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California ARB releases draft Mobile Source Strategy

5 October 2015

The California Air Resources Board (ARB) has released a draft Mobile Source Strategy for discussion. The documents outlines the regulatory and policy options considered by the ARB to meet federal air quality standards, achieve California targets for GHG emission reduction and petroleum consumption, and decrease health risk from transportation sources through 2030. In particular, the targets include (1) attaining federal standards for ozone in 2023 and 2031 in the South Coast and San Joaquin Valley, and PM2.5 standards in the next decade, (2) reduction of GHG emissions by 40% by 2030 below 1990 levels, (3) reducing petroleum consumption by up to 50% by 2030, and (4) deriving 50% of electricity in the state from renewable sources by 2030.

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In addition to the general strategy, the ARB released two detailed assessment reports of heavy-duty engine technology: (1) Draft Technology Assessment: Lower NOx Heavy-Duty Diesel Engines, and (2) Draft Technology Assessment: Low Emission Natural Gas and Other Alternative Fuel Heavy-Duty Engines.

Mobile sources—cars, trucks, and off-road equipment—are the largest contributors to the formation of ozone, PM2.5, diesel PM and GHG emissions in California. They are responsible for approximately 80% of smog-forming NOx emissions, 95% of diesel PM emissions, and 50% of GHG emissions.

ARB staff developed the draft strategy using a multi-pollutant scenario planning tool, Vision 2.0, that quantifies changes in ozone and PM2.5 precursor emissions, GHG emissions, petroleum usage, and diesel toxics emissions as various technologies become widespread in vehicle and equipment fleets.

The ARB modeling shows that the State’s public health, climate, and petroleum reduction goals can be met with a strategy consisting of cleaner vehicle technologies, energy sources, and fuels. For passenger vehicles, the strategy calls for increasing the penetration of plug-in hybrid electric vehicles (PHEV) and non-combustion zero-emission vehicles (ZEV) including battery-electric (BEV) and hydrogen fuel cell electric vehicles (FCEV) by over 50% compared to current programs. The electrical grid and hydrogen supply supporting these electric vehicles will need to represent 50% renewable energy generation. A large portion of the liquid fuels for combustion engine vehicles will also need to be sourced from renewable feedstock.

For heavy-duty vehicles, combustion technology will continue to dominate over the next 15 years. The strategy therefore calls for engine technology that is effectively 90% cleaner than the current standards, with renewable fuels comprising half the fuels burned. To position the heavy-duty sector for longer-term targets that extend beyond 2030, the strategy calls for targeted introduction of zero-emission technologies in suitable heavy-duty applications, to foster the development of ZEV technologies so they become suitable for broader use in the future. Off-road equipment will need to reflect the same type of transformation to a mix of zero and near-zero technologies operating on renewable fuels.

Along with the widespread use of cleaner technologies and fuels, the strategy calls for improvements in community design and efficiency improvements to the freight transport system—efforts intended to reduce growth in vehicle miles traveled (VMT).

The estimated benefits of the strategy in reducing emissions from mobile sources are: (1) an 80% reduction of smog-forming emissions (NOx), and a 45% reduction in diesel PM emissions in the South Coast from today’s levels, (2) 45% reduction of GHG emissions, and (3) a 50% reduction in the consumption of petroleum-based fuels.

The ARB will hold a public workshop on the draft mobile source strategy on October 16, 2015 and a Board meeting on October 22, 2015. After the meeting, the ARB staff will work with stakeholders, the South Coast and other air districts, and other state agency partners to develop detailed measures.

Source: California ARB