On Sun, 6 Nov 2005 23:32:21 +0000, Clive wrote:

In message , Richard J.
writes
Clive wrote:
In message , David
Bradley writes
On Sun, 6 Nov 2005 17:31:23 +0000, Clive
wrote:

In message , David
Bradley writes
Then I am one ofthe few because there is no such thing as a clean
diesel, only a less dirty one. Progress would have been served
if the route had been electrified with zero polluting,
Such a thing doesn't yet exist.

Please explain further. In my book a trolleybus IS zero polluting.

David Bradley

Not only do trolley buses pollute, (carbon from motor brushes
asbestos from brake pads etc.) but there is also the pollution
from the source of the traction current supplied.

Asbestos is no longer used in brake pads. From the DfT website:
"Regulations introduced under the Consumer Protection Act, the Road
Vehicles (Brake Linings Safety) Regulations 1999, prohibited the
manufacture, supply or fitting of asbestos-based brake linings."


Modern trolleybuses [and trams] use brushless AC motors - the amounts of
carbon dust released into the environment by traditional trolleybus [and tram]
DC motors was hardly enough to be any kind of issue anyway.

Both trams and trolleybuses need to make some use of friction braking
material. Fundamentally modern trolleybuses and trams have rather similar
friction braking arrangements and are about equally polluting at a level which
in practice must be considered as negligible, particularly because both trams
and trolleybuses do most of their braking electrically, unlike diesel buses
which depend heavily on friction braking systems.

Yes - there is pollution "from the source of the traction current" for all
electric vehicles, trams and trolleybuses. But this pollution is NOT directly
dumped into the air breathed on the streets AND the levels are much lower than
from diesel vehicles, a fraction by comparison in fact, even if the power is
generated by burning fossil fuels in thermal power stations.

A study done in Sweden comparing the emission levels into the environment as a
whole for Netherlands trolleybuses, which are powered from an electricity grid
with a similar generation mix of coal, gas, etc., to our own, showed the
following comparison for pollutants emitted directly by diesel buses and
indirectly from power stations on behalf of trolleybuses:-

NOX - trolleybus 7% of diesel
CO - trolleybus 3% of diesel
HC - 0% of diesel
Particulates - 2% of diesel
CO2 - 73% of diesel

If I accept that and the juice is generated somewhere, car to explain
how, and why are there no losses between power plant and consumer?

There are power losses between power plant and consumer. In the UK grid,
these losses have been quoted as 9%. The above pollution figures factor in
all losses between power station and trolleybuses.