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From date pits to ammonia: Developing clean and sustainable fuels
Exploring alternative engine fuels that are sustainable and don’t impact human health.
4 July 2023
Exploring alternative engine fuels that are sustainable and don’t impact human health.
As a society, we have known for some time that we cannot continue to use fossil fuels, due to the impact on global warming. Many alternative fuel sources have been previously suggested, but some of these would compete with food production and availability. Truly sustainable fuel options must consider the whole fuel life cycle, from the sustainable feedstock, to its conversion into a sustainable fuel source to run engines. In addition, sustainable fuel options must work efficiently and not have a negative impact on human health.
In response to the need to find clean and sustainable fuels that do not have other negative consequences, Dr Paul Hellier from UCL Mechanical Engineering is collaborating with a number of partners to explore different aspects of sustainable fuel production.
Together with his team of approximately 10 PhD students and his close working relationship with Professor Emeritus Nicos Ladommatos, Dr Hellier has worked with BP, Johnson Matthey, the Port of London Authority, the Advanced Propulsion Centre UK, the UK Health Security Agency and the World Maritime University in Sweden. He has also partnered with academics spanning other disciplines at UCL, including in biochemical engineering, structural and molecular biology, civil and environmental engineering, and chemistry. His work has been funded by a variety of bodies, including UKRI through EPSRC, Innovate UK, and UCL funds such as the UCL Global Engagement Funds.
Exploring fuel life cycles
“We’re trying to look at the whole life cycle of the fuel,” Dr Hellier explains. “We’re thinking about where it's coming from, the process to take it from that raw material to being a useful fuel, and then how it behaves once we get it in an engine.”
Dr Hellier has been working with partners in different contexts to explore viable, clean and sustainable fuels. “Fuels that we're going to start using quite soon, in the next five to 10 years, don't need to resemble current fuels,” Dr Hellier says. “They will come from a different starting point. They could be things like hydrogen or ammonia – literal zero carbon fuels. And so, if they're going to be different fuels, can we use that to our advantage?”
Dr Hellier believes ammonia has a lot of potential. The team has been able to test different types of fuels on various boats on the River Thames, through their partnership with the Port of London Authority. The results show that a mixture of ammonia and water does produce energy that is usable on ships. “We're hoping to follow up on that work with bigger industrial partners, who will be able to start deploying that on the scale of shipping worldwide,” Dr Hellier says.
The team has also worked with a range of waste products to see if they could be converted into fuel. One of these products was coffee grounds. Although the team proved it was possible to create fuel from coffee grounds, the cost and energy investment involved in drying the coffee grounds makes this currently unviable. But Dr Hellier applied this concept to date pits in the Middle East, and they found that biodiesel could be produced from the huge volume of date pits thrown away in this region. As a result of this project, there is now an ongoing process to commercialise the use of date pits for use as biodiesel.
Impact on human health
Dr Hellier and his team are focused on finding sustainable fuels that do not have a negative impact on human health, or cause other environmental issues we haven’t considered yet. “We have a responsibility to make sure that these new fuels don't make the air quality situation worse, and can hopefully improve it,” Dr Hellier says.
One of the ways the team examine this is through their work with the UK Health Security Agency (UKHSA). Along with toxicologists from the UKHSA, Dr Hellier is looking at links between the starting fuel composition and the health impacts of the particulate matter produced in engine exhausts. To do this, they trap soot from exhausts on filter paper, and measure the harmful chemicals present. The UKHSA is also able to expose the soot to human cell cultures to measure the health effects of changing fuel composition. Dr Hellier explains that the tiny particles in soot – known as ultrafines – can travel deeply into the lungs. “And when they do that, they can transfer chemicals into our blood, and some of those are toxic,” Dr Hellier says. “So we’re trying to establish the link between the health impacts and the fuel.”
Dr Hellier is also clear that in the current age, many things can be used as a source of energy. But selecting what should actually be used as a fuel source requires a more nuanced approach. “Everything has energy content,” Dr Hellier says. To make an energy source sustainable, it needs to fit with our infrastructures for burning fuels, and it has to be locally available. “The date project is a good solution for the Middle East, but doesn’t quite work for the UK, because we don't eat many dates,” he explains.
Taking this 360-degree view of creating sustainable and clean views is vital if we are to invest in energy sources that will genuinely help to solve our current problems caused by the use of fossil fuels. “Our research has helped to highlight that a broader range of fuels can be used,” Dr Hellier says. “That has helped fuel companies choose what kind of renewable fuels they're going to start making use of. What we do in the labs directly feeds into their thinking.”