Transport is the UK’s largest source of greenhouse gas emissions, and public sector fleets – from waste collection to emergency services – are under pressure to lead the way to net zero
There are certain renewable fuels that can achieve immediate carbon savings, and act as a short-term solution until viable zero-emission options are mass market. So what are they?
For public sector operators, this presents a unique challenge. Heavier vehicles – from refuse trucks to fire appliances – must deliver reliable services across long duty cycles, often on extended routes. Range limitations and charging times risk disrupting essential operations, while the high upfront cost of electric trucks makes them prohibitive for many local authorities and emergency services.
There is a handful of zero emission trucks on the market, and a growing number of fleet operators using them. But it is nowhere near the scale that it needs to be. While these challenges are being ironed out, the pressing issue of climate change continues. There are certain renewable fuels that can achieve immediate carbon savings, and act as a short-term solution until viable zero-emission options are mass market. Here we investigate what renewable and alternative fuels there are on the market, as well as the fleets that are using them.
Hydrotreated vegetable oil
Hydrotreated vegetable oil (HVO) is a drop-in alternative to diesel that is made from renewable raw materials and sustainable waste from verified vegetable fats and oils. It reduces carbon dioxide emissions by 99 per cent compared to traditional diesel and cuts nitrous oxide emissions by 25 per cent, improving air quality.
HVO supplier Certas Energy defines HVO as being a “paraffinic fuel, with near-zero sulphur and very low aromatics content”. Compared to standard diesel, it produces fewer regulated emissions of toxic hydrocarbons, nitrous oxides (NOx) and particulate matter (PM), which are all harmful to human health and the environment.
Crucially, fuel-related emissions can be cut by up to 90 per cent compared to standard diesel. What’s more, it can be used with no engine modifications needed. Because of this, HVO is proving popular with fleet operators. In January 2025, Brentwood Borough Council announced that 56 of its vehicles including waste trucks now run on HVO.
The Leader of Brentwood Borough Council and Chair of the Clean and Green Committee, Councillor Barry Aspinell said: “This is a really exciting initiative. Switching to more environmentally friendly fuels will have a E F very positive effect on air quality and provide enormous benefits to our residents.
The move to HVO demonstrates our commitment to addressing climate change and improving local air quality, all while ensuring that essential waste collection services remain reliable and efficient. While the Council is taking this brilliant step, we hope to encourage the private sector to join us in transforming their petrol or diesel-fuelled vehicles to alternative energy sources. This initiative is a key part of the Council’s broader ambition to achieve net-zero carbon emissions by 2030, paving the way for a cleaner, greener future for Brentwood”.
Biomethane
Renewable biomethane is a compressed natural gas that is a low-carbon alternative to diesel, reducing carbon emissions by up to 90 per cent.
CNG Fuels, who operates the UK’s largest CNG refuelling network, sources its biomethane from waste products including food, animal, and waste water, and it is independently verified and approved by the Department for Transport’s Renewable Transport Fuel Obligation (RTFO). The company claims up to a 40 per cent lifetime fuel cost saving when switching from diesel to bio-CNG.
Major fleet operators are using bio-CNG, such as John Lewis Partnership, Waitrose, Royal Mail, Warburtons, Aldi, AO, Farm Foods, Hermes and Wessex Water. Nottingham City Transport is running the largest fleet of bio-gas double deck buses in the world. Launched in 2017, these buses reduce CO2 emissions by up to 84 per cent compared to an equivalent brand new diesel double deck bus and have prevented over 26,000 tonnes of CO2 and 180,000Kgs of NOx being emitted. Wessex Water trucks are powered by sewage and food waste.
Every truck that makes the switch from diesel to biomethane achieves a carbon saving equivalent to removing more than 100 cars from the roads. All fuel used in the trucks comes from the anaerobic digestion of sewage and food waste at Bristol Bioresources and Renewable Energy Park.
Sean Hill, Wessex Water’s director of bioresources, said: “The tankers collecting sewage sludge for treatment and the trucks delivering the output fertiliser are both powered by the gas generated from this treatment, so we’re closing the loop when it comes to our recycling. “
This will make a huge difference to our carbon footprint and help improve the air quality of communities in our region, as well as improving operational efficiency and bringing cost benefits. “Two vehicles have been purchased initially and we hope to eventually roll out the use of Bio-CNG across our entire tankering and biosolids fleet.”
Hydrogen
Hydrogen has long been touted as the answer to zero emission heavy goods vehicles. Refuelling is quick and ranges are comparable to ICE trucks.
Hydrogen fuel cell vehicles emit only vapour, meaning they release no harmful emissions. However, as of December 2023, there are only 16 operational hydrogen fuel stations in the UK. Hydrogen fuelled trucks are also expensive, and there are only a small number available. However, there is a project to roll out 30 hydrogen fuel cell HGVs UK roads by 2026 as part of the government’s Hydrogen Aggregated UK Logistics (HyHaul) project.
Wales & West Utilities completed a month-long trial of hydrogen fuel cell vans with First Hydrogen to evaluate the potential of hydrogen for its commercial fleet. Due to the lack of hydrogen vehicle refuelling infrastructure, the project was supported by Protium Green Solutions and Hyppo Hydrogen Solutions to create a hydrogen eco-system. Green hydrogen was produced at Protium’s Pioneer 1 site in Baglan via electrolysis and renewable power, meaning that there are no emissions produced as part of the process. The trial van completed more than 2,000km over the four-week trial, travelling up to
189km per day on mostly urban roads and highways.
Data collected showed that the vehicle has the potential to fulfil more demanding duties, like carrying heavier payloads, driving over hilly terrain or powering auxiliary equipment. Moreover, there was positive feedback from the WWU team with feedback agreeing that FCEVs could help fulfil operational demands in future.
Public sector fleets sit at the frontline of the UK’s net zero journey. From waste trucks in Brentwood running on HVO, to Nottingham’s biomethane buses, and hydrogen trials with Wales & West Utilities, these examples show that renewable fuels are not just theoretical solutions – they are already delivering measurable carbon savings and cleaner air for communities. By embracing these alternatives, public sector operators demonstrate leadership, resilience, and innovation – proving that the path to net zero is achievable, practical, and already underway.
