Is this renewable energy nonsense-on-stilts?

[sharpener]

Don't know if this has been covered before but it has only just come to my attention (July/August issue of Engineering and Technology magazine).

LNER have installed lineside wind turbines by the ECML at Craigentinny to capture the energy from passing trains according to this more or less identical press release.

Having worked in the wind turbine industry I am deeply sceptical this is an economically or technically viable idea. They claim "A single turbine can generate enough energy to power a third of a small station's lighting needs" which may be true for continuous operation. But passing trains will only take say 18 secs to go past and with a minimum headway of 3 mins that is a duty cycle of only 10%.

Also they appear to be vertical axis turbines which are notoriously much less efficient at capturing the wind energy than the horizontal axis turbines which predominate in the market for good reason.

It's possibe that Treeva's technology has a use for providing remote power near busy main roads but I can't see it being useful for the railways. Or am I missing something?

 

[thenorthern]

Given that trains will already be slowing down to stop at Edinburgh by train point I think the location is relatively poor to trial this.

Also in the grand scheme of things, the amount of wind produced by passing trains isn't that great and it's for a very short time.

 

[Zomboid]

Presumably the wind of the prevailing weather will also spin them. Train generated turbulence is "wasted" energy which might be harvestable.

It won't be much use as traction supply, but for a remote low powered something the possibility of being able to avoid a grid connection is worth investigating.

Everybody laughed at the Swiss solar panel track, and that hasn't been the total failure that many would have expected.

 

[edwin_m]

Probably uneconomic as a wide-scale power source but may have uses where low-power equipment needs to run with no supply nearby, with battery storage. The sort of thing where a solar panel might be used, but maybe in deep cuttings that don't get much sunlight? However, it's a small niche.

 

[contrex]

(1) it's proof-of-concept; (2) three of these turbines would provide the lighting needs of a small station. Not so silly.

 

[sharpener]

Probably uneconomic as a wide-scale power source but may have uses where low-power equipment needs to run with no supply nearby, with battery storage. The sort of thing where a solar panel might be used, but maybe in deep cuttings that don't get much sunlight? However, it's a small niche.

(1) it's proof-of-concept; (2) three of these turbines would provide the lighting needs of a small station. Not so silly.

Concept is already proven for remote sites, I have seen mobile phone repeaters powered by a combination of small turbines and solar panels on hilltops in the Canaries 10 yrs ago for example. Presumably there was battery storage in the equipment cabins for still nights.

Wind turbines having moving parts require more upkeep than solar panels and any capital equipment at lineside is not very accessible for maintenance. Still remain to be convinced that Treeva have any USP.

 

[gazthomas]

With modern LEDs power requirements aren't that high necessarily. I haven't looked at the article, but if battery storage is part of the solution that will definitely be helpful

 

[The exile]

Concept is already proven for remote sites, I have seen mobile phone repeaters powered by a combination of small turbines and solar panels on hilltops in the Canaries 10 yrs ago for example. Presumably there was battery storage in the equipment cabins for still nights.

Wind turbines having moving parts require more upkeep than solar panels and any capital equipment at lineside is not very accessible for maintenance. Still remain to be convinced that Treeva have any USP.

Is not the concept here the extra energy to be gained by the turbulence from passing trains? As you say, the energy to be gained from that may not be much, but if there might be extra to be gained from positioning, then why not put it to the test.

 

[Zomboid]

Concept is already proven for remote sites, I have seen mobile phone repeaters powered by a combination of small turbines and solar panels on hilltops in the Canaries 10 yrs ago for example. Presumably there was battery storage in the equipment cabins for still nights.

Wind turbines having moving parts require more upkeep than solar panels and any capital equipment at lineside is not very accessible for maintenance. Still remain to be convinced that Treeva have any USP.

I don't have especially high hopes for it, but it's worth testing these ideas out to see. If they can power something in a location where getting power would otherwise be very difficult and/or expensive then there might be some use for them.

