3mo ago

Solar panels between railway tracks?

www.euronews.com Solar panels will be rolled onto Swiss railway tracks ‘like a carpet’

After long delays, the removable PV system will finally be tested on a western track next spring.

I'm all for putting solar panels all over the place, but won't these get dusty and oily and need loads of cleaning after trains pass over?

Also, costing €623,000 over three years sounds rather expensive for just 100m (although that roughly equates to 11KW).

92 comments

Jeez, solar freaking railways.
Railways are dirty, brake dust, oil and lube leaking, human waste (from a car toilet if there is no tank).
- This is Switzerland, not India. Also, it's a test. It's designed to find out exactly how serious those problems are and if they prevent the system from being effective.
  
  Is this the same bunch of people that wanted to make solar roads/bike lanes too?
  I could see a solar road working with some kind of passive heating medium circulated underneath but even then, the maintenance on that would be a nightmare. We can barely maintain all the roads we have already, and that's just goopy rocks and grading.
  
  Next test: solar panels on the bottom of the ocean.
- They make a better roof over the tracks that the train passes under than being on the ground. They could even be tilted to better face the sun.
  
  This but for cycling pathways in cities (no cars allowed).
- There are “defect detectors” on railways to warn engineers when their train has a chain, air hose, etc dangling and dragging along the ground - which is a potential for accidents of many varieties.
  I guess now you can replace that with trains that automatically stop when the Katamari of dislodged solar panels eventually builds enough mass to force a car off the rails.
- Surely the maintenance of such problems would be very easy though, given it's already on rails you could run a carriage with washing machinery underneath to clean these occasionally. Interested to see how serious the deterioration over time is due to the grime.
- Don’t forget that maintaining all this means people working directly in the track trying to fix high voltage electrical issues while dodging trains and hoping dispatch doesn’t forget about them, or that ballast(the gravel between the ties) needs to be renewed regularly, much less all the things like realignment and rail grinding that use specialized machinery that needs to go right in the space between the rails.
  This means that those panels are going to have to be removed and installed often, at best vastly increasing wear and tear on them as compared to a fixed installation, and adding the risk that a failure in the pickup/deployment process could scrap a significant number of panels if not caught immediately.
  Or that the hard part of installing solar panels is the wireing, inverting, and grid interconnection, all of which are just made that much harder by having to have electricians doge trains.
  Look, if there really is absolutely no possible available space, like say desert, farmland, roofs, parking lots, yards, fences, well just put the panels up on a simple metal frame over the railway, maybe even integrate the catenary hangers if your feeling daring.
  This at least provides some benefit to running the railway by keeping snow and leaves off the tracks to some extent while also keeping the panels out of the way of running the railroad.
  
  Yes because they never close the lines for maintenance or repairs

you have to keep the panels clean in order to work. this is not a great position to do so
- Hopper cars lose coal and ore all the time
  
  This is Switzerland, outside of a small number of corridors the majority of tracks see virtually nothing but passenger trains.
  
  Trains with hoppers are not present on all railways though.
  
  i'd be more worried about about smudgy stuff. they get dusty, then it rains and the panel is covered in a film of dirt. bird shit on solar panels is already plaguing home users
- could trains have some kind of mechanism that might help? physical contact seems too much, maybe a blower?
  
  I'm sure enough air is moved simply from the train moving by, but there will probably still be rocks and stuff flying around
  
  won't really help against bird poop and such

Why not on the sides of the railroad? Often, there is significant free space on both sides of the track.
- I was about to comment that it makes more sense to put panels in open space, but looking into it does appear some numbers crunchers did the math on efficiency gains from being able to swap old panels with a dedicated machine on the rails, versus the other option.

have we run out of convenient places to put panels? that's news to me, last i checked we still had a hilarious amount of free roof space and stuff like parking lots where we can just slap up the panels.
- Putting a solar roofs over any open-air carpark you happen to own is just a hilariously easier option. Hell, you could erect these OVER the train tracks.
  https://greenox-group.de/photovoltaik-carport/ (Article is in German, but it's really more around the picture)
  According to a completely un-sourced picture I found online, one carpark (in the USA) is typically around 5.5 x 2.6m, so if you had even 50 carparks on your site you could have ~715 square metres of panels. More, if you figure a way to cover the aisles between the rows of carparks too.
  At the top end of all applicable figures (panel efficiency, solar irradiance, inverter efficiency), that could net you ~160kW at solar midday.
  Now on the other side, standard-gauge railway is around 1.4m wide, and maybe you could cram a 1m width of panels between the rails.
  That sounds like a lot - 1000 square metres per kilometre, and there are thousands of kilometres of railway lines out there - but it's harder to install, harder to service, gets dirty faster, is liable to get damaged, and now you have to figure out how to extract power from somehing a kilometre long, instead of an area that could be a square only around 35m (~115') on a side (for the above 50 carparks).
  I know which one of those I'd want to run the cables for.
  As has been pointed out many times when this dumb-ass idea comes up, only once you've exhausted every other possibility (carparks, rooftops, putting panels ABOVE roads/rivers/canals/cycleways/railways) and have literally no other viable installation locations, then we can talk.
  
