Solar cell is the only practically viable power source with no moving parts. Stop trying to attach it to moving things. Movements breaks things. Just put the panels by the rail, e.g. as vertical sound barriers in reasonable distance (to lower the pressure waves from train) from tracks. Or on a nearby field where it can be protected and inspected all at one place.
It does seem kind of silly to put the panels between the rails, more prone to damage there from stuff falling off the trains, derailments, etc. and not angled for optimal sun exposure though I guess it's easy open space.
Before I read the article I was thinking the electricity from the panels would power the trains but doesn't sound like the output is enough.
They're getting 180 watts per meter, so it would take 50 km of panels to power one high speed train. And that's when the sun is shining. Double this at least if you want to store the energy and run trains in the evening.
It's obviously not 180 kWp/m. If it was I could put 1 meter of panels on my roof and power my house and 200 of my neighbors.
I didn't try to calculate the amount of energy it produces in a year, just the length of panels required to power a high speed train when the sun is shining. 18,000 watts / 100 meters is 180 watts per meter. At 180 watts per meter, 50 km gives you 9 MW, which is about what a high speed train consumes at cruise.
Or don’t put the panels near a railway at all. We have so much land and even empty rooftops that would be easier and safer to use first. Running panels along a railway means the electricity has to be carried all the way back to some point, meaning either giant cables to handle the current or specialized equipment and high voltage transmission lines. None of that was addressed by this pilot program that was 100 meters long.
You can do a pilot test of solar panels anywhere and call it a success, but the real test is scaling it up in an economically viable way compared to alternatives. None of that was tested.
Putting panels in a line is the worst arrangement. Just put them on roof tops or fields and keep it to places where they don’t have to be armored and reinforced.
Conveniently, there's already an electric cable sized to transport a few MW nearby. This might reduce the cost of installation, also there'll be no land acquisition/impact study issues.
However, I agree that putting solar panels in between or near rails will increase the cost of maintenance: the technicians will need to travel longer times to the work site, and now they also need to be certified to work near railroads.
That's just inefficient use of labour. I wish government used grants (or loans really) for solar farms instead. Batteries maybe, but even then it would be likely more efficient to install them on a substation level than every home.
I'll never understand why people latch onto these kinds of solar "solutions" in search of problems. Like that solar roadways fiasco a decade or so ago.
Just normal-ass solar is already safe proven and effective. Why do we need to remix it when there are still so many easy wins to be achieved?
Yeah, I can understand putting solar on things when it lets them become standalone off-the-grid setups but for something like railroad track it’s just not that much space and the costs are so much higher. Except on the tightest urban lines, just putting rows of normal panels next to the tracks should be significantly more space with much easier engineering.
Exactly. For example, I think the lifted solar panels that have been popping up over parking lots are a perfect win-win. Cars get shade, power gets generated, it's out of the way of most day-to-day threats, and if they have to do repairs, it's just blocking off part of a parking lot instead of a major thoroughfare.
If there's a single downside I'm not sure what it is.
The closest thing to a downside I can come up with is that, at least in CA, there's more than enough solar already. Adding solar to the grid without batteries included isn't really productive.
I think that’ll rebalance over time but one of the biggest questions I’d have is how to use all of the batteries people are driving around. A buddy shifted his car charging to work because they have a convenient setup with a bunch of solar panels and that seems like a good path to encourage going forward: let sunny day over production shift vehicle charging off of times where load would need to come from grid batteries, fossil, or wind.
Would be interesting if solar panel rows laid right on the ground could make sense for autonomous vehicle parking lots where cars can drive over the panels precisely enough to not crush them.
Not really. Solar panels laid flat on the ground are less efficient than solar panels raised above ground and angled to get more yield (if you're in the Northern hemisphere the Sun is never* in the North, vice versa for the South).
People hate the idea of solar in currently-unused space. Even if that space is bare desert. So you can get a big PR boost if you propose "solar, but on a thing" (roadways, water, and now trains).
Which is just odd to me because why are we holding one of the cleanest means of generating electricity to a higher standard than like, coal and oil? Why does solar have to have 0 footprint when everything else gets as much of a footprint as it wants? (I know the answer is profit)
This is bizarre to me, because the energy markets in my country (the UK) are bent to benefit solar and wind over all else. We banned oil and gas exploration, and even regulated out coal from the entire market. It's extremely hard to see how this benefits fossil fuel companies.
I'm a big fan of solar but this seems like a stretch. Generating the same amount of power as one fossil fuel plant requires a vast amount of land area, so of course that's why people complain about it. Coal plants and mines can be pretty large but natural gas plants, the realistic alternative, are pretty compact. I'm not sure how the size of oil/gas fields compares to a similar amount of solar, but they are generally sited far away, where people don't see them - and can be built relatively visually unobtrusively (see LA). And then there's nuclear plants, pretty big, but putting out multiple gigawatts.
Again, I think fossil fuels need to go and solar is our best bet, but no sense in hand waving the entire argument. They need a lot of land area.
> Like that solar roadways fiasco a decade or so ago.
Should have many of the same drawbacks, with 2 big differences:
1. Trains not driving directly on the panels' surface (which makes solar roadways a bad idea in any case). And
2. Trains on their own track, so the 'road surface' conditions of the panels (rain, snow etc) don't matter safety-wise.
That said: imho there's still so many spaces better suited to put solar panels, that between train tracks is among the last places I'd go for. Especially if it requires custom-design panels.
