Re: Bio-diesel 159

Tony Polson wrote:
"Stephen" <newsmail04@xxxxxxxxxxxx> wrote:
But is electrification any more environmentally friendly?


That's the 64 billion dollar question.


At the source of traction its certainly cleaner, and can produce more power to weight, but its just moved the pollution from the train to the power station. Plus there's all the transmission losses to consider which, when generating electricity from fossil fuels, makes this less efficient and creates more pollution.

Transmission losses from power station to pantograph are about 5%.

You conveniently ignore the fact that electric trains can, and indeed do, *generate* energy during braking which can then be returned to the traction supply system, and in the case of AC, the grid. Typically between 10 and 25% depending on the stock and service in question. Like to see a diesel train do that (without lugging around a bloody great battery).



There may be a small saving in energy consumption. Whether this is
enough to justify the embedded energy in the electrification works is
another matter entirely.


However if the generation is to be from hydro or nuclear sources then electric trains become more viable in terms of efficiency and certainly pollution. Admittedly nuclear will leave a legacy but what other viable alternatives to a "clean" source of power other than hydro? With wind power the whole country would have to be covered with the blot on the landscape turbines and still wouldn't be able to produce enough power for our needs.


On the basis of the current and projected 'mix' of UK electricity
generation, the electrified railway would actually produce *more*
carbon emissions than the diesel railway it would replace. Of course
the trainspotters will howl in protest, claiming that the electricity
for their "new" train set will all be from nuclear or renewable
sources, but this is of course total nonsense.

As I pointed out to you the last time you made this assertion, the evidence suggests otherwise:

"Analysis has been carried out for this study on greenhouse gas
emissions, based on fuel consumption and emission levels. This
demonstrates that electric trains produce 20% to 36% less carbon dioxide
emissions than diesel trains, although these projections are affected by
uncertainty over long term energy policy and fuel availability (see
Tables 3.1 and 3.2)."

- "Study on Further Electrification of Britain's Railway Network", RSSB,
2007, page 22

Last time you declined to respond. Care to back your assertion up with some data from a trusted source this time?


It isn't as if other industries and consumers of electricity will
stand idly by while the rail industry claims all the new "zero carbon"
sources of power. They will want it at least as much as the railway
does. So unless the railway constructs its own dedicated nuclear
stations and/or renewable sources (which we all know won't happen) it
will be using exactly the same mix of power as everyone else.

True, but the other *transport* industries would have an interesting time drawing their energy from nuclear or renewables, and it's these industries that rail will be compared with.


And for the foreseeable future, the vast majority of this power will
come from fossil fuels - primarily Russian and Arab gas, and coal from
a world market whose prices doubled in the first half of 2008 alone.

The projected mix for UK electricity in 2020 is surprisingly similar
to now. Slightly less coal. Slightly more gas. More renewables, but
nuclear about the same as today because the number of new plants will
be roughly balanced by the old ones being closed down. The carbon
content of the electricity mix will therefore be much the same as
today, maybe just a little less.

So the electrification enthusiasts' claims for a low- or zero-carbon
source of power for their new OHLE are utterly false.



Not true - see above.
.

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