The role of Life Cycle GHG Analysis in Zero Emission Bus Policy

Background and Challenge

There’s increasing interest in the greenhouse gas (GHG) emissions’ impact of zero emission bus technologies, notably battery electric and hydrogen fuel cell, from both the bus market and policy makers.

Zemo Partnership has been at the forefront of integrating well-to-wheel GHG emissions thresholds and measurement into UK bus policy over the last decade. This will now be taken a step further by examining how to integrate whole vehicle life cycle GHG emissions analysis into zero emission bus policy. Specifically, this will consider vehicle manufacture, operation and end of life disposal.

Objectives

  • To understand the embedded GHG emissions associated with manufacturing components such as lithium batteries, electric motors, fuel cell stacks and hydrogen storage cylinders.
  • To account for materials used to produce the bus chassis (glider) and determine the GHG emissions associated with bus assembly.
  • To develop a standardised life cycle GHG emissions analysis (LCA) methodology framework for buses and determine what metrics will be chosen to report final life cycle CO2e values.
  • To establish a set of common LCA assumptions such as the bus life cycle boundary, build of materials, source of GHG emission factors used for component manufacture, hydrogen and electricity used for propulsion; and factors such as lifetime mileage, battery replacement and material recycling (credits) at the end of life.
  • To consider the location of bus assembly and vehicle component manufacture as this will have a material impact on GHG emissions.
  • To reach agreement on key assumptions regarding the diesel bus comparator.

Actions and Outputs

  • The Partnership will engage with Bus Working Group members through a series of workshops to agree a framework for integrating life cycle CO2e metrics in zero emission bus policy. 
  • The workshops will share learnings from existing bus LCA studies, current experience of bus manufacturers use of LCA, insights on new regulations and work towards developing a bus LCA methodological framework.
  • A paper recommending a framework for integrating life cycle CO2e metric into zero emission bus policy.

Timeline

July 2021 – December 2021

Zemo Partnership Lead:
Dan Hayes

Project Manager, Bus Working Group

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