The report examines the potential role of decarbonized gas fuels, and the existing gas pipeline infrastructure, to help meet California’s long-term climate goals. It compares two technology pathway scenarios for meeting the state’s goal of reducing GHG emissions: an electrification scenario, where all energy end uses are electrified and powered by renewable electricity; and a multi-energy framework, where both electricity and decarbonized gas fuels play significant roles in California’s energy supply.

The study concludes that a technology pathway for decarbonized gas could help meet the state's GHG reduction goals and may be easier and could be less costly to implement in some sectors than a high electrification strategy. The findings point to the need for a significant program of research and development to make decarbonized gas a reality and allow consumers, businesses and policymakers greater flexibility and choice.

—Rodger Schwecke, vice president of customer solutions for SoCalGas

Four broad findings suggest that decarbonized gases distributed through the state’s existing pipeline network are complementary with a low-carbon electrification strategy by addressing critical challenges to California’s transition to a decarbonized energy supply.

1. Decarbonized pipeline gas can help to reduce emissions in sectors that are for technical or customer-acceptance reasons difficult to electrify: 1) industrial end uses, such as process heating; (2) heavy duty vehicles; and (3) residential and commercial uses, such as cooking, and existing space and water heating.

2. The production of decarbonized gas from electricity could play an important role in integrating variable renewable generation by producing gas when renewables are generating power, and then storing the gas in the pipeline distribution network for when it is needed.

3. A transition to decarbonized pipeline gas would enable continued use of the state’s existing gas pipeline distribution network, eliminating the need for new energy delivery infrastructure—dedicated hydrogen pipelines or additional electric transmission and distribution capacity—to meet the 2050 GHG target.

4. Decarbonized gas technologies would help diversify the technology risk associated with heavy reliance on a limited number of decarbonized energy carriers, and allow consumers, businesses and policymakers greater flexibility and choice.

On-road vehicles. The decarbonization strategy pursed in the transportation sector differs by scenario. Both scenarios assume a significant reduction in VMT and improvements in vehicle efficiency in the LDV fleet compared to the Reference scenario. This leads to a significant reduction in total energy demand by LDVs by 2050 in these scenarios.

Top: 2050 LDV energy share by fuel type by scenario. Bottom: 2050 HDV energy share by fuel type by scenario. Click to enlarge.

Among the HDV vehicle fleet, VMT reductions and vehicle efficiency improvements are more difficult to achieve than in the LDV fleet. The Mixed scenario relies on a high proportion of fuel cell vehicles using hydrogen or liquefied pipeline gas, which have less efficient energy conversion processes than conventional diesel engines, leading to higher energy demand. As a result, the HDV sector does not show a significant reduction in energy consumption by 2050 relative to the Reference case, although total carbon emissions are significantly lower.

Electricity is the largest source of fuel for the transportation sector among LDVs in both the Electrification and the Mixed scenarios. The HDV fleet is harder to electrify, so the Electrification scenario assumes HDV energy demand is largely met with hydrogen fuel and fuel cells. In the Mixed scenario, the majority of HDV energy demand is assumed to be met with liquefied pipeline gas (an equivalent to decarbonized LPG), with some compressed pipeline gas (the equivalent to decarbonized compressed natural gas), electrification and hydrogen fuel cell vehicles.