9 ms·

Output of Dutch solar bike lane exceeds expectations

80 points by Rafert 11y ago

gus_massa 11y ago
> The cycle path was opened in November as a pilot project for three years and was followed with great interest, also by foreign media. I'm not following this new very closely. "Open" means that they allow cyclist, pedestrian (and dogs) to use a small 70m pilot segment, or that they have a 70m segment in the middle of nowhere?
- panarky 11y ago
  Here's a photo. It's a bike path between two towns, and about 2000 cyclists per day ride on it. http://www.theguardian.com/environment/2014/nov/05/worlds-first-solar-cycle-lane-opening-in-the-netherlands http://www.theguardian.com/environment/2014/nov/05/worlds-fi...
  - ChrisGranger 11y ago
    It cost three million euros but can only power three houses? A million euros to use solar to power a house? Am I missing something?
    - learnstats2 11y ago
      Since this is the first prototype, I'm guessing the R&D cost that much. You're installing cycle track plus power generation infrastructure in one hit. Neither of those things is cheap on its own, e.g.: "Cycle track costs at anywhere between £100,000 and £900,000 [per km]" from https://transportretort.wordpress.com/2011/02/09/how-much-would-cycle-paths-cost/ https://transportretort.wordpress.com/2011/02/09/how-much-wo...
    - fche 11y ago
      Government economics, working as designed.
      - learnstats2 11y ago
        >Government economics, working as designed. You've been downvoted perhaps because it's not clear if you're being sarcastic, but I agree earnestly. The primary purpose of government is to organise things that benefit people: and they only need to do this when business can't or won't. Governments should act as a balance to the negative aspects of capitalism. As such, I genuinely believe that governments should be "uneconomic".
    - jkestner 11y ago
      Do you know how much the first Apple Watch to come off the line cost? Billions. R&D cost gets amortized through mass production; this is what it looks like at the beginning.
    - IkmoIkmo 11y ago
      Consider that the cost of a kilometre of ordinary road is a few million dollars, and that prototypes are orders of magnitude more expensive than a mass produced optimised supply chain with economies of scale.
- cyphax 11y ago
  It's not in the middle of nowhere, it was being used by cyclists. Apparently, over 150,000 cyclists rode over it since it was opened. Source (Dutch, but includes a photo): http://www.noord-holland.nl/web/Actueel/Nieuws/Artikel/Zonnefietspad-SolaRoad-levert-meer-energie-dan-verwacht.htm http://www.noord-holland.nl/web/Actueel/Nieuws/Artikel/Zonne...
- URSpider94 11y ago
  A nitpick, but being a Dutch bike lane, there will not be any pedestrians and dogs on it. Bike lanes are for bikes.
stephengillie 11y ago
Interesting points: 1. > That is more than the upper limit calculated on the basis of laboratory tests. Does this mean the panels generated more than they were tested to generate? 2. Part of the purpose of the project was to beta test the suitability of their glass surface treatment as a biking/walking surface. (I'm imagining it's textured like a truck bed liner, but transparent.) They did have an incident early on with a bicyclist slipping, related to a stick-on surface, so they switched to a spray-on surface. 3. Commenters slinging arrows at a Conservative strawman for the high price and comparatively low (factor of 500) energy output vs government building rooftops.
- Rafert 11y ago
  1. No, it means that the panels generated more than the predicted upper bound. As a commenter on the source article mentioned, this year's April was one of the most sunny in recorded Dutch weather history, which might have contributed to this fact.
jkot 11y ago
What were the expectations?
- Rafert 11y ago
  According to http://www.solaroad.nl/wp-content/uploads/2013/06/Artikel-SolaRoad-BU2013.pdf http://www.solaroad.nl/wp-content/uploads/2013/06/Artikel-So... it was 50 kWh per square meter.
  - fche 11y ago
    (over what unit time)?
    - icebraining 11y ago
      Per year.
invisible 11y ago
Sounds like the first comment hit the nail on the head: there being 25% more sunlight hours than expected.
jimrandomh 11y ago
Numbers from the article: 3000 kWh in six months = 684W average 70 kWh per m^2 per year = 8W per m^2 As a comparison point, https://en.wikipedia.org/wiki/Photovoltaic_system#Solar_array https://en.wikipedia.org/wiki/Photovoltaic_system#Solar_arra... gives a typical output for a square-meter panel as 0.75kWh per day, or 31W.
- jsnell 11y ago
  That's the wrong 6 months though, since it's including the whole winter and none of the summer. Looking at the graph, April accounted for as much power production as the other 5 months combined.
ukandy 11y ago
Why anyone would pursue such a suboptimal installations is beyond me. Researchers finding ways to waste grant money I guess..
- Someone 11y ago
