The aim of GH2 is to replace fossil fuels with hydrogen in a range of modes of transport in Galway City and County – trucks, buses, and eventually, ships and airplanes. “This is achieved through electrolysis, in which electricity splits water into hydrogen and oxygen.” Hydrogen has often been dismissed as an energy-intensive product, but Monaghan assures that renewable electricity is used to create the hydrogen for GH2. “Since GH2’s electricity will be renewable,” he says. “So will the hydrogen. This is what is commonly called ‘green hydrogen’.”
How is hydrogen produced?
Monaghan compares green hydrogen to a ‘chemical battery’ for renewable electricity. “Ireland is a world leader in generating electricity by wind,” he says. “Our efforts to decarbonise energy currently have four key strands: (1) encourage and incentivise behavioural change towards less energy-intensive practices (think higher carbon taxes, more cycle lanes, better bus services), (2) reduce demand for energy through efficiency measures (think deep retrofits), (3) electrify as much of the economy as possible (think electric vehicles and heat pumps) and (4) increase the amount of renewable electricity supply from wind, solar and other sources.”
With world-class wind and ocean energy resources, Ireland is succeeding in decarbonising electricity. “Decarbonising the direct use of fossil fuels in heating, transport and industry, which together make up 80% of Ireland’s energy use has proven much harder,” says Monaghan. Green hydrogen offers various benefits. Firstly, it contains much more stored energy for the same weight of batteries. “This is crucial for heavier vehicles travelling long distances like buses, ships and airplanes. Hydrogen vehicles are also fuelled much faster than electric vehicles are charged,” he says. Secondly, hydrogen allows for “higher temperatures demanded by industrial processes.” And lastly, the technology offers large-scale, long-term energy storage and transmission. “As Ireland moves from a system where electricity comprises 20% of energy end-use (40% of which is renewable) – to one in 2030 where electricity comprises 50% (80% of which is renewable) – the need to store renewable resources is clear. Green hydrogen provides a long-term solution.”
Monaghan is particularly fascinated by recent improvements in electrolysis, including the direct use of sunlight to split water. “This is being studied by Dr Pau Farras in Chemistry at NUI Galway. An Irish company, dCarbonX, is also developing new technology for storing hydrogen underground for perfect geology.” When it comes to hydrogen uses, he foresees radical changes in aviation and shipping. “Will planes and ships burn hydrogen in engines or turbines? Will they use fuel cells to reverse the electrolysis process and power electric motors? Or will they combine hydrogen with sustainable carbon dioxide, producing “electrofuel” chemically identical to the fossil fuel it replaced?” “It’s a great time to be an engineer or scientist,” he says. “There are innovations in every direction.”