In Conversation
February 2020

In Conversation with: Dr Paul Greening

In this issue of our “In Conversation with” we are pleased to have Dr Paul Greening, Emissions & Fuels Director in the European Automobile Manufacturers’ Association (ACEA), share his views and outlook on the latest release of the Worldwide Fuel Charter (WWFC) with our readers. ACEA is an advocate for the automobile industry in Europe, representing manufacturers of passenger cars, vans, trucks and buses with production sites in the European Union. Representing vehicle and engine manufacturers from around the world, ACEA and the WWFC Committee announced the release of the sixth edition of the Worldwide Fuel Charter for Gasoline and Diesel Fuel as well as the first edition of the new Charter on Methane-based Transportation Fuels on 28 October 2019. We would like to thank Dr Paul Greening for his efforts to comprehensively answer our questions which provide some highly valuable insights into the work ACEA undertakes to define and advocate the common interests, policies and positions of the European automobile industry.  

A comprehensive version of the 6th edition of the WWFC can be downloaded from ACEA’s website.


Dr Paul Greening  
Emissions & Fuels Director

Dr Greening has a long experience working on European and global regulations addressing the environmental performance of road vehicles. Previously working for the UK government until 1996 and the European Commission in Brussels until 2004, he joined the European Automobile Manufacturers Association (ACEA) in 2006 where he is responsible for co-ordinating the European automotive industry position on pollutant emissions and the applicable testing procedures, renewable energy and fuel quality and he is involved in assisting policy makers regarding their future legislative plans, as they will affect the European automobile industry. The Green Deal presented in December 2019 by the new European Commission presents new challenges.

Dr Greening obtained his PhD in the field of steel making.

Q: Before looking into some of the specific findings, conclusions and recommendations of the sixth edition of the WWFC, could you please share with our readers what ACEA’s work and mission comprises of and what the overall objectives of the organization are? Please also introduce your specific role in the organization.

A: Dr Greening is the Emissions and Fuels Director in ACEA. ACEA has a number of Directors supporting the Director General on a wide range of current and future policy-related issues impacting the European auto-industry and ACEA has a total staff of about 38. While ACEA deals with policy matters, a team in EUCAR deals with EU research activities. ACEA is based in Brussels but it also has an office in Beijing, a representative in Seoul and it works closely with the Japanese Automobile Manufacturers Association (JAMA) in Tokyo. ACEA members cover European based passenger car, light commercial vehicle and heavy commercial vehicle manufacturers and, this year, ACEA welcomed Ferrari as its 16th member.

ACEA’s mission is to define and advocate the common interests, policies and positions of the European automobile industry; engage in dialogue with the European institutions and other stakeholders in order to advance understanding of industry-related issues, and to contribute to effective policy and legislation at both European and global levels; act as a portal for expert knowledge on vehicle-related regulation; communicate the role and importance of the industry, using reliable data and information; monitor activities that affect the automobile industry, cooperating with the other stakeholders involved; and undertake strategic reflection on the increasingly global challenges of mobility, sustainability and competitiveness.

Q: The WWFC was first established in 1998 in order to increase understanding of the fuel quality needs of motor vehicle and engine technologies, and to promote worldwide fuel quality harmonisation in accordance with those needs. On 28-October this year the 6th edition of the WWFC for gasoline and Diesel fuel and the first edition of the new charter on Methane-based transportation fuels have been successfully released.

Based on the above listed intensions, how do the proposals and recommendations of the fuel charters fit into the co-operation between the various stakeholders, i.e. in terms of aligning common goals between vehicle and engine manufacturers and oil industry? Which role does the WWFC play among policy makers and in the political arena in general?  

A: The global vehicle and engine manufacturers and their associations represented in the World Wide Fuel Charter committee have a clear view on needs for fuel quality and have developed the WWFC over the years so that the WWFC covers the development of engine and exhaust aftertreatment technology and the development of global regulations. That is the basis for the WWFC while also retaining Categories covering areas of the world where the pollutant emission and fuel economy standards may not be as well advanced compared to areas like the European Union or North America. That being said, the Categories in the WWFC are recommendations and global fuel regulations do not (yet) match the latest Categories.