People have been convinced by energy company propaganda that solar still needs a trick or selling point other than protecting the environment. There’s widespread disinformation about cost and environmental impacts from the panels themselves.
More like engineered and worked around to be safe (unless you are in Australia lol). 400v around people is unforgiving. Batteries catch fire occasionally too - a lot of places you are not allowed to install indoors.
Protecting the panel from the freak large hail storm from inside the track also seems a lot harder than having it in a field with angle adjusting mounts/software.
None of the new solar fields in my area (upstate NY) have adjustable mounts. I presume it's not worth the maintenance overhead. Easier to build more panels.
That video is good - seeing the train-car dropping the panels into place makes it clear that you have some immediate labor savings on the initial deployment. Not sure if the post-installation labor was significant or could be automated away.
Still not sold on the idea. For something with a 20+ year life span, the initial deployment effort seems kind of irrelevant and should be better located somewhere that does not require ongoing activity. Train ballast requires replacement every N years which is going to require ripping up all of those panels.
> seeing the train-car dropping the panels into place makes it clear that you have some immediate labor savings on the initial deployment.
Dropping panels in place is not the hard part. Getting all of that electricity back to a connection point is one of the many problems created by this idea.
Putting panels in a multiple kilometer long end-to-end row is very inefficient compared to rectangular layouts that can be clustered around connection points.
And yet it did work, with positive results shown over a year, right? It seems that the reasons why this "could never work" like cracks, dust, and vibrations might have perfectly reasonable solutions. Solar panels have gotten so cheap that it might not be as important to install them in perfect conditions, and other factors like real estate, ease of maintenance, access to the grid come into play in interesting ways. I suppose long term results are yet to be seen, but it doesn't seem ridiculous to me.
You can put panels on anything and generate power for a couple years.
This system was only 18kW. That’s less than what we put on some residential houses. They didn’t address any of the hard parts like a transmission system capable of scaling up along a linear row of panels extending kilometers long.
> Solar panels have gotten so cheap that it might not be as important to install them in perfect conditions, and other factors like real estate, ease of maintenance, access to the grid come into play in interesting ways.
They had to use special panels for this, not the cheap ones you know. Any installation in an area like this requires reinforced and protected panels, which are more expensive than what you’re thinking.
You did identify some of the problems: Maintenance on this is terrible. They’re not going to shut down train routes to fix problems with the solar, so when something breaks it’s probably broken for years until a maintenance window can shut down transpiration.
Access to grid is terrible. You can’t re-use the train power lines, so I guess we’re running new transmission lines? A linear array is the worst possible configuration for a solar array because it maximizes the transmission distance and starts to require high voltage equipment to work.
Would you ever think it would be a good idea if someone suggested we go put solar panels out in the middle of nowhere between towns? Or would you agree it’s better to put them close to the towns on unused space like rooftops where they can feed directly into local loads? I think the visual of putting these on train tracks is misleading a lot of people into thinking we’re getting something for free when really this is an absurdly expensive way to place and connect solar panels.
A first version is always going to be low in scale and problems will of course be found. The question isn't 'are there problems', of course there are, the question is 'are the benefits here worth more than the problems'. If you already have the land, a maintenance operation, a user of energy, etc etc then integrating solar into that system has a lot of strong benefits that can make the problems manageable. Start looking for the upside here and you may actually find the cost benefit equation balances out, especially if this scales out.
> A first version is always going to be low in scale
They don’t have a first version of the hard part: The electrical transmission.
Maybe this isn’t obvious to people who haven’t worked on solar power systems, but you can put a couple panels anywhere and generate electricity for a couple years. It doesn’t prove that it’s viable to run thousands of kilometers of panels.
It’s like baking a tray of muffins in your kitchen and saying you proved that you can run an industrial scale muffin factory. They are different problem sets.
I've been nerd-sniped into google fueled napkin math.
18kw/100 m = 180kw/km
The most powerful Swiss electric locomotive [1] maxes out at 7900kw. That's 44km of track.
The most common Swiss electric (4/4) typicaly maxes at 6100kw requiring up to 34km of track.
Switzeraland has about 5000km of track and 180 is about 200, so a million kilowatts if all the track has solar panels.
Assuming 3000kw per locomotive and 100% efficiency [2], that's 300 electrical locomotives running simultaneously. The Swiss fleet is about four times that.
You don't need peak power all the time. The point of trains is that they're extremely efficient; most of the time they're essentially coasting, they only need a lot of power when accelerating or ascending.
If you want hard numbers, SBB used 1685GWh for passenger trains in 2025 [0].
The bigger problem with this idea is solar in Switzerland. It's fantastic during the summer but close to nonexistent during the winter [1]. Trains need to run year-round, so you'd need to overbuild solar monstrously to power SBB during the winter, or you'd need to solve seasonal electricity storage, which isn't easy. Pumped hydro is great but Switzerland has already built about as many artificial alpine lakes as the population is likely to tolerate.
What are the economics of this? Cost to install vs other available options? Durability will certainly be an issue I’m sure. Genuinely curious and not because I think it’s a bad idea. I want solar on all underutilized areas, I just prefer low hanging fruit from a cost perspective at the current time.
Seems likely that safe access for maintenance makes this unappealing economically. Likely easier to have wider rail right of way and then put a panel farm on the side.
With the added benefit of being able to mount the tracks at an angle, and the added disadvantage of occupying area near the tracks that is occasionally used for maintenance equipment.
