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6. Comments and Observations on the Consultants Trolleybus Study
By Eur Ing Irvine Bell BSc CEng MIMechE CDipAF PGCE
Dear Edmontonians:
I am a British Chartered Mechanical Engineer with over a quarter of
a century's experience and interest in the engineering and operation
of diesel and trolleybuses.
I have been following via the web current developments in Edmonton
which seem to be leading towards the abandonment of Edmonton's
trolleybus system essentially for narrow short term budgetary cost
savings. While I have no personal gain or loss from any decision
Edmonton makes with regard to the future of its trolleybus system, I
must express concern that your city seems headed down the wrong
road. With its trolley abandonment proposal, Edmonton now stands in
stark contrast to many cities around the world that are retaining
and developing their trolleybus systems. Re-investment in
trolleybuses is taking place in North America in cities such as San
Francisco, Seattle, Vancouver, Boston and Dayton. In Europe the
examples of Arnhem, Athens, Bergen, Bologna, Geneva, Lucerne, Lyon,
Milan, Moscow, Naples, Salzburg and Solingen come to mind. A new
system in Rome is due to open this September.
Around the world towns and cities find trolleybuses to be a very
effective means of providing high quality urban transportation with
minimal local and environmental impact. Trolleybuses operate
successfully and reliably in all regions and climates of the world.
They often complement light rail systems, feeding light rail
stations as they do in Edmonton. On well run systems, trolleybuses
are generally popular with the public who travel on them, live or
work near them. There is real evidence to suggest this popularity is
reflected in significantly increased patronage compared with
comparable diesel bus operation.
I have seen a copy of the Booz Allen Hamilton Report entitled
Trolley Operation Review-Strategic Alternatives. Overall I consider
that the Report is a poor basis on which to base decisions on the
future of Edmonton's trolleybus system. In the following, I offer my
opinions on what I consider some of the Report's more serious
shortcomings. Please bear in mind these observations are not meant
to be all-inclusive or absolute.
I would urge the citizens of Edmonton to look long and hard at any
notion of abandoning their trolleybus system. Your city needs to
consider seriously how the operation could be continued and the cost
effectiveness of the trolleybus system improved. The study does not
address either consideration.
On the whole, the following observations can be made regarding the
Report:
- There are rather obvious problems with the analyses of key
environmental and financial issues.
- It contains much irrelevant material like the fleet histories of
former North American trolleybus systems, or pointless mathematical
exercises such as counting the number of individual bus stops served
by trolleys.
- It is incomplete. It contains many sweeping generalisations
without much in the way of qualification or expansion. Particularly
noteworthy in this regard is on page 11 where it fails to record
that the decision to close the Toronto system has been officially
regretted. It takes a narrow North American view [p. 11], ignoring
trolleybus developments in Europe and elsewhere that would put
Edmonton's situation in a totally different perspective.
- It is unbalanced. It focuses predominantly on pro-diesel
arguments, and either excludes or minimizes arguments which would
favour trolleybuses.
The Report majors on two areas, environment and cost related issues.
Let us consider each of these in some detail:-
ENVIRONMENT
Energy Efficiency
On page 16 the Report tries to develop the argument that energy
efficiencies for trolley and diesel are similar [24.4 % for trolley
and 22% for diesel]. The Report has not allowed for more efficient
future power plants, or for regeneration technologies. At a quoted
efficiency for Edmonton's power plants of 34%, there is considerable
scope for improvement just by applying existing technology. Using
Report figures as a baseline, allowing for regeneration boosts
trolleybus efficiency to 34.9% [24.4/0.7] and increasing power plant
efficiency to a conservative 50% [e.g. through high efficiency
turbines, combined heat and power, etc.] further boosts trolleybus
efficiency to 51.3% [34.9*50/34].
By contrast improving diesel efficiency very much from the 22%
figure is likely to be difficult or impossible. For example,
producing low sulphur diesel fuel boosts refinery CO2 output and
reduces refinery efficiency. Adding on complex and as yet to be
fully developed emission control equipment to diesels is unlikely to
do much to improve diesel efficiency - in fact it will very likely
have the opposite effect [contrary to the assertion on page 39].
Thermodynamic considerations dictate that there is negligible scope
for improving the best efficiency of diesels beyond presently
achievable levels.