For ACEA, it was important to complete the latest WWFC in time for the review of the Fuel Quality Directive (FQD) that has started and, we trust, will result in a forward-looking proposal from the European Commission to update the FQD in 2021. With on-going pressure on CO2 reduction and in respect of the Green Deal published by the new European Commission on 11 December 2019, major changes to the FQD (and other EU legislation) to facilitate the wide availability of low carbon liquid and gaseous fuels will be necessary as one of the tools to help reduce CO2 emissions from new vehicles and, at the same time, help reduce CO2 emissions from the existing fleet that can use such new fuels.

In that respect, ACEA and the European fuels industry have some strong common interests to ensure that the improving internal combustion engine will have a future as part of the transport & mobility programs in the Green Deal which aims to move the EU towards the goal of carbon neutrality by 2050.

The draft WWFC was circulated widely to stakeholders to receive comments, and the WWFC committee discussed all comments and have tabulated the reply to each comment. So, while auto and oil may not agree some of the content of the WWFC, the overall need to provide access to cleaner and greener molecules is supported - and both industries are working hard on that.

Q: In the 6th edition of the WWFC the Committee has introduced some important changes to the charter in terms of gasoline categories and their definition. Category 1 has been retired as obsolete, after significant quality improvements have been achieved, particularly regarding lead and Sulphur content, while Category 6 has been added to reflect the emergence of a new generation of emission control limits and fuel efficiency requirements in several major markets.

We noted that the WWFC recommends Category 5 gasoline to be comprised of Unleaded Premium (RON95) and SuperPlus (RON98) only, while the recommended octane standards in Category 6 are for RON98 and RON102 gasoline. The proposed, extra octane requirement in both categories is predominately supported by an increase in the maximum oxygen limit to 3.7 wt.%.

What are the drivers behind the recommendations? What are the advantages, from an engine manufacturer’s point of view as well as on environmental grounds?

A: Octane can be used to help improve the efficiency of the spark-ignition engine. With pressure to reduce CO2 and improve fuel economy, the WWFC committee agreed it was timely to include a new Category 6 petrol aiming at higher octane petrol. Higher octane petrol is available across the EU in differing volumes, but countries like France have quite a high share of 100+ octane petrol already. Data shows that existing high octane petrol is achieved by the blending of ethers with a very low amount of ethanol and oxygen content in the range 2 – 3.5 wt%. However, considering that the WWFC Categories are recommendations and we have recognised that some countries permit a certain level of ethanol blending in petrol, the new WWFC Category 6 sets the maximum oxygen content at 3.7wt% but also foresees that higher ethanol blending is a route to delivering the octane required in Category 6. Hence, footnote 5 to Category 6 recognises a higher oxygen content level of 8wt%. Of course, if the higher ethanol route would be chosen to deliver octane, only compatible vehicles could use it. Higher octane achieved by using, for example, E10 like in the EU plus ethers would make the fuel compatible for use in a much bigger fleet, old and new.

The general consensus is that one octane increase enables 0.5% engine efficiency improvement, and we have seen engine efficiency gains of 1% quoted. There is quite a lot of data out there from many sources comparing 102RON to 95RON petrol. Efficiency gains at certain operating points may be high (up to 15% improvement) and full cycle (e.g. WHTC) CO2 benefits from engines optimised to take advantage of higher octane in the range of 102 indicate benefits around 2.5 – 3%. While those figures may seem low per vehicle, the bigger picture suggests a very worthwhile contribution to CO2 reduction, especially considering what is coming, at least in the EU up to and beyond 2030.

While older vehicles are, in general, compatible with the use of higher octane petrol the actual CO2 benefit is likely to be minimal. But this suggests the market for consuming high octane petrol isn’t one that depends on the rate of fleet renewal with new vehicles; but it can be dependent on the price at the pump.