  The company leading the project claims commercialization is five years away. They likely are optimistic or biased, but I am not sure they are outright lying. Prices of solar cells drop fast. Extrapolate a few years, and costs of solar installations will be dominated not by what solar cells cost, but by what it costs to install them. In this case, something must be installed anyways to build the cycle path. It might well be that installing a (cycle path, solar cells) combination will only be marginally more expensive than installing a traditional cycle path. Will we get there? If solar cells and the electronics needed to wire than together (which, in this case, are more complex because the road may see highly variable shading patterns) get dirt cheap, we might.
  - mason240 11y ago
    Do you really believe that it is more efficient to build a bike lane paved with solar panels, rather than a bike lane paved with asphalt and separate, dedicated solar facilitates? EDIT: Looking at the pictures others have posted you still have to use asphalt (or more likely concrete because you need better stability, which is even more expensive) underneath, so there really is nothing saved by doing this. What a waste of money.
    - drabiega 11y ago
      How is the presence of asphalt underneath an issue? The deciding factor will be whether the marginal cost of a solar path over an asphalt path will be greater or less than building an equivalent solar facility. That seems like it could go either way.
      - IkmoIkmo 11y ago
        Very good point. Plus even if the marginal cost is lower than a dedicated solar facility, we don't necessarily have that luxury. We do if we want just 5% sustainable energy, not a problem. But if we want 99% sustainable energy, surface area is a very tricky challenge [0] and so it'd be a matter of the one and the other, instead of the one or the other. [0] https://www.youtube.com/watch?v=GFosQtEqzSE https://www.youtube.com/watch?v=GFosQtEqzSE
Giorgi 11y ago
Why is it bike lane though? any practical considerations?
- acjohnson55 11y ago
  I would assume this is because far less weight needs to be borne by the roadway. But that's just my guess.
- Maarten88 11y ago
  In the video they explain they use a bike lane to learn before going to real roads. Bikes are much lighter than cars and trucks, and they want to learn what materials work best.
lotsofmangos 11y ago
Well, it makes slightly more sense than the solar roads for normal cars and trucks, if only because it doesn't have to be quite as tough, but I do suspect that it would be cheaper to install, easier to maintain and far more efficient in terms of power generation, to put a normal cycle path down and put a roof of solar above it.
- reirob 11y ago
  Yes, but it wouldn't be as pleasant to ride on the road. Riding a bike with a roof over your head? I don't know, but I appreciate seeing the sky and the horizon when riding a bike.
  - lotsofmangos 11y ago
    It wouldn't be a roof exactly. Because you can angle the panels and have much better transmission of light to the panel from not having to have a bike-proof coating, you wouldn't be completely covering the path and you would get the same amount of power from a strip that is thinner than the path, angled and fairly high up, this would cost far less money as it is available off the shelf, so you have more cash to spend on making more of it. Also, if you integrate it with lamp posts for your support pillars, you are not increasing the amount of street clutter either.
meric 11y ago
Roads are quite a good place to place solar panels, logistically speaking. Yes they are 30% less efficient, but they are also closer to where the electricity will be used, and the marginal opportunity cost of real estate is zero since road use is retained. You don't need new land and you don't need to worry about transporting power at great distances. I'm glad such experiments are being conducted to see how well this idea performs in practice. It's good they started with bike lane as opposed to truck roads. It will give them opportunity to iterate on the panels resiliency.
- guiomie 11y ago
  Not sure why you are being downvoted, but I thing your comment makes a lot of sense, and I'd like to know why some think otherwise.
  - _Adam 11y ago
    The economics of solar panels in roads are horrible, given current technology. Here's an excellent engineering analysis of this exact project: https://www.youtube.com/watch?v=HOZBrHqTJk4 https://www.youtube.com/watch?v=HOZBrHqTJk4
    - meric 11y ago
      I wrote a comment there. Panels on roads, if they can suffer being driven on well, can be economical when rooftop spaces run out. Rooftops are only sufficient for 25% of Netherland's electricity demand. I notice now there is a couple of inaccuracies but they are only minor ones financially. The benefit from saved real estate is too big. Local council governments may have access to its road real estate, but have no legal right to install panels on roofs. Netherland land value, per square meter, is €4,907. There is a local property tax is 0.05% - 0.3%. (http://www.shelteroffshore.com/index.php/property/more/property-tax-expats-in-netherlands-10540 http://www.shelteroffshore.com/index.php/property/more/prope...), and a wealth tax of 1.3% per year. Assuming 1.4% total taxes per square meter, the revenue received by the government is €68 per square meter. Since building the solar panel on the road means they don't have to build solar panels on real estate that can generate tax revenue, the benefit is €10 of generated electricity, plus the €68 of tax revenue that is preserved (assuming all municipal building rooftops are exhausted, already). That makes a payback of €78 per year. In 15 years, this would equate to €1170, compared to building a solar array on free land. The savings would be even greater compared to the local government renting rooftops to place solar panels.