And getting approval to widen the right of way, where it’s even physically possible, and issues around flora suppression.
I imagine that the cost to install is fairly low since train tracks require regular monitoring and maintenance so it's fairly cheap to add the installation and maintenance on top of the existing schedule.
The manufacturer claims that durability should not be an issue. Time will tell.
Yes, worsened inspection is a non-trivial problem. Very high quality sleepers (I wouldn't expect any other kind in Switzerland) mitigate this, but copying such approach in other countries could spell trouble.
I'm not an expert but I think the SBB is already pretty good at handling this. I think they already run measuring wagons (Oberbaumesswagen) with grond penetrating reader and ultrasonic measurement and use flow sensors to monitor drainage.
I would expect that the solar panels impact the efficiency at least somewhat but apparently not enough to cause real and enough issues for the SBB or perhaps they see ways to improve this in the future.
This might be exactly what you are asking for: low cost and low hanging fruit.
On paper, this should be pretty cheap. Normally, you need some mounting infrastructure to put the panels on, land preparation, etc. In this case, the train track provides the supporting infrastructure. You can bring in the panels via train wagons. Installation should be pretty quick and straightforward. And for cleaning, you could just do that from a rail wagon as well. Not having to truck in anything seems like it should be a big bonus here.
Durability might actually be fine. Solar panels are pretty reliable. And it's not like the train is in direct contact with the panels. The vibrations might be a challenge but presumably that would have shown up in the trials. It's something you could engineer solutions for. And so what if a small amount of panels fail?
Another issue with solar deployment is that there needs to be power cables that can consume the electricity.
But a train company practically always has running trains when the sun is shining. So they wouldn’t need to worry about disabling and losing money on the panels.
The real challenge is economically connecting the panels to a rail substation.
This is another bad idea in the same vein of solar roadways. To the layman, these ideas sound fantastic. To the knowledgeable they sound downright absurd. Put them on roofs, over car parks, over land. No way should they be on difficult to access locations with vehicle traffic.
It makes more sense than the road, because at least the train isn’t driving directly on the thing. I wonder if the power could be delivered directly to the train. Although the only savings really would be transmission costs, not sure how big of a deal that is…
Initially, he planned to remove dust from the surface of the photovoltaic cells using a cylindrical brush mounted on the rear of a train. “However, we realised that each time a train passes, it creates an airflow that sweeps away all the dust,” he said.
That seems pretty optimistic in the long run. Even a high power leaf blower won't get all the dust off of a dirty surface, especially if any sort of hydraulic oil, bearing grease or other viscous fluid mists onto the surface.
One thing that has struck me with our own solar panels is that they have to be very dirty before I notice any significant degradation in efficiency. And when they do get completely covered in pollen or leaves, a brief rain is usually enough to clean them.
Until you realize that polan is super stick and is really had to remove. I had a table outside and just 'blow away' dust didn't work at all. You need to actually clean with friction, water and cleaner.
It's solar, of course the unit economics are going to pencil out positive in the majority of climates and energy markets. The real question is "why should we put them here instead of somewhere else."
I wonder if the benefits are legal/jurisdiction/political. The total amount of track they could install this on is huge, and it doesn't seem like something that will be disagreeable on the local level. It could just be the easiest place to put it to deal with property law and zoning etc.
Another political benefit is that it means work for a very large number of jurisdictions, as there are suitable tracks just about everywhere.
If PR value gets panels installed faster than they otherwise would be who cares. The most important thing is we install as much solar as possible as quickly as possible, because we're killing ourselves fighting wars for other energy sources that poison our entire planet to use.
This is a great example of the solar ecosystem finding new niches. Tracks are likely good because there is already constant maintenance and inspections on them as well as ready hookup to the grid or, as the article mentions, directly providing power for trains. The point here isn't that this is 'the most efficient way to use solar' it is that it works and provides benefit. It is like agrovoltaics. The solar production is lower than a dedicated solar installation, but the dual use of the land and potential secondary benefits make it worth while. It looks like this could even get to the point where solar could actually power the trains completely assuming this expanded a little beyond just the track surface which could be interesting for the design of trains.
I'm in the south UK, live off grid, and have a bunch of solar panels, none of them are flat aside from the 640w of panels on my van, which generate almost nothing during the Winter.
Panels on the sides ot trains might be a better solution.
Putting solar panels in familiar places is always popular as an idea, but rarely better than putting them on the usual roofs or as rectangular arrays on the ground.
> the railway was fitted with 48 specially-designed solar panels with a combined power of 18 kWp.
18 kW is less than what gets installed on a lot of houses. It took 100 meters to do this. The farther the panels get from the interconnect, the higher the losses along the line.
It’s easy to set up 18kW of panels in one spot. Covering an entire railway with panels would require a different transmission setup to get the power back to somewhere useful.
I really wish we could just forget all of these ideas to put solar panels in places that are highly trafficked and serving double duty. Just put them in unused space that isn’t used for anything else: Rooftops, empty fields, or over parking garages. I often get downvoted for saying this because a lot of people like these ideas of putting solar panels in space that they see, like sidewalks or roads or railways, but we have so much unused space that isn’t near foot traffic, road traffic, or railways that is so much cheaper and easier to use for solar. These projects usually turn into political grifts to get government funding because the ideas are not economically viable alternatives.
> Thankfully, Switzerland has lots of meters of railway.
The linear meters of railway are nothing compared to the square meters of rooftops. Putting panels in a long row is the maximally worst arrangement you can come up with.
