onthecushions
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« Reply #30 on: January 27, 2018, 11:36:18 » |
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You might have added that hydrogen (.....)
Didn't want to over-egg the case. I could just wear LNG or LPG▸ as these are relatively safer although a history graduate like Grayling should still read up on gas lighting in trains, (Quintinshill, Ais Gill and Hawes). A bus only needs to carry energy to move 10t for less than a daily 100miles, a rail vehicle needs energy for a large multiple of both. A steam loco has a low pressure (<20bar) fire tube boiler that experience and process have now tamed. A water tube boiler in a power station can run at 180bar, all you then need is some of ET's overhead cables.... Have a nice weekend. OTC
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broadgage
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« Reply #31 on: January 27, 2018, 16:45:46 » |
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Hydrogen though highly flammable is not that dangerous as has already been said. Any leakage will normally escape and disperse upwards. It is however a new risk, and I am not in favour of introducing new risks, unless this leads to an overall reduction in risk.
The greater risk is arguably the bursting of the large pressure vessel, with the almost inevitable ignition of the contents being secondary.
I also have misgivings about the hazards of producing and transporting the hydrogen.
It sounds to me as though this will be a splendid gravy train of studies, consultations, new safety rules, and ever growing safety requirements adding ever more cost and complexity.
IMHO▸ , the near term future is diesel power for non electrified routes. Diesel/battery hybrids are a distinct possibility since this would permit of a smaller, cheaper and lighter diesel engine that is sized to meet the AVERAGE power demand, with peaks being supplied from a battery. Adding extra motored battery coaches to an existing DMU▸ sounds a worthwhile experiment. Consider for example a 4 car voyager to which an extra 2 battery vehicles have been added. The 4 existing engines would meet the average power demands with the battery being used for acceleration and ascending inclines. The battery would charge when coasting or stopped or proceeding slowly.
The longer term future is more electrification of longer distance, high speed, or busy routes, with battery power for secondary routes and branch lines.
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A proper intercity train has a minimum of 8 coaches, gangwayed throughout, with first at one end, and a full sized buffet car between first and standard. It has space for cycles, surfboards,luggage etc. A 5 car DMU▸ is not a proper inter-city train. The 5+5 and 9 car DMUs are almost as bad.
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stuving
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« Reply #32 on: January 27, 2018, 17:09:08 » |
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Back to hydrogen trains. interesting comment in a letter to Modern railways,
German trains will be used on lines without tunnels! Suggests roof mounted tanks could be a fire hazard ir they leaked in tunnels of which we have quite a lot.
Of course the reason for this observation (which is where we came into this bit of the thread) is much more prosaic. That the trains for this trial service won't go through tunnels tells us nothing about whether it's too dangerous, just that it needs some kind of safety authorisation. That calls for making a safety case, proposing suitable measures, getting it considered by the competent authority, and all that complicated and time-consuming stuff. So you obviously wouldn't do that for a trial, whatever the outcome's going to be - from 'impossible' down to 'OK as the trains a built and operated now'.
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Rhydgaled
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« Reply #33 on: January 27, 2018, 18:06:22 » |
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The longer term future is more electrification of longer distance, high speed, or busy routes, with battery power for secondary routes and branch lines. In my view, there should be a vauge high-level target for very extensive electrification of the network, where only long stretches of track with less than an hourly service remain unwired. For the remaining few lines, the hydrogen concept possibly has one or two advantages over battery power. The main one is that a 5yr old battery appears to hold alot less charge (or decharges faster when you use it) than a brand new one, meaning the batteries would probably have to be replaced about 7 times over the life of the train. I don't know if hydrogen fuel cells are likely to degrade similarly. The other possible advantage is weight; batteries are heavy so maybe a hydrogen train would be lighter than a battery powered one. The important thing though is that only regional trains for rural railways ought to have a self-powered mode. Batteries, diesel engines and hydrogen fuel cells all should have no place on new intercity trains once the current orders for the Hitachi 80x series units are delievered (a few more for the Midland Main Line might not hurt, as long as they don't order enough to replace all the current fleet, since that will allow for a new fleet of pure-electric trains after resurection of the electrification project for the core routes to Sheffield and Nottingham).
