When consumed – whether via combustion (burning) or through electrochemical processes in a fuel cell – hydrogen’s only by-product is water. It’s also incredibly energy-dense, delivering three times the amount of energy per kilogram compared to other fuels such as petrol, and has a broad spectrum of applications, from heating through to powering vehicles.

Professor Tim Mays from Bath’s Department of Chemical Engineering, who has been researching hydrogen since 2003 and is leading the University’s Future Fuels research beacon, explains:

Before 2019, when the UK’s Net Zero 2050 initiative came in for carbon emissions, hydrogen was seen as a rather nice, obscure, interesting, but not very practical area. But of course, after Net Zero came in, everyone went, ‘Wow, what do we do now?’ My research has since become very visible and popular.

Tim recently won a £400,000 UK Research and Innovation grant to set up a national research programme, UK-HyRES, and establish Bath as a UK Centre of Excellence for Hydrogen Research. Kicking off in April 2023, this will cover all aspects of hydrogen as an energy carrier, from production to storage and end use – all key challenges that need to be overcome.

While hydrogen is very clean at the point of use, its production at present is primarily carried out by reacting steam with natural gas – creating so-called ‘grey hydrogen’ if the resulting carbon dioxide is not captured. Not only is this energy-intensive, it also relies upon a fossil fuel with ever-declining reserves. One option is to capture this carbon dioxide to produce ‘blue hydrogen’. However, the environmental ideal is ‘green hydrogen’, made either by the thermochemical treatment of biomass or, more commonly, by splitting water into its constituent parts of hydrogen and oxygen through a process called electrolysis, powered by electricity from a renewable source.

Currently, the UK doesn’t produce a lot of green hydrogen – although the South West’s first production facility is set to open at our new Institute for Advanced Automotive Propulsion Systems (IAAPS) research facility in 2023. One of the areas Tim will focus on includes expanding hydrogen’s use as a ‘buffer fuel’ to store energy when supply from renewable sources outstrips demand. He explains: “If you have the Sun shining all day, but you don’t need a lot of electricity consumption, what do you do with the excess? You can electrolyse water and generate hydrogen.”

Storing hydrogen also throws up its own hurdles. As it’s an incredibly light element, you need a lot of it in terms of volume. Powering your car, for example, might only take 5kg of the stuff – but in normal atmospheric conditions that’s 60m3. This means that, to store it efficiently, you need to either compress or liquefy the gas.

Tim says:

There’s a lot of energy spent on densifying hydrogen and there’s a lot of energy and investment in materials to keep it there. But you need to weigh that up against the benefits of the lower storage volumes.

Tim is working alongside several industrial partners, including GKN Aerospace, Siemens Energy and ITM Power, to ensure that the research will make a real-world impact. He concludes: “We will make sure that, while our projects are fundamental academic work, industry will help us to co-create them so there are tangible impacts including carbon reduction, lower costs and potential commercialisation.”

Professor Alison Walker from our Department of Physics is working on enhancing solar power technology using thin films of materials called perovskites to convert the Sun’s energy into electricity very efficiently. Professor Petra Cameron’s group in Chemistry, with whom Alison collaborates, are undertaking experimental studies on this type of solar cell.

Alison explains:

The point about perovskite cells is that they’re cheap to make. They’re also low-budget in terms of the energy you need because you can produce them at low temperatures. With silicon, which is currently widely used, you have to purify it at very high temperatures.

The current issue with perovskites, however, is that they degrade quickly in comparison to traditional silicon solar cells – after around one year instead of 25 years, although this lifetime depends considerably on the type of cell and is constantly being improved.

This degradation is caused by the way in which electrical charges move through the cells to generate electrical power and is affected by the cells being soft and easily deformed. Alison and her team are using computer models and machine learning to identify and better understand how these charges move, so they can suggest ways of reducing degradation when designing new perovskite cells. This increased longevity will in turn make them more cost-efficient.

She continues:

We’ve produced models, which are now widely used across the community, to explain how the charges created by solar illumination generate electrical currents. But these charges have to get out of the cell and into the circuit, and sometimes on the way out the generated electrical power is lost. So we are working on understanding those mechanisms with our models.

For now, stacking a perovskite solar cell on top of a traditional silicon solar cell boosts the energy output of the silicon cells. These stacked cells can be more quickly commercialised and are just a few years away from being widely available. However, Alison believes that her modelling will help to pave the way for all-perovskite cells.

Most silicon solar cells are currently produced in China, meaning that they’re not just energy-intensive to produce, but also need to be transported great distances. Alison’s hope is that ease of production will mean all-perovskite cells can be produced locally to their use, minimising carbon emissions. All-perovskite cells have other advantages, such as being lightweight and flexible, that will create applications for the cells.

Anna – who was part of the University's PPE production effort during lockdown – is leading a Developing Bath Beacon on zero-carbon offshore power. Her research takes concepts previously used in aerospace engineering and adapts them to tidal power, where she’s applying her knowledge of fluid mechanics to tackle underwater turbulence.

She says:

The tide is really predictable, which is great – on average the flow does what you’re expecting it to do. It’s not like with wind where you might get a day when the wind doesn’t blow. But on top of that very predictable average, you’ve got factors such as waves and the seabed not being flat, so you get a mess as the flow goes over the bumpy seabed. This turbulence is quite a big challenge for tidal power.”

Anna has recently developed a probe named the Barnacle – so-called because “you can stick it anywhere” – that’s cheaper, more robust and more accurate than those currently in use. It measures turbulence by comparing pressure readings from different sensors to model its flow. So far, the Barnacle has been tested in Northern Ireland’s Strangford Narrows, and Anna is hoping to carry out larger-scale trials using 20 of the devices.

