Reducing emissions from NRMM with alternative fuels

Rebecca Swann of Certas Energy
Rebecca Swann

By Rebecca Swann, product manager for fuels and services at Certas Energy

IT is an uncomfortable truth that there is no single fuel solution to the air quality problem for the construction sector.

Despite advocating the use of alternative fuels where it is convenient, safe and commercially acceptable to do so, an investigation by HM Treasury and DEFRA into the high volumes of red diesel being used for non-road mobile machinery (NRMM) goes no further in setting out confident recommendations to lower emissions. 

With so many solutions available in the new liquid energy stack yet no clear directive, where can construction businesses start to make quick wins that can propel them on the path towards a net-zero emission future? 

What’s holding back uptake of cleaner alternatives?

NRMM requires the sudden and powerful burst of energy that is delivered by the combustion of diesel. So it can be difficult to switch to other energy sources that can pack the same punch.

While NRMM is subject to emission standards, older ‘legacy’ equipment can produce higher levels of air pollutants due to less stringent standards when the product was manufactured. Yet to move all legacy NRMM to equipment that meets Stage V standards would be prohibitively expensive.

A lack of infrastructure also means that construction businesses must be realistic when evaluating how they can most effectively power the transition to lower emissions on construction sites – especially when it comes to electrification. In fact, many respondents to the recent consultation on NRMM believe that – at this time – no viable cleaner alternatives are available. This is simply not the case. The technologies do exist to tackle emissions from NRMM and improve local air quality immediately – without causing disruption or requiring investment in new machinery.

At the same time, it must be acknowledged that low levels of uptake are first and foremost a commercial (not necessarily a technical) challenge. Without incentive, and while the tax rebate on red diesel remains so attractive, the case for investing in the majority of alternative technologies is a difficult one to build.

As much as this is a challenge, it also represents a huge opportunity for wider uptake to have an immediate and tangible impact on air quality. It’s here that readily-available alternative liquid fuels are kickstarting construction on the path towards the ultimate zero-emissions end point.

Making the case for change

There are many liquid fuel technologies that are already being tested and trialled. These include gas to liquid (GTL), power to liquid, biomass to liquid, hydrothermal liquefaction and hydro-treated biofuel products. However, many of these technologies and developments remain unproven.

In the case of GTL, part of the paraffinic family of fuels, the benefits have been proven for NRMM. This particular formulation is based on gasification chemistry and can achieve similar performance levels to diesel while reducing emissions of NOₓ, PM and carbon monoxide. With noted benefits including high energy density, ease of use and safe handling – supported by security of supply and approvals from many OEMs – GTL delivers an exceptionally strong value proposition.

Paraffinic fuels could also prove to be more effective than other alternatives, with drop-in technologies such as GTL requiring no modifications to existing or legacy NRMM. 

Alternative fuels in action

GTL is one of the few available paraffinic fuels in the UK, helping its early adopters transition to a cleaner fuel future. To-date its uptake has been largely by commercial users and construction businesses seeking to lower emissions and improve social value in large cities. 

GTL is being used for a number of high profile applications. J Murphy & Sons Ltd, for example, has deployed Shell GTL Fuel on a project to facilitate the construction of the High Speed 2 (HS2) Railway; while Morgan Sindall has adopted the fuel to power its site at Heathrow.

Shell GTL Fuel is also helping Jackson Civil Engineering to minimise the impact of its operations on the Environment Agency’s Perry Barr and Witton Flood Management Scheme. As well as reducing the company’s environmental impacts as a result of its biodegradability and lower emissions, GTL is creating a healthier working environment and lessening disruption to the local community by producing less odour, smoke and engine noise than conventional diesel.

Looking to the future

A broad mix of energy sources will surely enable the most cost-effective and robust transformation path to a low-emission future – while driving towards all the strategies and government policy initiatives. The fact that the infrastructure and supply chain is strongly in place for liquid fuels means they can immediately fuel the transition for NRMM.

It’s possible that the quick wins offered by alternative liquid fuels are being overlooked because of an over-emphasis on the zero-emission end goal. Naturally, that is where we all want to be. But without embracing evolving enhancements in fuel technology, the truth is it will take us much longer to get there.

Certas Energy has developed a three-part Energy Reality series to help construction businesses understand today’s new alternative energy mix. To discover the readily-available ‘fuels for now’ that can kick-start the transition to a low-emission future, download the first report – The Future of Liquid Fuels – for free from