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---------------------------- Don't DOO▸ it, keep the guard (but it probably wouldn't be a bad idea if the driver unlocked the doors on arrival at calling points).
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onthecushions
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« Reply #34 on: January 27, 2018, 18:27:42 » |
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R101?
Hindenburg?
OTC
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stuving
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« Reply #35 on: January 27, 2018, 18:38:11 » |
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The important thing though is that only regional trains for rural railways ought to have a self-powered mode. Batteries, diesel engines and hydrogen fuel cells all should have no place on new intercity trains once the current orders for the Hitachi 80x series units are delievered (a few more for the Midland Main Line might not hurt, as long as they don't order enough to replace all the current fleet, since that will allow for a new fleet of pure-electric trains after resurection of the electrification project for the core routes to Sheffield and Nottingham).
I would question that. Much of the network is so intensively used that the loss of OLE▸ at just one point on one track has severe consequences. It's not just a question of closing that track and working another bidirectionally, to support the full timetable. So some battery reserve, which needs a high power output but relatively little energy storage, would make that situation - presently all to common - no longer a big issue for operations and hence for passengers. Cost would be a consideration, but prices on batteries (and supercapacitors, which might suit better) are still falling. There would be other uses for such a capability too. I'm sure.
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stuving
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« Reply #36 on: January 27, 2018, 18:51:55 » |
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R101?
Hindenburg?
OTC
I think you'll find they weren't using hydrogen for propulsion, nor storing it at high pressure in steel vessels. When their big bags first ruptured, the hydrogen was mostly retained and burned in situ, close to those on board and (for the R101) the ground. Of course if they did use steel pressure vessels, they would never have got off the ground - and likewise a train with a big bag of gas on its roof would never fit in a tunnel anyway.
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« Last Edit: January 27, 2018, 19:43:33 by stuving »
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Red Squirrel
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« Reply #37 on: January 27, 2018, 19:20:43 » |
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...a 5yr old battery appears to hold alot less charge (or decharges faster when you use it) than a brand new one...
Depends on how you define 'a lot'. Real world experience of Tesla cars shows an 8% degradation over 100,000 miles (about 161,000km). Tesla anticipate that this loss of capacity is not linear; their simulations suggest a 20% capacity loss over 500,000 miles (~804,000km)*. I can't lay my hands on mileage figures for typical branch line DMUs▸ but I'm guessing that a properly-specified battery pack would not need to be changed many times in the life of a BEMU - and it would have decades more potential use as, for example, grid storage after that. * source: https://electrek.co/2016/06/06/tesla-model-s-battery-pack-data-degradation/
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Things take longer to happen than you think they will, and then they happen faster than you thought they could.
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broadgage
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« Reply #38 on: January 31, 2018, 04:20:13 » |
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Catch a bus instead,
One of these? As has been suggested that might be a demo run, but these vehicles or something similar, did run fairly regularly in London, on route RV1 I think. Reliability seemed poor with conventional buses often being used instead. The technology undoubtedly works to an extent, but that does not mean that it is sensible on environmental or financial grounds. AFAIK▸ , the costs were substantial with hydrogen costing a lot more than either diesel fuel or battery power.
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A proper intercity train has a minimum of 8 coaches, gangwayed throughout, with first at one end, and a full sized buffet car between first and standard. It has space for cycles, surfboards,luggage etc. A 5 car DMU▸ is not a proper inter-city train. The 5+5 and 9 car DMUs are almost as bad.
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TonyK
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« Reply #39 on: February 13, 2018, 17:54:29 » |
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R101?
Hindenburg?