One of the biggest problems caused by turbulence is its detrimental effects on machinery, such as the turbines used to generate tidal power. By developing more precise ways of understanding turbulence flow, Anna hopes that turbines can be developed to better withstand it – and that manufacturers can also give a more accurate estimation of products’ lifespans:

We want to be more certain about how long tidal turbines are going to last, because that feeds into cost models. If you’re not very certain, you have to be very pessimistic. Let’s say you think your blades will last five years and they last five months: you’ve got a big problem because you’ve suddenly got to buy loads of extra blades. If you think they’re going to last five months and they could have lasted five years, then you’re going to have replaced parts when you didn’t need to.

This greater certainty, she believes, will lead to wider buy-in on tidal power from industry: “You want to be as close to correct as possible.”

This is vital for us to be able to make use of the existing networks when integrating new tech such as electric vehicles. Monitoring the entirety of the UK’s electricity network would be a vast, prohibitively expensive undertaking. But Professor Furong Li from Bath’s Department of Electronic & Electrical Engineering, and Director of the Centre for Sustainable Power Distribution, has developed a method of predicting energy usage patterns for the last miles of electrical distribution system from just a small proportion of the network.

Furong has been working in partnership with network operator Western Power Distribution on developing an understanding of how low-voltage electricity networks can best cope with the future, low-carbon world. The Low Voltage Network Template project involved setting up monitoring equipment in 800 substations across South Wales.

Furong explains:

It was an area spanning from Newport to Swansea. In between, you have major industries; you have big cities, small cities and countryside. The questions we set out to answer were, do we need to monitor every single substation? Are there common patterns? Can we use readily available information to estimate energy usage patterns without expensive monitoring?

What Furong uncovered is that we don’t need to monitor every single distribution substation, which would cost over £1bn to install monitoring devices: “In fact, we can find ten typical patterns representing energy usage, including one designated to street lighting. Using these, we were able to use fixed information, such as customer mixes and the details of the network’s infrastructure to infer demand for a given area without the need to install monitoring devices.”

Understanding these patterns is particularly important in identifying any bottlenecks for the takeup of electric vehicles or heat pumps, to inform when and where demand management offers the greatest rewards for energy customers.

The ideal next step, according to Furong, is making consumers more aware of these fluctuations in availability, and even incentivising users with lower prices for green electricity when supply is at a peak.

"Fundamentally, we think smart meters are a bit boring as far as the customer is concerned,” says Professor David Coley from our Department of Architecture & Civil Engineering. “People lose interest relatively quickly.”

David carried out a piece of research where sensors were placed into 40 homes to track energy use. From this, he was able to deduce things such as the insulation level in the buildings and how people used windows.

He says:

We managed to predict things like how much money you would save if you used your windows differently. Most people know that leaving the lights on, for example, or a fridge door open or the heating on when they’re not there is going to use energy, but they have no idea of the cost of a window being open overnight.

He continues: “It’s also to make sure people don’t make incorrect choices and shut all their windows when at least one should be open, or get paranoid about the lights being on when actually it’s something else using energy.”

David’s work on educating people about the environmental consequences of their decisions includes the design of buildings themselves. He uses the Latin phrase defornocere, meaning ‘ugly through harm’, to describe the concept that our moral values should inform our aesthetic choices. If a traditionally ‘beautiful’ building is responsible for large amounts of carbon emissions, should we still consider it attractive?

In addition, David has also developed a free modelling tool called ZEBRA – or Zero Energy Building Reduced Algorithm. This enables architects to input their moral positions in terms of energy use and carbon emissions at the start of a building project, predict the building’s energy use and carbon footprint, to quickly see where the biggest issues are and adjust their design to reduce the harm the building will do. Thanks to Bath’s close links with the architecture industry and our placement students, David hopes that ZEBRA will soon be widely used in industry and other universities.

It’s not just designing our buildings that calls for careful consideration. Professor Marcelle McManus from our Department of Mechanical Engineering, Co-Director of the Centre for Sustainable and Circular Technologies (CSCT), has spent years investigating life cycle assessment. This technique examines every aspect of a product, process or technology to determine its environmental impact from start to finish.

For example, to calculate the life cycle impact of a cup of tea, you’d not only need to consider the electricity used to boil the water, but also everything from the materials used to manufacture the mug through to the air miles required to transport the tea leaves.

Marcelle explains:

Basically, with life cycle assessment, you’re looking at everything that goes into the system and everything that comes out of it, and you’re modelling the impact of that on the wider environment

“It’s important when we’re talking about renewable technologies such as solar and wind power, for example, and we talk about them as being zero carbon – they’re never actually zero carbon,” she continues. “Even though the Sun and the wind don’t have an environmental impact when used in energy production, the actual aspect of making the solar panels or wind turbines does. By using life cycle assessment, we can really understand where the impacts occur and how we can reduce them.”

Marcelle has worked with wind turbine companies to help them reduce the environmental impact of their products through steps such as increasing the amount of recycled aluminium in the turbines themselves, or minimising the amount of concrete used to lay their foundations. She also works with companies producing bioenergy and is exploring options for making new materials and power from waste emissions from large industry.

She is working to decarbonise industry and energy provision through the new Industrial Decarbonisation Research and Innovation Centre (IDRIC), where she is a Research Director.

She concludes:

A lot of the new technologies need to be built, and building them will produce a spike in greenhouse gases at the very time that we do not want this. How we overcome that is critical. We don’t want to be building a ton of solar panels or wind turbines and, in the process, emitting a huge amount of greenhouse gas.

“We’re halfway there in terms of the Net Zero target,” adds Tim. “But the next half is going to be about ten times as difficult as the first half.” We may have a long way yet to go, but here at Bath, we’re proud to be working towards powering a more sustainable future.