Global demand for hydrogen is set to grow exponentially over the next decade with the fuel poised to become a major player by 2030. In 2015, the global demand for hydrogen was estimated to be about 8 exajoules (EJ). The current market for hydrogen as feedstock has an approximate value of about USD 115 billion and is expected to grow rapidly to an estimated value of 155 billion by 2022. This market growth would entail a large increase in production volumes, and, with current production methods, would result in a substantial increase in GHG emissions. 95% of hydrogen being used today is sourced from fossil fuels through steam-methane reforming (SMR) and oil and coal gasification – production pathways that are extremely emissions-intensive.
In a world grappling with the effects of climate change due to anthropogenic activities, this is simply not feasible. Hydrogen produced via electrolysis presents a potential solution to this issue as electrolysers can be powered by renewable energy sources like wind and solar, making hydrogen a clean fuel and an avenue through which variable renewable energy can be stored and distributed globally.
Green hydrogen from electrolysis could be the solution, but it comes at a significant cost
From the looks of it, hydrogen from renewable energy via electrolysis seems to be the natural solution to a lot of the major environmental issues related to current hydrogen production pathways, and although only 4% of current hydrogen production is through electrolysis, this share is expected to increase significantly over the next few years. But, the process of electrolysis requires the use of large amounts of freshwater to produce hydrogen. With acute water shortages being faced by both developed and developing nations all over the world, if hydrogen has to power our cars and cities, electrolysis with freshwater is simply not feasible on a large scale. But what if hydrogen was produced by electrolysis through seawater instead of freshwater? This would decouple hydrogen production from a critical resource like freshwater, and, in theory at least, would make this fuel truly sustainable. Saltwater electrolysis however, causes very quick erosion of the electrodes of electrolysers due to the production of sodium, chlorine, calcium and other components, and results in such a process being unfeasible. Well, at least, this was the case, until now.
Recent developments have demonstrated that saltwater electrolysis is feasible
Research and development by various institutions in this area has yielded promising results and concepts which have the potential to make saltwater electrolysis a commercial reality in the not-so-distant-future. In one study, scientists have developed a new oxygen reaction evolution catalyst using transition metal-nitride that manages to avoid many of the obstacles that have prevented earlier attempts at effective saltwater electrolysis. This method also allows hydrogen to be produced from wastewater – opening up another source of hydrogen from water that is otherwise discharged as waste and is unusable without costly treatment methods. This pathway for producing hydrogen is capable of achieving electrical densities capable of supporting industrial requirements while requiring relatively low voltage to start the process of electrolysis.
In another breakthrough development, nickel-iron hydroxide was layered on top of existing nickel sulphide in order to repel chloride and slow down the decay of the underlying anode material. This has resulted in the life of the electrode being extended to more than a thousand hours, from 12 hours for standard saltwater electrolysis. The method also generates 10 times more electricity, resulting in hydrogen being produced at a much faster rate, at current levels the same as what is used in the industry today.
Hydrogen is poised to fulfil it’s true potential but it needs help via investments and supportive policies
From the above examples it is pretty evident that the potential for commercially viable solutions to many challenges faced by saltwater electrolysis exist and has been proven through various scientific demonstrations in recent years. Furthermore, once the extracted hydrogen gas is used as fuel, the hydrogen and oxygen will react together to from a very useful by-product: pure water. Now imagine a situation where hydrogen is produced from renewable energy via electrolysis of seawater and when this hydrogen is used as fuel, a precious commodity like pure water is formed as a by-product. In a future where rapid economic and population expansion will place an increased amount of stress on finite natural resources, hydrogen could have the potential to solve 2 significant problems through one, highly sustainable process. The onus now falls on public and private entities worldwide to commercialise these production pathways and enable hydrogen to fulfil its potential as a game-changer in the global fight against climate change.
