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Building an evidence bank about 'green' technologies for heavy vehicles

By FLEET e-news posted 26-02-2014 09:43

Rare Consulting, a division of infrastructure consultancy pitt&sherry, is working with the NSW Government’s Roads and Maritime Services agency (RMS) to build an evidence bank demonstrating the true performance of environmental technologies in heavy vehicles – with intriguing results.

“Relatively little has been done to evaluate and document the real-world economic and environmental performance of heavy vehicle technologies in Australia,” explains Rebecca Williamson, from Rare Consulting/pitt&sherry. “Overseas programs have looked at these issues, but differences in factors such as road conditions and vehicle types mean that Australia can’t necessarily apply the results of overseas trials and presume the outcomes will be similar.” Thinkstock

Conscious of the need to address this research gap, the ‘Green Truck Partnership’ was formed in 2009, driven by a Steering Group representing eleven stakeholders, including Boral Transport, Murray Goulburn Co-operative, Star Track and several government agencies. 

The Partnership aims to:

1. Independently test technologies that claim to improve the environmental performance of heavy vehicles, and 
2. Give fleet operators a credible research foundation on which to base their purchasing decisions.

Heavy vehicle fleets across Australia can participate in trials.

Real-world case studies

The Steering Group advises RMS on technology selection and testing protocols. Using its industry connections, the Group finds out which technologies fleets are already considering trialling. If a fleet agrees and the trial is suitable or can be readily adapted, it is brought under the Partnership umbrella. 

“Sourcing participants from fleets already trialling a particular technology not only helps the Partnership to build a library of real-world case studies,” says Williamson, “but provides the trial fleets with a robust evaluation of the trial technology, which they may not have undertaken otherwise.”

Data from each trial is collected via ‘loggers’ fitted into participating trucks’ engine management systems. The loggers wirelessly transmit data to an online platform. Williamson and her colleagues can log into this platform remotely to watch the data accumulate in real time, although the data-logging provider also sends daily aggregates for each truck. The data collection can run for as long as four months, which provides a solid bank of data, while allowing time to evaluate the data thoroughly and write the case studies.

With specialist expertise in data analysis, Rare/pitt&sherry developed the data collection protocols for the Partnership. “A lot of data collection companies offer loggers that can tap into trucks’ engines and pull data from them,” says Williamson, “but it’s how you use this data to verify any potential fuel savings or greenhouse emission reductions that makes or breaks the analysis.

“For example, it wouldn’t be sound methodology simply to compare fuel consumption data from a hybrid truck with data from a standard truck as a basis for measuring fuel savings. Differences in factors like loads, drivers, routes, terrain and ambient air temperature can all affect fuel consumption.”

Comparing apples with apples

To address this issue, Rare/pitt&sherry developed a model with parameters that ‘quarantine’ certain data – enabling a direct comparison of vehicle performance during the baseline and trial data collection periods.

The other key to a successful and reliable trial is to ensure that the vehicles operate under similar conditions during the baseline and the test periods. To ensure this is achieved, Williamson and her colleagues undertake ‘before and after’ mapping. This tracks each truck’s engine load and speed variance over the course of a day, to make sure it is doing exactly the same thing when the technology is in use, as when it is not.

These kinds of measures help ensure a valid comparison between the kinds of technologies or vehicles being trialled. They also give RMS and participating fleets confidence that any benefits demonstrated by the technologies are due to the technologies themselves and not to other factors.

Rare/pitt&sherry uses agreed criteria to analyse the data from each trial and write the case study, providing further assurance that the results presented accurately reflect the differences between the technologies and/or vehicles trialled.

Given the complexity of the technologies trialled, and the need to ensure an absolutely robust comparison, each trial can take many weeks or months to establish. Ten trials have been completed and published on the RMS website since the first round took place in 2010.

One trial in 2012 assessed the performance of a hybrid electric vehicle compared with a conventional diesel vehicle. The trial was carried out using two local pick-up and delivery trucks operating in Sydney’s metropolitan area. 

The most common form of hybrid combines a petrol or diesel-powered internal combustion engine with an electric motor powered by on-board batteries. The energy used by the electric motor is drawn from an on-board battery pack charged by the kinetic energy recovered from the braking system. Using this recovered energy during acceleration reduces overall fuel consumption. On the other hand, hybrid vehicles are more expensive to purchase – making independent trials a valuable source of knowledge when fleets weigh up ‘whole-of-life’ costs and benefits during purchasing decisions. 

The Partnership’s 2012 trial demonstrated a 21 per cent saving in fuel costs, and the same figure for greenhouse gas emissions. 

“This was a significant result,” says Williamson. “Although some manufacturers claim significantly higher savings, we had only ever seen average figures around 15 per cent in Australian on-road applications.”

Another recent trial involved assessing the effectiveness of ‘environmental driver training’, which aims to help drivers operate heavy vehicles in a way that reduces fuel consumption. The trial took place over 10 weeks in mid-2012, using a prime mover on Melbourne’s urban distribution routes. The driver undertook simulator and in-cab training to improve knowledge of gear shifting, speed, acceleration, cruise control, braking, idle time, route planning and observation. Analysis of logger data revealed an eight per cent reduction in fuel costs and the same figure for greenhouse gas emissions, compared with pre-intervention levels.

In the regional sphere, a 2011 trial comparing an LNG-powered vehicle using High Pressure Direct Injection (HPDI) technology with a conventional diesel-powered vehicle also yielded noteworthy results. Carried out over six weeks using B double trucks doing line-haul work in regional Victoria, the trial was designed to test the industry’s observation that HPDI delivers superior fuel savings and environmental benefits compared with other natural gas engine technologies. The trial demonstrated a greenhouse emission reduction of 22 per cent, compared with the diesel-only powered vehicle.

“No other program in Australia does what the Green Truck Partnership is doing in the heavy vehicle sector,” says Williamson. 

“We hope that the case studies developed under the Partnership will serve as a valuable resource for fleets when they’re approached by companies making claims about a product’s ability to cut fuel consumption or greenhouse emissions. We believe it will give fleets real-world examples with which to judge that business case, rather than going solely on what the manufacturer says.”

Original source:
pitt&sherry e-news

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