Diesel electric hybrids may [implied reference on page 39] improve
overall diesel efficiency but at a potentially considerable increase
in diesel life cycle cost. Diesel fuelled gas turbine electric
hybrids [one is currently being trialled in London, England] may
allow the post 2008 diesel emission targets to be more readily met,
but small gas turbines cannot compete with the fuel efficiency of
diesels and life cycle costs are unlikely to compare favourably with
diesels.
Wide area emissions
On page 40 the Report attempts to assert that while current wide
area diesel emissions are greater than trolley, post 2008 diesel
emissions will actually be less.
There are four main sub-issues here:-
- The first is whether the legislated post 2008 diesel
particulate and NOx emission levels will actually be achieved at all
in regular daily operation of a large fleet over an extended period
of time [20 to 30 years]. It should be well known that while
specially prepared test engines or vehicles can be made to achieve
stringent targets during tests, regular production engines in
vehicles in daily use can perform much less well.
- The second is whether achieving future targets will only
prove possible by radical change in diesel technology that will
impose direct substantial cost and weight penalties and increase
long term costs of ownership significantly compared with current
diesels [for example frequent battery renewals on hybrids]. In which
case this could make nonsense of the Report's assertions about cost
advantages of diesel-based alternatives to trolleys.
- The third is that the Report's figures for power plant
emissions would seem to be way over the mark compared, for instance,
with European power plant data. This suggests there must be
considerable scope for improvement using established technology. For
example the Report quotes 2020 trolley emissions of particulate as
expected to be 0.23 g/km against post 2008 diesel expected of 0.06
g/km. A Swedish Report [which probably went more thoroughly into the
issues] studied Netherlands [Arnhem] trolleybus emissions, based on
a large proportion of coal fired generation and came out with a very
different and much more favourable set of trolleybus figures. The
Swedish Report's European data shows that trolley emissions of 0.012
gm/km - one fifth of the post 2008 diesel particle standards - are
already being achieved at power stations in Europe! There are
similar discrepancies with the NOx data.
- Coal containing more carbon than diesel, will other factors
being equal, produce more of the global warming gas CO2 [which tends
to disadvantage coal fired trolleybuses compared with diesel].
However, current European coal fired power generation also does much
better in this regard than the figures cited in the Edmonton Report:
1380 g/km for trolley compared with 1880 g/km for diesel according
to data in the Swedish study cited above. Again, there appears to be
considerable room for improvement in Edmonton area power emissions,
and it may even prove practical in future to 'capture' the CO2 at
the power station.
- There is also an essentially political judgement to be made
when comparing emissions based on coal or diesel as the base fuel.
In Alberta, coal is a locally produced and an economically and
politically stable fuel. Diesel costs depend to a large degree on
the world petroleum market. Thus, it might be felt a prudent
political decision to power public transport to an even greater
degree than presently using electrically from locally owned utility
companies using locally produced coal or natural gas. This is a
significant issue that Report does not address.
Local area emissions
Local emissions are actually what matter. Trolleys exhibit a major
advantage in this area because they produce ZERO local emissions.
Although the Report includes considerable detail on the potentially
harmful effects of diesel exhausts - even acknowledging on page 26
that near bus stops pollutant concentrations can be magnified as
much as 40 times - the Report fails to develop the issue to the
extent necessary to properly evaluate the trolley's zero emission
advantage in this regard.
Trolleybuses provide absolutely guaranteed zero local emissions
under all circumstances - idling, cold running, stop start duty
cycles, sub optimal maintenance, aging vehicles, etc throughout
their lives. This cannot be said for diesels.
The Report also fails to address the issue of air quality inside
vehicles. U. S. and European experience suggests that this is could
be a much bigger problem than external levels. The authors of the
Report would appear to know little about bus aerodynamics and are
unaware that diesel buses tend to drag their own exhaust inside the
salons because of the area of very low pressure that occurs toward
the front of the vehicle. There are health impacts on driver to be
considered, who suffer even more sustained exposure than passengers.
Open windows during warm weather also serve as an entry point for
harmful diesel emissions.
COST RELATED ISSUES
The Report makes much of cost arguments asserting that cost
considerations favour diesels. There are several observations that
can be made about the Report's assertions:-
- The Report seems to base analysis only on cost per kilometre
considerations for three years when almost 50% of the diesel fleet
is brand new, and the trolley fleet is 20 years old. Costs simply do
not physically accrue on a per kilometre basis. Some costs like fuel
accrue approximately on a per km basis if exactly similar duty and
loading cycles are being compared, while other costs tend to be more
time based e.g. corrosion. Basing an analysis on quoted cost/km
basis, as the Report appears to have done is not a reliable way to
come to valid conclusions.