dorfsmay 11y ago
I'd love to see some financial analysis: 1) cost of producing the same amount of electricity with Netherlands' most common electricity production 2) cost of building this vs. a normal bike path, and time for recovering the cost considering #1 3) expected life of this system + anual maintenance cost 4) cost of a typical roof installation for the same surface
- quchen 11y ago
  5) Cost of a normal bike path with ordinary solar cells of equal area next to it
  - holri 11y ago
    6.) CO2 and energy saving.
  - ghshephard 11y ago
    5.1 Cost of a normal bike path with ordinary solar cells on top of it (providing shade, and shelter from the rain, with presumably greater efficiency)
    - mod 11y ago
      This is actually what I envisioned before I looked up some pictures (if there were any in the article, they didn't load for me). It seems more practical, in particular for a bike path.
      - greglindahl 11y ago
        That's already well-studied, for parking lots with shade structures. I'm astonished how many people are weighing in to trash a small project researching something new that might be interesting!
        ghshephard 11y ago
        I'm definitely not trashing it - I'm enthusiastically interested in whether it's viable. What I'd love to know is what the expected cost structure, at scale might be, in comparison to other options.
rebootthesystem 11y ago
Sorry, this is beyond silly. Do they actually have any scientists with some command of mathematics working on this project? Other than to screw ignorant government morons out of lots of money I could not imagine any reputable scientist or engineer not falling to the floor laughing uncontrollably when presented with the idea of putting solar panel on a sidewalk/bike path. The whole thing is so utterly ridiculous that the only possible explanation is someone is making millions with this project.
- rebootthesystem 11y ago
  The dynamics of down-voting on HN can be interesting. I have this --possibly flawed-- mental image of emotional impulse voting devoid of any effort to analyze what is being said. For the benefit of those who didn't take the time to think before down-voting my prior comment I'll try to spell it out here. A few facts: - Good commercial cells deliver an efficiency in the 14% to 19% range. - This efficiency assumes the cells are aimed at the sun - Optimal winter angle for the Netherlands is approximately 76 degrees from horizontal - Peak efficiency also assumes the cells are clean and have nothing obstructing or altering light from reaching it's surface at the optimal angle - In all cases you can Google my claims and verify their veracity Option #1: - Cover the solar panels with glass - Scuff-up the surface so people and bikes don't slip and slide all over the place - As an alternative, apply a film to achieve the same effect - Mount them flat on the ground - Place trees around it - Have people, bikes and dogs walk on it Analysis: - The cost of encasing panels in concrete and glass modules and installing them is monumental - The optimal angle for Amsterdam is approximately 76 degrees. Panels mounted flat simply throw away a significant amount of available energy. - Solar cells laid flat will produce between 20% and 30% less when compared to optimally aimed cells. - Glass will create problems based on how light enters. You have reflection, diffraction and scattering as possibilities. A percentage of the energy will never reach the cells. - A non-slip surface will scatter and absorb a significant amount of energy. Based on the images I've seen of these road modules I am going to guestimate that at best 70% of the light entering the road reaches the cells. I base this on years of working with a wide range of optical diffusers. - Dirt and particles on the cells can have huge efficiency effects. From light scattering to simply blocking and absorption. I'll go ahead and guess that you can't keep a roadway clean 100% of the time, therefore, you probably pay a, say, 20% penalty on average for having dirt, leaves and dog shit on the road. This is entirely a seat-of-the-pants number. It could be 10% or 50%. It isn't going to be zero. - Power generation is now utilization dependent. With more people on the road more light is blocked and less power is generated. I won't put a number to this. I will rather make a statement: If nobody uses the road, what's the point of building one in the first place or building one that is so much more expensive than simply pouring plain concrete? - Depending on angle, trees, buildings and even tall vehicles on the road will