Developing the Zero Emission Vehicle Retrofit Accreditation Scheme: Assessing the Impact of EV Retrofit on CVRAS

Background and Challenge

The ‘clean vehicle retrofit accreditation scheme’ (CVRAS) has primarily focussed on conversions associated with exhaust aftertreatment systems and internal combustion (IC) engine replacements.  However, electric vehicle (EV) retrofit conversions are increasingly starting to emerge in the passenger car market and have the potential to expand rapidly.

The project examines and addresses the challenges that an EV conversion presents to the CVRAS scheme and identifies the gaps where a 'zero emission vehicle retrofit accreditation scheme' (ZEVRAS) could optimally provide support.

The Department for Transport has set a target of 4,000 new in service zero emission buses by 2025. To support this, the All-Electric Bus Town scheme has allocated £50m of funding to Coventry and a further £120m to the Zero Emission Bus Regional Areas (ZEBRA) scheme – but there’s currently no funding to support the retrofit of existing buses to run on zero emission powertrains.  As part of this project, Zemo will examine the demand and potential for such a funding stream.


  • To create a high-level Zemo Partnership briefing paper describing how the EV retrofit conversion market is currently understood to operate in the passenger car sector. 
  • To establish an evidence base for the role of zero emission retrofit in the UK bus market.
  • To engage with suppliers, operators and local authorities to understand the current status of the retrofit supply chain, as well as potential demand for retrofitting buses to zero emission.
  • To form a new EV retrofit special interest group for review and input to the briefing paper(s).

Actions and Outputs

  • A high-level briefing paper identifying current market practice in the passenger car sector, key challenges to be addressed by the introduction of ZEVRAS and recommendations on next steps.
  • Formation of a zero emission retrofit special interest group.
  • Two bus focussed workshops with zero emission retrofit suppliers, operators and local authorities.
  • A high-level briefing paper describing the existing zero emission bus retrofit market, alongside barriers to market.
  • Publication of the briefing paper(s) on Zemo Partnership website (members only).


June 2021 – September 2021

Jonathan Murray

Zemo Partnership Lead:
Jonathan Murray

Policy and Operations Director

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