Buses

Proof Of Their Popularity Comes From Experience In The Towns & Cities Which Use Them!

In Arnhem, Holland the transport operators have seen ridership increases in the order of 17% on routes converted from diesels on a "like-for-like" basis. Their five year "Trolley 2000" Trolleybus Rapid Transit (TBRT) strategy was conceived knowing that by using trolleybuses passenger levels would be up to 21% higher than would have been expected using the best type of diesel buses. In Salzburg, Austria ridership increases have been 16% and the city is part way through a long term trolleybus expansion project which includes several brand new trolleybus routes (one of which will be an express service with the overhead wiring configured for overtaking) and converting several more diesel routes to electric operation. Another aspect of these ambitious plans is to see an almost total elimination of fossil fuel powered buses from Salzburg's streets. (This is being done for environmental reasons). Increases in ridership have also been noted in the USA, for instance Seattle and San Francisco where experiences have been even more significant because not only has it been found that electric buses will attract more passengers than the diesels but also that replacing electric buses with diesels (even temporarily) can lead to passengers pro-actively choosing to avoid the buses! (almost certainly similar would have been found here in Britain, if anyone had bothered to conduct a passenger survey)

The San Francisco passenger survey found that while the streetcars are the overwhelming 1st choice - even for routes where they are not a viable proposition - the electric buses are considerably more popular than the motorbuses, which are actively disliked, being rated as noisy and smelly. Indeed when roadworks caused temporary motorbus substitution of some electric bus services (with service frequencies and journey times remaining unchanged) there was an 11.33% downturn in passenger patronage that can only be explained by passengers making a pro-active choice to avoid the motorbuses.

Even When The Electricity Is Sourced From Fossil Fuel There Is Still A Reduction In Global Air Pollution!

In an ideal world the electricity would be sourced from renewable sources as then the electric street transports would be truly 100% non-polluting and help humankind to follow policies for sustainable development. However in many places the electricity is sourced from fossil fuel burning power stations.

Critics often allege that by sourcing electricity from fossil fuels all that is really happening is that the pollution is being shifted up the energy chain to the power station. However, following extensive research in the University of California it has been found that even with low grade coal that produces a lot of carbon dioxide (as is used in Germany) electric traction offers an almost complete elimination of carbon monoxide and hydrocarbons, resulting in a significant global air quality benefit. Of course if the fuel used is high grade coal or natural gas (or another so called 'cleaner' fossil fuel) the benefits are even more admirable. Experience in Sweden has shown that when a type of coal-burning power station known as 'pressurised fluidised-bed' is used then the emission of sulphur oxides and nitrogen oxides are also considerably reduced; furthermore, when these facilities are linked in with combined heat and power facilities (ie: provides both electricity and hot water which can be made available to industrial and domestic consumers alike) then they are about 40% more efficient than their traditional large coal burning equivalents, (75% efficient opposed to 35% efficient) and are so clean that they can be located within cities.

As a contrast at best diesel engines are only 40% efficient and if you include idling, part loads etc., then this reduces to below 30%. Engines powered by other fossil fuels achieve even lower figures. Plus all the pollution is released in the street environment...

Electric Buses Are Environmentally Sound!

The environmental case for electric traction is that even with so-called 'cleaner' (but still finite) fossil fuels (eg: LPG, CNG, etc.,) the only proven viable vehicle propulsion system that will not pollute the air that we breathe in our towns and cities comes from electricity. Whilst renewable liquid fuels are available (gasohol, bio-diesel, etc.,) they still pollute their local environments so are more suited to quieter rural routes where air quality issues are less severe and economics suggests that electrification would simply not be a viable proposition.

Click either this link or the projector icon to download a 32 second hand-held video clip named 'Ped-zone-bus320.mpg' showing a seriously (air) polluted bus + taxi pedestrian zone in London plus this clean air equivalent scene from Geneva.

So, Knowing The Benefits, Why Aren't More Cities Investing In Electric Traction?

Perhaps the primary reason why more cities (outside of Britain) are not investing in electric traction is that the continuing limitations of battery technology means that the only way to obtain sufficient electrical energy for a full days' work is by making that energy available wherever the vehicle happens to be, and the only proven viable way to achieve this (and maintain safety within the street environment!) is through the installation of an overhead wire power supply system. Sadly every community has its negatively orientated 'NIMBY' (not in my back yard) people and it seems that a few of them dislike these overhead wires. Oddly enough though, these people are hardly ever heard complaining about the clean, breathable city air that electric traction brings!

Trolleybus System Installed - To Protect Urban Environment

As part of a policy for cleaner urban air, and having investigated all the alternatives and the financial benefits from reduced healthcare costs, in March 2005 the Italian capital city of Rome opened its fist trolleybus route since 1972.

These vehicles also feature powerful batteries giving them an expected 10km off-wire range. The reason for this is that within Rome city centre there is a 3km unwired section and in an effort to maintain urban air quality the use of diesel (or other fossil fuel) power systems was felt to be undesirable. The extra long range of the batteries is also to ensure that they have the endurance to cope with traffic delays in stop start (rush hour) travel conditions and to guarantee power to the brake compressor & air conditioning. Battery mode operation will usually include 5-15 minutes laying over between journeys at the central bus terminus in Rome city centre.

Recharging takes place whilst running under the wires.

In January 2008 Rome announced the creation of a 60 vehicle trolleybus system serving another part of the city.

Why The 'Double-Standards?'
Surely Buses Should Be As Clean As Trams?!

Trams (streetcars) are almost always electrically powered - indeed this feature is often touted as one of their major benefits - and there really is no reason why buses should not be equally city (and town!) friendly. It really is most strange that so many transport 'experts' (& environmental advocates / lobby groups etc) have such double-standards with respect to air quality (or lack of) and bus / tram propulsion systems.

As yet none of the proposed tram systems for Britain have been advertised as using diesel powered trams, yet all the proposed British bus-based rapid transit schemes feature diesel (or other fossil fuel) powered buses.

Bus Derived Air Pollution Is The Easiest To Solve

Whilst it is true that motor buses are not the only vehicles which create tail-pipe pollution (cars, lorries, motorcycles and taxis do too) bus derived air pollution is the easiest to solve. This is because buses generally follow fixed routes along comparatively few of the roads in a cities' overall street network. Effectively this means that significant air quality gains can be achieved by equipping just a few roads for trolleybuses.

Whilst modern trams (streetcars) usually collect their power from a single overhead wire via a pantograph fitted to the vehicles' roof (with electrical return being via the running rails) electric buses will use a pair of overhead wires (one each for power & return) and twin 'trolley' poles fitted to their roofs. This explains why they are called "trolleybuses".

In North America they also use other terms, such as trolleycoaches; etb's / electric trolley buses (to distinguish them from diesel-powered 'trolley' buses that look like an old fashioned "trolley-car" as is often used in the leisure industry) & trackless trolleys - "trolley" is another American term for "tram" or "streetcar" so a trackless trolley is a "trolley car" that collects power from overhead wires using "trolley poles" but travels without rails.

Although there are upfront investment costs associated with new trolleybus networks - and because they tend to be built in small batches the vehicles themselves are more expensive to purchase - experience has shown that once operational trolleybuses can be cost competitive with diesels if you take a "lifetime" view of an installation (20 years or so) and factor in their expected longer life, lower maintenance costs, increased availability, increased attractiveness to passengers (higher revenues), better energy efficiency, etc. In Arnhem (Holland) the management of the trolleybus system have quoted about six vehicles per hour (10 minute headways) as about the break even point when it becomes more economic to operate a service with trolleybuses than diesels.

