Solar roadways - but next level - Page 1
Forum section: electronics / general

author: Zeitkind
author_rank: Contributor
timestamp: September 23, 2022, 11:25:04 am
content: So, finally someone seems to get it right?Well, guess not. In Germany parts of the Autobahn will be covered by solar panels - but on a steel roof. They want to start testing with a 10m x 17m roof about 5,5m high above the road.https://www.heise.de/news/Solardaecher-ueber-Autobahnen-Deutsches-Pilotprojekt-beginnt-demnaechst-7273829.htmlBut because of the cost of such a roof construction, a wider coverage of the Autobahn is "not expected to happen". Oh, really? A 5,5m high construction made of steel.. *sigh*Can someone calculate the amount of steel that is needed to get some GWh?

author: coppice
author_rank: Super Contributor
timestamp: September 23, 2022, 12:00:07 pm
content: Quote from: Zeitkind on September 23, 2022, 11:25:04 amAround Munich a lot of the Autobahn verges are covered in solar panels. I wondered if that cuts maintenance costs, by suppressing weed growth, or increases it, by making weed control more awkward.

author: Ranayna
author_rank: Super Contributor
timestamp: September 23, 2022, 01:34:13 pm
content: Nothing in the article says that it is a steel roof, where the panels are put on top of. It just says "steel construction".I suspect it will be steel pillars, with a steel grid, to which the panels are mounted. But maybe a protective sheet underneath is required to prevent damage to the panels from below by grit or stuff like that.Considering the quickly rising costs of land, a setup like that does not sound unreasonable. But this particular project has many other issues.First: It will not actually cover the main Autobahn, but a side road. Bad, because thats not a reasonable test.Second: They want to look at the system "scientifically" for a year. Why? It's a damn solar system. They have existed for many years now. They should already know now how much it will produce.Third: They don't even know yet if they want to even connect this to the grid.

author: coppice
author_rank: Super Contributor
timestamp: September 23, 2022, 02:44:14 pm
content: Quote from: Ranayna on September 23, 2022, 01:34:13 pmThe basic panel performance is known, but there always important factors to assess. Maintenance, especially cleaning needs and costs, isn't easy to assess without a real world trial.

author: Ranayna
author_rank: Super Contributor
timestamp: September 23, 2022, 04:15:52 pm
content: Quote from: coppice on September 23, 2022, 02:44:14 pmTrue. But then they should place it over the main area of the Autobahn, and not on a side road. Very likely the vehicles there will be significantly slower, and there will be less traffic overall.

author: nctnico
author_rank: Super Contributor
timestamp: September 23, 2022, 05:35:17 pm
content: Quote from: coppice on September 23, 2022, 02:44:14 pmIndeed. And think about rain, snow and ice and how that tends to slide off solar panels which may cause all kinds of problems for the traffic below. And then there are safety concerns: what happens if a large truck (*) takes out a number of pillars that support the panels? How long does it take to repair? And emergency exits in case the pillars are closely spaced together? Putting solar panels over a road can become very costly.* Last summer I was driving on a highway through France. At some point we started to spot all kinds of truck parts on the road. I joked to my wife 'if we stop to pick all those parts up, we can built ourselves a truck'. A few hundred meters further there was a truck crashed into the berm at left side of the road. The person driving that truck is a hero; no other cars involved but it was huge mess. I hope the driver made it out in one piece.

author: Marco
author_rank: Super Contributor
timestamp: September 23, 2022, 07:14:02 pm
content: Silly idea. If you want PV for roads, make soundwall panels with PV.

author: EEVblog
author_rank: Unknown
timestamp: September 24, 2022, 01:36:05 am
content: Quote from: Ranayna on September 23, 2022, 01:34:13 pmYes, it would just be a basic frame with the usual solar panel mounting systems. You might have to think about water runoff or whatever, but you could also just ignore it.QuoteYeah, this is something you can easily calculate on a whiteboard and be sure it's going to be either viable or not, not need to test it in terms of solar output.

author: EEVblog
author_rank: Unknown
timestamp: September 24, 2022, 01:39:05 am
content: Quote from: Marco on September 23, 2022, 07:14:02 pmStill an order of magnitude better than solar roadways. I can this progress!Soundwall panels vs roofs depends on the local requirements at the location.

