Conserving Fuel, Reducing Emissions
TriMet strives to conserve fuel and lower emissions, reducing impact on the environment. Here's how we do it.
Energizing MAX
MAX Light Rail uses only electricity, and even supplies some of its own power through braking (like hybrid cars). With MAX factored in, TriMet is more than 10 times as fuel-efficient per passenger as the average car.
Burning less fuel
Burning less fuel means fewer emissions and a more sustainable transit system. TriMet is one of the most fuel-efficient transit providers in the country, thanks to creative operators and mechanics who keep finding new ways to conserve fuel.
- TriMet is the nation’s first transit agency to test and operate buses cooled by a NASCAR-inspired system. Traditional systems draw up to 50 horsepower off the engine, draining power and consuming fuel. The NASCAR system's electric fans use less engine power, resulting in nearly four percent better fuel economy. The system also significantly cuts maintenance time and costs, and is safer to maintain.
- A drivetrain computer in the engine compartment of each bus saves fuel and improves driving safety. It monitors the engine, transmission, and braking system, and uses the data to adjust acceleration, braking, traction control and fuel injection.
- In 2005, TriMet maintenance crews boosted gas mileage on buses an extra 0.32 miles per gallon by adjusting transmissions, front-end alignments and steering control arms, and maintaining a set tire pressure. This saved about 500,000 gallons of fuel per year.
- Bus operators began saving more fuel by turning off buses while waiting at transit centers, instead of idling.
Using improved fuel
TriMet employee Mark Smith fills
a tank from the first official batch
of ULSD biodiesel fuel.
TriMet buses use a cleaner burning B5 biodiesel fuel blend: five percent biodiesel and 95 percent petroleum diesel. TriMet is the largest biodiesel user in Oregon.
The blend, including the petroleum-based share of the fuel, meets new federal standards for ultra-low-sulfur diesel (ULSD). It reduces emissions, especially carbon dioxide, carbon monoxide, sulfur dioxide, and particulates (smoke).
Other benefits of biodiesel use include:
- Reducing greenhouse gases—the number one contributor to global warming
- Reducing dependence on foreign oil
- Moderating the volatile price swings of petroleum-based diesel
- Helping to build the biodiesel industry
TriMet chose B5 because engine manufacturers and the biodiesel fuel industry are still working on B20 specifications—20 percent biodiesel and 80 percent petroleum diesel—which could come within the next year.
Reducing bus emissions
Older TriMet buses to run 90 percent cleaner
Forty-five older low-floor TriMet buses are being retrofitted with high-tech filters to reduce exhaust emissions up to 90 percent, making them run as clean as new ones.
The filters, paid for and installed by Cummins Northwest, LLC, reduce both particulate emissions (soot) and unseen pollutants. With the retrofit, these buses run much cleaner than required by the Environmental Protection Agency for their model year. Emissions are reduced to levels comparable to those of brand-new models.
Cummins is providing the particulate filters, spare parts and installation for the TriMet buses, which have Cummins engines, at a cost of about $432,000. Cummins selected TriMet as part of a nationwide EPA decree to reduce emissions from diesel engines.
The filter installations are made possible by the use of new fuel that meets federal standards for ultra-low-sulfur diesel (ULSD), and also is a five-percent biodiesel (B5) blend.
A cleaner fleet in progress
With this project, TriMet will have 84 out of a fleet of 321 low-floor buses meeting 2007 EPA standards: 45 from the Cummins project and 39 new buses. By 2010, about a third of the fleet will see similar emission reductions.
Results from a long-term commitment
Emissions from TriMet buses already have been reduced in the last several years due to new pollution-control equipment, testing programs and cleaner-burning fuels:
- Even without the new filters, TriMet buses emit 90 percent fewer oxides and particulates than they did 10 years ago.
- TriMet voluntarily tests buses for exhaust opacity (visible smoke) to comply with stricter California standards.
Hybrid technology
In recent years, TriMet has been testing hybrid-electric bus technology, similar to hybrid cars. Hybrid buses cost 50% more than non-hybrid buses. During testing, the average fuel savings were only 8% over regular diesel buses.
With our innovative attention to buses, TriMet believes new buses will achieve nearly the same efficiency as our existing hybrids, at a fraction of the cost. This technology can also be retrofitted to our existing fleet rather than waiting for a new bus purchase.