When it comes to decarbonising transport, the greatest risk that humans pose to the planet is the act of doing nothing. Reducing the environmental impact of moving goods across long distances stretches the limits of current zero emission technology and presents an opportunity for the UK to lead the innovations needed.
If asked ‘how will the UK decarbonise passenger cars?’, you may cite the government’s commitment to ban the sale of conventional combustion engines by 2030 or reflect on the numerous electric vehicle (EV) models available on the market as evidence for a transition to fully electric powertrains. Given the growing popularity of EVs over alternative zero emission powertrains, this seems like a reasonable assumption for the short- and medium-term future, at least.
However, if asked again ‘which technologies will be deployed to achieve the decarbonisation of large vehicles such as heavy goods vehicles – or even aircraft?’, the answer may not come to you so readily. And yet, there is a similar government ban placed on diesel HGVs by 2040 which is getting ever closer. Despite the lower publicity, it has never been more important to reduce the environmental impact of these modes. In 2019, Heavy Goods Vehicles travelled just 5% of the total vehicle miles in the UK but contributed 16% of the greenhouse gas emissions (GHG) from road transport. Meanwhile, aviation emissions accounted for 7% of total UK GHG emissions in 2018, with emissions being 88% higher than 1990 levels. To reach the target of Net Zero by 2050, the emissions of these growing industries must be addressed, and fast.
The Connected Places Catapult is accelerating the transition to zero carbon solutions for the more challenging mobility modes in the UK through two pioneering projects:
Zero Emission Road Freight Trials
The Zero Emissions Road Freight Trials (ZERFT) is a pivotal programme for determining the UK’s pathway to decarbonising Heavy Goods Vehicles (HGVs). Funded by the Department for Transport and working with Innovate UK, the trials will demonstrate the feasibility of two zero emission powertrain technologies; hydrogen fuel cells and battery electric.
A key difference in the technologies is the relative efficiency of fuel production between hydrogen and electricity. Producing hydrogen using electricity from renewable sources (green hydrogen) is regarded as a low carbon commodity. However, using electricity to make hydrogen rather than to directly charge batteries onboard a vehicle leads to significant system losses. In fact, it is estimated to be over 3 times more energy efficient to fuel a vehicle through electricity than hydrogen. This may sound like an instant victory for batteries, but there are many other factors to consider such as cost, supply and resilience. Furthermore, if the UK reaches a point of producing surplus renewable energy then the efficiency hurdle becomes less significant yet other benefits of hydrogen such as fast refuelling stand strong.
Both powertrain technologies require significant investment in new infrastructure. Three infrastructure deployments for the refuelling of these vehicles will be trialled:
- Hydrogen refuelling stations – filling a hydrogen fuel tank on board the hydrogen fuel cell vehicle via Hydrogen Refuelling Stations located at services similar to the current diesel refuelling network.
- Electric Road System – dynamic charging while the battery electric vehicle is driving along sections of the road network.
- Battery electric chargers – overnight charging of battery electric vehicles at the depot, complemented by static ultra-rapid chargers located at service stations.
Hydrogen fuel cell vehicles have a hydrogen fuel tank onboard which must be filled with liquid or gaseous hydrogen dispensed from Hydrogen Refuelling Stations. This process is similar to a diesel refuelling station of today and offers minimal downtime for refuelling. The major potential challenges lie with generating sufficient green hydrogen to satisfy demand and overcoming the increased unit costs of hydrogen compared with diesel. Developing practices for the safe handling of hydrogen during production, distribution, storage and dispensing is also paramount for the transition.
An Electric Road System could see the installation of overhead catenary lines, similar to tram systems, along the UK’s strategic road network (SRN). While the vehicle is in contact with the catenary, via a pantograph fitted to the vehicle’s roof, power is directed to the motor to facilitate motion. The vehicles will also have a residual store of energy in the battery for completing journeys which start or end away from the SRN. Alternative technologies include; magnetic induction charging built into the road surface itself enabling wireless dynamic charging of compatible vehicles as they travel over it, and conversion of the roadside crash barriers into power sources with vehicles making contact using an arm protruding from the side which can retract when not required.
