What can I do to reduce carbon emissions?

Martin Flach Reports.

Since the 1950’s, the Diesel engine has been the only real choice for commercial vehicle operators. With all the alternatives, life is more difficult and usually you will find that one size no longer fits all.

Before we look at alternatives, it is important to remember the basics of good fleet operation:

Driver training and monitoring with telematics
Vehicle in optimum condition particularly tyre pressures
Aerodynamic aids on Cab, Bodywork and Trailer all optimised and correctly adjusted.

Getting these right can have significant effects on CO2 at minimal cost.

GTL and HVO (bio diesels)

The simplest alternative to reduce CO2 is to use a biofuel where the carbon emitted from the exhaust is balanced by the carbon absorbed in the growing phase of the organic material.

The first-generation FAME bio diesels are not stable enough at anything except low blends with Euro VI engines. Gas to Liquid (GTL) and Hydrogenated Vegetable Oil (HVO) are second generation bio diesels, these are usable as “drop in” fuels.

This means that the engine will work well with no changes to maintenance regimes etc even at 100%. Availability in the UK is limited, and costs are an issue at present but fleets who have trialled them report good results.

The challenge that any biodiesel will have is public perception.

With the current demonization of diesel, this could prove to be a losing battle.

Electric

Electric vehicles are not a new concept in fact some of the earliest vehicles were electric. The game changer has been the development of new battery technologies such as Lithium Ion which have improved energy densities and are capable of being recharged in relatively short times.

In the passenger car world, Electrics have moved from small quirky vehicles to mainstream from most OEMs.

For commercial vehicles it is still very early days, there are a few “car derived” LCVs on the market and, in the large van segment, products are available from LDV, Iveco, Renault and soon Mercedes, Volkswagen/MAN and Ford. New starters such as London Electric Vehicle Company and Arrival have products coming to market. The Fuso E Canter is also available in light to medium 7.5t sector.

The Batteries are still the limitation for all these products. If you want to achieve a decent range, you need more batteries which have adverse effects on payload and more importantly cost. The range available will almost certainly mean that these vehicles will be destined to urban operations.

Purchase costs are high but partly helped by the “plugged-in van grant” – up to £8000 for vehicles up to 3.5t and up to £20,000 above 3.5t. Other than in the London congestion charge zone it is difficult to make the economics stack up.

Moving up the weight range, all OEMs are developing products generally for the rigid market as the range and payload will rule out most artic work. For Artics, in particular 6×2’s so loved by the UK, the space available for batteries renders pure electrics only.

Range extended Electric

Tevva have successfully converted several vehicles for UPS (mainly Euro V Mercedes Vario models) to range extended electrics. The technology lends itself to a zero emission capable vehicle.

Natural Gas CNG and LNG

Gas fuelled spark ignition engines have been around since the birth of the internal combustion engine. Indeed, Nicholas Otto used town gas as the fuel for his early developments. In Euro VI, spark ignition offerings are available from Scania and Iveco. Power ratings are now 400 – 460hp. Volvo and Mercedes have rigids at circa 300hp available as well. Volvo has also recently returned to the market with a 460hp engine featuring HPDI (high pressure direct injection) technology. This is still a compression ignition cycle but using only a small amount of diesel as a liquid spark plug. Whilst the spark ignition engines are available with either Compressed Natural Gas (CNG) or Liquid Natural Gas (LNG), the Volvo HPDI is only available for LNG. The choice of LNG or CNG will depend on the vehicle operation. LNG has an energy density that is circa 2.5 times that of CNG. This means that in a limited space available for tanks, the LNG vehicle will have a range 2.5 times better than the CNG vehicle. LNG is a cryogenic liquid and needs drivers to have the necessary training and Personal Protection Equipment. At circa – 160deg C, it must be treated with respect.

Filling a CNG vehicle is simpler with no PPE required. As the fuel is identical in composition, the emissions will be the same with either fuel. The difference being only the storage system. With 6x2s now available from Volvo and Iveco and the economics looking good for long distance, now seems to be the time for gas vehicles to take a significant slice of the market. Natural gas (methane) can also be produced as bio methane from land fill or more typically now from Anerobic digestion. Bio methane is useful as it can reduce the CO2 emissions from vehicles (on a well to wheel basis) by 80% and more. Natural gas vehicles are a “here and now” technology that may well be replaced in the long term with other zero emission technologies but for now are the only real game in town for long distance operations.

Hydrogen

On the face of it, Hydrogen sounds like the ideal alternative. It can be used in a fuel cell and the emissions from the vehicle are water. Hydrogen has a low energy density meaning that space is required for tanks. On Artic vehicles this will be an issue. There are currently a few buses running in the UK on hydrogen. These are short distance, back to base operations using long wheelbase single deck vehicles with plenty of space for fuel tanks on the roof. Range is not an issue in this operation. Costs are at present very high. Hydrogen has been the fuel of the future for many years and is seems still many years away from mass production. The most likely use of Hydrogen could be as a zero-emission range extender for an electric vehicle if the costs and weight of the fuel cell and hydrogen tanks can be competitive against an additional battery.