As of Spring 2007 Geneva decided that to both cater for the increasing numbers of passengers travelling and reduce urban air pollution it will convert its busiest trolleybus routes to tram - and then use the displaced trolleybuses and LighTrams to both lengthen existing trolleybus routes and electrify more motorbus services. In Geneva they have found that the sight of the overhead wires is seen as a positive advantage, because "people see the wires and know that quality public transport comes here" (ah, so different to this country).

Trolleybuses Are Flexible Enough To Avoid Road Obstructions!

Trolleybuses can travel with the overhead wires either directly above or to one side of the vehicle. Usually their ability to 'wander' is by as much as four metres, which equates to three traffic lanes.

Apart from helping them to fit in with existing traffic flows this ability to switch lanes also gives them an ability to around obstructions, such a broken down cars.

Extending Beyond The Wires...

Many modern trolleybuses are also equipped with either a low power fossil fuel engine or batteries so that if they need to travel away from their wires they can do so, albeit perhaps at reduced speed. Another use for these secondary power systems is in the depôt, giving them the ability to gain access to every part of the facility without having to provide sufficient wiring.

In most instances these APU's will only be for emergency (& depôt) use allowing the vehicle to travel a short distance around an obstruction (eg: a road traffic accident) at reduced speed. However in some cities they use more powerful alternative power systems as this can give the possibility of scheduled operation of longer distance off-wire travel too.

In Landskrona, Sweden, (which opened a brand new system in late 2003) the depôt is unwired and around 1km away from the nearest wiring. Batteries are used to power the trolleybuses to and from the service wiring.

Rome's new trolleybuses feature batteries powerful enough to allow as much as 3km of unwired operation through the heart of the city centre. The option which Rome did not want to follow is to use what is known as a duo-bus (see below) - this was for reasons of air quality.

In Beijing, China, all the routes crossing the main east-west boulevard or operating through the central shopping streets do so using powerful batteries which permit quite smart acceleration and several kilometres range at 30-40 kph. After crossing the visually sensitive areas the trolleybuses are driven into a marked box on the highway where the driver depresses a button to raise the trolley booms hydraulically into inverted V-shaped re-wiring troughs on the overhead. As with Rome's trolleybuses the batteries are recharged during the remainder of the journey.

Duo-buses are 200% power vehicles which can operate freely - at full power - in either electric or fossil fuel modes. When in electric mode they operate as trolleybuses, collecting power from overhead wires via twin trolleypoles.

Used in a few cities globally, duo-buses are usually fitted with motorised trolley poles, so changing between modes is simply a case of the driver stopping and pressing some buttons - (s)he does not even have to leave the cab! When raising the trolley poles correct placement is ensured by fitting inverted 'V' shaped wiring guides to the overhead wires, naturally for them to be effective the vehicle must stop in the correct location, so it is very important to prevent illegal parking at the up-points. Lowering the poles can take place anywhere, even when the vehicle is moving. In either case modal changeover takes less than a minute so when it is located at bus stops the only delay to the service comes from the time taken for the passengers to pay the driver as they board.

Duo-buses are more suited on routes where buses need to operate significant distances beyond the range of the overhead wires but the route is infrequent and therefore electrification is not commercially viable. Apart from the effects of the waste gases the primary disadvantage of the duo-bus is that the weight of the two drive systems increases their unladen weight and if this brings them close to the legal weight limit for buses it potentially could reduce the passenger carrying capacity.

In the late 1980's and early 1990's the German city of Essen had a fleet of duo-buses which mostly ran as diesel buses when on surface sections of route and as trolleybuses when travelling through part of the city's underground tram / light rail system.

More information on the former underground operation of duobuses in Essen can be found on these pages...
Buses02.htm#Kerb (condensed version) and
Kerb Guidance - The 'O-Bahn'
(full version, with many pictures, NB: large page, opens in a new window).

Click the projector icon (or here) to see a 12 second video clip named 'Essen-eastern-ramp-arms-up320.mpg' showing this action taking place.

Other Types of Electric Buses.

Battery Electric Buses.

In the early 1990's Oxford, England, trialed a fleet of four electric minibuses. A report on their first 500 days of operation found that compared to similar diesel buses (and after taking account of extra emissions at the power station) there was:-

21% less carbon dioxide,
98% less carbon monoxide,
42% less acid gases,
93% less hydrocarbons and
95% less particulates. (the fine particles of soot which clog our lungs, causing lung disease)

Maintenance costs were comparable to diesels, but because of high design and development costs which were spread over just four vehicles they were twice as expensive to purchase. Their lead-acid batteries weighed-in at 2 ¼ tonnes, making them about 2 tonnes heavier than the regular diesel buses.

However despite the environmental advantages the use of battery electric buses in British towns and cities is virtually zero. This is most likely because to Britain's cut-throat deregulated bus industry (where finance is seen to be the only thing which matters) such innovation does not make (financial) sense.

Whilst it is true that rechargeable batteries are very unlikely to last the vehicles' lifetime and the making / half-life reconditioning / disposing of spent batteries also has environmental consequences these are still easier to resolve at specialist facilities (factories, etc.,) than dealing with the human (ill)health consequences of fossil fuel exhaust fumes.

The buses seen above uses 'conductive charging', which is also known as 'direct wired contact' or 'direct coupling'. In addition to plugging a cable into a socket on the vehicle a variant of conductive charging sometimes sees the batteries being removed from the vehicle for recharging. If there are several sets of batteries then immediately replacing them with a fully charged set of batteries would mean that the bus could be back in service within minutes / without having to wait for the removed batteries to be recharged.

Small fleets of battery electric buses are used in several cities in Europe and the USA, where they are often seen to provide a very effective transport solution in pedestrianised and so called environmentally sensitive areas.
(Surely our entire 'living space' aka: the whole planet should be regarded as being 'environmentally sensitive' - not just a few streets in a city centre?)

Perhaps one of the main constraints in the greater use of battery electric buses is that being a niche market the small production runs tend to make them comparatively more expensive (to purchase) than they could otherwise be. This is a 'catch-22' situation, because if a city was to purchase a larger fleet then the drop in unit prices could make such investments seem more financially viable to other cities.

Roadway Power

In addition to 'conductive charging' another way to charge the buses' batteries is via electromagnetic 'inductive charging'.

Induction chargers typically use an induction coil to create an alternating electromagnetic field from within a charging base station, and a second induction coil in the portable device takes power from the electromagnetic field and converts it back into electrical current to charge the battery. The major advantage of the inductive approach over conductive charging is that there is no possibility of electrocution as there are no exposed conductors.

Inductive charging is well known for low power domestic electrical items - such as toothbrushes and wet/dry electric shavers - where the reasons why it is favoured include that the battery contacts can be completely sealed to prevent exposure to water.

A drawback with inductive charging is that it is a relatively slow way to charge batteries - which admittedly is not an issue for toothbrushes and shavers as they can be left on charge at all times - unlike buses and other transports which generally need to be in service as much as possible during their working day.

In autumn 2008 a major transport vehicle manufacturer announced proposals for an inductive system which would be installed under the road along (much of) the transports' route, with the vehicles drawing power as they drive over it. Although primarily promoted as being for trams it was stated as being suitable for electric buses too, and for buses an extra feature will be the ability to travel in battery-electric mode over other sections of road away from the power supply.