> There's caternary on 99% of Swiss rail, every few dozen meters, that already transmits power.
I guarantee this wasn’t oversized to accommodate power transmission duties, too.
It’s also high voltage line. The solar setup would need additional and expensive high voltage equipment to interface with the line and to work within the design parameters of a line that was designed to deliver to the train, not carry extra power.
You could put the panels anywhere else and connect them normally to the grid like every other installation.
> You understand that wire doesn’t have infinite capacity, right?
Why would it need that? Your original complaint was "18 kW is less than what gets installed on a lot of houses". Which is it? Too much to handle or too little?
Remains to be seen, considering how much snake oil there is in the solar market (but to be fair, this makes more sense than solar roads). A news article summary of a press release isn't proof of much.
I have tried entrepreneurial stuff twice before, in my 20s, though without much success. Having ideas good enough to get investors interested is a sign that perhaps I should have another go at it.
These are not ideas worth pursuing from an engineering standpoints. It doesn't make any sense compared to just doing the cheap and proven at scale thing of just placing them in normal fields.
But I will agree that the idea has proven marketing merit. This is a class of truly top tier snake oil. The solar roadways people continue to go unbelievably far on almost the same grift.
I don't know why people fall for this stuff. It doesn't make any kind of sense. You put the panels in a rectangular array in any convenient place. That's what wires are for.
Did we really fill up all the area on top of roofs, parkings lots, industrial areas, etc., and we're running out, and we have to put solar cells on railroads?
> Did we really fill up all the area on top of roofs, parkings lots, industrial areas, etc., and we're running out, and we have to put solar cells on railroads?
I guess it is easier to control the deployment since they own the railroads.
They don't need to because it is just a PoC and I don't think it hs been said anywhere that soloar panel between rain tracks would be the unique source of energy.
There are also a lot of vertical sound proofing barriers that could be equipped with panels.
Since the 90s our energy policy has been idiotic. Basically just politicians saying 'lets do nothing we can always buy cheap power form Germany or France'. All we had to do is build a single new nuclear power plant and we would have been fine.
But no, instead we have this grifting rail solar nonsense.
Solar cell is the only practically viable power source with no moving parts. Stop trying to attach it to moving things. Movements breaks things. Just put the panels by the rail, e.g. as vertical sound barriers in reasonable distance (to lower the pressure waves from train) from tracks. Or on a nearby field where it can be protected and inspected all at one place.
It does seem kind of silly to put the panels between the rails, more prone to damage there from stuff falling off the trains, derailments, etc. and not angled for optimal sun exposure though I guess it's easy open space.
Before I read the article I was thinking the electricity from the panels would power the trains but doesn't sound like the output is enough.
They're getting 180 watts per meter, so it would take 50 km of panels to power one high speed train. And that's when the sun is shining. Double this at least if you want to store the energy and run trains in the evening.
This is incorrect, you mean 180 kWp/m.
> in one year, the project has produced around 16,000 kWh.
160 kWh per meter.
It's obviously not 180 kWp/m. If it was I could put 1 meter of panels on my roof and power my house and 200 of my neighbors.
I didn't try to calculate the amount of energy it produces in a year, just the length of panels required to power a high speed train when the sun is shining. 18,000 watts / 100 meters is 180 watts per meter. At 180 watts per meter, 50 km gives you 9 MW, which is about what a high speed train consumes at cruise.
Sorry, I ran away from the keyboard without validating. The point I was trying to make was that Wp means you don't even get 180 W per meter.
> This is incorrect, you mean 180 kWp/m.
This is incorrect. 18000 Wp/100m = 180 Wp/m or 180 kWp/km. So parent is correct, and you can either add or drop a "k".
That is peak power, obtainable in summer months & muuch less in winter.
Over the whole year: 16000 kWh/100m = 160 kWh/m = 160 MWh (160,000 kWh) per km.
Yes yes, and no. The k was obviously wrong, I cant believe I wrote that. lol
But you cant just drop the p. The p means you won't even get that.
This part seems correct tho:
> ...so it would take 50 km of panels to power one high speed train.
160 MWh/km * 50 km = 8 GWh = 8 000 000 kWh
High-Speed train after acceleration uses about 30 kWh/km
8GWh / 30kWh = 270000km
A typical high speed train in Europe drives between 300 000 and 450 000 km/year
The 50 km solar wouldn't be enough.
A passenger train using 6 kWh/km could drive 1 350 000 km using 50 km of solar.(27000 km/km)
There is about 10 000 km of high speed rail in the EU and about 200 000 km of rail in total. All combined trains travel some 4.1 billion km per year.
4 100 000 000 km / 27 000 km = 151 851 km
It fits but very slowly.
We should order the 72 888 480 panels. If they cost 50 euro each it would only cost 3.6 billion.
Took them 3 years to install 48 so 72 million would take 4.5 million years.
Maybe the Chinese can help.
Or don’t put the panels near a railway at all. We have so much land and even empty rooftops that would be easier and safer to use first. Running panels along a railway means the electricity has to be carried all the way back to some point, meaning either giant cables to handle the current or specialized equipment and high voltage transmission lines. None of that was addressed by this pilot program that was 100 meters long.
You can do a pilot test of solar panels anywhere and call it a success, but the real test is scaling it up in an economically viable way compared to alternatives. None of that was tested.
Putting panels in a line is the worst arrangement. Just put them on roof tops or fields and keep it to places where they don’t have to be armored and reinforced.
