The use of hydrogen for fuel, also known as the hydrogen economy, is a concept that has been around for a while. Due to the aggravation of climate change, the need to reduce greenhouse gas emissions, and the necessity to achieve energy security, one aspect of this economy has been gaining widespread attention in recent years: green hydrogen. This term describes the process in which renewable energy sources such as solar, thermal or wind are used to generate electricity using hydrogen, contrasting with grey hydrogen (produced using fossil fuels emitting carbon dioxide) and blue hydrogen (produced using natural gas and storing carbon dioxide). Currently, countries including Chile, Japan, Saudi Arabia, Germany, and Australia are leading the charge in the race to find efficient, affordable and sustainable ways to use green hydrogen technology.
Hydrogen is the lightest, and the most common element in the universe, making up around 90% of its mass. On earth, its omnipresence cannot be overstated, as it can be found in water, living beings, fossil fuels and other organic matter. Despite its abundance on earth, it is never found alone, but rather in combination with other elements such as oxygen, carbon or nitrogen. Thus, to be used in its pure form, it has to be separated from other elements. But there is one major problem: the separation process requires energy.
There are many methods to produce hydrogen. The preferred and most environmentally friendly method of producing hydrogen is through a process known as electrolysis. Since water (H2O) is made up of hydrogen (H2) and oxygen (O) atoms, an electrical current is passed through the water to split it into hydrogen and oxygen.
One of the main advantages of green hydrogen is that it is a flexible energy source that can be used in a wide variety of sectors that are proving hard to decarbonise, namely, the transport sector, heavy industries such as steel production, and electricity generation sectors. The assimilation of green hydrogen in these sectors would support the reduction of their heavy reliance on fossil fuels.
Another advantage of hydrogen is that it weighs less than air and filling a tank can be done in a matter of minutes. A rather large improvement over the hours that it can take to recharge a battery. To address the elephant in the room, a clear drawback of green hydrogen is the use of electricity from renewable energy to compress a gas that would itself generate electricity, giving the appearance of a redundant process. However, in a context in which there is a surplus of electricity generated from renewable energy sources, green hydrogen could be used in areas in which it holds an advantage over electric batteries.
What strategies to pursue
Current research shows that hydrogen does not appear to be clearly a better alternative to simpler sources of energy such as solar or wind. However, there are two potential applications in which hydrogen is poised to become very efficient: long-haul transport carriers (aviation or oceanic shipping) and storage. Elon Musk's characterisation of hydrogen as a foolish idea is understandable when one examines its applications in the automobile industry. Although electric batteries take longer to charge than hydrogen-fueled vehicles, hydrogen's advantage over long distance travel dissipates for personal use: one might need to travel over five hundred kilometres to justify the use of hydrogen over an electric battery. Over long trajectories, however, hydrogen's weightlessness and higher energy density compensate for the size of the container required to store it, making it a more attractive option than electric batteries. However, it is hard to foresee Namibia having the necessary level of investments and capacity to produce these hydrogen-fueled airplanes or trucks for trade in the near future.
Conversely, the second very appealing application of hydrogen for powering human activity is where policymakers and investors should set their sights: energy storage. In this case, hydrogen could be a great alternative to cases in which renewable electricity generation cannot keep up with demand. Succinctly put, whenever there is excess solar or wind, that electricity can be used to electrolyze hydrogen and store it. For this process to work, excess supply of renewable energy needs to be generated. In this regard, Namibia is known for being one of the most sun-lit locations worldwide, as it receives between 300-340 sunny days per year. In addition, the more than 1 500 km long Namibian coastline allows for enormous potential for wind turbine installation, adding a second source of renewable energy generation. Overall, the possibility of a large-scale harnessing of both solar and wind energy paired with existing techniques for generating green hydrogen can truly be seen as a match made in heaven.
One of the challenges experienced when it comes to exporting electricity is the dissipation of energy that occurs when transporting it from a location to another. For instance, wind turbines on the Namibian coast can be far away from major demand centres such as Windhoek, leading to long distances from the grid. This problem is exacerbated with exports to other countries, where the excess electricity would need to be carried through the grid through transmission lines. If Namibia wants to be a net exporter of energy, hydrogen could be a way of overcoming this issue. For one, it would take out the need to build hundreds of kilometres of infrastructure to transport renewable energy from one spot to the next. This is because hydrogen can be transported under a compressed form in canisters, thus not requiring physical infrastructure to transfer the electricity.
Secondly, the long-distance travel of electricity generated from (for example) a wind turbine in the Namib desert to a household in Angola would lead to energy dissipation. In addition, electricity generated in real time would need to either be stored in a battery or consumed immediately. Since electricity generation from renewable energy sources is an uninterrupted process, excess supply (where demand is lower than supply) of electricity could be used to generate hydrogen via electrolysis, successfully storing that energy. Once this "excess" energy is stored in canisters, the possibility to export it to neighbouring countries opens up.
Another potential issue refers to the main input required for electrolysis: water. According to Kudakwashe Ndhlukula, the Executive Director of Southern African Development Community (SADC) Centre for Renewable Energy & Energy Efficiency (SACREEE), water scarcity constitutes the main challenge to the development of this technology. Indeed, Namibia is an arid to semi-arid country, with a serious water deficit. With its presence above ground being low and rainfall being erratic and increasingly unpredictable, water scarcity is a serious and longstanding problem in the country. To make matters even worse, projections are now showing that by 2025 the Southern African region, which includes Namibia and neighbours Botswana, Angola, and South Africa will be even drier.
Although betting on a future solely powered and dependent on green hydrogen might be very unlikely, its weightless properties, promising potential for storage and transport and the fact that it is completely nonpolluting puts it at the forefront of alternatives to fossil fuels.
* Enzo Boccara is an economist interning at UNDP Namibia and Paulus Ndinoshiho is a natural resource scientist.