition, a solution has been conceived designed to limit the influence of shadow (trees, road furniture, the road user) on yield. Smart ICT applications efficiently share energy production on days with many sunshine hours with times of scarce sunshine. Electronics provide the link with the power grid.

“Lots of sunshine, little sunshine? Smart ICT applications distribute the energy yield.”

Each solar panel in a SolaRoad element generates 37V, which is converted by a mini convertor into 400VDC. Due to that high voltage it can be converted in the main convertor into a grid voltage of 230V with minimal losses.

Connection

The separate elements are joined together to form a single road. The connection has been developed such that in the event of maintenance or repair the elements can be easily lifted from the road and if necessary, replaced. The transition between elements is seamless for optimal driving comfort.


 

Pilot

The first SolaRoad pilot has been installed in the autumn of 2014 along the N203 provincial motorway near Krommenie. A bicycle path has been selected for this purpose. The reason a bicycle path was chosen is the relative ease of making interim adjustments and improvements. The pilot with the electricity producing bicycle path is designed to show over a period of two years how the road will behave, how much power is actually generated and how users respond to it.

Continuous Improvement

Alternative options will be investigated during the project for the solar cells as well as the glass. If during the project new solar cell technology-related developments emerge, they will be fitted in. In 2014 Ooms Civiel has installed the first 27 elements. This will be followed by another 6 elements in total in 2015 and 2016 designated for promising, new solar cell-related options. The possible applications for the generated power will also be further developed during the pilot.

Pilot Configuration:

  • Concrete prefab housing
  •  ‘Regular’ crystalline silicon solar cells in hardened glass (16 mm thick)
  • Panels embedded in rubber
  • Rough surface created using transparent epoxy resin with glass beads
  • Able to withstand ‘normal’ loads (ranging from cyclists to maintenance vehicles)
  • Electronics for yield optimisation and connection to the power grid
  • Electricity can be widely applied: from roadway lighting to household use
  • No glare or other visual annoyance
  • Dirt-resistant (to allow as much sun as possible to pass through)
  • Can be adapted to new generations of solar cells (for example, thin film)
  • Driving comfort due to coupling of elements
  • Insusceptible to substrate shrinkage, expansion and settlement
  • Approx. 70 m of SolaRoad bicycle path supplies electricity for 3 households per year (10,000 kWh)

 

About SolaRoad

91641192

The road of the future

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