electric frequently asked questions

How many electric buses do you have?

There will be 24 electric buses in our first batch – 14 for purple 17, 6 for claret 21 and 4 ‘generic’ buses that can run on any route – three of them have some special eye-catching designs though. We have also ordered a further 8 buses for yellow 26 which will be entering service soon! 

Why were those routes selected?

Purple 17 is our most frequent and intensive service, running 24 hours a day through an air quality management area, so there is the most potential to reduce carbon with the fewest vehicles. It is also one of our busiest routes - so keeping these buses up to date is essential. Claret 21 also runs 24 hours a day to the heart of central Reading and through Reading University to Lower Earley. The University is a world-leading institution for climate science, renowned for creating the "Climate Stripes" and contributing to IPCC reports, so it felt appropriate that it should be served by our second zero emission route.

What features do these electric buses have?

New on these buses is full, automatic air conditioning and heating – electrically provided using a heat pump. The front windscreen is curved and designed to reduce risk of injury in the unlikely event of a collision.

They also come with our usual high standard specification, featuring:

• audio and visual next stop information system including hearing loop
• USB-A and USB-C charging points at each seat
• seat-back phone holder with wireless charging
• comfy high back seats
• LED mood lighting
• lower deck rear tables and extra luggage space in place of rear seats
• free WiFi

This brings some of the features of our current purple 17 buses to claret 21:

• second multi-use wheelchair and buggy bay
• glazed staircase and ‘sunroof’ for extra natural light
• additional tinted glazing – staircase, roof lights and front dome – to keep heat gain down
• coffee shop style flooring
• upper deck table / family area
• staircase CCTV screen displaying free seats upstairs in addition to interior and exterior cameras
• coat hooks

There are also features for the driver:

• Camera mirrors for improved visibility
• Reversing sensors
• PA system

How many miles can these new electric buses do in a single charge?

These buses can travel up to 385 miles on a single charge in ideal conditions, although the actual range will depend on the weather and driving conditions. This is still more than enough for a full day of operation on most of our urban routes in Reading. Even our 24/7 buses do less than 200 miles in a day.

The buses use more electricity in winter and summer to run the heating and cooling, but will still have more than enough for a full day’s running. The amount of charge on the bus is monitored remotely at the depot as well as on a display for the driver, so if there is a problem with the amount of charge remaining, we can take action before it causes any disruption to the service.

The capacity of the batteries degrades gradually over time, and this has been modelled for our network and guaranteed for 12 years. At that point we can replace some or all of the batteries if needed, or use the buses on routes with lighter schedules.

How do you charge the electric buses?

The buses are charged overnight, using electric charging points that we have installed at our depot at Great Knollys Street. They are very similar to the ones you often now see at motorway service stations that look like an American fridge freezer.

We have 16 fast chargers which can charge two buses from empty to full in 6 and-a-half hours or give one bus a fast charge in 3 and-a-quarter hours. We also have one super-fast charger which can charge a bus from empty to full in 3 hours, and a mobile workshop charger to help with maintenance. 

This charging infrastructure draws electricity from the National Grid, just like most homes and businesses. 

We have plans to install additional solar panels on our depot roof through Reading Solar to help further offset our electricity use.

How many Zero-Emission buses are there in the UK?

A lot! We don’t know the exact number as more and more buses are being introduced all the time, but latest estimates put the figure at close to 6,000 buses of which TfL alone have more than 2,000, and Manchester 300.

What does zero emission mean?

Quite simply, they do not generate any tailpipe emissions when they are on the road unlike diesel or even our CNG buses.

The technical definition of zero emission is supplied by a body called the Zemo Partnership who support the Department for Transport. This states that buses can only be called zero emission if:

• they have no combustion engine on-board
• has no regulated tailpipe (exhaust) air pollutant emissions
• achieves a 50% well-to-wheel (WTW) greenhouse gas saving compared to a conventional Euro VI diesel bus over the UK Bus Cycle

Our new electric buses are 100% electric, with no diesel heater or tailpipe emissions. They actually achieve an 86% saving in Well-to-Wheel greenhouse gas emissions compared to existing Euro VI diesel buses, making them even more environmentally friendly. 

This does not, of course, mean that the buses are entirely without emissions in their life cycle. They are powered by electricity which produces emissions in its production and the building of the vehicle itself produces emissions, however these are more than compensated over the operating life of the vehicle. Operating an electric bus (the Well-to-Wheel figure) produces less carbon than a diesel bus and greatly reduces the amount of emissions in the air around the town due to the lack of emissions from the tailpipe. 

What does all this cost?

Electric buses cost around two thirds more than diesel buses, plus need the infrastructure and grid capacity to be provided. We have spent around £14m in 2025, and are expecting to spend an additional £4.5m in 2026.

We have secured £4.7m from the second round of the Department for Transport's Zero Emission Bus Regional Areas (ZEBRA2) fund for purple 17 and claret 21, and a further £1.35m for yellow 26. This funds 75% of the infrastructure costs, and 75% of the additional cost of buying electric buses rather than diesel. The remaining 25% is being funded by Reading Buses including projected cost savings from running on electric instead of diesel.

The ZEBRA1 scheme helped bring about 1,278 zero emission buses with ZEBRA2 helping a further 955 being introduced outside of London. 

Will buying these buses put the fares up?

No! We need to replace the oldest buses in our fleet each year to ensure that the fleet remains reliable and economic to maintain, so fleet investment is always part of what we factor into the fares we charge. Any investment that we do is also carefully targeted to help keep bus travel attractive and to encourage more people out of their cars. In fact, by having high profile launches and keeping our fleet age young, we attract more customers which helps to pay for the buses!

What is the emission savings from these buses?

