Alternative fuels and additives in construction

As part of High Speed Two (HS2)’s Innovation programme, a trial of alternative fuels was carried out in partnership with the Centre for Low Emission Construction at Imperial College London and the Main Works Civils Contractor at their HS2 construction site near Coventry in April 2021. The trial measured tail-pipe emissions to determine the potential emission savings of using alternative fuels when compared to red diesel.

The ‘real-world’ emission measurement tests were carried out on two 20-tonne excavators - a Liebherr R920 compact excavator (Stage IIIB) and a Komatsu PC210 excavator (Stage IV). The fuels tested included standard red diesel (EN590) to provide a baseline for comparative purposes, red diesel with F18 fuel additive and two biofuels - Hydrogenated Vegetable Oil (HVO) and Enhanced HVO.

While the results showed limited air quality benefits when compared to red diesel, the trial highlighted the potential carbon reduction opportunities through the sustainable sourcing of alternative fuels, for example fuels derived from wastes or crops rather than from fossil fuels.

Both machines used during the trial had exhaust gas after-treatment technology installed to reduce nitrogen dioxide and particle emissions. As such the study also recognises that older machines with no after-treatment technology may have a greater potential for reducing emissions through the use of alternative fuels.

Further studies, across the construction industry, are underway to better understand alternative fuels, and where the use of alternative fuels has the biggest emission saving potential.