The concept is not new, as in the early 1990's 'proof-of-concept' trials were carried out with a 35 seat Roadway Powered Electric Vehicle (RPEV) at the University of California Richmond Field Station. The trials saw the burying of power conductors under a 700ft (about 213m) test track and an operational RPEV which featured a needle dial so that as the vehicle travelled along the road the driver could see the 'strength' of the charging current being received and accurately locate it above the under-road power supply.

The RPEV system was shown on television as being able to draw enough power from below the road surface that it could also roam away from the power source, so that perhaps a main road serving many bus routes would be electrified but they would be able to make short scheduled detours in battery electric mode. However it seems that the trials did not progress further. Since then the USA had a President who was a member of the oil industry, so the lack of further development is not at all surprising.

This is not the only time that the concept of buses sourcing their power from the road surface has been promoted. For instance, in 2000 a roadway power system which had been specifically designed for buses was tested with several electric buses in the Italian city of Trieste. Unfortunately however it seems that the trials coincided with a change of local government - and whilst it seems that the outgoing politicians were keen to see the system expanded to more routes the new politicians were not.

Perhaps at least in part this was because the trials were on one of the cities' busiest bus routes and there was some disruption, especially when it was being installed.

The technology was based on twin metal conductors located on the road surface. To ensure safety and avoid the possibility of electric shock the conductor that carried the live power was split into short sections that would only be live when the bus was actually over them. As yet this system has existed in experimental form only, however one specific technical problem which the Trieste trials identified was that the metal (of the power conductor) on the road surface could be slippery, especially when wet.

Hybrid buses...
are these even a partial solution - or just 'cloak and mirrors'?

Some cities have been looking at what are known as 'hybrid' buses as ways to reduce air pollution, improve the attractiveness of their bus services and operate (partially) electric full-size buses without overhead wires.

Trials conducted with these buses between 2004 and 2006 have shown that as a general theme they are less polluting and use less fossil fuel than regular (diesel) mechanical buses, and based on this their advocates are trying to hoodwink the public into believing that use them would represent both the best / most advanced way forward which present day technology (in the public domain) can offer - as well as being 'the' solution to bus sourced air pollution.

It cannot be reiterated enough that fossil fuel powered (diesel, etc.,) hybrid buses are NOT 'ZEVs' (zero emission vehicles) and that as with ordinary 'mechanical transmission' buses they still pollute their local environments - ie: the streets we use / the air we breathe.

The only buses capable of being true 'ZEVs' are battery electric, roadway power and overhead wire trolleybuses. These - along with electric trams, streetcars & light rail - do not give off any tailpipe pollution at all!

Because this is a complex topic which also creates a diversion away from the central theme of this page so hybrid buses are more fully explored on their own dedicated page.

Seeking The "Holy Grail" - Viable Alternatives To Batteries.

Over the years there have been several attempts to create workable, practical alternative solutions which feature electrically powered buses that can be used for a full day's operation - but without either overhead wires or heavy batteries. Although commendable unfortunately none have yet been proven viable.

Super-Capacitors.

In June 2005 "early stage" experiments commenced in the Chinese city of Shanghai with a new form of electric bus powered via energy stored in large onboard super-capacitors.

Initial testing suggested that when fully charged the capacitors could be able to supply enough power for a bus to travel a total distance of 5km (about 3 miles & 200yds) at 44km/h (a little over 27mph), although for practicality it was proposed that recharging stations would be located approximately every 3 stops. As the images below suggest, recharging was by means of a railway-style pantograph fitted to the buses' roof that made contact with an overhead power supply. For added benefit regenerate braking energy was recycled back into the super-capacitors - instead of just being lost via wheel brakes or rheostats.

For the initial testing the Shanghai Sunwin Bus Plant built four prototype super-capacitor electric buses, each one costing as much as 800,000 RMB, this being almost as twice expensive as a conventional Sunwin air-conditioned trolleybus. However in February 2006 it was reported that with all four test vehicles having broken down the opening of a proposed demonstration system had been postponed indefinitely.

However to properly evaluate the technology a further batch of super-capacitor buses has been built, and on 28th August 2006 was placed into experimental service. These more extensive commercial trials involve Shanghai's route 11, which is a short circular trolleybus route of just 5.5km in length. This route is noted for lower levels of traffic congestion than the others, a constant passenger volume and high flow rate, with most passengers only travelling for three to five stops.

The trials involve super-capacitor buses travelling on the clockwise loop only, with conventional trolleybuses remaining on the counter-clockwise service. Furthermore, the trolleybus overhead for the clockwise circle is still being properly maintained, so that if the trials prove to be unsuccessful then conventional trolleybuses can return immediately.

Advance testing has shown that in theory the air-conditioning is not in use then the super-capacitor buses should be capable of completing a complete loop on only one charge. However, to reduce the risk of a bus delayed in traffic congestion dissipating all its stored energy (and hence becoming stranded) plus to allow the air conditioning to be used there are in fact seven charging stations located around the loop.

There are also seven super-capacitor buses, again costing as much as 800,000 RMB each (approximately £6,600) a figure which includes the research cost. It is estimated that if the trials prove successful and super-capacitor buses go into mass production then the cost will go down to 650,000 RMB; in comparison an air-conditioned Sunwin trolleybus costs only 400,000 RMB!

Hmmm, not a good start. Within a week of the trials commencing five out of the seven super-capacitor buses had already broken down, so to rescue the service some regular trolleybuses had to be reinstated. Apparently the problems have been blamed on the capacitor overheating under Shanghai's scorching heat. Even though it was officially autumn the weather was still hotter than had been expected. However by the end of September some of the failing super-capacitor buses had returned to service, with clock-wise services now being provided by a mixed fleet of super-capacitor and trolleybuses.

In addition, the super-capacitor bus drivers have been told that when travelling between route 11 and the garage they should use roads equipped with trolleybus overhead; this is because whilst theoretically they should be able to make the journey without recharging the high unpredictability of Shanghai's extremely congested streets makes it desirable to 'play safe' and not leave the safe haven of the overhead power lines. Although not planned as a regular feature in an emergency a super-capacitor bus can recharge from trolleybus overhead.

Reports from a visitor to Shanghai in February 2007 suggest that the trials are proceeding reasonably well. He also said that it is perhaps just as well that there are as many as seven charging stations along the loop, as buses traversing the loop are not always able to charge at every one of them. Apparently route 11 encompasses Shanghai's oldest historic relics and tourist attractions and tour buses often inadvertently park so that they block the charging points. He added that accurate docking is also essential because the charging process requires the charging facility to detect sensors on the super-capacitor bus - and this is only possible when it is stopped close to the footpath.

The visitor also reported that compared to normal trolleybuses the super-capacitors had slower acceleration and were smoother to ride - especially above 30km/h [20mph].

Perhaps the most significant issues (apart from the overheating when the trials commenced) is that because of the lack of recharging facility when returning to the garage bus drivers must drive to conserve the stored energy, which means switching off the air-conditioning, very modest use of the accelerator pedal, etc. Whilst in theory it is possible to recharge from the trolleybus wires the reality is somewhat more complicated. One issue is that with the trolleybus wires being located over the centre of the road so to reach them the super-capacitor bus would have to block the traffic flow. Another issue is that the trolleybus wires are often much higher than the charging stations, so that even when fully stretched the pantographs on the buses might not reach them.