From a European perspective, high octane petrol seems to be one of the low hanging fruits that will benefit vehicle CO2 emissions and could be relatively easily delivered by the fuel industry, as well as continuing to work on the transformation from fossil fuels to low carbon liquid and gas fuel alternatives.

Q: The WWFC proposal clearly states the committee’s position on metallic additives as well as chemical and other contaminants which are all recommended to be avoided in gasoline blending. What are the main concerns, technically on engine performance and durability?

Having seen a steady number of incidences reported in which harmful contaminants were used in gasoline over the last few years, what are in your opinion the main drivers for fuel suppliers to utilize metallic and chemical additives? And, what needs to be done to avoid or reduce this in the future?

A: The technical background to the WWFC clearly addresses our concerns on the use of metallic additives in fuels as cheap octane-boosting components. The EU has dealt with manganese by limiting content to non-useful levels but there is still a risk that EU petrol could contain metals, especially since no fuel pump could be labelled to declare ‘contains metallic additives’ with each tanker delivery. We have seen data that indicates the occasional presence of metals, but thankfully this is rare.

However, we remain concerned that some countries still permit relatively high levels of metals in petrol. For example, South Africa still permits the sale of metal containing petrol alongside ‘normal’ petrol and data from some North African countries show levels of manganese as high as 13mg/l and also high levels of ferrocene.

In UNECE in Geneva, Working Party 29 (WP29) and the various Groups work on a range of vehicle-related standards under the 1958 Agreement (UNECE Regulations) and the 1998 Global Agreement. That forum is essential for developing global technical regulations (GTR) under the 1998 Agreement and has been successful by agreeing a range of GTRs, for example, test cycles for light & heavy-duty vehicle emissions (WLTP and WHDC) and many others and work continues on a GTR for Real Driving Emissions (RDE).

WP29 does not have a mandate to regulate fuel quality but it has taken a view on fuel quality. Consolidated Resolution on the Construction of Vehicles (R.E.3) was updated several years ago to provide a link between fuel quality and emission standards. Revision 2 to RE3 in 2012 covered sulphur and lead content in petrol and sulphur, ash and total contaminant content in diesel as applicable when the EU emission standards Euro 2, Euro 3 and Euro 4 for light and heavy-duty road vehicles took effect (and also the non-road mobile machinery standards). Revision 4 to RE3 in 2016 expanded the recommended fuel parameters to cover all of the parameters covered in EN228 (petrol) and EN590 (diesel) as applicable when the EU emission standards Euro 2, Euro 3 and Euro 4 for light and heavy-duty road vehicles took effect (also non-road mobile machinery). The last amendment to RE3 (agreed in 2019) has now updated RE3 to cover also the fuel standard parameters for the EU emissions standards Euro 5 and Euro 6 for light and heavy-duty road vehicles.

A very important point regarding RE3 is the position that the UNECE has taken on the use of metallic additives because in RE3, in the petrol table it is clearly written “Metallic additives – not permitted”.

RE3 is an important document to remind countries that may still allow the use of metallic additives to reconsider in the light of international opinion. The auto industry will continue to call on the need to ban or prohibit the use of metals in fuels to protect engines and aftertreatment components.

Now we are concerned about other components being used, also with cheap octane boosting characteristics. So, it was necessary for the WWFC committee to make a statement about such organic contaminants in all of the petrol Categories – e.g. methylal, aniline and aniline derivatives, secondary butyl acetate (SBA). The petrol technical annex provides some details about these and other contaminants such as phosphorus, silicon and chlorine. I am happy to also note that CEN and CEC have now started work to help define appropriate measurement methods for these unwanted components.

Q: The Diesel section of the WWFC – like done for gasoline - also divides the recommendations in five market categories. Category 1 still stands out as the one with a very low Cetane (48) and very high Sulphur level (2000ppm), while Category 5 matches the fuel specification standards, such as Euro 6 and GB-VI (China).

What is the reason behind still having the Category 1 standards in this new edition of the WWFC? What are the key changes and recommendations in the Diesel charter, compared to previous versions of the WWFC?  