Conveniently, there's already an electric cable sized to transport a few MW nearby. This might reduce the cost of installation, also there'll be no land acquisition/impact study issues.
However, I agree that putting solar panels in between or near rails will increase the cost of maintenance: the technicians will need to travel longer times to the work site, and now they also need to be certified to work near railroads.
What specs do you require for long-distance train electrification vs. the specs you need for electrical delivery to the grid?
Car parks, imagine if every car park and shopping center roof top was covered in panels..., literally fields of panels.
> empty rooftops
That's just inefficient use of labour. I wish government used grants (or loans really) for solar farms instead. Batteries maybe, but even then it would be likely more efficient to install them on a substation level than every home.
> solar farms
That's just inefficient use of land.
On the battery point I agree.
I'll never understand why people latch onto these kinds of solar "solutions" in search of problems. Like that solar roadways fiasco a decade or so ago.
Just normal-ass solar is already safe proven and effective. Why do we need to remix it when there are still so many easy wins to be achieved?
friends of friends simply need all that sweet government grant money
Yeah, I can understand putting solar on things when it lets them become standalone off-the-grid setups but for something like railroad track it’s just not that much space and the costs are so much higher. Except on the tightest urban lines, just putting rows of normal panels next to the tracks should be significantly more space with much easier engineering.
Exactly. For example, I think the lifted solar panels that have been popping up over parking lots are a perfect win-win. Cars get shade, power gets generated, it's out of the way of most day-to-day threats, and if they have to do repairs, it's just blocking off part of a parking lot instead of a major thoroughfare.
If there's a single downside I'm not sure what it is.
The closest thing to a downside I can come up with is that, at least in CA, there's more than enough solar already. Adding solar to the grid without batteries included isn't really productive.
I think that’ll rebalance over time but one of the biggest questions I’d have is how to use all of the batteries people are driving around. A buddy shifted his car charging to work because they have a convenient setup with a bunch of solar panels and that seems like a good path to encourage going forward: let sunny day over production shift vehicle charging off of times where load would need to come from grid batteries, fossil, or wind.
Would be interesting if solar panel rows laid right on the ground could make sense for autonomous vehicle parking lots where cars can drive over the panels precisely enough to not crush them.
Not really. Solar panels laid flat on the ground are less efficient than solar panels raised above ground and angled to get more yield (if you're in the Northern hemisphere the Sun is never* in the North, vice versa for the South).
* Midnight sun notwithstanding.
Definitely, the tradeoff is that it is cheap/easy to install things on the ground. https://erthos.com/ is testing that.
People hate the idea of solar in currently-unused space. Even if that space is bare desert. So you can get a big PR boost if you propose "solar, but on a thing" (roadways, water, and now trains).
Which is just odd to me because why are we holding one of the cleanest means of generating electricity to a higher standard than like, coal and oil? Why does solar have to have 0 footprint when everything else gets as much of a footprint as it wants? (I know the answer is profit)
That is not the answer (plenty of profit in solar), it's probably that society is literally older and so people don't like change as much.
I know there's profit in solar, but the game is rigged to favor oil and gas so that's still more profitable for the people who make the decisions.
This is bizarre to me, because the energy markets in my country (the UK) are bent to benefit solar and wind over all else. We banned oil and gas exploration, and even regulated out coal from the entire market. It's extremely hard to see how this benefits fossil fuel companies.
Legacy electricity generation isn't going to go down without a fight and a lot of overpriced PR campaigns.
I'm a big fan of solar but this seems like a stretch. Generating the same amount of power as one fossil fuel plant requires a vast amount of land area, so of course that's why people complain about it. Coal plants and mines can be pretty large but natural gas plants, the realistic alternative, are pretty compact. I'm not sure how the size of oil/gas fields compares to a similar amount of solar, but they are generally sited far away, where people don't see them - and can be built relatively visually unobtrusively (see LA). And then there's nuclear plants, pretty big, but putting out multiple gigawatts.
Again, I think fossil fuels need to go and solar is our best bet, but no sense in hand waving the entire argument. They need a lot of land area.
> Like that solar roadways fiasco a decade or so ago.
Should have many of the same drawbacks, with 2 big differences:
1. Trains not driving directly on the panels' surface (which makes solar roadways a bad idea in any case). And
2. Trains on their own track, so the 'road surface' conditions of the panels (rain, snow etc) don't matter safety-wise.
That said: imho there's still so many spaces better suited to put solar panels, that between train tracks is among the last places I'd go for. Especially if it requires custom-design panels.
People have been convinced by energy company propaganda that solar still needs a trick or selling point other than protecting the environment. There’s widespread disinformation about cost and environmental impacts from the panels themselves.
> safe proven
More like engineered and worked around to be safe (unless you are in Australia lol). 400v around people is unforgiving. Batteries catch fire occasionally too - a lot of places you are not allowed to install indoors.
Did you read the article?
Protecting the panel from the freak large hail storm from inside the track also seems a lot harder than having it in a field with angle adjusting mounts/software.
None of the new solar fields in my area (upstate NY) have adjustable mounts. I presume it's not worth the maintenance overhead. Easier to build more panels.
Better article with video: https://www.swissinfo.ch/eng/emissions-reduction/solar-energ...
That video is good - seeing the train-car dropping the panels into place makes it clear that you have some immediate labor savings on the initial deployment. Not sure if the post-installation labor was significant or could be automated away.
