Big Blue Bus committed to green with RNG and near-zero engines

Big Blue Bus (BBB) is the municipal transit agency for Santa Monica, California, operating a fleet of 200 vehicles that transports 13.3 million passengers annually. In 2015, BBB became one of the first transit agencies to convert its entire fleet to run on renewable natural gas (RNG).

In 2014, the City of Santa Monica set progressive sustainability goals for BBB. To meet these goals, BBB procured 77 buses equipped with Hexagon Agility’s CNG fuel systems and Cummins Westport 8.9L near-zero engines—all fueled by ultra-low-carbon RNG produced from landfill-generated methane.

By deploying buses with near-zero engines and Hexagon Agility's fuel systems, BBB's NOx emissions are 90 percent lower than conventional diesel buses. By using RNG, BBB reduced greenhouse gas emissions up to 125 percent and lowered operational costs with lower fuel prices.
Hexagon Agility supplies several OEMs involved in the BBB procurement process, including Type 4 CNG cylinders for New Flyer and complete CNG fuel systems for Gillig, Nova, and El Dorado.

Fueled by vision

Big Blue Bus (BBB) proudly leads regional efforts on sustainable public transportation, operating a fleet of 100 percent alternative fuel vehicles. Its efforts date back to 2002, with an initial investment in buses fueled with liquefied natural gas (LNG). Over the years, BBB has always maintained a fleet of buses that represents the latest in bus technology and alternative fuels. Ed King, Director of Transit Services, makes it clear that the BBB team is honored to serve the Santa Monica community as a vital transportation resource.

BBB has continued to invest in the latest technologies, investing $18.3 million in Federal Transit Administration (FTA) and California Proposition 1B Bond funds to replace 50 40-foot New Flyer buses that were originally purchased between 2004 and 2006. Additionally, seven 30-foot Gillig buses and 43 40-foot Gillig buses were commissioned and delivered. These buses were all equipped with Cummins Westport (CWI) near zero engines and Agility's composite CNG cylinders and fuel systems, and are fueled by RNG, reducing NOx emissions over 90 percent.

Agility enjoys long standing partnerships with all the major bus OEMs, supplying New Flyer for 25 years and Gillig for close to a decade. BBB’s fleet operations will benefit from the long service life and minimal service needs of Agility’s fuel systems and cylinders, knowing it can depend on Agility’s outstanding service and support.


lower NOx emissions than convential diesel buses


reduced GHG emission

“We are making a significant investment to modernize our fleet with new and exciting technology that will deliver a safer, more comfortable travel experience for customers and operators."

Ed King


Director of Transit Services

RNG and near zero engines

RNG is an ultra-clean and ultra-low-carbon natural gas made from methane that is produced when organic waste from food scraps, animal manure and sewage is broken down, captured and refined. RNG has the lowest carbon intensity rating of key transportation fuels when comparing the well-to-wheels greenhouse gas (GHG) emissions of today’s transportation fuels used in heavy-duty vehicle applications. The California Air Resources Board (CARB) has certified RNG as reducing GHG emissions by 40 to 125 percent or more, depending on the renewable feedstock used to produce it. Conventional fossil-fuel extraction methods are not used in the production of RNG.

The Cummins Westport 8.9L ISL G Near Zero engine used in BBB's buses is certified to CARB and U.S. Environmental Protection Agency (EPA) Optional Low NOx emissions standard of 0.02 g/bhp-hr — 90% lower than current emissions standards.

In 2014, BBB became the first transit agency in Southern California to procure buses with the near-zero natural gas engines. In 2015, the fleet became one of the country’s first municipal transit agencies to convert its entire fleet to RNG.

Setting an example

BBB has a history of maintaining a fleet of buses that represents the latest in bus technology and alternative fuels, and of operating one of the lowest emitting transit fleets in the nation. Since its establishment in 1928, BBB's goal has always been to provide outstanding service and value to its customers and the community. BBB is committed to continued leadership in fleet sustainability to ensure efficiency and environmentally responsible practices, and its leadership in using RNG is a testament to that commitment.