In a state leading the nation for natural gas-fueled buses and with ambitious goals for reducing carbon emissions, California is shaping up as the main battlefield for electric vs. natural gas-powered buses.

The California Air Resources Board (CARB) has set new guidelines for its funding of low-carbon vehicle technology, and the California Natural Gas Vehicle (NGV) Coalition is pushing to have renewable natural gas (RNG), such as that produced from landfills, included as qualifying for near zero-emission status. California regulators last year approved RNG for alternative transportation programs (see Daily GPI, Jan. 23, 2014).

Longer term, the issue of how many, if any, NGV buses are allowed under the program will be decided next year after CARB completes an assessment of available bus technologies. Officials have said they want to specify only zero-emission vehicles to meet the state’s greenhouse gas (GHG) emission reduction goal of being 80% below 1990 levels by 2050.

According to the coalition, NGVs qualify under the new CARB guidelines for higher incentive levels, allowing them to compete with diesel options for replacing, repowering or retrofitting heavy-duty diesel trucks, and for upgrading cargo-handling equipment at seaports and rail yards.

“Past [guidelines] have not provided an opportunity for NGVs to compete, but with this update, heavy-duty NGV projects that will help clean the air around these transportation corridors are eligible for funding,” said NGV Coalition President Tim Carmichael.

About 60% of the state’s buses currently operate on compressed natural gas (CNG), compared to 17% nationwide. About one in seven of the nation’s 67,000 buses run on natural gas. The CNG coalition is pushing for RNG to be included.

Traditional natural gas reduces carbon emissions by 15-20%, but RNG is rated as reducing them by up to 90%. Thus, the state coalition is pushing CARB to recognize the fuel coming from cow manure and landfills as a zero-emission fuel.

Longer term, California continues to be an even bigger plum for bus makers and alternative fuel suppliers.

There is no clear-cut answer for CARB officials, however, since the cost advantages of NGVs over electric buses ($525,000 vs. $800,000 per vehicle) are reversed when the cost of fuel is compared. Fueling an EV bus averages about $10,500/month, compared to $27,000 for an NGV version.

California’s NGV Coalition, NGVAmerica and a separate RNG coalition filed joint comments to CARB in its proposed read option of the low carbon fuel standard (LCFS), asking CARB to allow the sale or transfer of credits generated by facilities that have three months of data on the carbon intensity of the fuel they generate. The groups are challenging CARB’s temporary carbon intensity assessment of natural gas.