Londoners might not dream of electric buses, but this ordinary looking bus garage in Waterloo features in the dreams of people from across the world who come to visit it.

It looks fairly normal, lots of buses, a washer, some offices. Behind the buses though, what look like black hoses with petrol pumps aren’t pumping liquid fuel into the buses, but electrons.

This ordinary looking garage is a world leader in the deployment of a fleet of all-electric buses, and the first all-electric bus garage in the UK.

Why here and why now?

They’re here thanks to the two routes operated by Go Ahead from his bus garage being fairly short runs between Waterloo and either Victoria or London Bridge. A typical bus based here will run half the mileage that other routes would see — on average 70 miles per day.

That made the depot an ideal site to test alternative fuels.

The why now is thanks to the arrival of the Ultra Low Emission Zone from next April (originally 2020), but that affected decisions taken several years ago.

Bus routes are offered on 5-year leases by TfL, and routes 507 and 521 from the Waterloo bus garage were up for renewal in 2016. Knowing that the 5-year lease would take the company into the time that the ULEZ would be effective, Richard Harrington, Engineering Director at Go Ahead London had long been looking for a bus that would be zero-emissions from its tailpipe.

In 2011, he found a few at a biennial bus trade show in Belgium, Busworld.

One of the buses that stood out came from a Chinese supplier, BYD (Build Your Dreams) which was already operating a fleet of electric buses in Shenzhen.

These looked viable, so, off to China for a look around, and in December 2013, the arrival of two prototype buses to test. Later two more buses were bought from a European supplier, as well for comparison.

These were tested using two electric charging points installed in a corner of Waterloo bus garage. The tests shows that the buses could consistently run a 16-hour shift without a recharge being necessary.

So, the approval was given to go for a switch to electric buses.

Converting a bus garage to electric

What could be difficult about swapping out the old diesel pumps for electric chargers? A lot as it happens. An awful lot.

Firstly, you need a lot of electricity. That proved to be a steep learning curve for a lot of people involved, and many of the lessons transfered to other bus garages later.

A key difference is that diesel can “recharge” a bus in a matter of minutes, so buses simply queue up at a pump and then drive off. With electric, it takes a few hours overnight, so they had to install a long line of charging points right down the middle of the garage.

That then caused a major problem that took some testing, to decide how to fit all the buses in to the space overnight, and also have them within reach of a power cable.

Fortunately, around half the buses doesn’t run in the middle of the day, when passenger demand is lower, which gave the managers time to play with a number of different layouts and make sure that buses could get in, and out without hitting each other.

That lead to a slightly unusual layout for a bus garage – where buses usually line up in rows, and behind each other, here they are lined up in a chevron layout.

They also needed 2.5 megawatts of electricity to recharge the buses overnight — although the use of smart monitoring means they never reach that full load.

In comes 11,000 volts to two new substations on the site, which is then dropped down to 400 volts and sent via two routes to the various charging points around the depot. Four fast chargers at 800 volts are also available if needed.

As each bus knows what the state of its batteries are, the smart chargers level the load across the entire fleet when they’re plugged in to even out the power demand from the mains electricity supply.

The experience with how the smart chargers work mean that future bus garage conversions should be able to operate with much lower levels of demand than was predicted for the the Waterloo bus garage, hence reducing costs.

They also had to shift the bus washer, not because of the water/electricity problem, but simply because it was now in the way of how buses had to move around to get to their charging points.

A series of metal buffers in the floor were added to help the bus drivers park in just the right spot for recharging.

Over a year, there was roughly four months of construction works carried out for the conversion, all while the bus garage was still in use.

The charging points themselves look remarkably like conventional diesel pumps, and one modification puts a small led light inside the “petrol cap” on the bus to help the drivers plug in correctly in the dark.

The new fleet of buses

In the end, while the tests proved the viability of an electric bus service, there were concerns about the bus design, particularly the battery placement, and a hybrid was developed. BYD supplies the batteries, motor and chassis, while Alexander Denis fitted the coach on top at their factory in Falkirk.

The buses were also designed to take into account how batteries degrade over time. At the moment, they generally return to the garage at the end of a shift with around a quarter of their battery life unused. That will diminish over time, but will be well within tolerances.

The two prototypes were nicknamed “electric Ferraris” for their speedy acceleration, but the battery placement did tend to cause wobbling along the route.

The management worked quite closely with the drivers on the spec for the main fleet, although one reluctant voice was heard to ask on a visit why they couldn’t have that nice bus over there instead of these electric things they were being taken to see.

He was pointing at the electric bus.

