For the past six years, the NRMA has experimented with a variety of alternative fuel sources in an effort to make its service delivery fleet more efficient and environmentally friendly.

By Frances Sacco

With around 300 vehicles running on a range of alternative fuels, the NRMA service delivery fleet provides a valuable insight into the practical application of various fuel types.

The NRMA began to use LPG-converted vehicles in 2006 and 2007. Most of their fleet, which is one of the biggest in the country, now uses this system.

Furthermore, it recently redeveloped its fleet policy to include a greater focus on environmentally friendly cars. This has led to the introduction of diesel and electric vehicles.

“We have put a target in place to reduce carbon intensity by two per cent over 12 months and my belief is that we will meet that target,” says Chris Nolan, the NRMA’s Head of Metro Service Delivery.

Setting and revaluating these targets has been part of the NRMA’s overall strategy to remain at the forefront of environmentally friendly motoring, according to Nolan.

“It’s almost an obligation,” he adds. “People expect an organisation like ours to be out there doing that and reporting on how it works. There is a bit of courage needed to do that as well.

“We’ve been on the journey for the past few years now and there have been some good lessons for us.”

The options 

While LPG is considered greener than diesel, there are some practical drawbacks to using the fuel. To keep the engines running smoothly, the converted engines must have around 10 per cent of unleaded petrol to run them.

“The practicalities of this are sometimes a little bit awkward in that we are relying on the patrol service,” Nolan says.

“Not all fuel stations have LPG. In some cases we are using as little as 70 per cent LPG, so we have not realised the efficiencies to the extent that we would have liked.

“If we don’t manage that well, it can have an adverse effect and requires more maintenance time.”

This is added to the start-up cost of converting the vehicle from unleaded petrol to LPG. 

However, the recent introduction of diesel into the mix has alleviated these problems somewhat. Most petrol stations sell diesel, meaning the drivers don’t need to balance different types of fuel.

“The consumption and the results of using diesel fuel are a lot easier to manage,” Nolan adds. 

“We realise the benefits of lower emissions a lot more easily.”

LPG will continue as the predominant fuel type in the fleet for the next two to three years, but Nolan says the organisation would be leaning towards diesel and, as the technology became more practical, electric vehicles. The NRMA is trialling electric vehicles in the Sydney CBD as well as Canberra.

“We have received positive responses from our members regarding the use of electric vehicles,” says Nolan.

The pros and cons of alternative fuels

Diesel
Pros: Diesel combusts at a lower temperature than petrol and, while it releases more carbon dioxide by volume, it is 20-40 per cent more efficient. This means a diesel-powered engine emits 10-20 per cent less carbon dioxide than unleaded petrol.

Cons: The increased compression ratios in a diesel engine mean there are increased emissions of oxides of nitrogen from diesel engines. This is compounded by biological nitrogen in biodiesel to make mono-nitrogen oxide (NOx) 

LPG
Pros: LPG is a byproduct from the refining of unleaded petrol and diesel and produces 10-15 per cent less greenhouse gas emissions than petrol. It also produces almost 90 per cent less particulates (which contribute to smog) than petrol or diesel.

Cons: Not all petrol stations have LPG available and it can also result in higher maintenance costs. Managing the percentage of unleaded petrol that must be used to keep the engine functioning can also be difficult across large numbers of operators.

Electricity
Pros: Electric cars produce no exhaust, which reduces air pollution and smog. However, just how environmentally friendly they are depends on the power source. If the power source is renewable, there are significant environmental benefits. 

Cons: The range and carrying capacity of an electric vehicle is severely limited by the battery power. There is also very little in the way of infrastructure to power up electrical cars.

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