Still not sold on the idea. For something with a 20+ year life span, the initial deployment effort seems kind of irrelevant and should be better located somewhere that does not require ongoing activity. Train ballast requires replacement every N years which is going to require ripping up all of those panels.
> seeing the train-car dropping the panels into place makes it clear that you have some immediate labor savings on the initial deployment.
Dropping panels in place is not the hard part. Getting all of that electricity back to a connection point is one of the many problems created by this idea.
Putting panels in a multiple kilometer long end-to-end row is very inefficient compared to rectangular layouts that can be clustered around connection points.
This will never work, and it's ridiculous: https://youtu.be/7vItnxhWRqw
And yet it did work, with positive results shown over a year, right? It seems that the reasons why this "could never work" like cracks, dust, and vibrations might have perfectly reasonable solutions. Solar panels have gotten so cheap that it might not be as important to install them in perfect conditions, and other factors like real estate, ease of maintenance, access to the grid come into play in interesting ways. I suppose long term results are yet to be seen, but it doesn't seem ridiculous to me.
there may be solutions to it but there are just already existing places to put solar panels that don't even require coming up with solutions.
> And yet it did work,
You can put panels on anything and generate power for a couple years.
This system was only 18kW. That’s less than what we put on some residential houses. They didn’t address any of the hard parts like a transmission system capable of scaling up along a linear row of panels extending kilometers long.
> Solar panels have gotten so cheap that it might not be as important to install them in perfect conditions, and other factors like real estate, ease of maintenance, access to the grid come into play in interesting ways.
They had to use special panels for this, not the cheap ones you know. Any installation in an area like this requires reinforced and protected panels, which are more expensive than what you’re thinking.
You did identify some of the problems: Maintenance on this is terrible. They’re not going to shut down train routes to fix problems with the solar, so when something breaks it’s probably broken for years until a maintenance window can shut down transpiration.
Access to grid is terrible. You can’t re-use the train power lines, so I guess we’re running new transmission lines? A linear array is the worst possible configuration for a solar array because it maximizes the transmission distance and starts to require high voltage equipment to work.
Would you ever think it would be a good idea if someone suggested we go put solar panels out in the middle of nowhere between towns? Or would you agree it’s better to put them close to the towns on unused space like rooftops where they can feed directly into local loads? I think the visual of putting these on train tracks is misleading a lot of people into thinking we’re getting something for free when really this is an absurdly expensive way to place and connect solar panels.
It could make sense along an electrified rail line, if the power lines used to supply the trains can be leveraged for distribution?
But, putting panels between the rails seems foolhardy to me too.
Than you'd have to regularly add high-voltage inverters (15kV AC @ 16.7Hz), which also adds a lot of complexity.
A first version is always going to be low in scale and problems will of course be found. The question isn't 'are there problems', of course there are, the question is 'are the benefits here worth more than the problems'. If you already have the land, a maintenance operation, a user of energy, etc etc then integrating solar into that system has a lot of strong benefits that can make the problems manageable. Start looking for the upside here and you may actually find the cost benefit equation balances out, especially if this scales out.
> A first version is always going to be low in scale
They don’t have a first version of the hard part: The electrical transmission.
Maybe this isn’t obvious to people who haven’t worked on solar power systems, but you can put a couple panels anywhere and generate electricity for a couple years. It doesn’t prove that it’s viable to run thousands of kilometers of panels.
It’s like baking a tray of muffins in your kitchen and saying you proved that you can run an industrial scale muffin factory. They are different problem sets.
If you don't think about it, it doesn't seem like a bad idea. If you do, you realized how incredibly complex the whole thing is
I've been nerd-sniped into google fueled napkin math.
The most powerful Swiss electric locomotive [1] maxes out at 7900kw. That's 44km of track.
The most common Swiss electric (4/4) typicaly maxes at 6100kw requiring up to 34km of track.
Switzeraland has about 5000km of track and 180 is about 200, so a million kilowatts if all the track has solar panels.
Assuming 3000kw per locomotive and 100% efficiency [2], that's 300 electrical locomotives running simultaneously. The Swiss fleet is about four times that.
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Of course I am no expert.
[1] https://en.wikipedia.org/wiki/List_of_stock_used_by_Swiss_Fe...
[2] and ignoring the 10 per year efficiency loss of the panels mentioned in the article
You don't need peak power all the time. The point of trains is that they're extremely efficient; most of the time they're essentially coasting, they only need a lot of power when accelerating or ascending.
If you want hard numbers, SBB used 1685GWh for passenger trains in 2025 [0].
The bigger problem with this idea is solar in Switzerland. It's fantastic during the summer but close to nonexistent during the winter [1]. Trains need to run year-round, so you'd need to overbuild solar monstrously to power SBB during the winter, or you'd need to solve seasonal electricity storage, which isn't easy. Pumped hydro is great but Switzerland has already built about as many artificial alpine lakes as the population is likely to tolerate.
[0]: https://reporting.sbb.ch/en/sustainability?=&years=5,6,7,1&s...
[1]: https://energiedashboard.admin.ch/strom/produktion
You don't need peak power all the time
3000kw is about 1/2 power for the most common Swiss electric engines.
And peak demand determines grid size.
> they only need a lot of power when accelerating or ascending.
Regenerative breaking on trains is a thing.
What are the economics of this? Cost to install vs other available options? Durability will certainly be an issue I’m sure. Genuinely curious and not because I think it’s a bad idea. I want solar on all underutilized areas, I just prefer low hanging fruit from a cost perspective at the current time.
