The Future is Electric

Last week I got a chance to check out one of Metro’s new Proterra’s electric battery-operated buses. It was parked at Microsoft for an hour and I was lucky enough to talk with a rep from Proterra and the bus driver. Previous coverage of the new buses can be found here.

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The bus was 40 feet long. It has a charger on the top of the bus for use with the rapid charging system currently installed at EastGate. It also has a side charger port that you could theoretically also use to plug in the bus via a cord.

One thing that stuck out was that the bus body was made out of composite materials and not sheet metal. This significantly reduces the weight which helps increase the range of the bus. The interior of the bus has 40 seats and can accommodate 37 more standing passengers for a total capacity of 77 passengers. 28 seats are forward facing while the remaining 12 face inwards towards the center aisle. All interior lights are LED which also help efficiency.

The back of the bus houses the motor, inverter and the transmission. I was surprised to hear it has a 2 speed transmission, but apparently this was necessary to reduce the current needed to start the bus from a stop and for slow speeds. With less parts than a conventional diesel bus, it allows for a rear window, which most Metro buses don’t currently have. The top speed is rated at 65 miles per hour. 8 battery packs line the floor of the bus between the rear and front wheels.

The documentation I got from the Proterra rep states that the bus typically gets 1.7 kWh per mile with full passenger load and full HVAC. They claim a nominal range of 60 miles, which would but the battery capacity at 102 kwH.

I didn’t receive any information on the total cost of the new bus, but I’m sure it’s significantly more expensive than a diesel or hybrid diesel coach. But the maintenance and fuel energy costs will be much less. Over a 12 year lifetime, the company estimates that energy costs will be $81k while maintenance costs will be $300k. That’s much less than the cost of a Diesel or Hybrid bus which run between $700k – $800k for that same period. So that equals out to around a $300k savings over a conventional bus over its lifetime.

Metro is currently doing testing with large water jugs on each passenger seat to simulate a load of passengers and measuring how well the bus performs. The bus driver didn’t know when they would enter service, but they gave a hint that they were hoping they’d be ready by sometime in the spring and the likely first route would be from EastGate to Seattle.

I’m really hoping the tests go well and that Metro will not only confirm the large cost savings compared to conventional buses, but will be much better for the environment with how much hydro power our area produces.