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Comment by dvh | Hacker News Reader

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.

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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.

Want to take a stroll on Google maps with me and see all the unused or underused land in the US? People don't actually take up all that much space.

I just did a cross country drive a few days ago. We are not constrained on land.

US is not the whole world. Sure, if you have deserts, use them. Poland does not.

https://commons.wikimedia.org/wiki/File:Population_density_o...

Or are you talking about a different Poland?

People don't take up that much space and there is a strong tendency for populations to collapse into concentrated cities. In general, across the entire human species. All cultures and countries behave this way.

I think you've got plenty of free land.

Can you take a look at actual satellite map and tell me where all the unused land you apparently see is?

Pretty much all of the land in Poland is used - either for agriculture, forests or human settlements.

> Pretty much all

So like maybe 99%? Are you say it should be strictly 100% and none of it for solar?

You only need 1% of land for solar to sustain entire population.

> 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.

You aware, what always runs right next to a railway right? I mean the capacity might be already saturated for the driving current, but cables next to the railway won't be a new thing.

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.

yes but things on the ground are exposed to significantly more dirt and critters than things suspended off the ground.

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.

must be nice

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.

>Generating the same amount of power as one fossil fuel plant requires a vast amount of land are

Lets not forget that it's not just the land the power plant sits on that is used by fossil fuels.

VAST areas are mined and drilled out

Yes, I mentioned that. And especially for coal, it's a big issue. But realistically coal is dying anyways, it's natural gas that's the main competitor. And oil&gas:

- ... often has its land use sited far away, in Texas and the Dakotas, or even offshore. Solar would realistically have to go everywhere; even assuming perfect transmission(!), you don't want to bunch it up in one region so it's not a single point of failure.

- ... employs lots of people / requires constant high-paying labor. Solar is built once then mostly just sits there. Which is good! But explains why residents might be fine with the former, but not the latter.

- ... is more easily hidden away. See LA's hidden oil rigs.

- ... already kinda exists. Which is a lame argument, yeah, but obviously people are going to be fine with the pumpjack or oil field that's been there their entire lives, vs. new solar farms coming in and taking over what was forest or farmland.

Again, I'm on solar's side here, obviously it's a better land use. But we can't just handwave away the entire land use issue, it's that kind of stance that makes people grow hostile to it.

There's a load of land near me that's just used entirely for some horses to chill in.

Planning permission was put in to add a solar farm. Got "objections" because it's "farm land".

It's not viable to grow anything on...

> 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.

Because they are people who make trains. The people who own farms think about making solar fields. The people who own roads think about making solar roadways. The peo who make trains think about making solar trains. All of these possibilities can be trialed in parallel by different people. It is the same reason that if asked to design a combination lock safe, you would probably reach for a microcontroller and a keypad instead of a bucket of gears, because you are (I presume) a software person and the hardware people can try the other way.

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.

  Urban Metro / Trams: 2 to 10 kWh/km

  Commuter Trains (EMUs): 4 to 12 kWh/km

  Regional / Intercity Trains: 6 to 20 kWh/km

  High-Speed Trains: 15 to 60 kWh/km

  Freight Locomotives: 10 to 50+ kWh/km

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.

How often do stuff fall of the rails, and how common is derailment? In case of derailment you’ve got much bigger problems than some broken solar panels.

>more prone to damage there from stuff falling off the trains, derailments, etc

How often is a train derailed? And even then everything has to be replaced anyway...

Same goes for "stuff falling off", you can easily replace the panel(s)

> Stop trying to attach it to moving things. Movements breaks things. Just put the panels by the rail

Literally, they are not being attached to a moving thing and are being put by the rail lol. Just in between the tracks.

Like you say, PV cells don’t have moving parts and don’t need much maintenance. So mass produced cells you can slap anywhere are really not a bad idea.

The area between the rails does contain moving parts and needs maintenance though.

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.

> Solar cell is the only practically viable power source with no moving parts

Did you forget about batteries and fuel cells?

>rolling out 100 metres of photovoltaic (PV) panels in between active tracks in Buttes

RTFA

Did you read the article?

Of course he didn't, he partially described exactly what they're doing

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