The study, California’s Energy Future - Transportation Energy Use in California, is part of the California’s Energy Future (CEF) project.

One of the key findings in the California’s Energy Future Summary Report is that California will likely have limited availability of low-carbon biofuels for use in the transportation sector, because of biomass availability and competing uses for biomass for heat and power (CCST 2011). Given the median biofuels forecast of 13 billion gallons of gasoline equivalent (GGE) in 2050, it is necessary to place a high priority on electrification of the transportation sector, if large reductions are to be attained by 2050. In our scenarios, transportation subsectors were shifted to electrified (plug-in electric vehicles (PEVs) and fuel cell vehicles (FCVs)) vehicles as much as deemed realistic. And the remaining non-electrified transport was made as efficient as possible to reduce the amount of liquid fuels needed. This leads to scenarios where light duty vehicles are largely electrified, while aviation, marine and heavy duty continue to rely on liquids fuels.

—Yang et al.

The report focused on two main alternative scenarios: plug-in electric vehicles (PEVs) and combined PEVs and fuel cell vehicles (FCVs). A number of elements are common to both storylines, including the fuel economy and VMT assumptions for light-duty vehicles and assumptions about the other transportation sectors, including aviation, marine and rail sectors.

Realistic case for PEVs. PEV adoption is hampered by a couple of key factors (such as cost), both in the near-term and in the long-term; the report concludes that it is unlikely that PEVs can make up 80% of light-duty vehicles (i.e. passenger cars and trucks) by 2050.

The scenario outlines the introduction of more PEVs in different models and vehicle sizes in the 2015-2030 timeframe. Battery costs will fall, and the market will move well beyond early adopters. Subsidies and other financial incentives for PEV purchases will be phased out as vehicle costs decline, though some policies, such as feebates, may continue to persist.

The report anticipates that the majority of PEVs sold will be plug-in hybrid electric vehicles (PHEVs), with increasing average battery capacity. Hybrid vehicles grow to become the dominant type of new car sold (>50% in 2030), though PHEVs and battery-electric vehicles (BEVs) also grow become one quarter of the new car market in 2030.

In the period between 2030 and 2050, the growth of plug-in vehicles would continue with a shift towards higher levels of electrification, greater all-electric range, and larger battery packs. PEVs will continue to be more expensive to manufacture and purchase than conventional and hybrid vehicles.

Maximum fleet share for PEVs appears to be limited due to two factors. The first is that the cost of batteries for larger vehicle sizes (i.e. light trucks, vans and SUVs) is significantly higher than for smaller vehicles, so the incremental costs associated with large PEVs pose a major challenge. The second factor is the large percentage of consumers who do not have dedicated off-street vehicle parking at their home at night. These two factors inform the scenario that PEVs achieve a reasonable, but still optimistic fleet share of 58% (35% PHEVs and 23% BEVs) in 2050. To achieve this level of fleet share, PEVs would need to make up over 50% of new car sales after 2036 and reach 69% of new car sales in 2050.

—Yang et al.

In 2050, BEVs make up 23% of all vehicles in the fleet and are used by commuters and people who do not mind the range limitations associated with BEVs. PHEVs sold in 2050 are primarily large-battery PHEVs (i.e. 40+ mile all-electric range) to minimize liquid fuel use.

Realistic combined FCV and PEV scenario. FCVs are expected to be commercially introduced in California in 2015 at low volume and initially in limited markets, including Southern California and the San Francisco Bay Area. As in the PEV scenario, the first few years will have only a few automakers selling FCVs in a few models, though larger cars and trucks/SUVs are more likely because packaging of the fuel cell and hydrogen storage system will be easier due to their lower weight and volume constraints compared with smaller cars.

The scenario anticipates rapid sales growth for FCVs between 2020-2030 as new manufacturers begin building FCVs in many more makes and models. By 2030, 20% of new vehicles are FCVs, 12% are PEVs and 67% are hybrids, while conventional gasoline vehicles no longer sold.

After 2030, the scenario projects, FCV sales would grow quickly so that FCVs make up the vast majority of sales and represent 59% of the fleet by 2050 while PEVs make up 29%. By 2035, BEVs are sold in greater numbers than PHEVs as FCVs are used for vehicles needing longer range and quick refueling while BEVs are used for commuting and shorter range driving. BEVs are assumed to make up a greater proportion of smaller cars while FCVs are a larger fraction of the larger trucks and SUVs.

Other main findings. Among the other main findings of the report are:

• Improving efficiency with conventional combustion and hybrid technologies is the easiest and most cost-effective method for reducing fuel usage from the transportation sector, but this approach is not enough by itself to achieve 80% reductions in GHG emissions if petroleum fuels continue to be used.

• Electrification of vehicles using Plug-in Electric Vehicles (PEVs) or Hydrogen Fuel Cell Vehicles (FCVs) can further improve efficiency of light-duty vehicles (LDVs) while also lessening the reliance on liquid fuels and allowing for use of very low carbon sources for electricity or hydrogen.

• From a technology standpoint, PEVs and FCVs are commercially available or demonstration phase technologies although key component costs (batteries, fuel cells and H2 storage) are currently high and would need to be reduced by a factor of 2 or more for widespread adoption.

• Achieving high fleet penetration of efficient and alternatively fueled light-duty vehicles by 2050 will require rapid market adoption in the next few decades.

• High initial costs, consumer unfamiliarity with advanced technologies, and limited availability of those technologies across vehicle makes and models will slow the market expansion of advanced light-duty vehicles. The relatively slow penetration of hybrid vehicles into the market since 2000 is suggestive of the challenges facing PEV and FCV adoption; arguably electric drive vehicles could face even more difficult barriers.

• Because less than 50% of car owners have access to dedicated, off-street parking at home (for charging), and because battery costs will be high for larger vehicle sizes, universal PEVs adoption appears unlikely.

• Hydrogen fuel cell vehicles (FCVs) will offer a range of approximately 300 miles and a 5 minute refueling time, potentially avoiding the PEV limitations. This should make them potentially attractive for larger vehicles (light trucks and SUVs) and those without access to dedicated, off-street parking. FCVs are a useful complement to battery electric vehicles (BEVs), which have a more limited range and long refueling times.

• Even with substantial conversion of light-duty and some other sectors to electricity and hydrogen, liquid fuel demand will remain strong, likely exceeding the availability of sustainable, low-carbon biofuel supplies and thereby necessitating some continued use of petroleum-based fuels.

• Aviation, marine and heavy-duty trucks, are likely to continue to use liquid hydrocarbon fuels (from petroleum or biofuels) because of fuel energy density requirements.

• A policy framework targeting efficiency and low-carbon fuels exists to bring about GHG reductions in the light-duty and heavy-duty sectors, but may need to be expanded to other transportation subsectors as well, such as aviation and marine.

Even without a major shift in the drivetrain technologies associated with other transportation subsectors (aviation, heavy-duty trucks, marine) there is significant potential for improved efficiency and use of low-carbon liquid fuels to reduce emissions. The two realistic scenarios which push advanced technologies yield a total fuel usage in the transportation sector that is approximately 30% below 2005 and over 60% below BAU on an energy basis. The combined PEV + FCV scenario is able to reduce liquid fuel demand by approximately four billion gge relative to the PEV scenario.

—Yang et al.

Resources

• Christopher Yang, Joan Ogden, Dan Sperling and Roland Hwang (2011) California’s Energy Future - Transportation Energy Use in California