Click the projector icon (or here) to see a video clip (opens in a new window) on 'youtube' showing a Shanghai super-capacitor bus raising its pantograph to charge the capacitors, plus other vehicles - including the trolleybuses operating in the opposite direction around the loop. The video was made by a visitor from Japan.

The Gyrobus.

Shanghai's trials with super-capacitors are reminiscent of a system trialed in the 1950's with what was known as a gyrobus.

The gyrobus concept was developed by Oerlikon (of Switzerland), with the intention of creating an alternative to battery-electric buses for quieter lower frequency routes where full overhead wire electrification could not be justified. The buses were equipped with a large flywheel that spun at speeds of up to 3,000 rpm, gradually slowing as the stored energy was used to provide electricity for the buses' traction motor. Power for charging the flywheel was sourced by means of three booms mounted on the vehicle's roof which contacted charging points located as required / felt desirable (eg: bus stops en route, at termini, etc).

Fully charged a gyrobus could (typically) travel as far as 6km on a level route at speeds of up to 50 - 60km/h (depending on vehicle batch as top speeds varied from batch to batch) The installation in Yverdon (Switzerland) sometimes saw vehicles needing to travel as far as 10km on one charge, although it is not known how well they performed (or otherwise!) towards the upper end of that distance. Charging a flywheel took between 30 seconds and 3 minutes, and in an effort to reduce the time this took the supply voltage was increased from 380 volts to 500 volts. It can only be speculated whether such frequent delays would have been acceptable had the gyrobuses survived - in commercial service - into the modern era. Especially on longer routes where several charging stops could have been required or on busy, heavily trafficked roads.

In all three locations used gyrobuses in full commercial service, these being Yverdon, Switzerland, Gent, Belgium and Léopoldsville in Zaïre (former Belgian Congo and currently known as Kinshasa in the Democratic Republic Congo). Whilst the technology worked reasonably well for various reasons none of these systems lasted for more than seven years - at most.

Additional Gyrobus Information.

The gyrobuses used an asynchronous three-phase electric motor with condensers fitted on a common shaft. The motor was built on to a flywheel which (on the demonstrator) was 1.6m in diameter and weighed 1.6 tonnes. This was housed in an enclosed hydrogen-filled air-cooled casing.

To obtain tractive power condensers would excite the flywheel's charging motor so that it become a generator, in this way transforming the energy stored in the flywheel back into electricity. Vehicle braking was electric and some of the energy was recycled back into the flywheel, thereby extending its range.

The demonstrator was first displayed (and used) publically in summer 1950, and to promote the system this vehicle continued to be used for short periods of public service in a myriad of locations at least until 1954.

The first full commercial service began in autumn 1953, in Yverdon, Switzerland. However this was a route with limited traffic potential and although technically successful it was not commercially viable. Services ended in late autumn 1960, and neither of the two vehicles (nor the demonstrator) survived..

The next system to open was in Léopoldsville in Zaïre (former Belgian Congo and currently known as Kinshasa in the Democratic Republic Congo). Here there were 12 vehicles (although apparently some reports erroneously suggest 17), which operated over four routes with recharging facilities being provided about every 2km. These were the largest of the gyrobuses, being 10.4m in length, weighing 10.9t, carrying up to 90 passengers and having a maximum speed of 60km/h (about 37mph).

However all did not go well, with there being major problems related to excessive "wear and tear". But it seems that a significant reason for this was because the bus drivers often took shortcuts across unmade roads, which after the frequent heavy rains became nothing more that quagmires and marshes. Other problems included breaking gyro ball bearings and high humidity resulting in traction motor overload. The system's demise however came because of high energy consumption. The bus operator deemed that 3.4kWh per km, per gyrobus, was unaffordable, so closure come in the summer of 1959 with the gyrobuses being dumped next to bus garage and left to rust.

The third location to use gyrobuses commercially was Gent, Belgium. Three gyrobuses started operation in late summer 1956 but instead of being the first of a proposed multi-route network they did not last very long, being withdrawn late autumn 1959. It seems that the operator was blaming them for being unreliable "spending more time off the road than on" plus that their weight damaged road surfaces. They were also seen as being energy hungry, consuming 2.9kWh per km - compared to between 2.0kWh per km and 2.4kWh per km for much larger trams that carried several times the numbers of passengers. One of the three gyrobuses has been preserved, and is sometimes displayed as a curio (or even used to carry passengers!) at Belgian exhibitions, transport enthusiasts' bazaars, etc.

Much of this additional information was sourced from the January / February 2005 issue of "BusesWorldWide" as issued by the organisation of the same name "http://www.busesworldwide.org (link to an external site which opens in a new window).

In 1986 a planned trolleybus scheme in Bradford was scuppered because the British deregulated bus operating regime - which actively encourages cut throat 'free-for-all' competition between private bus companies often plying the same streets - encouraged a 'spoiler' company to split the fare base by introducing a rival service (along the same route) which would compete by providing part-time services using cheapo secondhand minibuses. Since then it has become pretty obvious that this free-for-all actively inhibits serious fixed-infrastructure transport investments - indeed it also lead to the near bankruptcy of the Sheffield tramway when rival bus companies set out to compete with the trams by offering low quality secondhand buses and dirt cheap fares.

Since then it was not until 2007 that any serious proposals for trolleybuses in Britain were proposed - because it was known that the regulatory system discourages such investments. The only city on the British mainland where cut-throat 'free-for-all' deregulation does not apply is London - here the competition is for the right to operate pre-defined bus routes under contract to the London-wide regional government body for transport, this being known as "Transport for London" (TfL).

So What About London?

London Buses Ltd in its publication "Cleaner Air for London - London Buses leads the Way" estimated that the cost of (human) health care which results from diesel bus air pollution equates to an equivalent of €0.20 (ie: 20 Euro cents) per km. Meanwhile, a different report prepared at the Roma Tre university in Rome suggested the cost as being €1.20 per km. As most readers will instantly note, the Italian figure is significantly larger! Using this figure helps justify for the investment in the new "filobus" (the Italian word for trolleybus) network detailed above because it suggests that installing the electric street transports would result in significant financial benefits in reduced health care costs.

At a presentation given by the TfL Managing Director for Surface Transport he made it quite clear (in a response to a question I asked him) that his primary duty is to run a cost effective transport system and that it would not be commercially viable to care about environmental issues, which in his view are for the government to decide. (He included issues which affect human health in this comment). Then he added that obviously if the government introduced new legally binding standards and / or someone else came up with the dosh (cash) then the situation could change.

It is a most terrible (even criminal?) indictment of our present-day system of government that under British financial criteria the Italian proposals would be seen as "uneconomic". Do we in Britain not value human health? (rhetorical question, of course we the people do) or is it because of the insane way in which the British government allocates funds to its various departments, with health care costs coming from a different 'pot' which is (not only) totally independent of the transport 'pot' but actually (at a governmental level) competes vigorously for funds with the transport 'pot'?

Poor health caused by air pollution is a big problem in London and with as many as 7000 diesel buses on London's streets it stands to reason that they must be part of the problem - with zero-emission (at point of use) electrically powered trolleybuses being part of the solution. In 1999 more Londoners died of air pollution related illnesses than in road traffic accidents. According to a report published by the Chartered Society of Physiotherapy - CSP - the PM10 air particles which are emitted mainly by diesel engines pose such a serious threat to public health that the World Health Organisation (WHO) believes there is NO SAFE exposure limit. The CSP's analysis revealed very high levels of this dangerous pollutant - not just in London but throughout the UK. The full story can be found here (Link opens in a new window).

