After a few teething troubles, engineer in the Netherlands say the solar bike path they built is working even better than expected.
The 70m long path converts sunlight into electricity in the town of Krommenie, 25 kilometres from Amsterdam.
Called SolaRoad, the pilot installation is 70 metres in length – by 2016, it will have been extended to 100 metres – and comprises modules measuring 2.5 metres by 3.5 metres.
Those in one direction of travel have solar panels beneath a 1 centimetre thick layer of tempered glass, said to be able to withstand the weight of a lorry.
The modules in the other direction don’t have the solar panels, and are being used to test a variety of surfaces.
Now, six months into the trial, engineers say the test bike path is generating 3,000 kWh, or enough electricity to power a small household for a year.
"If we translate this to an annual yield, we expect more than the 70kwh per square metre per year," Sten de Wit, spokesman for SolaRoad, the group behind the project, told Al Jazeera.
The solar panels used on the Dutch bike path are sandwiched between glass, silicon rubber and concrete, and are strong enough to support 12-tonne fire trucks without any damage.
The electricity produced can be fed into the national grid, or directly to street lighting.
"If one panel is broken or in shadow or dirt, it will only switch off that PV panel," said Jan-Hendrik Kremer, Renewable Energy Systems consultant at technology company Imtech.
One panel did break down a few months ago, but on the whole the road stood up to more than 150,000 cyclists, and the team at SolaRoad is now working to improve a laminated coating on the panels.
"We made a set of coatings, which are robust enough to deal with the traffic loads but also give traction to the vehicles passing by," Stan Klerks, a scientist at Dutch research group TNO said.
SolaRoad is now working with local councils around the Netherlands to try to roll the technology out in other provinces. A similar agreement has also been signed with California in the US.
We recently reported how the Dutch could be on track to get their own super-fast e-bike freeway, allowing commuters to travel the 30km between Groningen, Haren, Assen and Tynaarlo faster than ever before under (mostly) their own steam.
E-bikes are increasingly popular in Holland, and with speeds up to 45 kmph city authorities are looking at ways to exploit their use for intercity transport.
Henk Brink, a deputy from Drenthe, told Die Krant van Midden-Drenthe, “New rapid cycle infrastructure could be a nice addition to all measures that we have already taken in the field of cycling and accessibility in the Groningen-Assen region.”
The new paths could include features like sensors, alternative power generation, self-healing pavement and asphalt that glows in the dark.
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"..You talk about energy cost and I assume you mean financial cost...."
Not sure why you would assume that earth. To clarify, when I mentioned energy cost, I meant energy cost, likewise when I mentioned financial cost this is what I meant.
So I was saying that PV cells are energy neutral in two to three years.
They they are usually cost neutral in four to five years.
I was also saying that both these costs are continuing to plummet as improved manufacturing methods and yet better ways of making them are developed.
What I didn't say was that the reports I was reading are based on PV cells being used on the latitude(?) of Paris, London approx.
Such a shame that, that series of posts^^ reads like a series of scoffing Daily fail readers. Nothing positive at all.
I guess you are the people who twenty five years ago were scoffing at the whole idea of renewable energy (while choking in your own s**t).
Conventional PV cells are now cheaper than coal, gas and loads and loads cheaper than the whole life cost of nuclear. With none of the associated long term hazards. - before someone says it - they are energy neutral in two to three years, typically cost neutral in five and guaranteed for twenty five years. With the help of factories like the one Tesla US. are about to bring on line all these costs are continuing to be slashed.
It is a TRIAL to extend the use of solar power. The fact that California and other areas of the Netherlands are showing such an interest surely shows how seriously the development of this paving is being taken.
If you compare this to the cost of other types of road building it may not be so stupid, especially as the cost is bound to be tremendously lower as it is developed. I don't know of any other road surface that even has a chance of paying for itself in that way.
So people who know more than you regard the TRIAL with deep interest.
With Tesla type EV's and batteries - oil is about to become a dinosaur of the past and you haven't even noticed...
I think the problem here is that they have put the PV cells under the road rather than above. It is remarkably stupid to put a solar cell, that requires light to produce energy, on the ground where it will be obscured by passing opaque objects. Ever noticed plants and trees have their leaves above ground?
You talk about energy cost and I assume you mean financial cost. I've read factory gate prices for PV cells have come down so much that the financial cost is less than one dollar per watt of electricity generate. This is apparently on par with average grid prices. But the financial cost is not the issue. It is the _energy cost_ to produce the cells. They have to make equal to or greater energy during their life time than is required to make them. In Paris for instance they receive and average of 3.34 hours of sunlight per day so it will take many years to generate the energy required to make the cell even when the cell is not in the shadow of a bike and rider.
With this road you have the additional energy cost of producing the 1 cm thick tempered glass. Glass production is very energy intensive.
We need to start quoting the energy cost in Watts to produce energy rather than just the financial cost.
But which ever way you look at it the energy required to make this would be far better spent putting the panels above opaque objects rather than below.
I think Giles has a good point with:
The questions is which will be cheaper in the long run:
A) Solar path.
B) Path + supporting structure + solar panels.
Perhaps combining everything into a neat package will make it cheaper in the long run (or very close to a normal path price), after a few million solar paving slabs have been made. And people might not want every path to have a roof for aesthetic reasons. Maintenance could also be easier for just a solar-path vs maintaining path (awkward when hemmed in by supporting solar structure) + structure + panels.
/devil's advocate
It seems unlikely that this would work out cost effective, but then solar panels were insanely expensive 20 years ago and they are very cheap now (installation costs more than the panels now). Sometimes it's best to throw money at projects even though they fail, valuable lessons could still be learned. Money is 100% recyclable!.
70 meters of bicycle path at a huge extra cost (upfront and maintenance) and yet it can't even power an average household. Just a 'small' one, whatever that means (a single granny who has no computer, goes to bed when the sun goes down and doesn't watch TV?).
whoopee. that's around £150 worth of electricity for £2m outlay. doesn't look so clever to me
Like multifrag said, there are far better more economical ways to use renewables.
EEV blog has already proved that this is a dumb idea. In Korea they make panels as roofs on cycling lanes. It's easier to install them, costs less to maintain and produces twice or more power...
https://www.youtube.com/watch?v=6-ZSXB3KDF0
"Solar Freakin Roadways"
https://www.youtube.com/watch?v=qlTA3rnpgzU