Left, global light-duty fleet in the electric-favoring case; right, the hydrogen-favoring case. Top, without CCS and CSP; bottom, with CCS and CSP. In both electric- and hydrogen-favoring cases, availability of low-carbon electricity and hydrogen prolonged the use of petroleum-fueled ICE vehicles. Credit: ACS, Wallington et al. Click to enlarge.

Increased availability of low CO₂ sources of electricity and hydrogen could counter-intuitively delay, rather than accelerate, a large-scale transition to an electric and/or hydrogen vehicle fleet, according to a new study by researchers from Ford Motor Company and Chalmers University of Technology in Sweden. They reported the results of their modeling study online 26 February in the ACS journal Environmental Science & Technology.

For future scenarios where vehicle technology costs were sufficiently competitive

to advantage either hydrogen or electric vehicles, the increased

availability of low-cost, low-CO₂ electricity/hydrogen provided more cost-effective CO₂ mitigation opportunities in the heat and power energy sectors than in transportation. For example, the study found that the availability of carbon capture and storage (CCS) technology has a major impact on the lowest cost passenger vehicle fuel and technology choice.

The system dynamic at work is that CCS provides relatively

inexpensive low-CO₂ electricity and heat from coal which is

a lower cost CO₂ mitigation option than that offered by

replacement of petroleum-fueled, nonhybridized ICEVs.

…When CSP is also made available a substantial amount of CSP-generated electricity is used in the global energy system…This makes biomass, which would otherwise go to the stationary sector, available for conversion into biofuel for vehicles.

—Wallington et al.

In reporting their results, the authors emphasized that their interpretation of the results is “not that society should intentionally delay a transition to a large-scale hydrogen/electric-powered light duty vehicle fleet or that

problem (far from it).”

Rather, the importance of low-CO₂ electricity and hydrogen is highlighted as having equal or greater value in other energy sectors and would beneficially affect how these sectors deal with CO₂ mitigation. The cost-effectiveness of measures to address climate change is

enhanced through a multisector perspective.

—Wallington et al.

In the study, global CO₂ emissions were constrained to achieve stabilization at

400-550 ppm by 2100 at the lowest total system cost (equivalent

to perfect CO₂ cap-and-trade regime). The increased availability of low-CO₂ electricity/hydrogen was found to delay the large-scale introduction of electric/hydrogen vehicles for all CO₂ targets considered.

The team used a model (Global Energy Transition, GET-RC 6.1) to consider combinations of five fuel options (petroleum, encompassing both gasoline and diesel; natural gas; synthetic fuels; electricity;and hydrogen); and five vehicle powertrain technologies (internal combustion engine vehicles, ICEV; hybrid-electric vehicles, HEV; plug-in hybrid electric vehicles, PHEV; battery-electric vehicles, BEV; and fuel cell vehicles, FCV).

The study considered two cases: one with vehicle technology costs that favored hydrogen vehicles and the other using vehicle technology costs that favored electric vehicles.

Primary energy sources in model include fossil fuels (crude oil, natural gas, and coal); non-renewable non-fossil sources (nuclear); and renewable sources (hydroelectric, wind, solar, and biomass). These energy sources can be converted to transportation fuels or used for generation of heat, electricity, or

both (cogeneration).

Carbon capture and storage (CCS) was included as an option to

decarbonize fuels derived from fossil sources and biomass. The model allows solar energy to be used for (i) generation of low temperature heat; (ii)

generation of hydrogen from direct solar conversion; (iii)

generation of electricity from photovoltaic technology; and

(iv) generation of electricity from concentrated solar power (CSP).

While low-CO₂ sources are required for long-term use of hydrogen and electric-powered vehicles, because of the complex

dynamics of the global energy system, they may actually delay

a transition to alternative fuel vehicles under a CO₂ cap-and-trade regulatory environment. While the model we have used is simple in some respects and has limitations, it nevertheless provides the first insight into the existence and

magnitude of this effect.

While there are important societal objectives other than

cost-effective CO₂ mitigation (e.g., energy security, rural

development), the results presented here suggest that for

the next few decades an increased availability of low-CO₂

electricity and hydrogen may delay, rather than facilitate,

the introduction of a large-scale hydrogen or electric-powered

vehicle fleet. This paradox for hydrogen- and electric-powered

vehicles in a carbon cap-and-trade world deserves further

study by the scientific community and consideration by policy

makers.

—Wallington et al.

Resources

• T. J. Wallington, M. Grahn, J. E. Anderson, S. A. Mueller, M. I. Williander and K. Lindgren (2010) Low-CO₂ Electricity and Hydrogen: A Help or Hindrance for Electric and Hydrogen Vehicles? Environ. Sci. Technol., Article ASAP

  doi: 10.1021/es902329h