Smith Electric Vehicles has teamed with Trans Tech Bus to roll out a 42-passenger, 26,000lb electric bus, called the Newton eTrans, which it hopes will change the way children get to school every morning.
"Speed and predictability of route is important," Bryan Hansel, CEO of Smith Electric Vehicles, told us. "School buses tend to have very dedicated routes. You know the exact distance that you drive every day, so you don't have to have any concerns about range anxiety."
The duty cycle of a school bus could be well-suited to electrification. The Newton eTrans is expected to go into production in the second quarter of 2012. (Source: Smith Electric Vehicles)
Indeed, Smith is tuned into the idea of route predictability, so much so that the company offers customers a graduated series of lithium-ion battery sizes. Starting at 40kWh, its battery sizes increase in 20kWh increments, up to a maximum of 120kWh. The top-level bus, which carries about 3,000lb of batteries onboard, has a range of about 120 miles, and employs a permanent magnet motor with 150kW of peak power.
Smith's battery cells, configured like saddlebags across the bus's center frame rails, use a lithium iron phosphate chemistry, and are built by A123 Systems. Although the battery packs employ sensors to monitor cell temperatures, they have no active cooling system. If the battery management system "sees" elevated temperatures in any of the cells, it de-powers that part of the pack (although the company said that has never been necessary).
In that respect, electric buses have an advantage over small electric cars that accelerate quickly, Hansel said.
"When you have a smaller battery and need to accelerate more quickly, that's when you need active cooling," he told us. "You tend to get heating because you are trying to draw energy out of a small number of cells very quickly, whereas we have very large batteries, and we pull very little energy out of them."
To build the bus, Smith teamed with Trans Tech Bus. Smith builds the power chassis for the Newton eTrans, while Trans Tech does the body, structural design, and the interior. The two companies believe that the eTrans is the first all-electric school bus.
Wow - I was thinking that the temperature issue was just the effect that cold weather has on a battery (like trying to start your car in the middle of winter). I didn't think about heating, which I am sure is a major draw. Maybe that's another reason the current crop of electric vehicles tend to start at the smaller end. I can't see how they could even heat the volume of a bus off the battery.
You raise another good point, Jack. Weather can make a huge difference for electric vehicles. When Wall Street Journal writer Jonathon Welsh tested the Nissan Leaf in 20-degree weather in 2010, he put just 49.5 miles on the odometer before finding that the remaining range was in the single digits. That's a preciptious drop from its stated range (somewhere between 73 and 100 miles). The culprit was apparently the interior heater. Imagine how much the range would drop on a bus if a driver tried to heat the cabin.
Justajo - I think your comment about the budgets leads into another issue with range anxiety. How much safety factor is going to be built in? Are the school boards going to keep costs contained by looking solely at the range the bus currently drives and buying on that is the closest match? Then the anxiety hits when its cold, unusually bad traffic, the battery starting to wear out....
You write as if the government really has ever worried about the cost of anything. Just borrow the money, write the check and let the next generation worry how to pay for it. I am not very aware of any politician of any party affiliation that is unwilling to kick the can down the road for someone else to worry over.
Early bus designs were much more streamlined and pleasant on the eye than today's buses, even this one. To make a bus slippery the back end has to be tapered like a teardrop. And the front of this bus doesn't have much to suggest it went through any CFD or wind tunnel testing. The design is driven by practicality (how many passengers can fit in a given length) and safety (the front flashing lights have to be visible).
As far as servicability, electric is the way to go. Without the vibration of a diesel, electrics typically have far fewer problems. The electronics can't be any worse a challenge for a mechanic than the ECU on current diesels.
The economics of purchasing and running an electric bus will be the make or break issue. I am in total agreement. 120kWh of batteries would be, IMHO, $2,000/kWh x 120 kWh = $240,000. Hmmm, the banks will love the "gas tank".
However, electric buses do have some advantages. They could actaully drive into the school building since the don't give off any fumes. For special ed or educational field trips the quietness would be a definite plus.
Since electrics have no need for drive shafts or conventional frames I would expect an electric bus to be three feet lower to the ground that a conventional bus and have better weight distribution for better handling and tip over resistance. I would also expect electric buses to have battery modules that can be quickly removed and replaced much like fork lift batteries.
And a certain number of buses in any fleet are used throughout the day, sometimes on unexpected field trips.
The bus shell is innovative -- it doesn't look ugly like every other school bus -- and the range issue is adapted perfectly to the application. That said, Justajo and William K, make critical points about the cost of acquisition and service of these buses. To that I'd add, I don't know how it is in most cities, but in New York and New Jersey, there are a bunch of school buses companies and they're all independent companies which bid for business with the cities and various school boards. So it goes beyond getting school boards to buy these things; there has to be an economic argument at the contractor, which is orders of magnitude harder. So unless there are some special grants involved to test deployment of these electric buses, I think they're going to have a tough row to hoe.
Plus, for kids now in college, Electric School Bus is the name of a CD-based game from Microsoft, where the bus drives around in outer space, not an actual vehicle on the road :)
Good comment about the nighttime charging. With some of the new smart grid applications, the buses could automatically charge at midnight, even if they get plugged in immediately after the school day ends.
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