May 7, 2010

Biomethane: A Green, Renewable Fuel for Heavy-Duty Vehicles

by Karen Hamberg

Transport accounts for nearly one-quarter of global energy-related carbon-dioxide (CO2) emissions. To achieve the necessary deep cuts in greenhouse gas (GHG) emissions by 2050, transport must play a significant role. Current best-available and emerging vehicle technologies have the potential to deliver substantial reductions in CO2 emissions but they need to be introduced rapidly, at a rate and on a scale that is unprecedented in the last 40 years of the transport evolution.[1]  The transition to low-carbon alternatives will not be straightforward or unchallenged.[2]

The reduction of GHG emissions from the transport sector will require: i) alternative fuels that enable vehicles to emit less CO2 per unit of energy used through the use of less carbon-intensive energy sources, ii) efficiency improvements from new technologies and operational improvements for truck transport management that reduce the energy use of vehicles and, iii) modal shifts in urban short-distance travel and long-distance travel.[3]

Biomethane or renewable natural gas has the potential to significantly reduce the carbon intensity of transportation and generate a range of economic, environmental and energy security benefits. In comparison to other low-carbon forms of transportation such as electric vehicles or hybrids, biomethane is suitable for heavy-duty transport applications using the Cummins Westport ISL G or Westport GX engines and delivers greater lifecycle GHG emission reduction than other biofuels. 

Biomethane can be produced from a variety of biomass and biogas sources including landfill gas, waste water treatment plants and other municipal, agricultural and forestry waste streams. Biogas is produced by the anaerobic digestion of biomass using purpose-built anaerobic digesters or via the process of thermal gasification. Biogas contains approximately 15–45% carbon dioxide (CO2), 50–80% methane (CH4) and impurities. It must be purified to pipeline quality standards; a minimum of 96% of methane before it can be used as a direct substitute for natural gas in natural gas fuelled vehicles.

Economics play a key role in what transport technologies and fuels are adopted and how biomass is used. Numerous studies have shown that biomethane costs compare favourably to diesel but the recent drop and stagnation in natural gas prices has changed the competitive landscape. Anaerobic digesters, biogas upgrading facilities and liquefaction are capital intensive processes and many biomethane business cases have been negatively impacted by inexpensive natural gas. With the discovery of natural gas shale plays and new horizontal drilling and fracturing technologies, North America has an abundant, long-term supply of affordable natural gas.

However, a new economic model is emerging where natural gas suppliers and utilities are looking to increase demand via new markets and add renewable content. Transportation provides an opportunity to increase demand and biomethane allows utilities to add renewable content, making natural gas an even greener energy source. This model is similar to electrical utilities adding alternative or renewable energy to the grid or fuel providers offering biofuels such as ethanol or biodiesel blends. A recent International Energy Agency (IEA) report notes that 25% of global agricultural and forestry residues could produce enough biomethane to meet 14.9% of current transportation fuel demand.[4]

There are currently strong incentives for the increased use of renewable fuels in the transport sector worldwide. Some first-generation ethanol and biodiesel production routes have limitations with regard to resource efficiency and the reduction of greenhouse gases.[5]  A transition is needed to much more sustainable feedstocks and approaches to biofuels production to ensure there is no competition with food/feed supplies and poor performance in terms of GHG cost-per-tonne or land-use efficiency.[6]  Biomethane is a renewable energy source and presents an opportunity to turn abundant, marginal and zero-value waste products into useful fuel.

The transport sector is almost fully dependent on petroleum-derived fuels and finding alternatives remains a challenge. Deploying next generation technologies at the scale required will take time once they become commercially available.[7]  Biomethane holds an advantage over liquid biofuels as the refining and distribution processes are established, the fuelling infrastructure is expanding and natural gas fuelled vehicles are currently available from more than 50 original equipment manufacturers (OEMs).  Compared to the majority of liquid biofuels in use today, biomethane often has a far better performance with regard to both land-use efficiency and life-cycle emissions thereby positioning biomethane as a strong candidate for becoming one of the most sustainable vehicle fuels in the near future.[8]

  1. International Energy Agency (2009) “Transport, Energy and CO2: Moving Towards Sustainability” IEA/OECD, 2009
  2. Sperling, Daniel and James S. Cannon eds. (2009) “Reducing Climate Impacts in the Transportation Sector” Springer Science and Business Media 2009 pp.7
  3. International Energy Agency (2009) “Transport, Energy and CO2: Moving Towards Sustainability” IEA/OECD, 2009
  4. IEA (2010) “Sustainable Production of Second Generation Biofuels”. Available at http://www.iea.org/papers/2010/second_generation_biofuels.pdf
  5. Borjesson, Pal and B. Mattiasson (2007) “Biogas as a Resource Efficient Vehicle Fuel”. Lund University, 2007. Available at http://www.globalbioenergy.org/uploads/media/0711_Boerjesson_Mathiasson_-_Biogas_as_a_resource-efficient_vehicle_fuel.pdf
  6. International Energy Agency (2009) “Transport, Energy and CO2: Moving Towards Sustainability” IEA/OECD, 2009
  7. World Resources Institute (2008) “Plants at the Pump: Reviewing Biofuels’ Impacts and Policy Recommendations”. Available at http://www.wri.org/publication/plants-at-the-pump-brief
  8. Borjesson, Pal and B. Mattiasson (2007) “Biogas as a Resource Efficient Vehicle Fuel”. Lund University, 2007. Available at http://www.globalbioenergy.org/uploads/media/0711_Boerjesson_Mathiasson_-_Biogas_as_a_resource-efficient_vehicle_fuel.pdf

1 comment:

Leslie said...

Wait so let me get this straight. They are making trucks with natural gas compressors? Why don't they get this out on the market as soon as possible?

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