  My dad worked with a guy who is designing a system like this and it makes all the sense.
  you shade the parking spaces
  you absorb less heat into the ground than tarmac
  free energy
  direct panel-to-car charging for EVs
  
  solar canopys are actually quite expensive. Needs a very sturdy structure to hold panels high up and deal with wind loads. Solar panels are getting so cheap, that it becomes very reasonable to lay them on the ground instead of optimal angles, higher up.

Solar freaking railways

I expect it would turn out like this:
https://www.sciencealert.com/the-world-s-first-solar-road-has-turned-out-to-be-a-disappointing-failure
And here's a Hacker News thread discussing it

i think they'll crack from the vibrations, or to avoid that they'll need to be built a lot sturdier than normal.
In which case just make the cheap version put them on top of buildings, in cities, near to demand; like everyone with a quarter of a brain has known since their invention.
Don't install sensitive/ fragile equiipment in dangerous places near massive energetic machines uness it's neccesay for those machines or there is really no where else to put it.
Can I get 60 grand to shove a solar panel up my arse as an "experiment"? Maybe some of these dumb experiments will help figure out a way to manage all the challenges of idiots who have more money than sense - that might be worth it.
- how about those flexible printed ones? They're protected from the wind by two metal barriers
  
  Yeah but they have thousands of tons of steel going overhead and rocks and dust all around. I don’t really see the advantage compared to a solar farm or a roof where they’re easier to set up and maintain

An idiotic idea which will go nowhere just the one about putting PV modules on road surfaces was.

It seems like it a bad place. It would probably shorten the panels' lifetime, and maintenance would be tricky without interrupting train traffic.
Let's work on putting more solar panels on schools, malls, parking lots, train stations, and any structure with a large roof.

The 600000 € probably include the development cost. Thus, on a larger scale, the cost per unit length will decrease significantly.
- True, but it still seems rather excessive....
  
  That's like 1/7th of the cost of a single passenger car. I'm sure they can easily afford to take that hit if it doesn't end up panning out.

2 axis solar trackers are much more efficient, but fixed installation beats them in cost/W in many cases.
Any solar installation gets dirty, the question is do you save labor/equipment cost by having them cleaned by a single solar cleaning train, vs. tons of workers or automated brushes cleaning a large open field installation. Do you need to do cleaning passes after every train? Daily? Monthly? Yearly? Is there an intersection of efficiency loss and cleaning investment that is profitable?
If you could install and maintain them in a fully automated way with just a few specialized trains, I can see why it might be an attractive idea. Question is how automated can you make it really? Do you need to fasten the panels down? How do you tie them into the grid?
If the savings on installation, maintenance and cleaning offsets the loss in revenue from the suboptimal placement and dirt, it might work.
I could see this working out if deployed on large scales, where the up front investment of developing all the specialized process and equipment, like trains, becomes a small part of the cost.
Any such proof of concept installation of an unproven technology will be more expensive than if you really deploy it at scale.
If rail didn't exist today and we had to develop the first train and track and all the necessary infrastructure around it, the first 10km would be ludicrously expensive and would never pay itself off compared to the existing road network or shipping routes.
It's a finetuning and risk taking problem. Does the idea make sense in a vaccum? And does the idea work in competition with existing solutions? Is anyone willing to invest enough money to make it competitve?
I hate it when extremely complex multi-variate problems always get judged based on one or two possibly negligable variables because of ignorance or intellectual laziness. Sometimes you can successfuly jugde things this way, yes, but rarely are things that simple.

Even if not between the tracks, aside the tracks there is quite a bit of empty space. That space gets a lot less of a hard time from the trains rolling by

Also, costing €623,000 over three years sounds rather expensive for just 100m
It's hugely expensive, but I expect most of the cost to be in the wagon that lays panels down and picks them up - and could hopefully service a big stretch of railway (if it works). That kind of systems will cost a pretty big penny.
I doubt if this project will "fly", however. A totally horizontal solar panel at ground level is a far cry from producing energy efficiently.

