Exactly, I was recommending having a look at them as they show that we can't just stick solar panels everywhere and that they really don't make a lot of electricity. The road in America could barely make enough energy for the heating elements built into the solar panels on some days.
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Network Rail Recommends 80% of the network should be electrified by 2050
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I've just wasted far too much time trying to persuade people who thought it is cool that it is dumb. They ignore evidence for it being a total waste because they are so enamoured with the snake oil they've been sold.
I'm saying it is snake oil? It is similar to putting solar panels across the whole of HS1 in that sure it seams a great dream but would be far too expensive and not produce enough power.
Firstly, I hadn’t realised that Government was now allowing solar farms to bid for contracts for difference with wind farms. My apologies.
Two things here though
a) It’s 364 hectares, which by my maths is 364km at typical railway formation width (10 metres). And you don’t want to build over the top of open railway for all sorts of reasons, not least cost. On embankments / cuttings they need to face the right way, and for many only half will be useful. And then there is the electrical architecture of solar farms, which generate low voltage D.C. which needs to be rapidly stepped up to high voltage to avoid current loss, and inverted to AC to go into the grid. A solar farm will do this centrally in one (or a small handful) of ‘substations’ - a 360km long farm would need hundreds.
b) it’s in Kent, just about the sunniest part of the U.K. An equivalent in the far north of Scotland would generate about 60-70% of the power.
Therefore, solar is not practical for very thin, very long sites, and the railway is not a practical place for long thin solar sites in any event.
I’m a massive fan of renewable energy, but solar just doesn’t cut it for this sort of application. It’s best suited to micro generation for local sites, or larger sites concentrated in sunny areas. Wind is far better for large scale generation, and has the significant advantage of generating much more electricity per unit of installed capacity.
You’d be surprised how inefficient diesel trains are. I’ve posted elsewhere, but a typical modern DMU only beats a modern diesel car with single occupancy for carbon emissions on a per mile basis if it is more than approximately half full*. Clearly electric cars knock spots off diesel trains in that respect.
* with 4 people in a car it becomes very interesting. I can get my family to Lancashire and back by car at an average of around 30g/km CO2e per passenger. Compare to electric rail, let alone diesel. (I know there is wide variation in how you calculate CO2e for rail).
Mordac
Established Member
CO2 emissions are not the be all, end all of efficiency though. Even if they should be counted onto a comparative analysis, they don't exhaust it.
Deepgreen
Established Member
Exactly, especially given the staggering debt facing us after C19. I suspect, sadly, that cheap and nasty will be the norm for decades to come, with any serious investment absent. I fervently hope I'm wrong.
I noticed by the way, that the Budget, issued just before C19 really took off (but after it emerged and was posing a threat), contained seemingly 'generous' railway (and other) spending, which surely the government must have known could not be delivered, if it had anything like a handle on the crisis then unfolding? It looked very suspiciously like an attempt to appear generous to the electorate while knowing it wouldn't have to follow through with the goods.
Deepgreen
Established Member
This is going to seem very naive, I'm sure, but is there any reason why all new trains cannot have solar panels built into their roofs (and buildings, cars and so on, for that matter)? Obviously the power generated would not be adequate for traction, but there must be a significant power source available that is currently untapped. Roofs are generally unused surface areas (and are notorious for soaking up solar radiation in the summer anyway), so is it only the capital cost of panels that holds this back? I suspect the future of renewable energy will be from many inputs rather than singe-source, so all contributions should be explored.
For trains, it’s a matter of keeping the things clean, and avoiding them being damaged (a surprising amount of stuff lands on train roofs). A typical 240m long train might have space for enough panels to generate 70kW if all the panels were perfectly aligned to the sun, on a sunny day at 1300 in June. Their annual power generation would be about a 10th of that at best, and that assumes they don’t spend much time in tunnels or cuttings. They and their auxiliary equipment would also weig( about 10tonnes, which would have to be lugged around 24/7.
Far better to put the same panels on buildings. In my opinion all new buildings should have PV solar panels (and solar water heating) on their roofs where the orientation is correct. Especially public buildings (schools, hospitals and, yes, stations etc). See Blackfriars station.
Brissle Girl
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I guess one question would be how much the panels weigh, and thus the energy cost of carting them (and any associated electrical gubbins) around all day, just to generate some electricity during daylight hours. How much would that offset the power generated? Also, I presume it would not be possible on existing trains as the loading gauge wouldn't leave enough room. For new trains, that would presumably mean a slightly lower roof line, though whether that would be noticeable inside the train I couldn't tell.
I did read recently that there is the potential for a considerable improvement in solar panel efficiency likely in the next few years, which may make use of them in any scenario more viable.
My point is that I am.
Solar Roadways are drastically overpriced and don't work, but people lap it up and don't listen to reason with them because it sounds cool.
southern442
Established Member
Slightly off topic, but adding to the sustainability longer term, should we not be designing trains that will last a little longer than 35 years (which I believe is the design life of certain recent builds in this country). This could also include (probably much to the annoyance of some members) conversion projects and other more creative ways to make trains last longer, as with the class 230 project among others.
I shouldn’t worry about that. ‘Design life’ doesn’t mean much in reality. There’s plenty of trains in service now well into their 4th or 5th decade that had a design life of 30 years. If it’s good enough it’s young enough.
