IMechE returned to the Tottenham Hotspur Stadium in London last month (6-7 March) for Engineering Challenges in the Hydrogen Economy 2024, examining many of the key issues facing the sector with a wide array of speakers and attendees from across industry, academia and policy.
Here are five of the main challenges – and five potential solutions.
The main roadblock is the cost and speed of rolling out blue hydrogen, said Vamadevan. Unlike green hydrogen, which uses renewable energy to produce hydrogen through electrolysis of water, blue hydrogen is produced mainly from natural gas, requiring carbon capture and storage to trap carbon dioxide that is produced. “We see 5GW of new blue hydrogen coming into the picture, but we just don't see it scaling enough,” Vamadevan said.
Switching the energy system from fossil to non-fossil fuels needs to happen twice as quickly as it currently is if we are to meet net zero by 2050, he continued, and doing so will require a lot more hydrogen. Increased demand from electrification of fossil fuel-intensive sectors such as steel manufacturing and heating could provide much needed impetus to accelerate production.
The scale of the challenge is massive – but the UK’s rapid installation of offshore wind turbines shows that fast, widescale change is possible, Vamadevan said.
The challenge: Energy supply and demand are out of balance
A potential solution: ‘Power to hydrogen to power’
“Renewable energy is not as reliable and not as predictable as we would expect,” said Ghenadie Bulat, head of new technologies at Siemens Energy. With increasing electrification and growing demand for energy, this is a major challenge for the future net zero energy system – but hydrogen could be the “bridge” between unpredictable renewables and reliable energy supply.
The global energy technology company is exploring using hydrogen as an energy carrier, transmitting it through pipelines and using it to produce synthetic fuels such as e-methanol and ammonia.
Last year the firm also demonstrated another potential ‘bridge’, running a gas turbine on 100% hydrogen. Aiming to decouple demand from supply, the Hyflexpower project successfully demonstrated a ‘power to hydrogen to power’ system in France, using renewable energy to produce hydrogen, storing that fuel, then powering a 12MW gas turbine and returning green electricity to the grid.
While it was a success, the project also demonstrated the engineering and policy challenges for such a system. Despite being the best available when the project started in May 2020, the chosen electrolyser would have needed to operate for 55 hours to generate just one tonne of hydrogen – which would power the turbine for approximately one hour. Larger turbines could require 45 tonnes of hydrogen per hour.
“We use nine tonnes of water – eight tonnes of oxygen is generated to generate one tonne of hydrogen. The magnitude of the problem is quite blunt,” said Bulat. “If we are to move that conversion of electrons into molecules and back into electrons via gas turbines, we do need to store the molecules somewhere and somehow, and it's not going to be easy. From a gas turbine perspective, we are ready.”
The challenge: Aviation is not ready for hydrogen
A potential solution: Regulators working with industry and academia
Today’s aeroplanes and airports are not ready for what could be the most promising route to zero-carbon aviation. All aspects of the vast global industry will need examination and re-engineering, from the aircraft – rehousing fuel from the wings to the fuselage to handle heavier cryogenic storage, for example – to operations – ensuring the purity of hydrogen fuel at airports, amongst other issues.
Thankfully, the Civil Aviation Authority (CAA) is on the case. Project leader Helen Leadbetter set out the Hydrogen Challenge, which aims to determine what hydrogen planes, fuelling and safety infrastructure will look like. Running until February 2025, the project is enabling collaboration between industry and academia to identify gaps in policy and regulation, and propose new recommendations.
Higher combustion temperatures, contrails at lower altitudes and different fire risks are all among the considerations, Leadbetter said. “When we are retrofitting an existing airframe, how does that work? And how does that ensure that we keep our passenger cabin safe and free from hydrogen leaks?” she asked. “These are all areas of consideration that we need to look at.”
The challenge: We need huge amounts of storage
A potential solution: Storing hydrogen under the sea
Of the major challenges in the hydrogen economy, sufficient production is likely the most significant. Storage is not far behind, however, and was the focus of several sessions on the event’s first day.
According to Hydrogen UK analysis, 3.4TWh of hydrogen storage will be needed by 2030, increasing to 9.8TWh by 2035. “Hydrogen will be essential to decarbonise, and therefore storage is going to be essential,” said Robbie McCreath, senior mechanical engineer at global engineering firm AtkinsRéalis.
Salt caverns and reservoirs are likely to offer the bulk of storage, he added, thanks to their inherent scalability and economic viability. One such project is taking place at the Rough reservoir off the coast of East Yorkshire, the UK’s largest gas storage facility. Energy company Centrica aims to gradually convert the reservoir into the world’s largest hydrogen store, installing new infrastructure by 2027 to store natural gas at a much larger capacity, and becoming ‘hydrogen-ready’ as the market develops.
“We'll be able to store hydrogen as it's produced, and then when it's needed in market when other renewable sources aren't available, we'll be able to then extract that hydrogen and use it in things like power generation,” said Beau Gray, project manager in Centrica’s energy transition team.
The challenge: We need a national transmission network
A potential solution: Project Union
With production and demand both set to rapidly increase in the years to come, we will also need new ways of getting hydrogen between producers and consumers. National Gas aims to meet that need with Project Union, repurposing and building up to 2,500km of pipelines to link up production and provide flexibility.
Stretching from Southampton in the south all the way up to St Fergus in Scotland, development of the network will start with East Coast Hydrogen, which could connect over 7GW of hydrogen production by 2030. Pipes will be repurposed from 2026 to 2029, and by 2031 the project could have 330km of pure hydrogen pipeline.
Learn more about projects integrating low-carbon energy sources, carbon capture and hydrogen production at IMechE's Decarbonising the Industrial Clusters event (16 April). Book your tickets now.
Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.