Trains drop metal bits pretty often too. A lot of these panels will get shattered

A lot of the comments here are, pretty fairly, sceptical of whether this is a viable idea.
My question is, what's the advantage meant to be over just having an electrical railway and seperately some solar panels plugged into the grid? Especially since the article mentions the solar railway would be grid connected?

What’s the plan for when people start stealing the solar panels? Good luck trying to stop people
- The plan is the same for people stealing spikes and rail to sell as scrap: Railroad police don't fuck around.

It’s free real estate and incredibly efficient use of space. If it works, with all the challenges other have outlined - even at a reduced yield - it’ll still pay off.

Covered Highways. The benefits of additional PV and the benefits less rain and less sun glare on drivers. You could also install a tram like wires above in one lane for maintaining the EV charge on trucks and buses.

These people can get fucked. Everyone can get fucked. We don't need new ideas we need old ones.
We need the market to be able to react. Being able to build on land, fuck the NIMBYs. And being able to connect to the grid quickly, there is different ways to sort this but it comes from government intervention.
Then if you want more progress it's externalities. Tax fossil fuels and use the same money to subsidise renewables and batteries, and grid upgrades.
Or another possibility is mandate shutdowns based on a percentage over time (this will work better for EVs I think than than utility power. "Oh you want tariff on Chinese cars. Well fine you will have that for 10 years and in return 100% of your sales need to be evs in 10 years and to get you moving in 5 years its 25%, 6 40%, 7 55%, 8 70%, 9 75%.")
It's getting so tiring now that they have evidence of what works and instead just talk about how the worlds going to be different in 2050. Start building some fucking grid upgrades then. You know it is going to take 10 years tondo anything meaningful, you know you are 10 years behind, you know if you build it they will come.
Christ

As always with these fancy ideas it is a solution for something that is not a problem: We aren't even close to running out of suitable space to put solar panels. The problems for solar are usually just willingness, bureaucracy, or the electrical grid not being able to handle the additional load.
We've also had proposals for solar bricks for paving roads/parking lots, putting the panels as dividers between highway roads. It just doesn't make sense to overcomplicate things.
Come back once every single parking lot, large roof, unused radom patch of land, or even agricultural land (there are some interesting setups where the shade provided by solar panels is actually beneficial for the plants) is fully utilized. But chances are that at that point we already have more than enough capacity.
- On the contrary, I'm afraid. Land is in very short supply. The issue is that even if the land is not currently developed it is doing vital stuff already. If it's used for food production, if it's a bit of forest storing massive amounts of CO2, if it's home the insects pollinating our food supply, if it's....
  Finding scrap pieces of land, like roof tops/already developed land for solar will be crucial going forward.
  
  On the contrary, I’m afraid. Land is in very short supply. The issue is that even if the land is not currently developed it is doing vital stuff already. If it’s used for food production, if it’s a bit of forest storing massive amounts of CO2, if it’s home the insects pollinating our food supply, if it’s…
  I won't claim to be an expert, but I'm gonna push back on this point. Local conditions will ofc always vary, but take Germany for example, which is probably one of the more densely populated countries.
  Based on the numbers i can find anywhere from 14%-16% of our agriculturally used land is used to produce biomass. This is significantly less efficient than if even a fraction of this area were used for photvoltaics. And those rapeseed or corn monocultures probably have close to zero value for biodiversity, on the contrary i'd imagine that pesticide use will negatively impact nature overall. With solar panels on the other hand you can still use the underlying land to plant stuff like wild flowers and so on, if you wanted. There are also the already mentioned hybrid uses in agriculture where you plant crops below the panels or just use the land for grazing.
  On a side note since you mention forests. Just recently there was a number of articles on how due to their poor condition german forests have actually gone from being carbon sinks to carbon sources, releasing more CO2 than they bind.
  One more limiting factor that i forgot to mention above is lack of qualified contractors to actually build solar farms or put panels on roofs. Particularly with residential homes that seems to be another common complaint.

Wouldn't it be better to place panels on the train roofs?
- Or, hear me out: on the roof of the train stations
  
  Panels on the roof of everything, the roof of cars, the roof of buildings, the roof of your mouth...

To clean them, simply attach a big brush to the underside of the trains. 👍

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