Cenex-Study looks at alternative fuels for public transport

Cenex – the Centre of Excellence for low carbon technologies in the UK – recently announced the release of the ‘Green Fleet Technology Study for Public Transport’ report, commissioned by the Public Procurement of Innovation in Action Network (PPIA). The study is intended to inform the PPIA network of the main technological advances and possible future developments in the transport sector, which address the decarbonisation of transport in order to better face the challenge of reducing climate change.

The report, which is based on information from industry technology roadmaps, interviews with technology providers and industry experts, the report establishes current procurement practises from the PPIA network cities and attempts to gauge future demand for vehicles of the public transport sector. Drivetrain technologies for city buses and alternative fuels are covered, as well as technology relevant to lighter vehicles such as taxis and minibuses are alos looked into. The forecast range is focused on the short term performance for the next 5 to 10 years and includes suggested measures to be undertaken by the cities in order to implement  cleaner fleets in public transport.

LPG in a difficult environment

Due to the study’s bias on heavier vehicles and Autogas being much less well represented in this sector, it gives technology based on LPG lower marks. As a matter of fact, it is rather difficult to find heavy bus applications running on Autogas. The driver for these exceptions, mainly in the United States and China, being mostly air quality rather than decarbonisation. The forte of Autogas clearly lies with lighter vehicles, where existing technologies and the advantages of lighter and less costly equipment clearly play out so well, that LPG can offer both a CO2 reduction as well as an improvement in air quality. This explains why Autogas remains the number one choice alternative fuel with millions of vehicles operating in major cities of the world, like Seoul, Tokyo, Hong Kong and Sydney only to name a few.

That being said, the study does look into each of the available fuels individually and finds – very much surprisingly – that LPG is the best alternative fuel up to the year 2020, offering advantages over almost all other alternatives in the very favourable combination of maturity operability and cost. This is very much in contrast to the initial findings of the study, which favours other solutions.


The study recommends engaging with equipment and bus manufacturers and accurately measure the cost of implementation in order to correctly benchmark the different options prior to procurement. The report stresses that holistic environmental goals are set on a city-wide level.

Chris Walsh, Head of Technical Support and Consultancy at Cenex commented the report, “Cenex were pleased to be able to support the PPIA group in their mission to understand the clean technology landscape for buses and cars used in public transport. The report helps public authorities and operators to answer the question of ‘how’ and ‘when’ the many different low carbon technologies on offer can be supported.”

Hopefully some projects can be spun from this study. A successful implementation does not necessarily need to come from the favourite contender, many races can be won from any good starting position in the grid. Pole position is not necessary!

You can download the full report here.