ZIVAI CHIGUVARE
Sustainable and local energy production and supply systems can catalyse the industrialisation of developing nations, such as Namibia. The Green Hydrogen (GH2) Strategy of Namibia aims to produce 10 to 15 million tonnes of hydrogen annually by 2050. Such production requires massive infrastructure, financial and human resource capital, as well as favourable legislation that protects investments and secures long-term offtake markets for the hydrogen.
Green hydrogen is produced by harnessing solar and/or wind energy through energy conversion technologies, such as photovoltaic cells and wind turbines, to produce electricity that is then used to electrolyse water. Electrolysis breaks the water molecule, H2O, into two atoms of hydrogen and one of oxygen. Since the Hydrogen ions are positively charged, they will be attracted by the negative electrode (cathode), while the negatively charged oxygen ions are attracted by the positive electrode (anode). In Namibia, a water-scarce country, the water will mostly be sourced from the Atlantic Ocean, and it must be desalinated and deionised before it can be used in electrolysis. Fortunately, Namibia has cloudless skies for more than 300 days a year, with insolation exceeding 5kWh/day, and has vast tracts of open land that could be used for large photovoltaic fields.
STRATEGIC ADVANTAGE AND ECONOMIC IMPACT
The bold political decision by the Namibian Government to develop a Green Hydrogen Economy has generated significant interest both locally and internationally. Not many countries have a good combination of favourable conditions such as those in Namibia, which is also centrally located and has operational ports to service the American, European and Asian markets.
The Green Hydrogen strategy aims to produce and export 10 to 15 million tonnes of Hydrogen per year by 2050. This offers increased local employment opportunities, both during the construction and operational phases. An estimated 15% of the construction roles required to establish the plants are expected to transition into permanent positions during the operational phase of green hydrogen plants.
Hydrogen is particularly interesting as a fuel because of the substantial amount of heat released when it recombines with oxygen. It releases heat energy more than three times that of petroleum fuels, by mass. As the lightest element, hydrogen has the lowest density, meaning even a small mass occupies a large volume. For economic storage and transportation, hydrogen must be compressed or combined with other elements, such as nitrogen, to form ammonia, which is easier to transport as a liquid.
HYDROGEN, THE GAME CHANGER
Hydrogen has numerous applications, including use as a fuel for heating. So, homes in cold countries such as those in Europe could be warmed by burning Hydrogen. It can be used in hybrid diesel combustion engines, as is already happening for heavy trucks, tractors and ships.
When passed through a fuel cell, the recombination of hydrogen and oxygen can produce electricity. Therefore, hydrogen can serve as an energy storage medium, facilitating the supply of baseload electricity from intermittent sources like photovoltaics. By deliberately oversizing the photovoltaic field, more hydrogen can be produced during the daylight hours and then converted to electricity after sunset. This allows for a continuous electricity supply.
The growing market for electric vehicles to abate carbon dioxide emissions in the atmosphere is a strong motivation for using hydrogen for mobility. Electric vehicles are already a proven concept, but they suffer from extended battery recharging times (approximately 3 hours), which can easily be overcome if, instead of storing energy in the battery, compressed hydrogen is used through a fuel cell to produce electricity. Refilling a Hydrogen tank will take a much shorter time, less than 5 minutes. Refuelling stations will need to be established, and such a concept has proven successful in Asia, Europe and North America. Cleanergy has established the first green hydrogen refuelling station in Walvis Bay, Namibia, and imported two hydrogen-diesel hybrid trucks and a tractor, as proof of the concept. Hyiron will be using green hydrogen in the reduction of iron oxide.
Besides using hydrogen to produce heat and electricity, its use in the production of ammonia, also a fuel, allows the proliferation of chemical industries such as those that combine ammonia with sulphuric acid to make ammonium sulphate fertiliser for agriculture. It is also possible to produce ammonium nitrate and ammonium phosphate fertilisers, boosting agriculture through locally produced fertilisers and potentially exporting them. The Daures Green Hydrogen village has proven that it is possible to practice desert agriculture in Namibia. Ammonia is also a common ingredient in most household detergents.
Hydrogen opportunities are endless, including the production of synthetic fuels, such as jet fuel.
Namibia has taken the right decision at the right moment in development, and it stands to boost its economy through the large-scale production of green hydrogen, an environmentally friendly fuel.
Dr. Zivayi Chiguvare is a Senior Lecturer of Physics and Renewable Energy at the University of Namibia, with a focus on energy systems, renewable energy, and nanotechnology. He is also the Acting Director of the Namibia Green Hydrogen Research Institute at the University of Namibia. His research explores topics like organic solar cells and energy access in Southern Africa, with a strong emphasis on participatory approaches to renewable energy potential.
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