It is estimated that to produce one kilogramme of green hydrogen via electrolysis, about 10kg of water will be needed. Due to large quantities of deionized water that will be required for the development of Namibia’s much-hyped green hydrogen industry, seawater desalination will inevitably be needed to supply the required amounts of water.
A report sponsored by the German
research and education ministry, recommends the close monitoring and possible treatment of brine discharge due to its unconfirmed impact on the environment, including marine life. Brine is one of the by-products of desalinated water and the recent report recommends further investigations into
how a continuous discharge of brine will impact maritime.
The report, compiled by Robert Schmidt and Dr Daniel Frank from the Institute for Social-Ecological Research and DECHEMA, a non-profit tech research entity, noted
that although processed groundwater might be an option for the green hydrogen pilot projects, this will not be sufficient for a constant supply for green hydrogen production.
“No matter which technology is used, seawater desalination process chains, including pre- and post-treatment, not only produce deionized water, but also brine. General assumptions suggest that two to three litres of seawater are required for one litre of deionized water produced, if the most common desalination technology of
reverse osmosis is applied. This results in
one to two litres of brine that must be either further treated or discharged,” the report reads.
The report, released last month, further noted that prepared Environmental Impact Assessments (EIAs) for Namibia’s existing and near-term planned desalination plants give the impression that brine discharge has little or no impact on marine life and thus on fishing.
“However, they obviously consider
smaller quantities of brine than would be generated by the green hydrogen industry. Since the hydrogen economy in Namibia will expand over the coming years, the amount of brine produced and therefore the potential impact of brine on maritime life will grow in comparison to the current situation. Additionally, existing feasibility studies from Namibia focus on fish and not on bottom-dwelling creatures. It is known that brine from RO (reverse osmosis) can contaminate life on the seabed, depending on the discharge method (above or below the surface) as it has a higher density due to its salt load. Further, the impact of brine could be influenced by local current flows, as dilution in areas of high flows happens almost immediately,” the report reads.
In addition, Frank and Schmidt noted that on a global perspective, it needs to be evaluated how the future implementation of seawater desalination will affect maritime life, since more and more seawater is and will be needed as a water source for both municipal and industrial use, resulting in a larger brine discharge.
“In this evaluation, one must differentiate between inland seas and oceans, since the smaller the receiving water body, the higher its increase in salt load and the higher the impact of the brine onto the receiving water ecosystem,” the authors pointed out.
The report further stipulates that compared to total production costs of US$1 to US$3 per kg hydrogen in the future, the financial costs of desalination are little in comparison to the costs of hydrogen production itself.
One suggestion emanating from the report is to monitor the salt concentration and other physical-chemical parameters in the areas of discharge points from any new desalination plant.
“Additionally, it should be evaluated whether the occurrence of negative phenomena can be observed, such as H2S (hydrogen sulfide) plumes for example, which are prohibiting the continuous operation of the currently operating Orano desalination plant: brine discharge decreases dissolved oxygen and ultimately result in the formation of H2S plumes. It needs to be investigated in EIAs if these plumes can occur in other regions along the coastline,” the report adds.
Further recommendations to avoid potential impacts from brine discharge include implementing a system to dilute brine at the discharge points in the ocean, treating the brine onshore, using solar power to evaporate the water and recover the salt for further use or using the elevated Total-Dissolved-Solids concentration of the brine as feed-streams for new aquacultures.
“As the report deals with Namibia as a whole, follow-up reports are planned for the three hydrogen valleys mentioned by the Namibian Hydrogen Strategy: //Kharas, Erongo and Kunene. The follow-up reports will focus more on the existing and required infrastructure. Furthermore, they will look in more detail at the regionally affected marine systems and water supply,” said Robert Schmidt, part of the DECHEMA team.
Cleaner energy
As part of the drive to decarbonise its European refineries, in October 2023 Total Energies issued a call for tenders for the supply of 500 000 tonnes per year of green hydrogen. Last year, Shell announced its final investment decision to build Europe’s largest renewable hydrogen plant which is expected to produce up to 60 000 kilogrames of renewable hydrogen per day and will be operational in 2025.
“Multinational oil and energy companies operating in Africa need to demonstrate the same leadership in driving the transition to cleaner energy,” said President Hage Geingob last week at the Africa Energy Week in Cape Town. Geingob added that as oil majors announce African major discoveries, they should also announce corresponding commitments to build clean and sustainable industrial complexes on the continent.
“Doing so is essential to not only respect mother nature’s thresholds for bearing our unsustainable consumptive vices, but also to ensure that our natural resources are developed in a manner that maximise benefits for the African continent. Affordable energy for all Africans is an immediate and absolute priority. African countries have been working to ensure that our countries have access to energy to industrialise, to grow our economies and become dealers of hope for the largest demographic on the continent – our youth,” said Geingob. The Statistical Review of World Energy reported that in 2022, 85.6% of all electricity was generated using non-renewable sources, with coal and natural gas contributing more than half of the world’s electricity fuel sources.
However, Geingob pointed out that even as non-renewables clearly remain the dominant drivers of energy access, renewables, such as wind, solar, and geothermal, exhibited an extraordinary annual growth rate of 14.7%, in sharp contrast to the non-renewables, which only managed an anaemic 0.4%.
Calling for a robust energy mix to advance African economies, Geingob said the aim is to transform Africa from simply being a raw materials supplier for the rest of the world to a continent that actively uses its own resources, including energy, to ensure the continent’s economic development.
“Developed nations today are investing billions derived from hydrocarbon fuelled industries to subsidise cutting edge solutions to produce cleaner engines of growth. These subsidies and incentives, which are of course disproportionately deployed in developed nations, are undermining and in some cases totally undoing prospective business cases in emerging nations with the superior natural endowments necessary for the development of new green industries,” Geingob added.