Green Energy

air currents from trains, especially high speed ones throw rocks and debris everywhere.

It's companies trying to make a quick buck. They tried this with roads too.

Obviously every home should have them first and all newly built homes should be built with solar efficiency in mind.

Hell parking lots are massive areas of dead space, build them over the damned things, it'll help against the heat island affect and give shade.

Deployment on rails is dirty cheap. Can be highly automated and you have highvolt power line just a few meters away.

If you put solar upon your roof, 2/3 of the costs are labor costs. The material bill encompasses electrics, mounting system, cables, and pv panels that can get reduced on railways as well.

Roofs are actually not that great. Installation is expensive because you are working at height. Roof angles and directions are also not ideal on many houses. Compare it to a simple installation on a field: You just take some corn field, stop growing corn there and can put your panels on some cheap holders and you're good. You can access and service them without the danger of falling from a roof. You can install them on an industrial scale instead of a few square meters on every single roof. You need only one electrical installation.

People love to cry about the loss of agricultural space, but currently we are growing a lot of corn to convert it to fuel or to put it into biogas installations. If you convert those field to solar, you will get more energy from them. And the loss of a big monoculture that is using a lot of pesticides is also great.

Or in parking lots. It would also have the added benefit of providing cover for cars.

I’m guessing this installation is an experiment to quantify these figures rather than a commitment to roll this out more broadly.

No need to guess, it's right there in the article.

ROI would take a lonnnnng time, in my view. It's the same idea as installing modules under asphalt roads or even above them. It's not really worth the O&M hassle whatsoever.

The same idea goes for installations like canals. They're linearly too so not the wisest use of modules. But the benefit of modules over water like that is lower rates of evaporation as the panels block the sun. Same is true for water department reservoirs that see lots of algae. The panels block the sun and choke out the algae.

But you're right about the shading. If these panels are installed in higher latitudes, then odds are they might never see the sun directly at certain times of the year. Usually solar designers only recommend flat horizontal mounting for modules in hurricane- or tropical storm-prone regions like near the tropics, or close to the Equator where the Sun shines directly overhead most of the year.

What I COULD see happening is if governments around the world start transitioning railroads to have H-frame structures that suspend feeder lines like what's used in electric trains with pantographs. If you set up those H-frames frequently enough, you have the underlying structure similar to carports and can install modules 4-10 modules wide. THEN you can utilize string inverters every 7-8 H-frames or so, converting the solar DC power into AC which can help feed the train loads as they pass or feed the grid.

Bonus of the above system is that over time, all trains including rail freighters become electric or at least hybrid to make use of the free power generated above them throughout the railway.

Lots of ideas!

By "in series", do you mean linearly? Depends on context.

For Commercial & Industrial (C&I) applications like rooftops, canopies, façades, canals, floating islands, and the like, panels can be strung in series linearly sure. But because C&I arrays also tend to be arranged in polygons and more often rectangles, this allows the solar designer to string in non-linear ways.

One way to string in these contexts is to prioritize loops where the start and finish of the string are 1 module apart. A lot of RF enthusiasts don't like it when modules are strung this way because conductors arranged in a loop act as an antenna that can send and receive EM waves.

Another way to string is the snake or zigzag method where strings are patterned like this: ,,,,|'''''''|,,,,|'''''''' in rows that are 2-modules wide. The snake method can also be applied to 3-mod, 4-mod, etc. wide rows depending on what stringing method ends up being feasible.

For ground-mount applications at the community-, Distributed Generation- (DG-), and utility-scales, solar stringing is usually done linearly or in loops due to the constraints of the racking, although snake/zigzag can apply in some instances. Ground-mounts can either take the form of fixed-tilt (FT) racking, single-axis trackers (SATs), or dual-axis trackers (DATs).

With FT, the usually racking setup is 2-in-Portrait (2P) where you have 2 rows of modules abutted next to each other facing South. These are usually designed in long rows along a property line, so it's easy to make strings completely linear or half-loops where you turn the string around at the halfway point of what would otherwise be a string line. FTs can also be arranged as 3- or 4-in-Landscape (3L or 4L) which allows for more loops and snakes/zigzags.

With SATs, you're always stringing things linearly.

For DATs, you get the same benefits as C&I, 3Ls, or 4Ls because each DAT is separated from the rest of the array so the mini-array can track the sun. Lines, loops, or snakes/zigzags work, with a preference for loops and snakes/zigzags because DATs are rarely sized large enough to accommodate the entire widths of strings (sometimes 15-30 modules in length).

With railroad-based solar, my bigger concern is that since the modules have to be in a single line that CAN'T repeat in rows to the North/South in a typical array, this means all those strings will need to run a long way before being collected at an inverter to turn into AC. That long length adds to voltage drop in the circuit, which is an energy loss on the system. You can get away with this by adding microinverters for every 1 or 2 modules. Microinverters like that add a lot more complexity in terms of Operations and Maintenance (O&M) purely because there are more parts to break down. With string inverters and even central inverters, you have less O&M breakage but the flip side is that those work better with more centralized/rectangular-like arrays.

Doesn't mean it can't be done, but it's certainly more expensive than any other implementation of solar.

One of the benefits I can actually see with using microinverters over string or central inverters is that you break up the "array" of modules so that shading from the trains affects less of the "array" than if everything was collected at the DC level. You can isolate the shade-affected parts better, and promote better energy reduction.

Idk I'm interested to see what comes from this! Definitely a wild idea haha

I think the biggest limitations will be security, someone will definitely be trying to steal them

Not disagreeing, genuinely curious and hoping you know more than I do. Haha

You say minimum maintenance, but it seems like this would require almost constant maintenance to me. Animals shitting on them, trains blowing dust, rocks, shards of metal onto them, scratching their surfaces and diminishing their use over time by blocking sunlight from constant debris and scratching. Would it not make more sense to measure the height of the lowest bridge/tunnel on the track's route, and put these on a platform at that height? At that point, they could be angled, or even potentially have those motors that track the sun, while keeping them safe from damage from flying pebbles and dirt, and providing shade for the train to run under? I doubt the shade thing matters that much, but assuming these are passengers trains (I'm a USian, so I've only ever heard of passenger trains in folklore and western movies), it could limit the amount of air conditioning the train needed to keep passengers cool, perhaps?