cast shadows on the panels. A very rough calculation then says that, at best, our solar roadway will operate at 40% of peak efficiency. If we factor in the constant need for cleaning this number could very well go down significantly. For example, do we have a crew of a few people using gas powered leaf blowers cleaning the roadway a few times a day? Option #2: Build a light steel structure atop a conventional bike path. Angle the panels for optimal efficiency at that latitude. You might splurge and add active tracking. Analysis: - The cost of installation is significantly lower - By mounting the panels at the optimal collection angle we ensure converting power as near to the efficiency peak for the panel in question - Angled mounting also aids in reducing surface particulate contamination and makes cleaning potentially as simple as an automated water sprinkler system - The entire system is far less costly and efficient - The bike path gets "free" shade as a side effect So, yeah, the entire idea is absolutely ridiculous if anyone bothers to do a little math. Someone has got to be lining their pockets or whoever is leading this project is simply in denial. Go ahead and downvote, but, if you do, please show your calculations and how you arrived at the idea that this concept actually makes sense to deploy at scale. I'll bet you can't.
hoopd 11y ago
Really? On their website[0] they claim their glass surface doesn't require snow removal because the heating elements melt it and as such asphalt roads have a cost of snow removal that apparently comes for free with these. However, it takes more energy to melt snow than to push it to the side[1] which they simply ignore and that makes me question what other things they're leaving out in order to tell a good story. I'd really like to see the numbers crunched for how many snowy days a year will cause the system to consume as much energy as it produces. [0] - http://solarroadways.com/snow.shtml http://solarroadways.com/snow.shtml [1] - https://what-if.xkcd.com/130/ https://what-if.xkcd.com/130/
- woah 11y ago
  It takes moe energy to melt snow than push it to the side? This is northwestern Europe, where the snow never gets more than a few centimeters deep, and the temperatures never go more than a few degrees below freezing. I could definitely see heating a surface by a few degrees being cheaper than bringing a plow or other snow clearing machinery out to some path. Now, northern Canada would probably be a different story.
  - Bootvis 11y ago
    Can confirm, in the Netherlands on bike lanes black ice is a much bigger problem than snow. Heating should work fine against black ice while shoving isn't very effective.
  - onnoonno 11y ago
    The enthalpy of fusion for water is 335 J/g. The specific heat capacity of ice at -10C is 2.1 J/(gK). So the major part in melting the water isn't heating it until it melts - it is the melting itself that is expensive. That said, I do see some value in solar ways in the space savings.
    - stcredzero 11y ago
      Why not awnings over the bike path? This can be done in ways that look awesome and do not ruin the scenery and the view from the bike path. Thin film collectors in the form of tarps suspended from poles would make the installation cost commensurate with installing light poles. You'd need significant R&D in the aerodynamics, etc. However, you already need significant R&D for collector roadways, and you're starting out with an inherently disadvantaged design.
suls 11y ago
Could this be the missing link to make electric cars winning the battle? No need for plugs at gas stations, inductive charging [1] while driving on the road will do it. Am I being too futuristic? [1] http://en.wikipedia.org/wiki/Inductive_charging#Electric_vehicles http://en.wikipedia.org/wiki/Inductive_charging#Electric_veh...
- dredmorbius 11y ago
  No. And no. The fault isn't Futurism but fantasy.
deleted 11y ago
[deleted]
Someone 11y ago
The FAQ of the project at http://www.solaroad.nl/en/faq/ http://www.solaroad.nl/en/faq/ is worth reading. Among others, it explains that the €3.5M spent wasn't only used to produce this stretch of road (unfortunately without going into detail), and that covering _all_ rooftops in the Netherlands would only cover 25% of Dutch _electricity_ demand. Given European clean energy goals, more square meters are needed. Those are hard to come by in a densily populated country such as the Netherlands. Is this a sure win? No, but if it works, it can be a useful part of the energy mix. Also, if it works, I guess scaling it up will not meet much nimby resistance, unlike he alternatives of huge wind parks or sacrificing land or water area for solar arrays.
toast0 11y ago
Are Dutch bike lanes like US bike lanes? Adjacent to motor vehicle lanes, with no grade separation, and an expectation that motor vehicles will use the lane whenever it is convenient, regardless of right of way? If so, this is really solar panels for the right shoulder, and I would really expect a big truck to break them
- PhasmaFelis 11y ago
  The title seems to be inaccurate. The test area is a dedicated bike path, not attached to a standard road.

