Brilliant! I've had a similar idea for years that used capacitators and a charging station at each stop in a high density city such as New York or Chicago.

It is a brilliant application for the Titanate type of lithium battery that is extremely durable capable of over 10000 deep cycles. Such durability is not needed for most EVs but it will be needed here where a battery may be cycled almost fully 10 times a day 300 days a year. It should also be cost competitive to other types of EV or diesel busses as the needed size of the battery can be kept very small or just enough to do one bus route (20 miles range should needs less than 40kWh of batteries). However, I think Toshiba will take most of the market for this type of applications as they are currently the only producer with mass production capability for the Titanate type of lithium battery see http://www.greencarcongress.com/2010/09/toshiba-20100930.html#more

@ SJC & HarveyD, why does everything need a range extender? Practical engineering and economics are the key. This one energy storage/conversion system will be expensive enough. A bus is not a Swiss Army knife. A well engineered, economic version of this concept should have plenty of applications without making a Frankenstein-mobile.

A natural gas based heating system for operations in cold weather climates might make economic sense as a large bus in cold weather could draw 20kW just for heating and therefore require a much larger battery. There is zero need for a combustion engine for anything. Should the main battery fail you only need a small backup battery (less than 1kWh) to operate power steering, lights, brakes and doors.

You could squeeze in a 4 cylinder diesel spinning a 30kW generator and 20kW of heating if required.

Fully electric would be better, if the batteries can cope with it then even better.

HVAC (heating and cooling) could be supplied with ultra high efficiency Heat Pumps. Braking energy capture could supply most of the e-power required for HVAC on AWD stop and go city buses. Roof mounted solar panels could (soon) help to reduce the size of batteries. A few years down the road, when batteries performance are 2x to 5x todays, four to five quick recharges a day should do it. Flexible Modular battery packs would not need back ups.

There's a great future for city e-buses of various sizes.

Harvey solar panels would help a little when the sun shines. However, the bus needs to operate also on a cloudy day or at night so adding them will not help to reduce battery size at all. Plus 20 sq meters of 20% efficient solar panels only adds between 0 and 4000W and cost about 24.000 USD so they are out of the questing for any commercial bus service. The titanate type of lithium battery costs about 2000 USD per kWh from Altair and Toshiba could probably sell them for 1000 USD per kWh to large bus makers like Volvo, Mercedes or Fiat but smaller customers will still pay 2000 USD per kWh. A cheaper alternative may be A123 systems LiFePO4 batteries but they may not be durable enough for this type of application. Also you keep talking about better battery performance will solve all problems. This is wrong. Batteries already exist that can do the job for almost anything and certainly this bus application. The cost per kWh is a far more important showstopper than battery performance. Reducing costs are vital and that is not going to change until we get some volume going and this is why the EV industry needs to be subsidized in the beginning.

A charging system like this one was used by a company in the 1950's to charge up their flywheel bus. I believe it was tried in Sweden and also they had a system in Zaire. Because flywheel technology was not very advanced, the systems were not in service very long.

If you have 10 bus lines and need at least 10 high power charge stations at say 2 million dollars each. That could buy you 40 range extended diesel electric DME powered buses.

This is where the genset comes in, portable power. The engine cooling system could store enough heat for the bus parked for hours. The AC could be driven off the engine cooling a thermal mass as well.

Actually it's an expensive solution because of the use of powerful diesel engine and generator.

A much cheaper solution would be pure electric, with some towing trucks on stand-by if electric buses break down. The buses would also be lighter.

Harvey mentioned that Hydro Quebec was testing some batteries that can sustain 20,000+ charges (don't know at what rate of charge).

Instead of doing the charge for 5-6 min at max load to the grid and batteries (not good for either of them), it would make sense to extend charging period (ie charge at reduced power) if the bus stop lasts longer (say 15 to 20 min). Driver could enter/select the duration of charging period, or it could be done automatically based on bus schedule.

By splitting long bus routes into shorter ones, the system coverage could be increased.

Its only talking about 10-15 km of range per charge not 20 miles. This is strictly to enable some very short routes to be totaly electric powered simply via a converted hybrid bus and a changing station which admittedly is likely 4-500k or more in cost but still one hell of alot cheaper then most electric mass transit systems.

But again its for VERY short ranges. Also even with those batteries they are likely to eat through packs fairly often given how many times a day they likely will be charged.

Wow, lots of very good ideas here in the comments! Thanks! - The charging stations are more in the range of 300k, not 2 million, and can be shared by a number of buses, and last practically forever.

Dear Mr. Engineer-Poet, looks like you were already on the same road that I took about a year later. You said in your post "So yeah, I see these things taking off just as soon as some smart cookie finds a way to integrate a hands-off fast-charging system with a covered bus stop.". Hopefully I'm that cookie!

We've done a fair bit of analysis, along with Epyon, that predicts a reasonable battery lifetime of 6-10 years for a one-way route of 14km, charging at each end of the route. This assumes that the batteries can be kept around 25 degrees Celsius. Lifetime goes down dramatically if the batteries heat up.

The E-Traction bus in the video has a small 50kW VW diesel range extender, which should be plenty to run the bus indefinitely on diesel if required. However, with fast charging, the range extender shouldn't be needed very often. It's not very expensive, and makes the system much more flexible than a pure electric bus (like ProTerra). There are several other companies with suitable hybrid systems that can be converted easily.

As to heating - we are looking at a system in northern Sweden, and this is a big issue. Electrically heated seats was one suggestion, but I know what you mean GreenPlease, buses are typically overheated because the driver is in shirtsleeves, and the passengers in heavy coats. Here in Spain it is the opposite, AC is the issue, both for the people and for the batteries( Hmm, which one takes precedence on really hot days?)

Anyway, please send me any more suggestions and contacts, and forward this post to anyone you know. - Roger