Seems likely that safe access for maintenance makes this unappealing economically. Likely easier to have wider rail right of way and then put a panel farm on the side.
With the added benefit of being able to mount the tracks at an angle, and the added disadvantage of occupying area near the tracks that is occasionally used for maintenance equipment.
And getting approval to widen the right of way, where it’s even physically possible, and issues around flora suppression.
I imagine that the cost to install is fairly low since train tracks require regular monitoring and maintenance so it's fairly cheap to add the installation and maintenance on top of the existing schedule.
The manufacturer claims that durability should not be an issue. Time will tell.
Placing a cover over the area between the tracks makes it much more difficult to inspect the ties (sleepers) and ballast.
Yes, worsened inspection is a non-trivial problem. Very high quality sleepers (I wouldn't expect any other kind in Switzerland) mitigate this, but copying such approach in other countries could spell trouble.
I'm not an expert but I think the SBB is already pretty good at handling this. I think they already run measuring wagons (Oberbaumesswagen) with grond penetrating reader and ultrasonic measurement and use flow sensors to monitor drainage.
I would expect that the solar panels impact the efficiency at least somewhat but apparently not enough to cause real and enough issues for the SBB or perhaps they see ways to improve this in the future.
This might be exactly what you are asking for: low cost and low hanging fruit.
On paper, this should be pretty cheap. Normally, you need some mounting infrastructure to put the panels on, land preparation, etc. In this case, the train track provides the supporting infrastructure. You can bring in the panels via train wagons. Installation should be pretty quick and straightforward. And for cleaning, you could just do that from a rail wagon as well. Not having to truck in anything seems like it should be a big bonus here.
Durability might actually be fine. Solar panels are pretty reliable. And it's not like the train is in direct contact with the panels. The vibrations might be a challenge but presumably that would have shown up in the trials. It's something you could engineer solutions for. And so what if a small amount of panels fail?
Another issue with solar deployment is that there needs to be power cables that can consume the electricity.
But a train company practically always has running trains when the sun is shining. So they wouldn’t need to worry about disabling and losing money on the panels.
The real challenge is economically connecting the panels to a rail substation.
This is another bad idea in the same vein of solar roadways. To the layman, these ideas sound fantastic. To the knowledgeable they sound downright absurd. Put them on roofs, over car parks, over land. No way should they be on difficult to access locations with vehicle traffic.
This has some more photos of the solar panels and the laying of them https://www.swissinfo.ch/eng/emissions-reduction/solar-energ...
It makes more sense than the road, because at least the train isn’t driving directly on the thing. I wonder if the power could be delivered directly to the train. Although the only savings really would be transmission costs, not sure how big of a deal that is…
> at least the train isn’t driving directly on the thing
It’s just kicking up dust and dripping lubricant onto it.
Maybe this makes sense. I’m deeply sceptical. Especially when you could just be putting vertical panels to the sides.
https://www.swissinfo.ch/eng/emissions-reduction/solar-energ...
That seems pretty optimistic in the long run. Even a high power leaf blower won't get all the dust off of a dirty surface, especially if any sort of hydraulic oil, bearing grease or other viscous fluid mists onto the surface.
At least trains no longer drop literal shit between rails...
One thing that has struck me with our own solar panels is that they have to be very dirty before I notice any significant degradation in efficiency. And when they do get completely covered in pollen or leaves, a brief rain is usually enough to clean them.
Until you realize that polan is super stick and is really had to remove. I had a table outside and just 'blow away' dust didn't work at all. You need to actually clean with friction, water and cleaner.
It's solar, of course the unit economics are going to pencil out positive in the majority of climates and energy markets. The real question is "why should we put them here instead of somewhere else."
I wonder if the benefits are legal/jurisdiction/political. The total amount of track they could install this on is huge, and it doesn't seem like something that will be disagreeable on the local level. It could just be the easiest place to put it to deal with property law and zoning etc.
Another political benefit is that it means work for a very large number of jurisdictions, as there are suitable tracks just about everywhere.
> It's solar, of course the unit economics are going to pencil out positive in the majority of climates and energy markets
This is far from an of course. There were idiots trying to do solar roads a few years ago. The math didn't pencil out.
1. That was 20 years ago. I wonder how it would pencil out now.
2. Yeah it was kind of dumb to put the panels into a high wear environment like a road.
3. What matters more is which projects pencil out the best. There are too many to choose from that have a positive ROI.
> 3. What matters more is which projects pencil out the best. There are too many to choose from that have a positive ROI
Sure. I'm unconvinced a railroad is the best place we need to be putting panels for anything other than PR value.
If PR value gets panels installed faster than they otherwise would be who cares. The most important thing is we install as much solar as possible as quickly as possible, because we're killing ourselves fighting wars for other energy sources that poison our entire planet to use.
This is a great example of the solar ecosystem finding new niches. Tracks are likely good because there is already constant maintenance and inspections on them as well as ready hookup to the grid or, as the article mentions, directly providing power for trains. The point here isn't that this is 'the most efficient way to use solar' it is that it works and provides benefit. It is like agrovoltaics. The solar production is lower than a dedicated solar installation, but the dual use of the land and potential secondary benefits make it worth while. It looks like this could even get to the point where solar could actually power the trains completely assuming this expanded a little beyond just the track surface which could be interesting for the design of trains.
