Charging – Is charging going through the roof?
When it comes to charging your electric vehicle, there has been some attention going out to inductive charging. For example, there is a bus in my hometown Utrecht that uses inductive charging at one point in the route. It is a really nice system, the bus does its route and at the Central Station stop it parks for a bit longer and charges its batteries via this system. It seems to work pretty good and having read numerous articles on the system, I’m sure it is also perfectly safe for people (both in the bus or when walking over it when the bus is gone).
Another method which is aimed at charging a bus is something that caught my eye at the last DDW in Eindhoven. At the Design on Wheels Show (of the Dutch Design Week) there was a small section with projects from schools and universities and one case was on charging a bus, from the top. The systems that were shown varied in how the device actually worked, the mechanism remains the same. At the bus stop a device is moved over the bus (lowered, or pivoted) which connects (wirelessly?) and charges the bus. To my surprise I found a company from Spain, Opbrid, that actually has one of these in production (or is planning to have them in production). An even bigger surprise was to find that they had teamed up with two Dutch companies for their total bus solutions; Epyon for fast charging, E-Traction for the buses.
The system of Opbrid is all based on conventional technology, the charging mechanism can be fitted on a conventional bus stop and the pantographs on top of the bus are similar to those used on trains. At the bus stop, the charging mechanism is moved over the bus, the pantographs move up and connect and the bus can fast charge for some 10 minutes. The batteries used (nLTO) allow for fast charging for many cycles on end.
The advantages compared to other technologies are:
- Smaller battery compared to full battery powered bus
- Less need of the diesel generator (or fuel cell, etc.) compared to other hybrids
- No need for special tracks or power lines (trams, trolleybuses)
The mentioned range of 10-15km on full electric is enough for most European bus routes, especially in urban areas. After a round trip the bus would charge up for about 10 minutes, allowing the driver a small break after which he can go for another lap once the bus is recharged. The driving range depends on the actual route and wether or not heating/airco is on for example. To compensate for this a small diesel generator is added on the bus, just in case.
I’d say this looks like a very promising move for public transport to go into. The pros of electric buses are clear, if it will be induction or overhead charging remains to be seen.
Induction charging has a bit of extra loss (90% is what most inductive charging companies aim for) than direct contact charging, but induction charging is also something that can be used for other vehicles and other places. Try to imagine a large pantograph on top of a Leaf and it might just roll over. The pantograph method of Opbrid is a lot easier to install (no need to dig up the road and bury the inductive charger at the bus stop).