In this article, Richard Smith looks at the urgent issue of poor air quality and the legislative proposals intended to reduce the problem (such as the proposed changes to the Authorised Weight Regulations for HGVs) and considers options for operators when choosing vans and heavy vehicles with cleaner engines.


Poor air quality has a major effect on aggravating existing medical conditions, and perhaps causing them, so is rightly of concern, in densely populated London in particular, and the UK as a whole.

Perhaps the greatest cause of poor air quality in modern times is the internal combustion engine together with a huge increase in motor vehicles on the road (particularly those with diesel engines). The challenge now is to reduce or eliminate the current problem (just as legislation outlawed the causes of the last wave of air pollution, the so-called “pea-soupers”, in the 19th and 20th centuries).

Partly to this end, the Mayor of London has opened a consultation proposing to implement an Emissions Surcharge in the capital, which some estimate will cost the average small operator with five vans a significant amount extra (see Early Delivery of Ultra Low Emission Zone). And for the UK as a whole, the DfT is consulting on a proposed change to the Authorised Weight Regulations to implement some of the provisions of EC Directive 215/719 to come into force by May 2017.

See Cleaner Fuel Technologies in the legislation tracker or go to the DfT consultation.

Further afield, the German Bundesrat has just voted to ban new vehicles powered by gasoline or diesel fuel by 2030 and is encouraging the European Commission to impose an EU-wide ban. This follows similar votes in Norway and the Netherlands. While such a ban would still allow the use of existing petrol and diesel vehicles until the end of their life, we can expect an extension of Low Emission Zones (LEZs) such as London’s, and France has already banned older vehicles from entering Paris during the week. Operators, therefore, face an increase in costs, whether from paying charges to enter LEZs or from accelerating vehicle replacement cycles, and careful planning will be needed to minimise financial losses.

The next step

Although huge improvements in both emissions and fuel consumption have been made since the introduction of the Euro 1/Euro I standards, the internal combustion engine fuelled by petrol or diesel appears to be reaching the end of its possibilities. Future improvements, therefore, will depend on new fuels and/or new technologies.

Hybrid power

A partial solution might be a hybrid power unit where a smaller capacity internal combustion engine is coupled with an electric motor so that power provided by the electric motor makes up for the reduced power of the smaller combustion engine.

The electricity is provided from an energy store (battery) which may be charged by spare energy from the internal combustion engine when it is not needed to power the vehicle (eg under overrun conditions) and/or by regenerative braking where the kinetic energy normally lost during braking is converted to electrical energy. By generating electrical energy by regenerative braking and also by conversion of waste energy from the exhaust gases downstream of the turbocharger (a principle which steam engine enthusiasts will recognise as “compounding”), the current generation Formula 1 cars produce the same, or more, power at the wheels as the previous ones did from combustion engines twice the size.

Hybrid road vehicles may be able to travel short distances on electrical power alone and some are plug-in hybrids, which can have the battery charged from mains power when not in use. However, since current hybrids still use a petrol or diesel engine, in the current political climate they cannot be a long-term solution, indeed their day may have already passed.

Cleaner fuels

More refined gasoline and diesel fuels have greatly reduced or eliminated some of the polluting gases such as sulphur dioxide but, as with internal combustion engines, further improvements are becoming harder and harder to make. Other fuels such as liquefied petroleum gas (LPG) and compressed natural gas (CNG) have been available for some time and both are pollutant-free, the main exhaust gases being only water and CO2. They are also noticeably quieter and do not produce particulates.

Both CNG and LPG fuels produce CO2 as an exhaust product, however, and CO2 emissions are also a target for legislators. CNG, at least, has the advantage of being generated from biowaste and therefore is considered carbon-neutral, indeed may be carbon-negative to some extent since the conversion of the waste removes from the atmosphere some gases that would otherwise disperse into it.

Since both fuels still provide their energy through combustion, some oxides of nitrogen (which comes from the air not the fuel) may be emitted so a reduction catalyst is needed. A significant disadvantage to the use of LPG and CNG is that such vehicles are banned from the Channel Tunnel and many tunnels in continental Europe.

Electric vehicles

Battery and electric vehicle technology has improved to such an extent that some full-electric light vehicles are now able to compete successfully in terms of style, speed and range with petrol or diesel ones (though not purchase price). It is now possible to achieve a range of about 250 miles at 70mph and more than twice that at 40mph.

Using the manufacturer’s own special dedicated charging points installed at motorway service areas, a full battery charge takes up to 70 minutes but a half charge (enough for about two hours motorway driving) can be delivered in just 20 minutes.

Heavy vehicles are another question, however, and pure battery HGVs are probably not achievable in the near future. Light vans for local deliveries are, however, and their use in towns would certainly alleviate the pollution problem greatly.

Hydrogen fuel cell

The hydrogen fuel cell combines oxygen from the air with hydrogen from a pressurised tank to create electricity directly by a process similar to that which takes place in a battery. As no combustion takes place, the only exhaust product is water.

While the electricity generated by the fuel cell is used to power the vehicle directly, a storage battery is also fitted to provide temporary energy storage and this can also be charged by regenerative braking. One type of commercial vehicle in the range 7.5–12 tonnes is available.


Currently, only petrol or diesel hybrid commercial vehicles are readily usable since the refuelling infrastructure is in place. Electric vehicle charging points are now available in car parks and motorway service areas but converting completely to battery-electric vehicles seems an impossible dream given the number of charging points that would be required. Furthermore, the UK’s electricity generating capacity is extremely unlikely to be able to supply sufficient power.

While LPG is available from storage tanks at a reasonable number of public filling stations, there is thought to be only one public site for CNG in the UK, in Wincanton. About a dozen other sites are private supplies at operators’ premises. Low-pressure filling direct from the gas main is possible but a complete tank fill requires many hours. High-pressure filling takes no longer than filling a diesel tank but the equipment necessary to compress, store and dispense the gas costs in the region of £1 million. Hydrogen fuel is available at a roughly similar number of sites to LPG.


Poor air quality in towns and cities is a serious issue that can only successfully be addressed by the removal of diesel-powered vehicles. For heavy goods vehicles, on which the economy depends, the options other than diesel are currently severely restricted. It seems unlikely that the dreams of the Bundesrat can be realised in as little as 15 years and at least in the UK, the current policy seems more achievable. Nevertheless, operators, particularly those involved in international operations seeking to implement affordable and future-proof vehicle replacement policies, face a difficult time.

Last reviewed 21 October 2016