I'm in the south UK, live off grid, and have a bunch of solar panels, none of them are flat aside from the 640w of panels on my van, which generate almost nothing during the Winter.
Panels on the sides ot trains might be a better solution.
WTF is the downvote for?
You didn't promote nuclear power.
But promoting it seems like a way to get bombed back to the stone age by the Muricans.
Bad website. No photo, only a video, and that wants to start with an ad.
Putting solar panels in familiar places is always popular as an idea, but rarely better than putting them on the usual roofs or as rectangular arrays on the ground.
> the railway was fitted with 48 specially-designed solar panels with a combined power of 18 kWp.
18 kW is less than what gets installed on a lot of houses. It took 100 meters to do this. The farther the panels get from the interconnect, the higher the losses along the line.
It’s easy to set up 18kW of panels in one spot. Covering an entire railway with panels would require a different transmission setup to get the power back to somewhere useful.
I really wish we could just forget all of these ideas to put solar panels in places that are highly trafficked and serving double duty. Just put them in unused space that isn’t used for anything else: Rooftops, empty fields, or over parking garages. I often get downvoted for saying this because a lot of people like these ideas of putting solar panels in space that they see, like sidewalks or roads or railways, but we have so much unused space that isn’t near foot traffic, road traffic, or railways that is so much cheaper and easier to use for solar. These projects usually turn into political grifts to get government funding because the ideas are not economically viable alternatives.
> It took 100 meters to do this.
Thankfully, Switzerland has lots of meters of railway.
> Covering an entire railway with panels would require a different transmission setup to get the power back to somewhere useful.
There's caternary on 99% of Swiss rail, every few dozen meters, that already transmits power.
> There's caternary on 99% of Swiss rail, every few dozen meters, that already transmits power.
Switzerland runs on 15 kV catenary voltage. Transformers suitable for that kind of voltage cost a lot of money.
To be fair, swiss train tickets cost a lot of money too.
> Thankfully, Switzerland has lots of meters of railway.
The linear meters of railway are nothing compared to the square meters of rooftops. Putting panels in a long row is the maximally worst arrangement you can come up with.
> There's caternary on 99% of Swiss rail, every few dozen meters, that already transmits power.
I guarantee this wasn’t oversized to accommodate power transmission duties, too.
It’s also high voltage line. The solar setup would need additional and expensive high voltage equipment to interface with the line and to work within the design parameters of a line that was designed to deliver to the train, not carry extra power.
You could put the panels anywhere else and connect them normally to the grid like every other installation.
> I guarantee this wasn’t oversized to accommodate power transmission duties, too.
Its sole purpose is power transmission, to the trains.
You understand that wire doesn’t have infinite capacity, right? You can’t just point to a wire and say “problem solved”.
I can’t even tell if you’re honest or just trolling at this point in the conversation.
> You understand that wire doesn’t have infinite capacity, right?
Why would it need that? Your original complaint was "18 kW is less than what gets installed on a lot of houses". Which is it? Too much to handle or too little?
Always nice when something that I suggest in a random comment only to get a dismissive reply, turns out to be an idea worth persuing all along.
> idea worth persuing
Remains to be seen, considering how much snake oil there is in the solar market (but to be fair, this makes more sense than solar roads). A news article summary of a press release isn't proof of much.
Being right about things you have no control over is a bit like being right about your favorite flavor of jelly.
Can you be wrong about your favorite flavor of jelly?
Of course.
I have tried entrepreneurial stuff twice before, in my 20s, though without much success. Having ideas good enough to get investors interested is a sign that perhaps I should have another go at it.
These are not ideas worth pursuing from an engineering standpoints. It doesn't make any sense compared to just doing the cheap and proven at scale thing of just placing them in normal fields.
But I will agree that the idea has proven marketing merit. This is a class of truly top tier snake oil. The solar roadways people continue to go unbelievably far on almost the same grift.
This proves it is an idea worth selling to some people. Not the same thing.
(to me it seems especially nuts because there's plenty of space to the side of most railways!)
Trains AND solar power. Awesome.
I don't know why people fall for this stuff. It doesn't make any kind of sense. You put the panels in a rectangular array in any convenient place. That's what wires are for.
Solar sidewalks, solar roads, now solar rail?
WHY?! Dave from eevblog did the math and it's bad
Did we really fill up all the area on top of roofs, parkings lots, industrial areas, etc., and we're running out, and we have to put solar cells on railroads?
I think these kinds of ideas capture easily impressionable, elected representatives whose technical knowledge is non existent.
> Did we really fill up all the area on top of roofs, parkings lots, industrial areas, etc., and we're running out, and we have to put solar cells on railroads?
I guess it is easier to control the deployment since they own the railroads.
And all the train depots and train stations are already covered in solar panels, I presume.
They don't need to because it is just a PoC and I don't think it hs been said anywhere that soloar panel between rain tracks would be the unique source of energy.
There are also a lot of vertical sound proofing barriers that could be equipped with panels.
Since the 90s our energy policy has been idiotic. Basically just politicians saying 'lets do nothing we can always buy cheap power form Germany or France'. All we had to do is build a single new nuclear power plant and we would have been fine.
But no, instead we have this grifting rail solar nonsense.
Today we sail
On the Solar Rail
For there's much we just don't know
So farewell with a kiss
Then it's fast for the mist
Till we're sleeping in the cold below
Cold: the metal boxes going
Hard: the tracks on which we roam
Panels when the dark's not coming
Feel the weight of what we tow