80 points by Rafert 11y ago

> The cycle path was opened in November as a pilot project for three years and was followed with great interest, also by foreign media. I'm not following this new very closely. "Open" means that they allow cyclist, pedestrian (and dogs) to use a small 70m pilot segment, or that they have a 70m segment in the middle of nowhere?

panarky 11y ago
Here's a photo. It's a bike path between two towns, and about 2000 cyclists per day ride on it. http://www.theguardian.com/environment/2014/nov/05/worlds-first-solar-cycle-lane-opening-in-the-netherlands http://www.theguardian.com/environment/2014/nov/05/worlds-fi...
- ChrisGranger 11y ago
  It cost three million euros but can only power three houses? A million euros to use solar to power a house? Am I missing something?
  - learnstats2 11y ago
    Since this is the first prototype, I'm guessing the R&D cost that much. You're installing cycle track plus power generation infrastructure in one hit. Neither of those things is cheap on its own, e.g.: "Cycle track costs at anywhere between £100,000 and £900,000 [per km]" from https://transportretort.wordpress.com/2011/02/09/how-much-would-cycle-paths-cost/ https://transportretort.wordpress.com/2011/02/09/how-much-wo...
  - fche 11y ago
    Government economics, working as designed.
    - learnstats2 11y ago
      >Government economics, working as designed. You've been downvoted perhaps because it's not clear if you're being sarcastic, but I agree earnestly. The primary purpose of government is to organise things that benefit people: and they only need to do this when business can't or won't. Governments should act as a balance to the negative aspects of capitalism. As such, I genuinely believe that governments should be "uneconomic".
  - jkestner 11y ago
    Do you know how much the first Apple Watch to come off the line cost? Billions. R&D cost gets amortized through mass production; this is what it looks like at the beginning.
  - IkmoIkmo 11y ago
    Consider that the cost of a kilometre of ordinary road is a few million dollars, and that prototypes are orders of magnitude more expensive than a mass produced optimised supply chain with economies of scale.
cyphax 11y ago
It's not in the middle of nowhere, it was being used by cyclists. Apparently, over 150,000 cyclists rode over it since it was opened. Source (Dutch, but includes a photo): http://www.noord-holland.nl/web/Actueel/Nieuws/Artikel/Zonnefietspad-SolaRoad-levert-meer-energie-dan-verwacht.htm http://www.noord-holland.nl/web/Actueel/Nieuws/Artikel/Zonne...
URSpider94 11y ago
A nitpick, but being a Dutch bike lane, there will not be any pedestrians and dogs on it. Bike lanes are for bikes.

stephengillie 11y ago

Interesting points: 1. > That is more than the upper limit calculated on the basis of laboratory tests. Does this mean the panels generated more than they were tested to generate? 2. Part of the purpose of the project was to beta test the suitability of their glass surface treatment as a biking/walking surface. (I'm imagining it's textured like a truck bed liner, but transparent.) They did have an incident early on with a bicyclist slipping, related to a stick-on surface, so they switched to a spray-on surface. 3. Commenters slinging arrows at a Conservative strawman for the high price and comparatively low (factor of 500) energy output vs government building rooftops.

Rafert 11y ago
1. No, it means that the panels generated more than the predicted upper bound. As a commenter on the source article mentioned, this year's April was one of the most sunny in recorded Dutch weather history, which might have contributed to this fact.

jkot 11y ago

What were the expectations?

Rafert 11y ago
According to http://www.solaroad.nl/wp-content/uploads/2013/06/Artikel-SolaRoad-BU2013.pdf http://www.solaroad.nl/wp-content/uploads/2013/06/Artikel-So... it was 50 kWh per square meter.
- fche 11y ago
  (over what unit time)?
  - icebraining 11y ago
    Per year.

invisible 11y ago

Sounds like the first comment hit the nail on the head: there being 25% more sunlight hours than expected.

jimrandomh 11y ago

Numbers from the article: 3000 kWh in six months = 684W average 70 kWh per m^2 per year = 8W per m^2 As a comparison point, https://en.wikipedia.org/wiki/Photovoltaic_system#Solar_array https://en.wikipedia.org/wiki/Photovoltaic_system#Solar_arra... gives a typical output for a square-meter panel as 0.75kWh per day, or 31W.

jsnell 11y ago
That's the wrong 6 months though, since it's including the whole winter and none of the summer. Looking at the graph, April accounted for as much power production as the other 5 months combined.

ukandy 11y ago

Why anyone would pursue such a suboptimal installations is beyond me. Researchers finding ways to waste grant money I guess..

