4 ms·

Solar roads seem like a really cool technology. Like, if they worked great and were affordable and everything, then awesome! But, practically speaking, they s

by _Nat_ 7y ago

Solar roads seem like a really cool technology. Like, if they worked great and were affordable and everything, then awesome! But, practically speaking, they seem to violate the [single responsibility principle](https://en.wikipedia.org/wiki/Single_responsibility_principle https://en.wikipedia.org/wiki/Single_responsibility_principl...). By coupling a solar panel to a road, we're forcing the physical entity to comply with competing objectives. Seems like the future's prone to be different, anyway. For example, how long are we going to really need roads that're driven over at-random like today? Seems like self-driving cars could be designed-and-programmed to drive over just specific parts of the road meant to handle their weight, while the gaps between those load-bearing parts can have solar panels.

sigstoat 7y ago
> Seems like self-driving cars could be designed-and-programmed to drive over just specific parts of the road meant to handle their weight, while the gaps between those load-bearing parts can have solar panels. if you can drive that precisely, why even put anything in the gaps?
- _Nat_ 7y ago
  Same reason we have safety rails around roads. Plus, if we want solar roads, solar power would be a perk. I mean, once the road is dominated by self-driving cars, presumably we can implement new driving requirements beyond what human drivers could implement. For roads, we might want cars to drive over load-bearing parts, if that's optimal. Or if it's more efficient to have the wear-and-tear distributed, then cars can drive in staggered formations, much like a wear-leveling strategy in solid-state drives (SSD's). But, there's no reason to design a transportation system around the premise that self-driving cars can't control their patterns just because human-driven cars couldn't. Which isn't to say that we should assume that self-driving cars will be perfect or infallible, just that we can assume best-effort strategies. For example, we shouldn't assume that self-driving cars would never drive over a gap with a solar panel, but we can design a system in which self-driving cars try to avoid driving over the solar panels.
kolinko 7y ago
You know you kind of described how trains work? :) I just did a quick calculation for Poland - we have 11k km electrified train tracks, with ~1.5m of space between the rails. If I calculated correctly, putting solar panels there would give us ~8-15tWh energy per year, which is 5-10% of the required electricity production for the nation. I've never been a fan of the idea of solar roads, but solar railways might actually make sense...
- reaperducer 7y ago
  I don't know how they do it in Poland, but in some countries when you flush a toilet on a passenger train going above a certain speed, the nasty stuff just evacuates to the space between the tracks.
  - _Nat_ 7y ago
    Seems like any sort of solar panel on the ground is going to be prone to get nasty stuff on it. I guess they might just have them at an angle, then trust the rain provide some light cleaning, while a street/rail-cleaner could go by for more thorough cleanings periodically? I mean, I dunno what exactly their strategy is, but I'm assuming that they're not counting on a road to not get dirty. Cars leave rubber from their tires, drip oil, drop trash, etc..
  - RadioHacker 7y ago
    There's an old folksong: https://lyricstranslate.com/en/oscar-brand-humoresque-passengers-will-please-refrain-lyrics.html https://lyricstranslate.com/en/oscar-brand-humoresque-passen...
- dredmorbius 7y ago
  Mechanical equipment, and freight, tends to fall onto tracks. Axels need lubrication, there are hydraulic fluids, potentially septic drops, and bulk containers (coal, sand, gravel, metal, scrap, grain) also leak from bins. None of these do much to improve efficiency or lifetime of solar panels. Rail has adjacent easements. These have traditionally been used for complementary technologies, e.g., telegraph and other comms routes (which share a need for continuous rights of way, and provide a utility to the railroads themselves for communications and control services). There are reasons you might want to avoid certain co-sitings (e.g., unarmoured petroleum or natural gas lines adjacent to rail trackage). But solar could well be a reasonable adjunct.

by _Nat_ 7y ago

sigstoat 7y ago

> Seems like self-driving cars could be designed-and-programmed to drive over just specific parts of the road meant to handle their weight, while the gaps between those load-bearing parts can have solar panels. if you can drive that precisely, why even put anything in the gaps?

_Nat_ 7y ago
Same reason we have safety rails around roads. Plus, if we want solar roads, solar power would be a perk. I mean, once the road is dominated by self-driving cars, presumably we can implement new driving requirements beyond what human drivers could implement. For roads, we might want cars to drive over load-bearing parts, if that's optimal. Or if it's more efficient to have the wear-and-tear distributed, then cars can drive in staggered formations, much like a wear-leveling strategy in solid-state drives (SSD's). But, there's no reason to design a transportation system around the premise that self-driving cars can't control their patterns just because human-driven cars couldn't. Which isn't to say that we should assume that self-driving cars will be perfect or infallible, just that we can assume best-effort strategies. For example, we shouldn't assume that self-driving cars would never drive over a gap with a solar panel, but we can design a system in which self-driving cars try to avoid driving over the solar panels.

kolinko 7y ago

You know you kind of described how trains work? :) I just did a quick calculation for Poland - we have 11k km electrified train tracks, with ~1.5m of space between the rails. If I calculated correctly, putting solar panels there would give us ~8-15tWh energy per year, which is 5-10% of the required electricity production for the nation. I've never been a fan of the idea of solar roads, but solar railways might actually make sense...

reaperducer 7y ago
I don't know how they do it in Poland, but in some countries when you flush a toilet on a passenger train going above a certain speed, the nasty stuff just evacuates to the space between the tracks.
- _Nat_ 7y ago
  Seems like any sort of solar panel on the ground is going to be prone to get nasty stuff on it. I guess they might just have them at an angle, then trust the rain provide some light cleaning, while a street/rail-cleaner could go by for more thorough cleanings periodically? I mean, I dunno what exactly their strategy is, but I'm assuming that they're not counting on a road to not get dirty. Cars leave rubber from their tires, drip oil, drop trash, etc..
- RadioHacker 7y ago
  There's an old folksong: https://lyricstranslate.com/en/oscar-brand-humoresque-passengers-will-please-refrain-lyrics.html https://lyricstranslate.com/en/oscar-brand-humoresque-passen...
dredmorbius 7y ago
Mechanical equipment, and freight, tends to fall onto tracks. Axels need lubrication, there are hydraulic fluids, potentially septic drops, and bulk containers (coal, sand, gravel, metal, scrap, grain) also leak from bins. None of these do much to improve efficiency or lifetime of solar panels. Rail has adjacent easements. These have traditionally been used for complementary technologies, e.g., telegraph and other comms routes (which share a need for continuous rights of way, and provide a utility to the railroads themselves for communications and control services). There are reasons you might want to avoid certain co-sitings (e.g., unarmoured petroleum or natural gas lines adjacent to rail trackage). But solar could well be a reasonable adjunct.