There had been hopes to launch the entire fleet in one go, but that was impractical — it’s just not possible to move 51 battery powered buses from Scotland to London in one go. So a phased launch started in September 2016, with 10 buses on day one, and five more added each week thereafter.

The inside of the buses is notable for two things. A lot of standing room, but that’s due to the nature of the route and the passenger demand, not the fuel supply. The other is the lack of back window, which is due to the batteries on the back of the buses, although newer buses have managed to restore the window.

They feature a regenerative braking system which feeds power from kinetic energy recovered during braking and deceleration back into the battery.

A number of improvements were made following driver feedback, such as adjustable dashboards and seating that can be adjusted before the driver get into the cab.

For those who get a seat, there’s one extra treat — a USB slot for charging your phone. The power drain is minimal so doesn’t affect the bus performance, and being of considerable utility, they are remarkably undamaged. It seems that sticking chewing gum in things only applies when the vandal feels they wont personally lose out.

It’s also a reminder of the difficulties of battery power. Smartphones need charging regularly, as do electric buses.

For the past 18 months, the entire fleet based at Waterloo has been electric, and they’ve clocked up over a million miles between them.

Most rewardingly, the fleet of buses ran without a hitch earlier this year when the Beast for the East drove temperatures to minus levels. Electric buses coped without a problem in the low temperatures while diesel engines sometimes struggled.

The financials

While operating the electric buses has been proven to be as reliable as a diesel bus service, is it cost effective to switch from diesel to electric?

One issue is that while the operating costs are lower, the upfront capital costs are much higher, and that can prove a financial strain when the leases for the routes last just 5 years (with an optional 2-year extension).

Prices are falling all the time as battery technology improves. At the moment, a bus similar to the fleet in use at Waterloo is about twice as expensive to buy as a diesel equivalent.

The upside is that the fuel costs are better, with electricity around half the cost of diesel per passenger mile carried. The fuel is only around a third of the total cost of a bus operating costs — with 60% in wages — so the saving is good, but takes a long time to repay the cost of the more expensive bus.

A cost issue can be that more buses are needed. Some buses can be on the road for as much as 23 hours in a day, leaving insufficient time for recharging. In such situations, spare buses need to be bought to maintain the service. That increases the upfront costs of fleet conversion.

A 5-year lease is not really long enough to recover the investment.

To make the switch to electric more appealing, either TfL needs to stump up some of the cost, or the leases extended so that the bus operator can reasonably recover their investment.

Another factor involved in converting a garage to electric is that the planning permission can take too long. When a tender is put out for electricity supply, so that they can work out the costs involved, the provisional agreement for electricity from location X to bus garage Y may last for less time that it takes to get planning permission. In the meantime, someone else comes along, takes all the available current for their building, and the costs of getting electricity from a point much further away jumps sharply.

These are the sorts of issues that are now being ironed out for future garage conversions. The first garage was always going to throw up a lot of problems, but there are now electric buses running from other garages that have partially converted, and each time, the problems are reduced as experience increases.

The future

There are already other routes in London using electric buses, but at the moment, no other garage is entirely electric.

The BYD-Alexander Dennis collaboration, initiated by Go Ahead for its fleet, has since gone from strength to strength, and has just won its first order for electric double-decker buses, which will come into use next year on Route 43.

One of the issues holding back the rollout of electric buses is the battery problem. Quite simply, hydrocarbon fuels deliver a lot more energy for their weight than batteries, which is why electric buses have been humps on the roof for all the extra juice storage.

Richard Harrington was coy about what’s being planned at this early stage, but it’s no secret that newer batteries under development are smaller, so either the hump can be removed, or the distance travelled between charges extended.

There are also plans that could see a return, in a way, of the old trollybus. Rather than an unsightly electric wire running the entire length of the route, as say on a tram network, here there would be recharging points at bus stops.

As the bus pulls in, a pantograph on top of the bus would connect to an overhead power unit and suck down a large surge of power to top up the batteries. That enables the buses to run much further, or for longer between charges.

One huge advantage of the electric buses is noise, or more accurately, the lack of it. Many bus garages have to try and be placed reasonably away from residential areas due to the noise, and smell of the diesel engines, or have constraints imposed on them.

For example, the newish West Ham bus garage was designed to put the buses away from an expected residential development on the other side. Electric buses while not totally silent, are very quiet and don’t smell, so here at Waterloo, it’s less of an issue to be surrounded by residential flats.

Londoners might not dream of electric buses, but at least they wont be woken up by them.

Thanks to the staff at Go Ahead London for the site visit.