As a part of its annual outlook for CO2 emissions, the U.S. Energy Information Administration (EIA) has observed some key trends related to the use of natural gas as a transportation fuel.
The EIA's Annual Energy Outlook (AEO) makes long-term projections for the nation's CO2 emissions from various sectors, including power generation, industrial and transportation, and those results have long reflected a high reliance on petroleum-based fossil fuels. The past couple of AEOs, however, have taken into consideration a much heavier prevalence of natural gas – and the new 2013 outlook, which forecasts ahead to 2040, underscores that trend.
Natural gas usage has grown in the power sector over the past several years, as well as within industrial applications. But this year, the EIA specifically calls out natural gas vehicles (NGVs) as a new and strong influence on its projections.
Overall, the EIA expects the transportation sector's use of diesel and gasoline to decrease not only because of the implementation of federal fuel economy standards, but also because of an ‘increased penetration of alternative fuels.’ In particular, the AEO suggests that heavy-duty trucking fleets are steadily adopting alt-fuel vehicles, and this movement is expected to continue.
Energy demand for heavy trucks will increase from 5.2 quadrillion Btu in 2011 to 7.1 quadrillion Btu in 2035 and then to 7.6 quadrillion Btu in 2040. The 2013 AEO looks at these numbers in the context of emerging trends in fueling.
‘Factors used to calculate the economic effectiveness of heavy-duty alternative-fuel vehicles have been updated to represent the travel behavior of first-time buyers and economic breakeven hurdles that, when coupled with very competitive natural gas prices, significantly increase demand for natural gas fuel in heavy trucks,’ the report says. ‘As a result, natural gas use in heavy-duty vehicles increases to 1.7 trillion cubic feet in 2040, displacing 0.7 million barrels of liquid fuels per day.’
The new AEO projects an increase in the number of light-duty-vehicle miles traveled, but overall fuel usage in this sector drops. Energy consumption for these vehicles begins falling considerably after 2025, to 13 quadrillion Btu in 2035, ‘as a result of fuel economy improvements achieved through stock turnover as older, less efficient vehicles are replaced by newer, more fuel-efficient vehicles.’
The reference case in the newest AEO shows lower overall sales of alternative fuel vehicles relative to the 2012 outlook, due mainly to a downward adjustment in the number of flex-fuel vehicle sales. That number is now 1.3 million by 2035 – a decrease from the 2012 AEO's 2.9 million.
Projected sales of battery-powered electric vehicles (EVs) are also lower for the 2013 AEO, with annual sales in 2035 estimated to be about 119,000 (65% lower than what was forecasted last year). However, reductions in battery EVs are offset by increased sales of hybrid and plug-in hybrid vehicles, which grow to about 1.3 million vehicles in 2035 (20% higher than in the 2012 AEO).