• EEVblog #681 – More Solar Roadways BULLSHIT!

    Dave yet again debunks Solar (Freaking) Roadways. This time the prototype SolaRoad solar cycleway path installed in Amsterdam in Netherlands.
    Dave shows how to go about doing ballpark engineering feasibility calculations for such a project, calculates the expected payback period, and SPOILER, shows why Solar Roadways will never be a viable technology. This time using real measured data from the Netherlands cycleway prototype, and real measured solar insolation data for the Netherlands

    1st Video HERE
    Live output data from Dave’s 3kW solar system

    SolaRoad Project Website
    SolaRoad Newsletter
    Solaroads press release
    Road Construction Costs
    Road network
    Average Household Energy Consumption
    Price Per Watt for solar panels:
    PV System installation costs
    Solar Irradiance / Insolation data
    Electricity prices for households
    Sunpower P18 solar panel Datasheet

    Forum HERE

    This is what happened after less than 2 months:
    (Credit to @fishmech on Twitter)

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      • Hi Dave… I spoke to my father about Solar Roadways a few days ago and his response was that there were major engineering challenges in terms of the toughness of the glass, where it would be impractical to get panels strong enough for road use given the loading of truck tires, whilst being efficient solar panels and not slipping.

        And he should know… He did his third masters and his PhD looking at the rutting of Rooty Hill Road here in Sydney whilst working for the DMR. Given the numbers of sensors he put into the road, he has a fairly good idea of what forces are experienced from vehicles


        • Jarek Pelczar

          There are some basic LEDs near my home built into the pavement put by local mall. It’s probably aluminum frame with some tinted plexiglass on top of that. Half of the LEDs stopped working after some time. Some parts are failing. This is just result of wear coming from people walking and bicycles riding on top that. I wonder how quickly would solar panels start to fail … The plexiglass is rather thick and the mounts are probably 5-10cm wide.

          • TheSlider2

            Just throw a piezo under that to measure vibrations and forces then apply to a solar panel’ed setup.

            Thinking about it, you might generate more energy from the piezo than any solar panel. Hey Dave, you might want to compare energy gathered from walking to energy gathered from a cell on your hat.

            • rotopenguin

              That’d be hilarious. On the plus side, piezo wouldn’t need a moronic road surface like glass (who wants to drive on that in rain with a scosh of oil thrown in?). The electricity harvested may be a bit poor, but the possibilities for catching overweight trucks would more than make up revenue.

              Darkwing Duck had a little alternate world bit where they drove concrete wheels on an inflated rubber roadbed. When the road gets a flat, all traffic comes to a halt. If you want to change a road bed, it’s gotta come close to the qualities of bitumen/concrete, and be plausibly affordable. How is glass going to deal with thermal expansion, heaving, water, snowplows, buried utility access? How do you patch one? As broken and potholed roads are, they are amazing for the abuse they take and glass wouldn’t last a week doing their job.

              How well would glass roads hold up to teenagers just swinging around sledgehammers for the hell of it?

      • Ivan Berton

        He Dave, if you know that solar roadways are BS, in aspects of efficiency, cost nonsense and all that obvious things which shows a fail of this projects, why you continuing making videos about it? I think convince people to not believe in it it`s like convince people to not believe in religion. If people want to believe, they believe as long as they can.

        • Syd Jessop

          He has made another video about a similar concept because he wanted to reply in bulk to the thousands of people who had contacted him with their views. One of Dave’s fundamental principles is that things like this are NOT about belief. Engineering can be used to show they are not practical. Engineering cannot be used to prove there is no god, though I am sure Dave might think of an entertaining video about that. Engineering is a lot about planning and reasonable predictions.

          • Ivan Berton

            Yes Syd, it`s more or less obvious that Dave has to complete his mission and give some detailed fundamental information about projects like this. Change a point of view in certain aspects is sometime useful to help change minds. But I think in this case we fight against something invincible, I wonder if some of this projects will be abolished because of some solar roadway BS video. But provide info with some fundamental basics is almost not bad. There are a lot of other examples of BS projects worldwide forced by government which failed after finished. Positive if they learned of the fail and maybe can reuse the materials and infrastructures, bad if they leave infrastructures rotting away without any further uses.

      • Tommas

        Hi Dave,

        In the Netherlands the price for produced electricity is around 0.07 EUR. The price for consumed electricity is around 0.21 EUR, which is the result of various taxes.

        However, in the Netherlands there is a system called “salderen”, which means that as long as the produced electricity < consumed electricity, the price for the produced electricity will be the same as the price for consumed electricity (Because you only have to pay for the netto consumed electricity) I don't think this applies to the solar road, as it does not consume any energy. Perhaps they managed to do some legal trick to circumvent this problem, but for normal solar parks this is not possible .

        Also, the price for an installed roof solar system is usually < 1.5 EUR / Wp (my system was around 1.2 EUR / Wp)

        Finally, the average dutch house consists of 2.2 people and consumes around 3500 kWh/year and 1600m3 gas/year. (http://www.milieucentraal.nl/themas/energie-besparen/gemiddeld-energieverbruik-in-huis)

      • Erwin Beks


        I liked the video and your probably right on that a solar road are less
        efficient than rooftop installations. That said they are not claiming that a
        solar road is as efficient as rooftop installations. What they do claim is that
        in my country only 25% of the Dutch electricity demand can be generated by
        rooftop installation. Combine that with the fact that we are a fairly densely
        populated country there aren’t many alternatives to put solar installations. So
        I think they are merely try to find alternatives to increase the % of power
        generated by solar panels and to experiment with the ideas to find out of these
        are economical feasible.

