M-1A-11 - Alternative Fuels for Vehicles
Low-carbon or zero-carbon alternative fuels for ICE vehicles include natural-gas-based fuels, biofuels such as ethanol, ammonia, and other synthetic fuels, all of which offer potential pathways to reduce greenhouse gas emissions and dependency on conventional fossil fuels. Natural gas fuels, including compressed natural gas (CNG) and liquefied natural gas (LNG), produce lower emissions than traditional petrol or diesel. Biofuels like ethanol and biodiesel are derived from organic materials and can be used in existing internal combustion engines, often blended with conventional fuels to reduce carbon output. Ammonia and synthetic fuels, produced using renewable energy and captured carbon, present options for further emissions reductions with minimal infrastructure changes.
The development and use of these alternative fuels aim to diversify energy sources in the transportation sector, though challenges such as production costs, lifecycle emissions, and distribution infrastructure must be addressed for broader adoption.
Alternative fuels is outlined in sections 10.3.1 and 10.4.3 of (IPCC AR6 WG3 2022)1.
Mitigation Objective¶
The primary goal is for a resource shift from non-renewable fuels (i.e. primarily petrol and diesel) to renewable fuels.
Mitigation Potentials¶
Natural Gas¶
Potential
The AR5 report estimates the mitigation potential of natural gas in ICE vehicles at 10-15%.
Natural gas-based vehicles have certain advantages over conventional fuel-powered ICE vehicles, including lower emissions of criteria air pollutants, no soot or particulate, low carbon to Hydrogen ratio, moderate noise, a wide range of flammability limits, and high octane numbers (Kim 2019; Bayat and Ghazikhani 2020). ... natural gas as a transition transportation fuel may be limited due to better alternative options being available and due to regulatory pressure to decarbonise the transport sector rapidly.
- (IPCC AR6 WG3 2022)1
The energy efficiency of driving on CNG is typically similar to that for gasoline or diesel but with a reduction of up to 25 % in tailpipe emissions (CO₂/km) because of differences in fuel carbon intensity. Lifecycle GHG analysis suggests lower net reductions, in the range of 10–15 % for natural gas fuel systems.
- (IPCC AR5 WG3 2014)2
Biofuels¶
Potential
The AR5 report gives a wide estimation the mitigation potential of biofuels in ICE vehicles at 30-90%.
Biofuels have direct, fuel-cycle GHG emissions that are typically 30–90 % lower per kilometre travelled than those for gasoline or diesel fuels.
- (IPCC AR5 WG3 2014)2
Ammonia¶
TBD.
Synthetic Fuels¶
TBD.
Modelling¶
This mitigation method has been modelled with the following Transition Elements:
- T-1A1a-9 - Increase renewable proportion in petrol
- T-1A1a-14 - Increased proportion of public transport by LPG bus
Primary Reference¶
The primary reference for this mitigation measure is (IPCC AR5 WG3 2014)2.
Secondary References¶
TBD.
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IPCC AR6 WG3. 2022. Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Edited by Priyadarshi R. Shukla, Jim Skea, Raphael Slade, Alaa Al Khourdajie, Renée van Diemen, David McCollum, Minal Pathak, et al. https://doi.org/10.1017/9781009157926. ↩↩
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IPCC AR5 WG3. 2014. Climate Change 2014: Mitigation of Climate Change: Working Group III Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Edited by Intergovernmental Panel on Climate Change and Ottmar Edenhofer. Cambridge University Press. ↩↩↩