Deepgreen
Established Member
Yes, but apart from that...! The weight issue had occurred to me - I would imagine that technology may advance to a point where they could be almost a film-like coating to surfaces such that their physical presence would be far less significant. Agree completely about the application to buildings - it's scandalous how little this has been done so far.
GRALISTAIR
Established Member
Absolutely no doubt about that in my mind too.
Class 170101
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Could we not 'create' some structures on station platforms for solar panels that work both in the summer and the winter? In the summer they generate electricity and keep people cool by shading the people underneath and during the winter whilst not generating much electricity they give people a chance to keep dry undernaeth then whilst it rains?
A bigger scandal is how little solar there is in Spain, in a country that is ideal territory for it. In 2018, the U.K. had three times as much installed solar PV than Spain. The situation is changing rapidly now, but my goodness they have taken their time.
Well, that’s basically putting panels on canopies. There will never be a case for building structures specifically for panels, even if they have other use. But where the structures are being built, it does make sense to put panels on them, as long as the orientation is reasonable.
edwin_m
Veteran Member
Solar panels work well with a "north light" roof - ridge and furrow with the southern slopes well oriented for panels and the northern ones glazed to admit daylight but not sunlight.
Indeed so. Exactly what Blackfriars is. The extension at St Pancras would be perfect for a retrofit. Enough space for 2MW up there.
edwin_m
Veteran Member
It's probably in the shadow of the Barlow trainshed a lot of the time though.
While it is a problem that there is not that much PV in Spain, it's far more a scandal that the UK has so much, when it is one of the worst countries for them to be.
There's certainly situations in the southern parts of the UK (solar farms, optimally placed panels atop buildings) where they are useful net energy-producers, but so many will barely recover their manufacturing energy because we encouraged sub-optimal uses in places which don't get much sun for them for political reasons.
For years - the UK and other northern European* Governments subsidised PV cells for inefficient uses in some of the least suited parts of the planet. This meant that prices were artificially inflated globally and a vast proportion of the PV manufacturing process went on making cells that would be very badly deployed while making them too expensive for places where they would be better deployed. Now, OK, Spain and Italy could have paid the higher price before 2008, but they would have certainly bought more PV if the market wasn't skewed by Northern European subsidies for poorly placed panels.
The UK's desire for renewable energy ought to be primarily focussed on harnessing wind and water - we have a relatively high amount of both those natural renewable resources - unlike solar. Instead we've given far too much focus on solar. Part of this is due to insularity: climate change is a global problem needing global solutions and if we make it harder for green electricity producers to be deployed where they would do the best benefit as it doesn't matter as long as we look green, then that's just stupid.
*my semiconductors lecturer at uni 15 years ago went on a rant once about how Germany was encouraging - with massive subsidies - local government to buy PV cells for their buildings. His main concern was the sky high global price of optical quality silicon (which his research needed), because Germany was eating up so much of the raw resource capacity. But also he pointed out that Germany isn't that good a place for solar energy, and that these local governments made little effort to optimise usage: they bought them because they were cheap and because they were good publicity. A lot of our lab work on solar panels was designed to show that solar panels needed to be put in a highly optimised position, especially in the UK, or it's just wasteful.
Actually, not much is, certainly at the times when solar is actually generating useful power.
Can’t argue with much of that.
I think I once saw a map showing the area that would need to be covered by solar in the Sahara to satisfy the entire world’s electricity needs. It was surprisingly small; something like a square with sides 150miles long. Obviously it would need a lot of cables and an enormous battery!
Brissle Girl
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And the world would be somewhat of a hostage to fortune of whatever country the supply was sited in.
GRALISTAIR
Established Member
Exactly. It is more efficient to generate locally. So sure some solar in the UK on new build houses etc, some wind especially offshore and probably some tidal and please some nukes.
Obviously (I hope!) I wasn’t suggesting a large solar farm know the Sahara. Merely that the area that needs to be covered by solar panels at such a latitude to provide the wolrd’s Electricity needs is surprisingly small.
2MW doesn't sound very much for the area of the full extension.
edwin_m
Veteran Member
On the other hand the price of PV has come down dramatically in that 15-year period, partly due to those subsidies creating a mass market. So solar is now more viable even in areas where it is intrinsically less efficient.
There was a mass market to begin with (sadly mostly in places like Northern Europe that are ill-suited for solar, and would be better off with other stuff). Brits didn't really need subsidies to buy PV cells as we already wanted them - either as a status symbol, or as a way to get rid of the electricity bill (normally both) - the subsidies for household ones were just for the over-50s only as they were less likely to see return on a 20-30 year investment. The subsidies were bought in, because we were obsessed with solar and saw it as the solution and so wanted lots of it and the Government get political points for actively supporting that, etc.
We've seen some of the obsession over solar as a panacea in this thread with the "heh, there's this place where we could put a load - who care if it will only work half the year / needs a massively expensive rig to put the panels on" - that was around before the subsidies.
The main factor (though subsidies ending helped bring the price down) in price decrease - like with all electronics - is that the Chinese are producing tons of them cheaply (in very environmentally unfriendly factories) and flooding the market.
There's still a finite amount of raw materials, there's still a lot of energy needed to make the cells, and it's still a total waste to deploy solar panels in the UK in a just-because-we-can method. Targeted and limited deployment - even if there's not a small number - is the way forward. Putting some on the St Pancras annex might be a good idea (though I'd can't imagine they didn't look at it when designing and come to the conclusion that it wasn't).
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