The Electric Tbus Group has conducted a detailed study which suggests that for London the conversion of the busiest bus routes (eg: those with a frequency of every 5 minutes or more) would offer significant financial and environmental benefits. Thanks to the network effect where multiple routes operate along the same roads the situation would soon arise whereby many subsequent conversions would entail less additional wiring - both increasing the cost effectiveness of existing wiring and reducing the cost of the electrification of additional routes.

Plus of course Londoners would benefit from the significantly cleaner air in the streets where they live, work and play.

In the late 1990's a serious proposal was made for using trolleybuses in London, but only as part of a small local area "rapid transit" scheme (named East London Transit) where the sole reason for suggesting trolleybuses was because the projected ridership would have been too low to justify the cost of installing a new tramway. According to the "East London Transit - Summary Report" (published by TfL in July 2001) the use of trolleybuses on this 33 mile (53km) high-profile Bus Rapid Transit system for east London & metropolitan Essex would provide the most financially beneficial option, generating revenues 24% higher than a comparable diesel bus scheme.

Public consultations in the areas to be served by ELT were very positive too - especially towards the trolleybuses with public opinion being 2:1 in favour of the clean electrics AND against yet more polluting dirty diesel buses.

Yet despite this TfL back-pedalled and now plan to use diseasel (disease diesel) buses.

To avoid duplication and side-tracking further information about ELT and modal choice political machinations are on the A Bus For London. page.

The Need For Trolleybuses In Britain!

According to a Government report issued by the Committee on the Medical Effects of Air Pollutants air pollution hastens the deaths of between 12000 and 24000 British people a year and is associated with 14000 and 24000 hospital admissions and re-admissions - causing sufferers and their families untold amounts of misery and costing our health service & taxpayers £billions. Yet whilst motoring offences (especially speed related) seem to be attracting ever more diligent attention by the various authorities the issue of air pollution only receives the metaphorical "lip service".

In Britain more people die from air pollution than in motor vehicle accidents. The total deaths from road traffic accidents (including pedestrians knocked down) is approx 3,500 (DfT figures, 2002) - and whilst obviously even one fatality is too many the figures are still considerably fewer than the number of casualties which can be attributed to air pollution.

So, 50 years after the clean air legislation resulted in the ending of coal sourced smogs the air that we breathe in our towns and cities is yet again so heavily polluted that people are suffering ill health (and even dying) from it.

It could be asked why our predecessors bothered, only to be failed by future generations.

So (once again) maybe its time to take urban air pollution seriously???

Introducing trolleybuses into British towns and cities would help Britain meet its commitment to cutting carbon dioxide emissions by 20% by 2010. The House of Commons environmental audit committee says that carbon emissions from transport are 'still moving in the wrong direction' but apart from clobbering motorists with yet more taxes the govt. has failed to find effective ways to entice people out of their cars. Amazingly with respect to new tram schemes the government has actually taken pro-active steps to make the installation of new systems more expensive - see the Enough Stick! How about Some Carrot page for more information.

By attracting car users who would not switch to a motor bus electrification of Britain's urban bus routes could help reverse this upward trend. This would also help reduce overall road traffic levels too.

A nationwide programme of bus electrification here in Britain would help us justify to the other members of our planet-wide family of nations the urgent need for similar policies for improving both the global and their local environments. It would also "add value" to people's daily lives - something which current British government transport & environmental policies totally fail to do.

Government Action Urgently Required!

In an email from a major British operator they stated that (apart from the problems caused by bus deregulation, as detailed three sections above click link to go backwards) a significant impediment to trolleybus introduction and operations in Britain - including London - could be easily removed if the government really so desired...

"Trolley Bus systems require complex approval processes bringing further business risks and potential delays. The environmental benefits of alternative fuel technologies are difficult to quantify in cash terms making this benefit difficult to sell to Government when seeking capital funding for projects."...

"Furthermore, the inclusion in the UK of Trolley Buses within the remit of railway regulatory regimes introduces a significant additional burden in terms of the management of the operation and the infrastructure"...

"The combination of these factors makes the consideration of Trolley Buses low on our current plans for investment."

It could be said that the optimum solution for us here in Britain would be to use the same planning processes as are already used for highway improvement schemes, the introduction of bus lanes, bus stop shelters, new traffic signalling systems, replacement of street lighting etc. After all, the works for installing trolleybuses - erecting the overhead wires, building substations (etc) to power these wires and arranging connections to the national grid - will be considerably less disruptive to other road users than road works and about the same as the replacement of street lighting poles.

If new trolleybus systems were installed in conjunction with local government declaring the route a "high profile quality bus scheme" (such as already exist in a few locations) it should be possible to prevent spoiler companies from introducing rival services using cheapo secondhand motor buses designed solely to split the fare base and push the quality buses off the road.

Detailed Studies Of Costings...

Detailed studies of costings for new trolleybus systems in Britain have shown that installing the physical infrastructure (overhead wiring and substations) will work out at around £500,000 per kilometre. Of this about half would be for the wiring and support poles, etc., and about half the substation, feeder, etc. The costs of manufacturing and planting the (steel) support poles usually represents the largest item of the actual wiring costs, although once installed they would be expected to last for many decades (....indeed many of the poles planted in the 40's and 50's in towns around the country are still in use for street lighting and the aborted Bradford trolleybus proposals of 1986 would have re-used some of the still extant poles in that city in this way).

Some street sections of the Nottingham NET tramline feature overhead wiring supported invisibly from rosettes attached to building walls. Similar could be done for trolleybuses too.

To reduce street clutter it is often possible to hang wires from wall rosettes on buildings - although unfortunately only certain types of buildings are suitable for this. Alternatively it should be possible for the same poles to carry both overhead wires and street lighting - but this would still require the installation of new support poles as ordinary street lighting poles will not be strong enough to support overhead wiring (and the extra work involved in this latter option could see costs rise).

It is very possible that an enterprising electricity supply company would be interested in a mutually beneficial financial arrangement with respect to physical infrastructure and long term electricity supplies.

Something else which could affect the overall cost of the overhead wiring would be whether the trolleybuses are equipped with auxiliary power units (APUs - either battery packs or diesel generator sets) which allow the vehicles to operate away from the overhead wires. APU's will increase vehicle costs but then there probably wont be a need to install wires for access to the depôt - which could result in a substantial financial saving as to wire a depôt internally can require a great deal of 'special work' - points / switches / frogs, crossings, etc. - which are always very expensive compared with plain wiring.

The nature of the wiring and its source can also cause costs to vary. 'Elastic' overhead wiring from, for example Swiss sources could result in costs working out more than the £500,000 per km quoted above, which assumed British sources.

Yorkshire, 2 Glimmers Of Hope?

In Summer 2007 the city of Leeds announced proposals for an electric BRT (Bus Rapid Transit) system using trolleybuses. However there is a story here which in many ways demonstrates everything that is wrong with British Government transport policies. Originally Leeds wanted a tram system, however despite much encouragement from the (national) government suggesting that they would look favourably to a request for finance, and after spending £millions of taxpayer's money drawing up proposals, the national govt. happily 'pulled the plug' financially - leaving the local politicians with nothing. So trolleybuses are being looked at in an attempt to salvage something from the otherwise wasted monies spent on the tramway proposals. The idea seems to be to maintain the same clean air benefits as the trams would have provided and follow virtually the same routes too - just that the transports would be rubber tyred and not steel wheeled.