A: The WWFC committee did consider if diesel Category 1 was still needed. In the end the Committee agreed to keep it but at the same time give an indication that diesel Category 1 remains under review and may be retired at the next opportunity.

Otherwise, the main changes for the diesel categories can be summarised as follows:

  • Revision of the diesel Category descriptions in line with the petrol Categories.
  • Lowering the minimum diesel density from 820 to 815 kg/m3 in Categories 2-5, in line with what EN590 has recently done.
  • Clarification of footnote 2 in all Categories for relaxing minimum density in low temperature conditions.
  • Updating the technical annex with new data and some new elements and the test methods table.

Q: Fuel emission and specification standards globally are still far away from a harmonised and coherent picture. While standards in developed economies keep gradually improving, lesser developed regions keep trailing behind with some countries not even achieving minimum recommendations. This applies to gasoline as much as to Diesel fuels. What – in your opinion - can be done and needs to be done to align global standards over time? How can the WWFC help to accomplish the targeted harmonization?

A: The WWFC Categories are defined according to the level of emission standard and/or the level of fuel economy/CO2 standard. The WWFC contains recommendations from the auto industry to global policy makers and regulators so we do use the WWFC to help those policy makers make the right decisions.

The work in UNECE has been successful in linking emissions standards to necessary fuel quality and to recommend to policy makers that when you may introduce more severe emission standards please do not forget about the parallel improvement to market fuels needed to help the vehicle-based technology contribute to achieving the environmental policy aims.

Global technical regulations are always a welcome approach which the auto industry appreciates, to help reduce the burden of different regulatory tests in different global regions. While emission standards may not converge (they should be dictated primarily by local environmental need) and emission regulations may look very different on paper, the actual technology on the vehicles is converging. That means fuels and fuel quality should also converge because the engine, the exhaust aftertreatment system and the fuel are the three key parts of the system that together help reduce tailpipe pollutant and CO2 emissions, deliver vehicle performance and the level of driveability and NVH performance that customers demand and pay for, and to ensure the vehicle starts and runs without concern every day of the year.

Q: We would like to thank you very much for sharing your views and opinion on the above topics with us.

Are there any other aspects we have not raised in our questions which you would like to address, in order to explain and convey the importance of the work undertaken by ACEA, related to the WWFC or in general?  

Are there any other aspects we have not raised in our questions which you would like to address, in order to convey the strategy and work Sustainable Fuels is involved in? Any other specific topics, challenges and opportunities you see for Europe or elsewhere in the world? Please be so kind as to share your thinking with us.

A: We should not forget that while Category 6 focuses on CO2/fuel economy, it also, like Category 5, has a strong focus on pollutant emissions, especially the strong trend of regulators towards on-road emissions testing, for example Real Driving Emissions (RDE).

The WWFC committee decided to press for improvements in air quality emissions, particularly particles which can be impacted by, for example, the use of heavy (C9 and higher) aromatic components in petrol within a total aromatics limit. Here, the WWFC committee has introduced the PM Index parameter as a marker for future revision as the PMI test method is developed and, in the meantime, specific limits at points on the distillation curve (e.g. E130/E170 or E150/E180) will help control the use of heavier aromatics that are known to have a negative impact on particle emissions.

Despite the introduction of gasoline particle filters (GPF) on vehicles in some markets like the EU, RDE testing with market petrol is still a risk because petrol, despite it being “EN228 compliant”, can still vary a lot in composition from fuel station to fuel station. A total aromatics limit is not good enough.

The EU also plans to revise the particle number measurement method to lower the nominal cut-off of the PMP system down from 23 nanometres (nm) to 10nm. That means more ultra-fine particles will be measured and we expect the current EU PN limit of 6 x 1011 particles per km, for cars) will be updated in proportion. So, consistent petrol quality remains very important.

A new Charter on “methane-based transportation fuels” was also published in October 2019 and the WWFC committee will meet again soon to decide where its focus will be for the next revision of the WWFC and maybe something new. Perhaps this may be a strong global auto industry focus on renewable low carbon liquid and gaseous fuels. We shall see.

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