Someone 11y ago
The company leading the project claims commercialization is five years away. They likely are optimistic or biased, but I am not sure they are outright lying. Prices of solar cells drop fast. Extrapolate a few years, and costs of solar installations will be dominated not by what solar cells cost, but by what it costs to install them. In this case, something must be installed anyways to build the cycle path. It might well be that installing a (cycle path, solar cells) combination will only be marginally more expensive than installing a traditional cycle path. Will we get there? If solar cells and the electronics needed to wire than together (which, in this case, are more complex because the road may see highly variable shading patterns) get dirt cheap, we might.
- mason240 11y ago
  Do you really believe that it is more efficient to build a bike lane paved with solar panels, rather than a bike lane paved with asphalt and separate, dedicated solar facilitates? EDIT: Looking at the pictures others have posted you still have to use asphalt (or more likely concrete because you need better stability, which is even more expensive) underneath, so there really is nothing saved by doing this. What a waste of money.
  - drabiega 11y ago
    How is the presence of asphalt underneath an issue? The deciding factor will be whether the marginal cost of a solar path over an asphalt path will be greater or less than building an equivalent solar facility. That seems like it could go either way.
    - IkmoIkmo 11y ago
      Very good point. Plus even if the marginal cost is lower than a dedicated solar facility, we don't necessarily have that luxury. We do if we want just 5% sustainable energy, not a problem. But if we want 99% sustainable energy, surface area is a very tricky challenge [0] and so it'd be a matter of the one and the other, instead of the one or the other. [0] https://www.youtube.com/watch?v=GFosQtEqzSE https://www.youtube.com/watch?v=GFosQtEqzSE

Giorgi 11y ago

Why is it bike lane though? any practical considerations?

acjohnson55 11y ago
I would assume this is because far less weight needs to be borne by the roadway. But that's just my guess.
Maarten88 11y ago
In the video they explain they use a bike lane to learn before going to real roads. Bikes are much lighter than cars and trucks, and they want to learn what materials work best.

lotsofmangos 11y ago

Well, it makes slightly more sense than the solar roads for normal cars and trucks, if only because it doesn't have to be quite as tough, but I do suspect that it would be cheaper to install, easier to maintain and far more efficient in terms of power generation, to put a normal cycle path down and put a roof of solar above it.

reirob 11y ago
Yes, but it wouldn't be as pleasant to ride on the road. Riding a bike with a roof over your head? I don't know, but I appreciate seeing the sky and the horizon when riding a bike.
- lotsofmangos 11y ago
  It wouldn't be a roof exactly. Because you can angle the panels and have much better transmission of light to the panel from not having to have a bike-proof coating, you wouldn't be completely covering the path and you would get the same amount of power from a strip that is thinner than the path, angled and fairly high up, this would cost far less money as it is available off the shelf, so you have more cash to spend on making more of it. Also, if you integrate it with lamp posts for your support pillars, you are not increasing the amount of street clutter either.

meric 11y ago

Roads are quite a good place to place solar panels, logistically speaking. Yes they are 30% less efficient, but they are also closer to where the electricity will be used, and the marginal opportunity cost of real estate is zero since road use is retained. You don't need new land and you don't need to worry about transporting power at great distances. I'm glad such experiments are being conducted to see how well this idea performs in practice. It's good they started with bike lane as opposed to truck roads. It will give them opportunity to iterate on the panels resiliency.

guiomie 11y ago
Not sure why you are being downvoted, but I thing your comment makes a lot of sense, and I'd like to know why some think otherwise.
- _Adam 11y ago
  The economics of solar panels in roads are horrible, given current technology. Here's an excellent engineering analysis of this exact project: https://www.youtube.com/watch?v=HOZBrHqTJk4 https://www.youtube.com/watch?v=HOZBrHqTJk4
  - meric 11y ago
    I wrote a comment there. Panels on roads, if they can suffer being driven on well, can be economical when rooftop spaces run out. Rooftops are only sufficient for 25% of Netherland's electricity demand. I notice now there is a couple of inaccuracies but they are only minor ones financially. The benefit from saved real estate is too big. Local council governments may have access to its road real estate, but have no legal right to install panels on roofs. Netherland land value, per square meter, is €4,907. There is a local property tax is 0.05% - 0.3%. (http://www.shelteroffshore.com/index.php/property/more/property-tax-expats-in-netherlands-10540 http://www.shelteroffshore.com/index.php/property/more/prope...), and a wealth tax of 1.3% per year. Assuming 1.4% total taxes per square meter, the revenue received by the government is €68 per square meter. Since building the solar panel on the road means they don't have to build solar panels on real estate that can generate tax revenue, the benefit is €10 of generated electricity, plus the €68 of tax revenue that is preserved (assuming all municipal building rooftops are exhausted, already). That makes a payback of €78 per year. In 15 years, this would equate to €1170, compared to building a solar array on free land. The savings would be even greater compared to the local government renting rooftops to place solar panels.