The new electric buses replace CNG buses on purple 17 and diesel buses on claret 21. We are keeping the CNG buses to displace older diesel vehicles so we can compare the electrics to the diesels! The electric buses reduce carbon emissions by 86% compared to diesel based on current grid electric (and will improve with the grid). Our current biomethane gas buses reduce carbon emissions by 84% compared to diesel (but are not quite zero emission).

The average saving of grams of CO2e (Carbon Dioxide Equivalent) per Kilometre of our new buses versus an equivalent diesel Euro VI bus is 1125.5. This means that (roughly) for every 1000km our buses travel, we will save over a tonne of CO2e. During the course of a full year, we expect these buses to save around 1819 tonnes of CO2e versus the diesel buses they will be replacing! 

Are your buses British?

Our buses were built in Scotland by manufacturer Alexander Dennis. We tested a several electric buses and they came out top with the best interior layout for our customers, best range, and best electric motor efficiency. 

What batteries are you using, how long do they last and what happens to them afterwards?

The batteries are provided by Impact Clean Power Technology, and have NMC (Nickel Manganese Cobalt) lithium-ion chemistry. The battery system is designed to allow for upgrades to newer battery technology without needing major modifications. So, if new technology can make them more efficient, it shouldn’t need lengthy periods of buses off the road!

NMC batteries utilize a layered metal oxide structure as the cathode, with the ratio of nickel, manganese, and cobalt being the defining characteristic. They have high energy density, good power output, and relatively long cycle life compared to some other lithium-ion chemistries.

As with all batteries, they will slowly begin to lose the amount of stored energy as the years progress. Our buses’ batteries should last for around 12 years before needing to be replaced. Once they are no longer suitable for the intensive use we require onboard a bus, they still have significant capacity, and can be refurbished to power homes, or even as temporary power sources for festivals and events. 

I’ve heard that electric vehicles are more prone to fires than diesel/petrol ones – is this true?

In a word, no! 

Whilst vehicle fires can, and do, occur, there is no evidence that electrical vehicles have a greater risk than petrol or diesel vehicles. In fact, according to a few studies, including one from EV FireSafe, the risk of an electrical vehicle catching fire is 0.0012% compared to a 0.1% risk for ones with an internal combustion engine (petrol and diesel). 

The design of our buses includes specialised housing and monitoring systems.

The Battery Monitoring System (BMS) constantly monitors every cell in the vehicle to ensure that it is operating properly. If the system detects any issues, then the battery pack that has the affected cell is shut down and a warning message is transmitted to the driver and the depot via onboard telematics.

Each bus has 4 packs of batteries each totalling 118kWh, and only one pack is required to allow the bus to move.

Each battery pack also includes three levels of sensing to detect whether there is a risk of “thermal runaway” (essentially when a battery heats up uncontrollably) within a pack. If the system detects a rise in temperature beyond normal levels, detects hydrogen gas emitted as a result of a chemical reaction if a cell starts to breakdown, or coolant leak, a signal is sent to the BMS to shut down the relevant battery pack.

Beyond this, extensive testing has been undertaken to ensure that cells, modules and packs are resilient to a thermal event (heating) without triggering thermal runaway of adjacent battery packs. The testing regime includes (but not limited to):

• Nail penetration test – designed to simulate severe road debris being flicked-up into a battery pack
• Abusive over charge – installed charging systems are designed to shut-off when cells are fully charged. This test is intended to simulate if this shut-off fails for any reason
• Flooding – designed to simulate a condition where the battery pack undergoes a coolant leak and fails to shut down 

Obviously, no system is 100% guaranteed and history tells us that scenarios can occur that are beyond the experience and imagination of our suppliers and our own engineers. If something happens that cannot be avoided, detected or mitigated, the battery packs and surrounding vehicle environment is designed to contain and/or direct hot gases into safe areas. There are a number of levels of containment:

• Battery packs are enclosed within a steel container – maximum external temperature recorded during a simulated thermal runaway was 4,000C
• Each pack includes a vent system to guide hot gases away from areas at risk
• An additional thermal barrier is provided between the under stairwell battery and the driver (peace of mind action)
• All Glass-Reinforced Plastic surrounding areas where batteries are placed are specified to class-1 fire resistance – there is a legal requirement that a fire must be contained for 5 minutes to allow passengers to evacuate without risk of injury due to these overheating.

Why have you bought electric buses and not CNG or hydrogen?

Whilst we have been successfully running compressed natural gas buses to reduce overall carbon emissions since 2013, there is a desire continue improving air quality. Whilst our CNG buses produce much less carbon that our diesel buses, and very similar levels to our electric buses on current grid electricity, electric vehicles are zero emission and the grid will see further decarbonisation in the coming years! 

Unfortunately, there is currently not enough investment in the hydrogen industry around both the supply network and infrastructure to allow us to embrace this technology. As battery technology continues to improve it remains to be seen whether it will be necessary to invest in hydrogen to decarbonise our longer distance routes. If the hydrogen supply becomes more prevalent, clean and robust, you can be sure that the bus industry will jump on the chance to make our roads even cleaner!

What is happening with the current buses?

Our current biomethane purple 17 buses will be moving onto berry 23/24 and sky blue 15/16 following a mid-life refurbishment. This will allow us to dispose of the oldest diesel buses in our fleet. The berry buses will have the centre door removed, whilst it will stay in place on sky blue 15/16.

Why don’t the new buses have centre doors?

We reintroduced centre doors with the current purple 17 fleet in an attempt to speed up boarding and reduce wait time at bus stops. However, in reality there are several stops where there isn’t space to open both doors, and in the small number of locations where people do get on and off at the same stop only a very small number of people can board until they have to wait for people getting off from the centre door anyway. We haven’t seen a significant improvement in wait times, and the doors remove valuable seating capacity on the lower deck which older people, and people with mobility said is really important for them.