      • Nic Perrin

        Couple of extra points..
        Roads are meant to be used.. and they’re used more during the daytime when the sun is out. So while these things are meant to be generating power, there are shadows on them.
        In order for a shaded cell not to bring down the whole array you need an inverter on each panel.. the maintenance is going to be phenomenal.
        Also, living in the UK, we have this thing called rain.. (Yes, Dave probably doesn’t know what this is living down under), in order to disperse this rain and stop vehicles just aquaplaning about the roads are cambered to help drain water.. They’re not flat like say a solar panel… and they’re porous, unlike say a solar panel..

      • I like the message on the calculator @ 8:25.

      • Agree its totally fruit loop.

        Why not have a cycleway ‘solar roof’? Then you could at least set it up to be more efficient and also get the benefit of being able to use the cycleway without getting wet in the rain… Also avoid having to dig up the cycleway in the first place… Mind you it doesn’t look as green…

      • Edwin van den Oetelaar

        Hi Dave, like your show,

        I have to agree here. Return on investment for solar is very hard. Your calculations are in the ballpark.
        The situation is even a bit worse, the prices are below 6 eurocent.
        Prices can be found here : http://www.apxgroup.com/

        For Dutch people wanting to know more about Solar panels :

        My friend Joop wrote a nice paper on the subject.


        However there is another way of looking at this, since there is an economic crisis, the task of the government is to keep money flowing, which is what happens here.

        Best regards,
        Edwin van den Oetelaar

      • Pingback: Solar-collecting pathway | PA2OLD()

      • They’d be better off sticking solar panels on posts alongside the bike path than putting them under the bike path, that way they can be angled correctly.

      • Syd Jessop

        Dave, when saying you are very pro solar power it might help if you say that you want to speak up about impractical concepts like this precisely because you are so pro renewables and you do not want them ALL getting a bad name when poorly engineered projects like this fail. You almost said it but not quite.

      • Bernd Felsche

        Don’t the Dutch have deciduous trees near the cycleways? The leafblowers used to maintain PV generation may consume more energy in autumn than the cycleways collect via solar all year.

        Your statement at around 19 minutes into the video is incorrect.
        You said “Germany are producing over 50% of their ah … energy requirements … erm electricity requirements from solar power”

        That’s not true on “any day” of the year like today as can be seen from the actual production figures. http://www.transparency.eex.com/en/Statutory%20Publication%20Requirements%20of%20the%20Transmission%20System%20Operators

        While the nameplate peak electrical power capacity of PV solar in Germany is around 50% of that of conventional generators, so is wind. So together, by implication, Germany doesn’t need any conventional power stations. The peak is however very rare and unpredictable. When high production levels of wind and PV coincide, the grid requires frequent intervention to maintain stability. The renewables must be accepted onto the grid as priority so electrical power produced at conventional stations is dumped/exported and others are even paid to take it away to avoid paying the €0.19/kWh (notionally “generated”) for not accepting electricical power from renewables. The export peaks (area above consumption line) coincide with generation from volatile sources as illustrated more clearly by the following.

        Over longer periods, Agora provides cummulative generation data and draw pretty charts like this one. Solar doesn’t feature strongly. You can click on a button and see a whole year’s worth of typical PV supply.

        Over the year; conventional does all the heavy lifting. PV solar peaks for short periods, but has never achieved “installed capacity” (GWp)

        German Federal Bureau of Statistics said
        “Gross electricity production in 2013: 24% came from renewable energy sources

        Approximately 634 billion kilowatt hours of electricity were produced
        in Germany in 2013, 24% of which came from renewable energy sources.
        While regenerative energy sources accounted for almost one quarter of
        total electricity production in 2013, their share amounted to only 7% in

        At the time, the most important renewable energy source had been
        water power (4%). In 2013, green electricity was generated mainly from
        wind power (8%), biomass (7%) and photovoltaics (5%).


      • trustytrev

        Hello Dave,
        Do you dye your hair?

      • Jean (Slots) Liston

        Dave, have you considered that you’re missing the point? The point is to sell solar panels and lots of them. I would say that most solar forums/blogs are run/financed by vested interests that want to keep solar installers in business and to sell solar systems. You bought one so it worked on you. When you want to discuss smart use of solar power it dents their pockets so you get banned.

        On outputs from flat panels versus tilted ones I have have a 160W panel mounted on a shed roof (37 degrees) facing south and a 320W panel on a flat garage roof tilted 5 degrees west. The flat panel looses 50% of its output so your 30% is very generous.

        The biggest problem for design of smart solar systems is the lack of sunshine. Nearly all the solar panel simulators I’ve seen cost thousands (and you haven’t reviewed one yet?) and a simulated solar panel power supply is a must have. So why aren’t there any cheap ones around? Now here’s a real challenge for the engineering community.

        Sunpower E20 panels are about the best around but see if you can buy a high power single panel. It won’t happen because they sell systems not panels even though they make them.

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