dorfsmay 11y ago

I'd love to see some financial analysis: 1) cost of producing the same amount of electricity with Netherlands' most common electricity production 2) cost of building this vs. a normal bike path, and time for recovering the cost considering #1 3) expected life of this system + anual maintenance cost 4) cost of a typical roof installation for the same surface

quchen 11y ago
5) Cost of a normal bike path with ordinary solar cells of equal area next to it
- holri 11y ago
  6.) CO2 and energy saving.
- ghshephard 11y ago
  5.1 Cost of a normal bike path with ordinary solar cells on top of it (providing shade, and shelter from the rain, with presumably greater efficiency)
  - mod 11y ago
    This is actually what I envisioned before I looked up some pictures (if there were any in the article, they didn't load for me). It seems more practical, in particular for a bike path.
    - greglindahl 11y ago
      That's already well-studied, for parking lots with shade structures. I'm astonished how many people are weighing in to trash a small project researching something new that might be interesting!
      - ghshephard 11y ago
        I'm definitely not trashing it - I'm enthusiastically interested in whether it's viable. What I'd love to know is what the expected cost structure, at scale might be, in comparison to other options.

rebootthesystem 11y ago

Sorry, this is beyond silly. Do they actually have any scientists with some command of mathematics working on this project? Other than to screw ignorant government morons out of lots of money I could not imagine any reputable scientist or engineer not falling to the floor laughing uncontrollably when presented with the idea of putting solar panel on a sidewalk/bike path. The whole thing is so utterly ridiculous that the only possible explanation is someone is making millions with this project.

rebootthesystem 11y ago
The dynamics of down-voting on HN can be interesting. I have this --possibly flawed-- mental image of emotional impulse voting devoid of any effort to analyze what is being said. For the benefit of those who didn't take the time to think before down-voting my prior comment I'll try to spell it out here. A few facts: - Good commercial cells deliver an efficiency in the 14% to 19% range. - This efficiency assumes the cells are aimed at the sun - Optimal winter angle for the Netherlands is approximately 76 degrees from horizontal - Peak efficiency also assumes the cells are clean and have nothing obstructing or altering light from reaching it's surface at the optimal angle - In all cases you can Google my claims and verify their veracity Option #1: - Cover the solar panels with glass - Scuff-up the surface so people and bikes don't slip and slide all over the place - As an alternative, apply a film to achieve the same effect - Mount them flat on the ground - Place trees around it - Have people, bikes and dogs walk on it Analysis: - The cost of encasing panels in concrete and glass modules and installing them is monumental - The optimal angle for Amsterdam is approximately 76 degrees. Panels mounted flat simply throw away a significant amount of available energy. - Solar cells laid flat will produce between 20% and 30% less when compared to optimally aimed cells. - Glass will create problems based on how light enters. You have reflection, diffraction and scattering as possibilities. A percentage of the energy will never reach the cells. - A non-slip surface will scatter and absorb a significant amount of energy. Based on the images I've seen of these road modules I am going to guestimate that at best 70% of the light entering the road reaches the cells. I base this on years of working with a wide range of optical diffusers. - Dirt and particles on the cells can have huge efficiency effects. From light scattering to simply blocking and absorption. I'll go ahead and guess that you can't keep a roadway clean 100% of the time, therefore, you probably pay a, say, 20% penalty on average for having dirt, leaves and dog shit on the road. This is entirely a seat-of-the-pants number. It could be 10% or 50%. It isn't going to be zero. - Power generation is now utilization dependent. With more people on the road more light is blocked and less power is generated. I won't put a number to this. I will rather make a statement: If nobody uses the road, what's the point of building one in the first place or building one that is so much more expensive than simply pouring plain concrete? - Depending on angle, trees, buildings and even tall vehicles on the road will cast shadows on the panels. A very rough calculation then says that, at best, our solar roadway will operate at 40% of peak efficiency. If we factor in the constant need for cleaning this number could very well go down significantly. For example, do we have a crew of a few people using gas powered leaf blowers cleaning the roadway a few times a day? Option #2: Build a light steel structure atop a conventional bike path. Angle the panels for optimal efficiency at that latitude. You might splurge and add active tracking. Analysis: - The cost of installation is significantly lower - By mounting the panels at the optimal collection angle we ensure converting power as near to the efficiency peak for the panel in question - Angled mounting also aids in reducing surface particulate contamination and makes cleaning potentially as simple as an automated water sprinkler system - The entire system is far less costly and efficient - The bike path gets "free" shade as a side effect So, yeah, the entire idea is absolutely ridiculous if anyone bothers to do a little math. Someone has got to be lining their pockets or whoever is leading this project is simply in denial. Go ahead and downvote, but, if you do, please show your calculations and how you arrived at the idea that this concept actually makes sense to deploy at scale. I'll bet you can't.