Meanwhile in September 2007 it became known that trolleybuses were also being investigated in the nearby city of Sheffield. This is for a service linking Sheffield with the town of Rotherham. Sheffield already has a tram system which it would like to extend to Rotherham, however as the national government is (yet again) less than enthusiastic so Sheffield is looking at trolleybuses as being a cheaper option.

The case for NOT using Ultra Low Sulphur "clean" Diesel fuel and Regenerating Particulate Traps

Additional information gratefully obtained from the Electric Tbus Group www.tbus.org.uk (link to an external site which opens in a new window)

Why even so called "clean diesel" is still an environmental disaster!

Diesel exhaust has been found to contain over 41 different toxins, many of which form part of the particulate. These toxins are still present in "clean diesel" powered vehicles which use Ultra Low Sulphur Diesel fuel (ULSD) and Continuously Regenerating Particulate Traps (CRT). Vehicle emissions have their greatest impacts on those directly exposed, i.e. pedestrians, transit users, those living on busy transport corridors. Electric buses produce no in-street emissions. Unless all the emissions diesels release into the surrounding air can be completely eliminated, the diesel can never be competitive with an electric bus in terms of emissions impacts. This should not imply that efforts to reduce diesel emissions are wasted. Since diesel engines will continue to be used for a variety of purposes, every effort should be made to make them as clean as possible. But one needs to realize that making an internal combustion engine cleaner does not make it a universal substitute for an electric vehicle.

So called 'cleaner' diesel increases greenhouse gases!

Currently available data from the British Freight Transport Association (FTA, 1999) indicates that the production of Ultra Low Sulphur Diesel fuel (ULSD) [at refineries] results in some 20 tonnes more CO2 equivalent than the production of regular diesel. Indications are that powering a vehicle with ULSD requires more fuel than with regular diesel, meaning that, while some emissions may be reduced, the amount of CO2 released by the vehicle is likely to be greater

The environmental benefits of exhaust after-treatment devices was recently called into question when researchers discovered heavy metals from catalytic converters embedded in the ice in remote regions of Greenland. A European Commission study found that vehicle exhausts actually erode the metals in these devices, ejecting microscopic particles into the air. Some of these metals have also been linked to asthma and lung conditions. Researchers noted that some of these particles are soluble, meaning that they can be readily absorbed by vegetation and enter the food chain. New Scientist magazine concluded that this is already a problem is of global proportions.

Scientists say the release of heavy metals from exhaust treatment devices is a global problem that also stands to threaten human health.

Click the projector icon (or here) to see a 14 second video clip named 'Nancy-unguided-S-bend320.mpg' showing the TVR making this 's' shaped manoeuver (plus hear the above photograph being taken - oops!).

So called 'cleaner' diesel fuelled vehicles still emit lung-damaging particulates!

Trap devices such as the CRT primarily focus on reducing the amount of particulate matter that diesels spew into the surrounding air; there is also some concurrent reduction in hydrocarbon emissions. Some traps claim to reduce particulate emissions by up to 90% in tests, although their performance in real-world conditions may vary considerably. In any case, some particulate is still released, and because "clean" diesel particulate is so much finer than that from conventional diesel engines (and invisible to the naked eye) these toxins have an easier time entering our bodies and penetrating the linings of the lungs. There is no safe level of exposure. German researchers insist the toughest diesel emission standards are not tough enough. (PM10 particles with mass less than 10 microgrammes). The Daily Mail of December 27, 2000 reported that such particulate was found deeply imbedded in the lungs of very young children, in particular children who lived in homes located along busy roads. This particulate is believed responsible for an increase in lung disorders and asthma and has also been linked to heart disease. The incidence of asthma in children under five has doubled in Britain in the last ten years and is on the rise in many other countries. There is also strong evidence for a causal link to cancer, although the research as not (yet) established this beyond doubt..

In spite of trap devices Oxides of Nitrogen (NOx) still form a major component of diesel exhaust and pose significant health risks. Oxides of Nitrogen essentially comprise a mixture of Nitric Oxide (NO) and Nitrogen Dioxide (NO2). NOx is transportation's principal contributor to urban smog and poor air quality. In combination with the moisture in the lungs, Nitric Oxide (NO) forms nitric acid. This acid results in inflammation, leading to chronic respiratory problems. Eventually, all Nitric Oxide emissions are converted to Nitrogen Dioxide (NO2) in the atmosphere. Nitrogen Dioxide is a corrosive and very poisonous gas. At concentrations above 150 ppm it leads to death. The CRT (Continuously Regenerating Trap) uses a catalyst to convert Nitric Oxide in the exhaust stream to NO2 because it needs the NO2 for a reaction that 'burns off' particulate matter and hydrocarbons. There is a strong likelihood that the proportion of NO2 in the NOx emitted by CRT equipped engines operating in real world conditions will be greater than is the case with non-CRT equipped diesels. If so, it would put a greater quantity of the more poisonous constituent of NOx emissions directly into the airways of pedestrians, transit users and area residents than would be the case with conventional diesels, where the a slower process of oxidation in the atmosphere would be required to yield the same quantity of NO2. In other words, there is every possibility that ULSD in combination with the CRT may actually intensify some of the health effects of diesel exhaust.

The case for NOT using fossil fuel engines which meet "Euro 4" standards for urban bus services.

Being introduced in 2006 are regulations called "Euro 4" which has the aim of enforcing a reduction in the output of harmful particulates and NOx nitrous oxide from motor bus exhaust (waste) gases. Euro 4 can be seen as a stepping stone to "Euro 5" which in 2009 will cut NOx pollution (but not particulate emissions) even further. Both regulations will apply to new buses only - existing vehicles can continue to operate with their older even dirtier engines.

Of course it is right to use the propulsion systems which create the least pollution - and for rural areas where the cost of electrification plus maintenance of the infrastructure would simply render the bus service uneconomic then by using sustainably sourced biofuels in engines which meet the "Euro 4" and "Euro 5" standards is a logical solution. But there really is no justification for using the "less dirty" option for urban services - not when a clean alternative choice exists.

However apparently 'clean' Euro 4 / 5 diesels may appear to be it need be remembered that the supposed performance is measured on new vehicles / engines in tip top condition on test cycles. No matter how clean they are when new, experience with existing engines suggests that as they age their emissions performance will deteriorate.

Whilst optimal regular maintenance will help keep the engines cleaner this reflects extra expense and "downtime" spent in the garage instead of being on the road earning revenues. The fleet will also need to be larger to cover for the extra time spent in the garage.

More information.

In an effort to meet the new regulations motorbus suppliers are following two competing routes. These are known as EGR (Exhaust Gas Recirculation) and SCR (Selective Catalytic Reduction).

EGR uses an EGR cooler to reduce the temperature of a controlled amount of exhaust gas which is then recirculated into the engine to achieve lower combustion temperatures. thereby reducing nitrogen emissions at source. Around 10% of gases are recirculated for Euro 4, this is expected to increase to 25% to meet Euro 5.

