On the (electric) buses

It’s not just cars and lorries that are going electric in a bid to reduce carbon emissions and costs, public transport is also joining the low-emissions party. In particular, companies such as Volvo are developing the next generation of buses, which can run as electric or hybrid vehicles. These include a fleet of eight Volvo electric buses, which will be coming to Harrogate next year. Environment Journal spoke with Volvo Buses’ chief engineer, Edward Jobson to find out more.

Why is it important for a company like Volvo to develop electric and low-emission vehicles?

Volvo has been working on environmental issues for a very long time. In 1972, it became one of our core values and is strongly rooted in the organisation. In 2012, we took the decision about how to proceed with the Euro 6 engine, we had gas buses, diesel buses, and we could see that electrification was becoming more and more important. The Volvo Buses board took the decision that we should not proceed with diesel or gas for city buses beyond the point of the Euro 6. We excluded that from our business. I think that shows how important it is for us to take this seriously.

What kind of buses are you now developing?

We have three parallel products for Europe for city buses. We have a conventional hybrid, which uses the braking energy and runs in electric mode at slow speed, a plug-in or electric hybrid, which can drive electrically and have a combustion engine as range extender. We also have an electric bus, which does not have a combustion engine.

What kind of distances can these buses do?

It depends on the version of bus and the type of traffic. Our plug-in can drive approximately 7km in electric mode depending on the route, topography and load. Then the diesel engine kicks in as range extender. The [all] electric bus is optimised for 10km, but we are doing up to 20km. It’s a short range, but as the batteries become better, we will make this longer. We still think that’s still good, because the environmental impact is much lower with the fewer batteries you have on-board. We don’t think it’s a good environmental solution to carry around batteries for the whole day, even if you can afford it.

What do you think the environmental benefits would be by switching to electric buses?

You have much fewer emissions. Many of our customers buy electricity, which is renewable, which you can do by certification. Total energy use is important. The [lack of] noise is another important value we are promoting.

With these electric buses, are they able to use smart technology and smart city systems?

We think smart cities will be environmentally-adapted and public transport will be important for both transport efficiency reasons and capacity efficiency reasons. You probably want to have buses similar to the ones you are already used to do, except electrified.

What do you think buses and the supported infrastructure will look like in 30 years’ time?

They [the buses] will be electric. It’s more of a matter about how autonomous and how big they will be. We will still have humans on-board, but for different purposes. You will have stewards instead of drivers, who can help the elderly. We are not really after excluding the human factor at all.

Will the buses of the future be able to interact with traffic management systems?

Many big cities have traffic management systems, which are quite advanced now. We are providing a functionality called zone management that has not been available for buses before. You can decide where the bus should run electrically, where should it use a combustion engine, what speed should it have in different streets. One bus lane in one street can have a different speed setting than another bus lane in the same street. You can program the bus and this is something we are selling commercially and this running in all the cities we have plug-in and electric buses in now.

There have been tremendous advances with battery storage, how will that help the rollout of electric buses and other vehicles?

This is one of the main drivers for the electrification of the automotive sector as a whole. From 2005 onwards, we have lithium ion batteries, which have a much higher energy storage potential .This opened up standards we were not used to before. When you look to the future, we see battery development will continue and it will impact the range and price of new vehicles. As the prices go down, the competitiveness will increase. It will not take long until you will have to justify why you will not go electric. 

How important is the roll out of rapid charging technology?

If you take school buses, they will not need rapid charging. They go out one hour in the morning and one hour in the evening. It will be easy for them to charge at the depot. But most other buses, which are utilised 12 hours a day, they will either need to carry around a lot of batteries or to utilise fast charging. OppCharge is the name of the technology that is supplied by most manufacturers today, following ACEA recommendations. You will need enough batteries to handle the rush hour, during which you have non-stop driving. Some will need different schemes to ensure you have a full bus fleet out during a day.

How important is it to make sure the charging of these vehicles does not impact local energy grids?

The average city in Europe is quite small, with around 150,000 inhabitants. They have over-capacity in the electric grid in most places. The overall energy use has been going down for the last 10 years, with a few exceptions. If the full bus fleet is electrified, there is no case where we have increased the energy use by more than 5%. If we move to the total electric vehicle fleet, it might increase by 25%, but it’s mostly less. Sometimes you need to adjust the grid or build a new substation, but normally as a whole, the average city has good adaptability.

Is Volvo looking at any other technology, like hydrogen?

There are a lot of people looking at hydrogen. So far, we are focused on electrification. You can imagine in the future there will be fuelling stations for hydrogen. But the intrinsic problem with hydrogen is you lose a lot of energy. Going from hydrogen to electricity and then back again, you lose 30% twice and that is basic physics. Those losses are very costly, so when we compare the energy efficiency of a hydrogen driven bus to an electric bus, the electric is three times better in energy efficiency. It’s a huge advantage for an electric bus. But that’s not to say it’s not interesting, it could be complementary because you could get a larger range. But what is developing faster here? Is it hydrogen storage or battery storage? It’s battery storage.


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