First Solar Bike Path in Germany Is Now Live
cleantechnica.com
cleantechnica.com
Still, it paints an interesting picture that no government would care about angry residents or potential alternative uses when building a road or prospecting for oil or coal (remember the Hambach and Lützerath events in Germany where entire villages were cleared because there was coal to strip mine).
Meanwhile, for wind we're still debating whether the safety zone to the next inhabitated building should be 1km or 2km...
Secondly, what genius decided to make it a flat roof? Flat surfaces are the absolute worst both in capturing the most sunlight in temperate latitudes and in terms of dirt and snow removal. Even a 45° angle would mean a lot of the dust, leaves and snow will just tumble down or get washed down by the next rain, whereas flat surfaces are literally encrusted within months.
You want solar, put it in an uninhabited ground-level unobstructed serviceable cheap location near the grid outside of town. Because, wires can transmit electricity anywhere it's needed.
Elaborate structures for solar cost more than the panels these days. Never build them. At most, tilt them to the local lattitude. If tempted to do more, instead buy more panels. Power per dollar works out better.
They probably did the math, and at that location, the ROI for a single-axis tracker was better than the ROI for fixed panels.
> And they track over the day! not over the year.
This probably means it's a single-axis tracker, which points east in the sunrise and west in the sunset. To track over the year it would need a second (north-south) axis, but the ROI for that probably wasn't better than a single-axis tracker.
> Again, all that mechanism for so little gain.
A single-axis tracker isn't that complicated (and a single axis with a single motor can move a whole row of panels at once), so even if the gain is small, it can be more than enough to pay for the mechanism.
They've gotten so cheap that this Texas company claims that it's cheaper to buy more panels and lay them on the ground rather than using a rack to get them at a better angle.
https://electrek.co/2022/12/12/texas-solar-farm-flat-on-the-...
They probably didn't do the math. If they had they would have installed fixed panels. Panels are so dirt cheap that you'd have to come out more than 60% ahead on the cost of the tracker and that's never ever going to happen. Just add more panels.
I have 50 of them now in some pretty bad orientations, ~ 100 KWh on a good day and if I had half that many on trackers it wouldn't even come close. And on bad days the only thing that you want in a solar installation is surface area. Peak performance isn't interesting at all, and tracking at best gives you 20 to 25% more power at the price of the tracking mechanism being much more bulky than panels, panels shading each other when used with trackers so you'll use your space far less efficiently, fragility and finally complexity. Don't use trackers.
This method adds no land use. It also provides a roof for the users of the path.
Solar above car parks is great too -- it provides shade, means you don't get wet getting out of the car, and it provides energy.
You want a roof, build a roof. You want solar, build a solar farm. You should no more put solar over other structures than grow radishes up there. It's a terrible idea from every point of view (except eco-theatre).
> wires can transmit electricity anywhere it's needed.
Well .. yes, if you build the wires. A surprising amount of projects are getting held up on grid connection grounds. Whereas embedding the panels near urban demand reduces that problem.
I am a bike commuter and one of the great things about riding a bike is having the sky above my head. This is kind of a vibe killer.
I can see the benefits but I think a little more thought in the design could help us understand if this is something we really want.
How long is this stretch anyway?
Like they say, get a little relief from the sun. The elements will become harsher and harsher with the climate crisis.
At ~€1m total price, it's about 3500€/kW, which is roughly 2-3 times the equivalent rooftop solar price (but this likely includes paving the bike path, frame structure, etc).
Apart from the fact that this prototype is very ugly, some limitations come to mind.
- Maintenance without blocking the bike lane. Does this require a separate access road?
- Will this work when any trees are nearby? Falling branches are likely to cause damage and block the sun.
- How does this work when buildings are nearby? You will block all the light? I'm having trouble imaging how this will look good in a more dense area - not the mention the extra width required on the sides of the bike path will be hard to get where space is at a premium (cities).
All this seems to point to a rather limited use case: bike lanes in places with few buildings and few trees, and sufficient spacing around the structure to facilitate maintenance access. That presumably means: in sparse industrial zones near edges of cities (as pictured, I suppose).
Which leads to another question: how many sparse industrial zones in Germany actually have bike 4m wide bike paths?
The answer is: no where.
You are spot on and this is just a gimmick.
Design with almost no actual research budget
Buildable with contractors and off the shelf components
Aligned with local research grants
The result is quite similar to the CGI, but not finished yet. The length is 200m, as it is a PoC.
If I live in a hotter (and humid?) place, i.e., middle-east or SEA, I would love the idea. But, to have that in a colder place, i.e., nordic, I'll make sure to pick other routes without the shades. :-)
https://www.sciencealert.com/solar-roads-in-the-netherlands-...
It's far less use than solar over an open car park roof though.
https://imgur.com/a/ImWKbLo (no idea where the idiotic warning comes from it is definitely SFW).
[1] https://efahrer.chip.de/news/geniales-pilotprojekt-ist-ferti...
The sun is brutal here at 6500+ feet, and I would use this every day if it were available since there aren't many bike paths with protection from the sun.