The key challenges with these systems include the high critical mass of vehicles required to use the system to make it commercially viable, the complications with constructing continuous infrastructure along motorways with minimal disruption and ensuring that the technology is compatible with both domestic and international vehicle standards. In addition, the currently unknown reliability of the roadside infrastructure under adverse weather conditions or accidents could pose a challenge to operations.
Battery Electric Vehicles are the primary technology for zero emission passenger cars but scaling this solution for a Heavy Goods Vehicle is far more challenging. Essentially, they require very large batteries to provide sufficient range for long-haul logistics which is difficult to implement both from a weight and size perspective without significantly reducing the efficiency and/or payload capacity. As the energy density of battery technology is predicted to rapidly improve and the speed of charging is predicted to reach upwards of 1 Megawatt (this is equivalent to the energy produced by 10 car engines at once) in the near future, this option cannot be dismissed.
Today, the best overall solution for the environment, society and the economy remains unknown and any decision requires empirical evidence through trials like these. What is known, is that the alternative of continuing to rely on diesel-fuelled logistics is simply not an option if Net Zero targets are to be met.
The winners of the Innovate UK zero emission road freight trials feasibility studies can be explored here.
Zero Emission Flight Infrastructure
To decarbonise aviation and meet Net Zero by 2050, a huge shift in aircraft propulsion technologies is required. Just like for HGVs, hydrogen and battery electric technologies are key to net zero aviation and the infrastructure required to support zero emission aircraft is very different to what is currently in place.
The Connected Places Catapult is delivering the Zero Emission Flight Infrastructure (ZEFI) programme in collaboration with the Department for Transport. We are bringing together government, industry, and academia to better understand the infrastructure changes required at airports and airfields to prepare for hydrogen-powered and battery electric aircraft. The project focuses on the infrastructure changes required at different types of airports and airfields to enable the net zero transition. The planning, construction, installation, and operational implications for airports and airfields are significant, but the ZEFI programme will help the industry to plan for net zero aviation.
While hydrogen and battery electric technologies are key to decarbonising both aircraft and HGVs, there are some key differences:
- Vehicle technology maturity is much lower for aircraft.
- Whilst standardisation across Europe would be beneficial to HGV decarbonisation, the global interoperability of aircraft is even more critical.
- Aircraft are extremely weight sensitive and therefore the low energy density of batteries is an even more significant barrier to implementation.
- It is expected that liquid (as opposed to compressed gas) hydrogen would be required for aircraft propulsion, which is very energy intensive to keep cool enough to stay in liquid state. This adds to the lifecycle emissions and energy requirements of the system.
The elephant in the room (or on the runway) is that commercially viable hydrogen and electric aircraft alone will not enable net zero aviation by 2050. The larger aircraft which are required for long haul journeys, and aircraft not due for replacement in the near future, will need a different solution dubbed Sustainable Aviation Fuel (SAF). SAF is a synthetic fuel made from renewable or waste resources which offers huge carbon savings compared to conventional fossil fuels, but does not offer a zero emission solution. A combination of technologies and interventions is required to achieve the Net Zero 2050 target.
As part of the ZEFI programme, 15 projects have been funded under the first ZEFI Transport Research and Innovation Grant to accelerate hydrogen and electric infrastructure technologies towards commercialisation. Additionally, demonstrations will take place in 2022 showcasing UK technology and innovation in this area. We are engaging a wide range of stakeholders to inform forthcoming reports and case studies that airports and airfields can use to prepare for zero emission flight infrastructure.
Airports are transport hubs which offer a point of connection between modes. As such they need to support the net zero future of aircraft, road freight vehicles, passenger cars and public transport. Connected Places Catapult is working across all these areas and more, and through projects like ZERFT and ZEFI we spark new ideas, connect industries with innovative technology, and accelerate the transition to Net Zero.