Oh, the humanity! Let's do what Mr Grayling hasn't done, and think about this in slight detail. There are, on sale now, hydrogen powered vehicles. There are 14 publicly accessible refuelling points in the UK▸ , so for private vehicles, the infrastructure doesn't exist in a big way. If the technology is to prosper, many more plants need to be built. There are no hydrogen production facilities for railways at present, so new facilities will be needed wherever H 2 trains need to be refuelled. We had, during the Bristol Green Capital epoch, a hydrogen powered ferry with its own little solar powered production plant. That vanished as soon as the circus pulled out of town to fly to the next jamboree. If the idea is to become reality, there will have to be some serious money spent on facilities before the trains are procured. The way things usually happen with new train technology, we will end up with either sidings full of H 2 trains waiting for new fuel plants, or fuel plants and an army of trained technicians waiting for trains to service. Would it be worth it? I don't think so. Hydrogen is not a fuel as such, but a means of storing energy. You can mine coal, drill for oil and gas, and even harvest the magic moonbeams from radioactive stuff or the energy from tide and occasionally wind and sun. But while hydrogen is the most abundant element in the universe, it isn't in the UK. To make it requires a lot of energy. The process for making industrial quantities of hydrogen involves knocking methane atoms apart using superheated steam. If you are going to do that, with all the energy loss involved, you might as well send the power direct to the trains using OHLE. After all, a hydrogen cell only turns hydrogen back into electricity to power motors at the business end. The minister's stated aim is to not have trains powered purely by diesel. He could get away with a 1 Kw solar panel on top of every HST▸ and a lot of spin to achieve that. If Mr Grayling is serious, he will find that the easiest and most efficient way to decarbonise the railway is to copperise it.
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Now, please!
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Red Squirrel
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« Reply #40 on: February 13, 2018, 18:33:48 » |
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occasionally
Occasionally? Oc-CASionally? What, every third Wednesday after septuagesima? What fools they must be, those folks who are throwing their money away building wind and solar farms. And what fools we taxpayers must be to subsidise them - albeit at a fraction of the rate we subsidise nuclear and - yes - coal...
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TonyK
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« Reply #41 on: February 13, 2018, 19:35:52 » |
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occasionally
Occasionally? Oc-CASionally? What, every third Wednesday after septuagesima? What fools they must be, those folks who are throwing their money away building wind and solar farms. And what fools we taxpayers must be to subsidise them - albeit at a fraction of the rate we subsidise nuclear and - yes - coal... Alright, intermittently then, even if the 9-strong wind farm near my country home seldom has more than 6 actually turning, and frequently stands majestically still. And they're no fools - you don't think it's their own money, surely? It's our cheque book they sign ultimately. On the subject of money, I have yet to hear how £95 per MWh strike price for nuclear power equates to an "illegal subsidy", while £119 per MWh for offshore wind isn't. It drops to £114 next financial year, which is why the past few months have been a particularly good time to be a windmill builder. I shall ask Diane Abbott when I see her next. I shall also ask why on a windy February night, wind seems to be producing only a third of the 12 GW▸ it is claimed to be capable of. Is this because more wind turbines than usual require repairs? But I am no fan of Uranium as a fuel, even if nuclear will save the day in the long run. Fusion eludes us, but there is hope in Thorium, according to the New Scientist and other learned journals. Thorium could be the fuel that produces hydrogen in sufficient quantities to power the rail network. (See what I did there?)
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Now, please!
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Red Squirrel
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« Reply #42 on: February 13, 2018, 23:54:29 » |
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Not sure about those figures for offshore wind strike prices: strike prices for schemes commissioned for entry into service in 2022/3 are as low as £57.50.
Diane Abbott, eh? DIane Abbott? My hearing's not what it once was, but I'll swear I hear the muffled 'peep!' of yet another dog-whistle. There is obviously a problem in integrating wind and solar into the grid - chiefly their irritating tendency to produce more energy than required - but workable high-capacity grid-storage systems are not that far off. Even hydrogen generation might have a role, in extremis (see what I did there?)
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Things take longer to happen than you think they will, and then they happen faster than you thought they could.
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ellendune
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« Reply #43 on: February 14, 2018, 01:09:25 » |
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As I write on the very still frosty night 4.75GW of Wind power is supplying the grid with 14.83% of its total power needs.
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TonyK
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« Reply #44 on: February 14, 2018, 18:46:15 » |
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Not sure about those figures for offshore wind strike prices: strike prices for schemes commissioned for entry into service in 2022/3 are as low as £57.50.
Hence the rush to get them built now.
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