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: September 24, 2022, 01:52:37 am
content: As more vehicles become electric, won't sound walls be required less as most of the noise emanates from the vehicles exhaust?

author: Ranayna
author_rank: Super Contributor
timestamp: September 24, 2022, 07:04:04 am
content: Quote from: Ed.Kloonk on September 24, 2022, 01:52:37 amNo. The motors or exhaust are not the main source of noise. At least not in the most common european cars.I sometimes take a walk along one of our rural main roads, where the cars can (and do) drive 100 kph, or more. It's rare that i hear a motor sound. Most often it's the wheel and wind noise that is very noticable.Only when accellerating the motor noise can be quite noticable. And there are always at least some cars that seem to have an unreasonable sound design, where the engines are just obnoxious. And of course there are the motorbikesFor lorries that is somewhat different, but i don't see these electrified anytime soon. But even on those, the wheels are loud.

author: nctnico
author_rank: Super Contributor
timestamp: September 24, 2022, 12:27:33 pm
content: Quote from: Ed.Kloonk on September 24, 2022, 01:52:37 amNo. Noise from the tyres dominates. Actually BEVs are worse as these are typically fitted with very hard, low friction tyres that are extremely loud. If you find your car is noisy, then look at different tyres before anything else. The difference can be huge.

author: nctnico
author_rank: Super Contributor
timestamp: September 24, 2022, 12:34:00 pm
content: Quote from: EEVblog on September 24, 2022, 01:36:05 amThat is not the problem. However, before installing solar panels over highways on a large scale you really need to figure out any safety and maintenance issues (and the costs that come with it). Also think about routes that are being used for oversized transports. A while ago a study was done about putting solar panels over a highway near where I live. Turned out that the construction would classify as a tunnel which needs oodles of safety measures. The project got cancelled.

author: coppice
author_rank: Super Contributor
timestamp: September 24, 2022, 04:34:04 pm
content: Quote from: nctnico on September 24, 2022, 12:27:33 pmWhen accelerating I mostly hear my diesel engine. When up to speed I mostly hear the interaction between my tyres and the road. Each time the road surface changes, the noise in the car changes. This is not just an effect of being in the car. When waiting to cross a local 60MPH road I've listened to the Teslas and the non-electric luxury cars. They really don't sound much different.

author: Marco
author_rank: Super Contributor
timestamp: September 24, 2022, 05:21:30 pm
content: Quote from: EEVblog on September 24, 2022, 01:39:05 amBut if you are installing soundwall panels any way, might as well add them. It's a ton of steel and material facing high windloads, some PV isn't going to make much of a difference.This is true for a ton of surfaces on new construction. If government wants to do something useful, they should just mandate that all surfaces to which PV can be applied for a couple percent overhead after non recurring investments (given labor and other materials) they should be applied. With some subsidies to cover the initial NRI until there's a commoditized market for PV integrated building materials. The amount of PV which would suddenly be getting installed would make all the impossibly high hanging fruit projects irrelevant.

author: coppice
author_rank: Super Contributor
timestamp: September 24, 2022, 05:52:16 pm
content: Quote from: Marco on September 24, 2022, 05:21:30 pmIt depends where you are. In many places, one day after you cover a sound wall with conventional solar panels they will either be smashed or stolen. Some UK EV fast chargers seem to be loosing their leads overnight, as the copper is thick enough that even a few metres of lead seems to make it an interesting target for some people.

author: nctnico
author_rank: Super Contributor
timestamp: September 24, 2022, 07:14:20 pm
content: Quote from: Marco on September 24, 2022, 05:21:30 pmIMHO that reasoning is too shallow. The bottom line is; if it makes economic sense to put solar panels somewhere, it is a good place. One potential problem I foresee with putting solar panels on sound barriers is that solar panels have a hard surface which reflects sound instead of absorbing it.