- The only way to properly compare what are long term [20 to
30 year] investment decisions is by doing a life cycle discounted
cash flow [DCF] analysis and judge financial outcomes by net present
value [NPV] or internal rates of return [IRR] type considerations.
The Report does not appear to have done this. Such an analysis would
also permit factoring in the ridership [revenue], a point the Report
also misses.
- The Report does not seem to clearly distinguish between past
or current data [on a cost/km basis] and likely future data. The
reader is led to believe future costs will be the same as past
costs, which is unlikely. The Report should have compared future
trolleybus purchases against future diesel purchases and performed
life cycle analysis including testing financial models for
sensitivity to assumptions such as relative future costs of
electricity and diesel fuel, trolleybus and diesel maintenance costs
and extra costs associated with achieving post 2008 diesel levels of
emission compliance [see my earlier comments]. Just looking at the
Report's cost per km figures, there are a range of future
possibilities that should have been considered in a variance
analysis. For a sample variance analysis,
click here.
- The Report has assumed that diesel and electricity fuel
costs will remain similar. This is not likely over a 20 to 30 year
period. In the UK, for instance, over the last half dozen years
diesel fuel costs to bus operators [who pay little or no tax on
diesel fuel] have gone up around 60% while wholesale electricity
costs have fallen 40%. Probably over 20 to 30 years, the cost
advantage will be with electricity because of the greater ability of
a relatively smaller market to control prices, but modelling with
different assumptions is needed to determine the importance of the
effect.
- The Report has assumed that future trolley and diesel
maintenance costs will be similar to current costs. This is most
unlikely and the advantage is likely to be with the trolleybus, but
again modelling different scenarios will determine the importance of
the effect. Vehicle maintenance costs - assuming similar duty cycles
- can be divided into body, etc., costs like corrosion or wear and
tear, which are substantially independent of traction technology and
drive line and braking costs which are very dependent on traction
technology. Modern trolleybuses, for example such as those for
Athens get about as close to zero traction system maintenance as it
is possible to get. All major units can be expected to last the full
life of the bus and routine maintenance is reduced to occasional
changing filters and greasing motor bearings. No current diesel
technology can match that and the maintenance or unit replacement
requirements of post 2008 diesels could be considerably more onerous
than current diesels if the very demanding emissions standards are
to be consistently met. In addition, modern trolleybuses employ full
electric braking considerably reducing braking system maintenance
costs compared with diesel.
- The Report has assumed that future post 2008 diesel
acquisition costs will be similar to current ones. While current
trolleybus technology costs can probably be reasonably reliably
projected into the future, one cannot simply make this assumption
for diesel post 2008.
- The Report gives no consideration to trolleybuses being more
popular with passengers [and non passengers] and to the potential
revenue implications. Evidence from Seattle, San Francisco and
Arnhem [Netherlands] indicates trolleybuses attract more riders over
diesel buses by 10%, 18% and 21% respectively. This suggests that
trolleybuses could support significantly higher operating costs than
diesel and still come out financially ahead.
- The Report recognises the significance of trolleybus
overhead [in financial terms a 'fixed cost'] utilisation in the
overall economics of trolleybuses. The Report recognises that
current utilisation is below what it should be because of Edmonton
policy [unusual amongst other trolleybus operators] of frequently
substituting diesels for trolleybuses.
- However, the Report fails to consider the possibility of
expansion of the Edmonton trolleybus system. According to pages 5
and 6 Edmonton operates up to 39 trolleybuses on 140 route km of
overhead in amongst a fleet of 736 diesels; there are 20 spare
trolleybuses. It would seem highly possible that expansion of the
Edmonton trolleybus system could significantly improve overhead
utilisation [well beyond the Report's 95% maximal assumption to,
say, 150% or 200%], effectively reducing trolleybus costs while at
the same time bringing other financial benefits like increased
patronage. Other means of intensifying the utilisation of the
current system (such as increasing the mileage per vehicle and
reducing the number of spares) are also possible, but again were not
considered.
Irvine Bell
Eur Ing Irvine Bell BSc CEng MIMechE CDipAF PGCE
email: ibell@bell.go-plus.net
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