this post was submitted on 03 Sep 2023
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Sweden is testing a semi-truck trailer covered in 100 square meters of solar panels::A Swedish manufacturer wants to harness green energy from a cargo trailer's free real estate.

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[–] [email protected] 37 points 1 year ago (2 children)

Rough estimate of 72 cell panels at 2m² and 500W per panel puts this at a peak performance of 25kw. More than twice the average home installation.

[–] [email protected] 49 points 1 year ago

Yes, but also much less efficient due to the angles. These panels are either completely flat or completely vertical. Ideal conditions have them facing south at an angle.

[–] [email protected] 18 points 1 year ago (3 children)

I feel like it could be great for running cooling systems on trailers and stuff like that, not sure if it would be worth the hassle for adding range.

Even on a purposely designed solar car like the lightyear one it really only works because they used all the weight saving and aero tricks possible, which you can't really do with a truck that's supposed to haul cargo.

[–] [email protected] 11 points 1 year ago* (last edited 1 year ago)

Yeah. the one good use I see is reefer trailers. Since some times they have to sit long times, with still the coolers running to keep the cargo within demanded thermal limits to keep the cold chain uninterrupted.

Most cooling is obviously needed when it is hot... so in summer and thus sung light time. So the panels would probably nicely run the coolers instead of having a fuel burning generator keeping the coolers going.

During winter, when there is no light. Well it's probably cold enough ambient the reefer isn't using lot of cooling anyway.

[–] [email protected] 2 points 1 year ago (1 children)

Yeah but we're talking 100 square metres here, that could make a significant difference.

[–] [email protected] 6 points 1 year ago (2 children)

Only about half of it would actually be producing power at any one time, at a sub-optimal angle.

But I'm sure someone did the math and it makes some kind of sense for whatever use case they're imagining. Would still probably be better to have static solar panels along highways and charging trucks with some kind of pantograph setup instead.

[–] [email protected] 6 points 1 year ago

But I’m sure someone did the math

I would not put too much weight on that. The number of solar roadway projects and similar tech that when you run the numbers shows it being a complete waste of time - only for many different cities to invest in running a test (at their own expense) only for the project to fail later on for being too costly and not giving the benefits they were promised. Solar solutions seem to be the modern day monorail grift from the Simpsons...

Would still probably be better to have static solar panels along highways and charging trucks with some kind of pantograph setup instead.

This is the type of thing we should be investing in first IMO. A solar truck might make sense some day when solar is cheaper and more efficient - but we currently have a lot of static infrastructure around solar we could be building instead of these less efficient trucks (that is in terms of use of the solar cells, rather than the trust itself).

[–] [email protected] 5 points 1 year ago (2 children)

That's basically the way interurban trains operated for years before the highway system and personal vehicles replaced that mode of transport. It wasn't solar powered back then, but the idea makes a lot of sense.

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[–] [email protected] 2 points 1 year ago

20kwc capacity: nice also add 20kwh lithium storage at 200kg weight and it could help in few instances like cooling perishable cargo or driver's cabin when engine shut off, but definitely not to expand range

[–] [email protected] 34 points 1 year ago* (last edited 1 year ago) (4 children)

Putting solar on moving vehicles makes no sense except for very specific use cases.

Install those same panels on the ground and you can point them at a good angle for sunlight capture 24/7, don't have to literally carry the weight of them everywhere, don't have to worry about them getting dirty all the time from moving around winter roads, and are much easier to repair.

[–] [email protected] 39 points 1 year ago (5 children)

I'm not a solarogist, but how do you capture sunlight 24/7?

[–] [email protected] 7 points 1 year ago

Oops 🙊 you know what I mean though.

[–] [email protected] 6 points 1 year ago

bet on moonshine

[–] [email protected] 4 points 1 year ago (1 children)

Put solar panels on a vehical and move it around the globe xD

[–] [email protected] 2 points 1 year ago

Put the panels on a plane that flies above the cloud and chases the sun around the earth. And then use all the captured energy to power… the plane?

[–] [email protected] 4 points 1 year ago

It's Sweden, it works weird

[–] [email protected] 3 points 1 year ago

Solar panels on one side, lunar panels on the other! Boom! Free electricity 24/7!

[–] [email protected] 7 points 1 year ago (1 children)

It makes more sense than solar roads.

[–] [email protected] 4 points 1 year ago* (last edited 1 year ago) (1 children)

Solar ditches make more sense. Carrying solar panes add weight and air resistance. The trailer area is 416 ft which can hold ~33 panels if panel configurations are optimized for a trailer. Weight will be 3000 lbs, which cuts the tare payload by 6%. This is not enough electricity to run a semi with two drivers splitting driving responsibilities, running day and night, and in weather that does not have power for the cells.

Trains are the most efficient system that we have. I wonder how the math would work for trains? I expect that it would be a net gain, but the added complexity of connecting and disconnecting for each car as the cars get switched in yards would be a nightmare. Once travelling, there is little braking and acceleration, which lowers the power demands.

[–] [email protected] 6 points 1 year ago

Yes but sadly no one wants to talk about trains.

It's really killing the Utopian dreams of public transport

[–] [email protected] 4 points 1 year ago (1 children)

It'd be good for temporary power after a natural disaster or for an event.

[–] [email protected] 4 points 1 year ago

A tractor trailer FULL of solar panels would be great!

[–] [email protected] 2 points 1 year ago (1 children)

Pretty sure these solar panels aren't just your regular residential or commercial building panels. They are specially made for this purpose.

[–] [email protected] 6 points 1 year ago (8 children)

Those don't exist.

Amount of power that can be generated is dictated by the angle to the Sun. You need to be perpendicular. Panels on the ground can slowly move and rotate to kind of track the sun. Or you put a bunch of mirrors and make a tower made of solar panels.

Solar panels on roof tend to be fixed infrastructure. You get what you get.

So if they apply panels to a vehicle you have two options. Flat or angled.

If they're flat and the only time you're ever going to get the maximum amount of power from them is during noon when the sun is directly above your vehicle. If angled that means the height of the vehicle has changed and they direction that they work is very dictated. If they track the Sun then they're probably going to waste more power than they can ever produce by constantly moving because you're on a vehicle that's constantly moving.

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[–] [email protected] 24 points 1 year ago

It’ll help a little in the long summer days. In the winter, when it’s mostly dark, removing the panels to save weight may be a good idea.

[–] [email protected] 19 points 1 year ago (1 children)

So it seems they might cover a weeks travel assuming 1000km per day. I wonder how much extra weight this would add, and if it's significant compared to the extra weight of the battery and cargo.

[–] [email protected] 12 points 1 year ago* (last edited 1 year ago)

It's gonna be significant.

Every extra bit of weight is one less bit of freight.

Also gonna be a lot more annoying when a shipper punches a hole in the side with a forklift.

[–] [email protected] 9 points 1 year ago

It's free real estate.

[–] [email protected] 9 points 1 year ago (2 children)

Imagine testing solar panels in Sweden

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[–] [email protected] 7 points 1 year ago

I swear it seems like some of these harebrained schemes must be being created by people who want solar to fail so that they can point at the failure when the dumb idea doesn't work.

[–] [email protected] 4 points 1 year ago

I could see this working for either running cooling and such for refrigerated cargo or if they stick a battery in the trailer. In the latter case it would be possible to just charge it for free while the trailer sits in a lot somewhere. Then when the truck comes they plug in the battery and use the stored up power.

[–] [email protected] 4 points 1 year ago

I'm guessing it won't be driving to Lapland this winter.

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