News From My Backyard: Portland's TriMet Begins Using Biodiesel, Is Also Testing Hybrid Buses and Installing PV-lit Bus Shelters

TriMet, the public transit district serving the Portland, Oregon Metropolitan Area, announced this Tuesday that they would become the first transit district in the state to begin using biodiesel to fuel part of its bus fleet and one of only a handful of transit districts nationally that use the alternative fuel. TriMet will begin to test biodiesel in 75 of its LIFT fleet buses which provide door-to-door service for elderly and people with disabilities. The buses will be fueled by a B5 mix - a mix of five percent biodiesel and 95 percent petroleum diesel.

"TriMet has been interested in using biodiesel for some time, and now that high quality biodiesel is available locally and the price of B5 is similar to regular diesel, we're able to move forward on this environmentally friendly fuel," said TriMet General Manager Fred Hansen.


According to the press release, TriMet will receive 27,300 gallons each month of B5 from Carson Oil which will be deliverd to at the agency’s LIFT facility in NW Portland. LIFT vehicles are directly fueled from tanker trucks.

Carson is an Oregon-based petroleum services company that serves Oregon and Southwest Washington. The company purchase the biodiesel from a supplier and blend it with petroleum diesel at its NW Portland facility. The press release reports that starting in January, Carson will purchase its biodiesel from SeQuential Biofuels, a Salem, OR-based biodiesel refiner and the first local biodiesel manufacturer in Oregon. The local biodiesel will consist of vegetable oil and used cooking oil from such places as NW restaurants and Kettle Foods, in Salem (makers of Kettle Chips).

TriMet hopes that their use of biodiesel will play a small part in reducing their reliance on oil, reducing air pollution and emissions and increasing the demand for biodiesel in the region whil helping expand the supply of the alternative fuel.

TriMet plans to test the biodiesel in 75 of their LIFT buses until spring 2006. According to the press release, if all goes well, TriMet plans to have all 210 of the LIFT buses using B5 biodiesel within the year. The entire LIFT fleet would consume about 70,000 gallons of biodiesel per month. The agency will also evaluate the potential of using biodiesel in the their 611 fixed-route buses in the future.

Personally, I'm not sure what they are looking to 'test'. It seems like biodiesel has a pretty strong track record at this point in a number of applications across the world. I would imagine TriMet is more concerned about potential logistics and supply issues with Carson Oil than with performance or maintanence issues from the use of the B5 blend.

TriMet is the largest transit district and the largest diesel user in the state of Oregon. You may also remeber that TriMet also got some press here at WattHead last week for partnering with Google on the beta release of their new Transit Trip Planner.

While this is largely a symbolic gesture at this point - I'm sure the use of ~27,000 gallons of B5 per month is a drop in the bucket compared to the transit district's overall fuel consumption (and remember its only B5 so only 5% of each gallon is actually biodiesel) - but it is, nonetheless, a first step in the right direction and the folk's at TriMet deserve props for that.


TriMet is also in the process of testing hybrid diesel-electric buses. According to the transit district's environmental practices website, Hybrid bus manufacturer, New Flyer of America, along with its hybrid propulsion system suppliers Allison Drives, Inc., and Cummins Corp., have partnered with TriMet to test and evaluate an unspecified number of hybrid buses over the next two years.

The buses have a 'series hybrid' drivetrain in which a diesel engine runs a generator which charges a battery pack on the roof. The batteries then power an electric motor that drives the wheels. Regenerative braking, particularly effective in the stop-and-go driving cycle of a transit bus, provides additional charge for the batteries. As I've discussed in previous posts, this series-hybrid setup which allows the bus to be run on an electric motor and transmission rather than an internal combustion engine is quite a bit more efficient. Using the diesel engine as a generator also allows it to be optimized to run at only one speed for maximum efficiency.


According to TriMet, the diesel engines used in the hybrid buses are quite a bit smaller than those used in their conventional buses, about the size of a pick-up truck's engine. The reduced engine size and the use of regenerative braking and the more efficient electric drive means TriMet expects a reduction of 75% in emissions compared to their conventional buses. They also expect fuel economy improvements of up to 50%. This should save TriMet considerably as the transit district reports that their regular diesel buses cost about $10,000 to fuel throughout the year. The savings will more than offset the extra costs of the hybrid buses.

TriMet also expects the buses to be much quieter as its smaller diesel engine emits less engine noise. Also, the hybrid bus uses its electric drive to accelerates and go up hills without revving the engine.

Finally, TriMet expects the buses to be easier to maintain than their normal fleet due to:

Brakes that last twice as long, thanks to regenerative braking;

No transmission to maintain; and

Decreased wear on the suspension.

According to TriMet, if these initial tests are succesful (and I don't see why they wouldn't be), the transit disctric plans to buy more hybrids to replace its regular diesel buses as they are retired.

The eventually phasing in of hybrid buses like these to replace their conventional diesel fleet would have a substantial impact on fuel use, emissions and noise from TriMet's large fleet. I can't wait to see more of these on the roads in the Portland Metro and across the country.


One final plug for TriMet's enviro-conscious efforts: apparently the transit district is installing solar panels to power the lights on 40 of the bus shelters on their Number 57 line. The 'TV Highway' line happens to be the only line that makes it all the way out to my hometown of Forest Grove at the far west end of the metro area. The panels should be installed by the end of this month.

According to TriMet, each unit consists of a roof-mounted PV cell that charges a battery which in turn powers an efficient light-emitting diode (LED) that lights the shelter at night. A motion detector conserves power by boosting the light's brightness in five-minute increments when people are in or near the shelter. Although the solar lighting costs extra, TriMet claims that it saves the cost of power-conduit installation and ongoing monthly power bills.

[A hat tip to Treehugger who managed to pick up on the biodiesel story faster than I could get around to it after seeing it on the evening news this Tuesday]