hoopd 11y ago

Really? On their website[0] they claim their glass surface doesn't require snow removal because the heating elements melt it and as such asphalt roads have a cost of snow removal that apparently comes for free with these. However, it takes more energy to melt snow than to push it to the side[1] which they simply ignore and that makes me question what other things they're leaving out in order to tell a good story. I'd really like to see the numbers crunched for how many snowy days a year will cause the system to consume as much energy as it produces. [0] - http://solarroadways.com/snow.shtml http://solarroadways.com/snow.shtml [1] - https://what-if.xkcd.com/130/ https://what-if.xkcd.com/130/

woah 11y ago
It takes moe energy to melt snow than push it to the side? This is northwestern Europe, where the snow never gets more than a few centimeters deep, and the temperatures never go more than a few degrees below freezing. I could definitely see heating a surface by a few degrees being cheaper than bringing a plow or other snow clearing machinery out to some path. Now, northern Canada would probably be a different story.
- Bootvis 11y ago
  Can confirm, in the Netherlands on bike lanes black ice is a much bigger problem than snow. Heating should work fine against black ice while shoving isn't very effective.
- onnoonno 11y ago
  The enthalpy of fusion for water is 335 J/g. The specific heat capacity of ice at -10C is 2.1 J/(gK). So the major part in melting the water isn't heating it until it melts - it is the melting itself that is expensive. That said, I do see some value in solar ways in the space savings.
  - stcredzero 11y ago
    Why not awnings over the bike path? This can be done in ways that look awesome and do not ruin the scenery and the view from the bike path. Thin film collectors in the form of tarps suspended from poles would make the installation cost commensurate with installing light poles. You'd need significant R&D in the aerodynamics, etc. However, you already need significant R&D for collector roadways, and you're starting out with an inherently disadvantaged design.

suls 11y ago

Could this be the missing link to make electric cars winning the battle? No need for plugs at gas stations, inductive charging [1] while driving on the road will do it. Am I being too futuristic? [1] http://en.wikipedia.org/wiki/Inductive_charging#Electric_vehicles http://en.wikipedia.org/wiki/Inductive_charging#Electric_veh...

dredmorbius 11y ago
No. And no. The fault isn't Futurism but fantasy.

deleted 11y ago

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Someone 11y ago

The FAQ of the project at http://www.solaroad.nl/en/faq/ http://www.solaroad.nl/en/faq/ is worth reading. Among others, it explains that the €3.5M spent wasn't only used to produce this stretch of road (unfortunately without going into detail), and that covering _all_ rooftops in the Netherlands would only cover 25% of Dutch _electricity_ demand. Given European clean energy goals, more square meters are needed. Those are hard to come by in a densily populated country such as the Netherlands. Is this a sure win? No, but if it works, it can be a useful part of the energy mix. Also, if it works, I guess scaling it up will not meet much nimby resistance, unlike he alternatives of huge wind parks or sacrificing land or water area for solar arrays.

toast0 11y ago

Are Dutch bike lanes like US bike lanes? Adjacent to motor vehicle lanes, with no grade separation, and an expectation that motor vehicles will use the lane whenever it is convenient, regardless of right of way? If so, this is really solar panels for the right shoulder, and I would really expect a big truck to break them

PhasmaFelis 11y ago
The title seems to be inaccurate. The test area is a dedicated bike path, not attached to a standard road.