Instead of modifying the engine SCR is an exhaust gas after-treatment whereby a mixture of 32.5% urea and deionised water (known as AdBlue) is injected into the exhaust gases where the heat of the waste gases transforms it into ammonia and carbon dioxide. The ammonia then reacts with the nitrogen dioxide in a catalytic converter to form harmless nitrogen gas and water vapour. A clean up catalyst then converts any residual ammonia into nitrogen gas and water vapour.

On urban buses the waste gases must also pass through another catalytic converter which is fitted in front of the SCR catalyst. This is to ensure that the SCR system functions under operating conditions with low exhaust temperatures.

In cold climates the AdBlue starts to freeze at -11 deg C and until the engine is running and giving off heat the effects of the exhaust filtration system will not be felt. Vehicles which operate in climates where such temperatures are frequent can be equipped with heated Adblue tanks.

According to SCR advocates for the Euro4 standards urea consumption is 3-4% of diesel so 40 litres of Adblue should be sufficient for about 1000 litres of diesel. For Euro 5 it is expected to be about 5% of diesel consumption. The liquid itself is claimed to be low-toxic, non flammable, not explosive and not pose any known human health risk. Unlike fuel oil there are no special restrictions regarding its transport or handling. The urea consists of ammonia and carbon dioxide and the production process involves airborne nitrogen reacting with hydrogen from a source such as natural gas.

There are no such things as clean diesel vehicles. Just "less dirty".

Why biodiesel is not an alternative solution for urban bus services
(and maybe not elsewhere either).

Many of these comments also apply to ethanol, which some bus operators see as a 'green' (sic) solution.

As oil prices soar and some people feel a desire to source fuel from renewable sources so there is increasing interest in what is known as "biodiesel".

Biodiesel is usually sourced from vegetable oils derived from plants which are specially grown as a crop in a field, although it can also be sourced from animal fats too.

The theoretical advantage of biodiesel is that it should be CO2 neutral, because as much CO2 should be taken up growing it as is produced when it is burned. However, if the crop is heavily fertilised using fertiliser that has itself been sourced from fossil fuel, and if a lot of fossil fuel is used harvesting, transporting, converting the crop to biodiesel etc., (ie; the normal sorts of agricultural usage of fossil fuels) then biodiesel may still be a net emitter of CO2.

Sourcing Problems - with potentially disastrous ecological consequences.

It is also important to note that if the crops from which the biodiesel has been sourced would have been grown anyway (eg: wheat & maize [corn], for human or animal consumption) then using them for liquid fuels does not provide any ecological benefit - indeed if the result is a shortage of food and a consequential increase in food prices then there is a significant disadvantage, especially to the less financially wealthy members of our human family (who might then not be able to afford to feed adequately themselves) and to farmers who may not be able to afford to feed their livestock.

Reports from some countries suggest that people are going hungry because they can no longer afford to buy foods as the crops are being sold at higher prices for conversion into fuel. Other reports talk of gangsters stealing farmland to grow these cash crops, which frequently leaves the displaced farmers suffering severe hardship (eg: financial poverty, inability to afford to buy food, housing, healthcare). There have also been instances of corruption with the issuing of false certificates claiming that the crop has been sourced following the highest environmental standards - when it has not.

There is also no point in tearing down the Amazonian / equatorial rainforest (something else which is happening) - just to grow crops for fuel - as this sort of deforestation is very much a disaster of the worst possible magnitude. One reason why these ‘rainforest replacement' plantations are less than desirable is the loss of biodiversity (ie: a wide range of types of plant which support many different animals are replaced with one type of tree which is not beneficial for many types of animal life). Indeed it seems that this loss of habitat for the animals which live in the rainforests is leading to a situation whereby one species of monkey is now actively threatened with extinction. It may be that other ‘lower profile' / ‘less well known' animal species also face a similar threat, however the media reports do not state this.

It must also be remembered that the rainforests are our planets' lungs. Without them we (mankind) might have some more fuel, but we effectively will be signing the death warrants (through asphyxiation) of just about every oxygen breathing living being on the planet.

Any noticeable benefits?

The use of biodiesel does not turn buses into quiet zero emission vehicles - indeed very few people would notice any significant difference, apart possibly from the smell, which especially if recycled cooking oil is being used might result in the buses smelling like fast food outlets! However for buses operating on quieter routes and especially in rural areas (where electrification is simply not a viable option) then because it can be sustainably sourced so there is a good case for using biodiesel to fuel buses.

Pure or mixed with regular diesel?

When compared with mineral diesel the use of pure biodiesel to fuel a conventional motor bus engine results in a reduction of some pollutants and an increase in others. Biodiesel fuelled buses are just as noisy with the same levels of vibration as mineral diesel fuelled buses.

Because the carbon in biodiesel emissions is recycled from carbon that was already in the atmosphere [rather than from "new" carbon from oil that was sequestered in the earth's crust] so net emissions of carbon monoxide (CO) and carbon dioxide (CO2) are lower. The emissions particulates are also lower. Biodiesel contains fewer aromatic hydrocarbons (benzofluoranthene & benzopyrenes). However there is an increase in the harmful nitrogen oxide (NOx) emissions.

It is perhaps worth noting that the CO2 emissions from diesels into the streets only affects global climate change - it is not a direct human health issue. However emissions from diesel or other combustion engines into the streets of CO, NOx or particulates are human health issues. So whilst biodiesel may well have a part to play in reducing the use of fossil fuels and therefore reducing CO2 emissions, it is not a solution for reducing the noxious emissions like NOx from diesel bus exhaust pipes.

Biodiesel has a tendency to gel at low temperatures (less than 4 deg C), it also suffers from issues with micro organism growth and water absorption. Because of the potential severity of these problems biodiesel is usually deployed mixed with regular diesel, perhaps on an 80-90% mineral diesel and 20-10% biodiesel basis. In this format the use of biodiesel has been found to extend the life of various engine components. This is at least partly because of biodiesel's higher lubricity index compared to mineral diesel.

Some forms of biodiesel (eg: ethanol) have a lower 'energy' rating which means that for mile for mile more liquid fuel is consumed than with regular diesel.

Sourcing Problems - Deception!

In late 2007, a bus company which operates local buses in the English town of Reading bought 14 new ethanol fuelled double deck buses to replace the existing fleet of biodiesel powered vehicles. At the time this was the largest order for ethanol fuelled buses in the UK. These buses were introduced into service in May 2008.

However, in October 2009 it was discovered that instead of the ethanol fuel having been sourced from sugar beet grown in the English county of Norfolk (as everyone in Reading had been led to believe) it was actually made from wood pulp imported from Sweden. On learning this Reading Borough councillors launched an investigation into how they, the Reading Transport Board - which runs Reading Buses - and the people of Reading could have been deceived.

In a press release issued by Reading Borough Council on 2009-10-15 it was stated that the use of ethanol would be terminated, although the reasons cited were primarily financial, and not because of the deception. The press release points out that although the current cost of a litre of ethanol is just 2.61% more expensive than biodiesel, the ethanol powered buses are a massive 44.5% less fuel-efficient, making them more than twice as expensive to run than the biodiesel powered buses. The press relase can be read here http://www.reading.gov.uk/latest/mediareleases/PressArticle.asp?id=SX9452-A7845EA5 (link to an external site which opens in a new window).

The case for NOT using alternative fuels

Often touted as cleaner fossil fuels are liquefied petroleum gas (LPG) and compressed natural gas (CNG). However these fuels also have both financial and environmental drawbacks -

Liquefied Petroleum Gas.

