LNG derived from biomethane is a low carbon fuel, which, under some conditions, offers a carbon intensity (CI) equal to or lower than that of electricity. The chart shows that latest version of California Air Resources Board (ARB) LCFS pathway certified carbon intensities, with electricity and Bio-LNG (i.e., LNG derived from renewable natural gas) marked with arrows. Click to enlarge.

Big Blue Bus, which includes 200 natural gas buses, plans to replace more than 100 of their existing bus engines with the new Near-Zero natural gas engine over a three-year period, making BBB one of cleanest transit agencies in the nation.

When the transition is complete, BBB is expected to have reduced their NO_x emissions by more than 90% and their GHG emissions by 8,000 tonnes, annually.

Introduced by CWI earlier this year, the new Cummins ISL G 8.9L Near Zero 0.02 NO_x engine is designed for medium-duty truck, urban bus, school bus and refuse applications and is available on the market today.

The ISL G NZ is built off the current ISL G platform, but requires Closed Crankcase Ventilation (CCV); a larger maintenance-free Three-Way Catalyst (TWC); and a unique engine calibration.

The chassis-mounted CCV system prevents crankcase emissions, generated by the engine during normal operation, from escaping into the atmosphere. Crankcase emissions are captured and redirected through the CCV filter, where oil is removed, before sending the gases back to the intake manifold to be reintroduced to the combustion chamber. This reduces engine related methane emissions by 70%.

The ISL G NZ features the same stoichiometric cooled Exhaust Gas Recirculation (SEGR) combustion technology and spark ignition as the ISL G natural gas engine.

The Cummins Westport ISL G and ISX12 G spark ignited natural gas engines use Stoichiometric combustion with cooled exhaust gas recirculation (EGR) and a Three-Way Catalyst (TWC). This technology was developed to meet the stringent 2010 EPA emission requirements and was introduced with the ISL G in June 2007.

The cooled-EGR system takes a measured quantity of exhaust gas and passes it through a cooler to reduce temperatures before mixing it with fuel and the incoming air charge to the cylinder. Stoichiometric combustion in combination with cooled-EGR creates the ideal combustion process with the chemically correct mixing of fuel and air, offering increased power density and thermal efficiency. It also reduces in-cylinder combustion temperatures and creates an oxygen-free exhaust, which then enables the use of a TWC for NO_x control.

Cummins-Westport plans to begin delivering an 11.9L version that is also EPA and ARB certified for the heavy-duty trucking industry in 2018.

The City of Santa Monica is a nationally recognized leader for its sustainability policies and actions. BBB has progressively contributed to the City’s sustainability narrative through its use of alternative fuel and ultimate phasing out of diesel-fueled motor coaches. Through this commitment, clean burning RNG and the new 0.02 NO_x engine will power BBB’s entire fleet.

Clean Energy believes that Redeem is the cleanest transportation fuel commercially available in the US according to EPA data regarding carbon emissions for transportation fuel. Redeem is a renewable natural gas vehicle fuel, often referred to as biomethane. It is derived from biogenic methane or biogas, which is methane that is naturally generated by the decomposition of organic waste. The methane gas is processed, purified and sent into the interstate natural gas pipeline and made available exclusively to Clean Energy customers. Redeem biomethane vehicle fuel is procured from biomethane production facilities, including two owned and operated by Clean Energy.