 

[cadder toad]

Using the air turbulence created by a train to drive a wind turbine sounds an inefficient form of regenerative braking

 

[The exile]

Using the air turbulence created by a train to drive a wind turbine sounds an inefficient form of regenerative braking

Maybe, but it is always going to exist and if you can tap into it with turbines a)at minimal extra expense and b) without losing the wind that would otherwise be powering those turbines there may be circumstances where it makes sense. This is a trial, isn’t it ? Let’s give it a chance.

 

[quantinghome]

Everybody laughed at the Swiss solar panel track, and that hasn't been the total failure that many would have expected.

It's been a success inasmuch as it has produced power for a year without getting bashed by the underside of a train. Which is not surprising given it's at the end of a sleepy branch line which sees one low speed train per hour.

But reliability is not really the issue. It's whether creating a very long single line of solar panels is a scalable proposition. There's a reason grid-scale large arrays of solar panels are arranged within an area rather than a line - it minimises the length of wire needs to connect them all up. Stretching those out in a single row means you either have the mother and father of all resistance losses, or you use much thicker wires (nice thief magnet), or you have to have a very large number of inverters and transformers. Either way it rapidly becomes uneconomic.

The other issue is the claim of rapid detachment of the panels to allow track maintenance to take place. It's actually 10 minutes per 6 metre panel. So how much time does that work out as when you need to replace ballast, rail or sleepers? Efficient high-output machinery will replace in the order of 1km in one night shift. So how do you remove 100-200 panels before you start the actual work, then replace them afterwards on a night shift when every minute counts?

 

[Zomboid]

It's been a success inasmuch as it has produced power for a year without getting bashed by the underside of a train. Which is not surprising given it's at the end of a sleepy branch line which sees one low speed train per hour.

But reliability is not really the issue. It's whether creating a very long single line of solar panels is a scalable proposition. There's a reason grid-scale large arrays of solar panels are arranged within an area rather than a line - it minimises the length of wire needs to connect them all up. Stretching those out in a single row means you either have the mother and father of all resistance losses, or you use much thicker wires (nice thief magnet), or you have to have a very large number of inverters and transformers. Either way it rapidly becomes uneconomic.

The other issue is the claim of rapid detachment of the panels to allow track maintenance to take place. It's actually 10 minutes per 6 metre panel. So how much time does that work out as when you need to replace ballast, rail or sleepers? Efficient high-output machinery will replace in the order of 1km in one night shift. So how do you remove 100-200 panels before you start the actual work, then replace them afterwards on a night shift when every minute counts?

So at most that'll have a similar use case to these wind turbines - small scale generation for small loads remote from a proper grid connection.

It's not going to provide anything measurable for traction or anything like that.

 

[quantinghome]

So at most that'll have a similar use case to these wind turbines - small scale generation for small loads remote from a proper grid connection.

It's not going to provide anything measurable for traction or anything like that.

Yes, the 100m trial array has a maximum output of 18kW. The capacity factor looks to be around 9% (going from the stated output from the developer), which is towards the lower end of the typical CF from Switzerland.

 

[sharpener]

There's a reason grid-scale large arrays of solar panels are arranged within an area rather than a line - it minimises the length of wire needs to connect them all up. Stretching those out in a single row means you either have the mother and father of all resistance losses, or you use much thicker wires (nice thief magnet), or you have to have a very large number of inverters and transformers. Either way it rapidly becomes uneconomic.

It would be trivial to make a divided panel with 4 connections so the start and finish of the array are at the same end. Or there might be an advantage to having mulitple microinverters with a high voltage AC bus. (Though actually 8 typical panels in series produce 240V d.c. anyway so the loss is about the same for a given current.)

100m is not very long for a return run in any case. One of my solar arrays has 4 x 20m downleads, it is divided in two both for redundancy and to halve the lead resistance/voltage drop.