• LPG is a low pressure mixture of propane and butane, which on the bus is stored at pressures between 4 and 7 bar.
• LPG does not contain any lead, sulphur or benzene.
• Overall it contributes 10% less to global warming than petrol - and 3.4% more than diesel.
• Compared with diesel buses, LPG buses emit 5 times as much carbon monoxide and consume 75% more fuel - making favourable tax regimes a necessity for bus operators to use this fuel.
• In the event of an accident where the LPG escapes into the atmosphere it would be much more dangerous than either natural gas or hydrogen in that being heavier than air it would behave like a liquid fuel (ie: petrol and diesel) and spread along the ground, which is where most people and buildings are usually to be found.
• As with petrol (but not diesel) LPG is highly flammable.

Compressed Natural Gas.

• Compressed natural gas is stored on buses at high pressures of up to 200 bar.
• CNG spark ignition engines are much less fuel efficient than compression ignition diesel engines - consuming 20% more fuel than low sulphur diesel buses.
• CNG bus exhaust may contain less NoX than diesel bus exhaust but it also contains more carbon-dioxide (CO2) than from diesel fuelled buses.
• In addition CNG buses also emit methane, which has a greenhouse gas value 21 times greater than CO2 - in effect this means that they actually increase greenhouse gas production by a typical 19% (compared to a low sulphur diesel bus).
• It has been reported that although the mass of particulates emitted by CNG may be lower than diesel, the particles are finer.
• Both CNG and diesel require exhaust after treatment to try to limit noxious emissions.
• Compared with diesel buses, CNG buses are heavier, carry fewer passengers, have problems with range, are less reliable, more expensive to maintain and the cost of the re-fuelling facilities is horrendous. Transport operators who use them report that the overall lifetime costs of CNG tend towards being double those of diesel.

In 1990 the Canadian city of Toronto introduced a fleet of CNG s replacements for both electric trolley and other buses. At the time they were hailed as being 'no-pollution replacements' (sic) the trolleybuses, however withing five years CNG operation had been withdrawn from the city. Whilst 50 buses were converted to diesel, 75 had very abbreviated lives and went straight to the scrap pile. It seems that few people want to talk about what has become seen to have been a disastrous money-wasting fiasco.

Fuel-Cell Buses

In December 2003 London received three experimental Hydrogen powered "fuel-cell" buses. This is as part of a global series of trials being carried out under the European Union’s CUTE (Cleaner Urban Transport for Europe) project. In all 9 EU cities are involved plus Reykjavik (Iceland), Perth (Australia) and Beijing (China). The reasoning behind the ‘CUTE’ program is to test the buses to see how they cope in different traffic and climatic conditions - which implies rigorous usage to test endurance, reliability, to look for weaknesses, etc. London is a key city in these trials because of its extreme stop-start traffic conditions where travelling for much more than a minute without stopping is fairly unusual. The trials in these 11 cities are part of a long-term development programme which previously saw the testing of one fuel-cell bus in the Canadian city of Vancouver.

In theory fuel-cell technology sounds wonderful. The hydrogen "fuel" stored on the bus is converted into electricity, with the only waste product being water vapour (ie: steam!). This means that these are electrically driven buses - and there is no pollution at point of use.

But...

Fuel-cell technology is still very much experimental and is so energy inefficient that whilst using these buses will improve their local air quality producing their hydrogen fuel will negatively impact upon the global environment. According to information obtained from oil company BP when renewably sourced electricity is used to produce the hydrogen emissions of the harmful greenhouse gas CO2 increases by 582 tonnes for every Gwh of power generated. Furthermore, for every 9Gwh of energy invested just 1Gwh of usable power will reach the buses wheel - generating, compressing & storing the hydrogen will waste the rest of the energy. As a contrast trolleybuses are a tried, tested and proven technology successfully used in over 350 towns & cities globally. They are also very fuel efficient - when sourced renewably over 90% of the electricity actually gets usefully through to drive the vehicle. When trialed in Vancouver, Canada they found that one fuel-cell bus consumes as much power as a dozen trolleybuses and unlike trolleybuses which can work 24+ hour duties without even needing to be refuelled (OK, so occasionally they do change the bus drivers!) the fuel-cell buses needed refuelling after just 4.5 hours - barely half a workday! So for this plus other reasons resulting from their comparative trials they are now buying a fleet of 230 brand new low-floor trolleybuses.

Another issue for these fuel-cell buses is that they are so heavy that their unladen weight is roughly similar to that of a diesel bus carrying a full complement of passengers. Since governments usually set legal limits on how much a bus may weigh (partly to reduce wear & tear on the road surfaces) the net result is that passenger capacities of fuel-cell buses are lower than fossil fuel or trolleybuses of comparable size.

As with CNG buses, hydrogen fuel-cell buses must be equipped with leak detectors because hydrogen is extremely volatile.

As an aside, the CUTE trial was extended for an additional 13 months from the initial completion date of December 2005, and finished on 12 January 2007. The London hydrogen fuel cell buses have now been withdrawn from service and because of their unique nature have been donated to museums, albeit without their hydrogen equipment, which has been reclaimed by the manufacturers for further development works. They have gone to the London Transport Museum, The Science Museum and the Beith Collection in Ayrshire, Scotland. Being modern buses which in no way could be considered to be ‘life - expired‘ it is unfortunate that further use could bot have been found for them, perhaps as battery electric or trolleybuses at one of the living museums.

Because the decision makers are more interested in possible future solutions for 20+ year‘s time and not seriously working to reduce air pollution ‘right now‘ further trials have been proposed, this time using ten hydrogen powered buses, of which five will be fuel cell buses and five will be hydrogen powered motor buses. In addition there will be some other types of fuel cell vehicles (such as dustcarts) ‡ and London's senior transport managers have issued a stern rebuke to the various fuel cell bus manufacturers for making them so expensive(!) All this is being done under the auspices of TfL and the London Hydrogen Partnership's 'London Hydrogen Transport Programme'. Since TfL have allowed the hydrogen filling station used by the previous fuel-cell buses to be decommissioned so a replacement will have to be built. How much this will cost is not known.

‡ In August 2008 a different Mayor (Mr Boris Johnston) who won the Mayoral election earlier in the year decided that as part of a policy of reducing expenditure and not increasing the local taxation levied on the people of London he would scale back his predecessor's plans and now only 10 fuel cell buses will be delivered.

Fuel-cell Hybrid buses

Being trialed in the USA is a midi sized bus (30 ft) powered by a low power (20 kw) Hydrogenics fuel-cell which is being designed for the motor car industry. This vehicle operates as a 'series' type hybrid bus where the fuel-cell charges the main battery propulsion unit and provides limited additional range. The advantage of this configuration is the ability to use technology which is already in development, this being something that helps spread the potential return on the R&D investment.

In June 2009 a German bus company unveiled the first of an experimental fleet of fuel-cell hybrid buses. These are being seen as successors to the CUTE buses described above and the idea is that a small fleet will be supplied to several towns and cities to evaluate the technology. As with the CUTE buses the 'greeness' of these vehicles largely depends on how their hydrogen fuel is sourced - typically (at present) it comes from fossil fuels and requires so much fuel to be used that when comparing the total energy input these vehicles consume even more energy / result in more air pollution than ordinary diesel buses.

Considerably more information on fuel-cell buses can be found here (link to an external site which opens in a new window)