South Africa has the combined solar and wind potential to produce competitive hydrogen, which is emerging as an energy carrier that can meet the world’s new environmental requirements.
The country’s combined solar and wind power provide a hydrogen production capacity factor of close to 100% during daylight hours and 30% during the night, which is above the international norm of about 22%.
The plan is to electrolyse seawater close to a port for the hydrogen that is exported and to meet inland hydrogen demand from contaminated water sources, such as acid mine drainage (AMD).
The high energy costs normally associated with desalination enter a different context when electrolysis is involved. While about 50 kWh are required to electrolyse 1kg of hydrogen, only 3 kWh to 5 kWh are required to produce a cubic metre of desalinated water, which is equal to 1 000 kg.
A potential site is the Eastern Cape’s under-used deep-water Port of Ngqura, where the Coega Special Economic Zone (SEZ) already has a renewable power designation. The desalination plant could simultaneously provide water to the Eastern Cape, where water shortages arise from time to time.
As demand for hydrogen is building globally, the export potential of clean renewable hydrogen is also under intense scrutiny in South Africa.
Japan, which is known to be planning to import up to 800 000 t/y of hydrogen from 2030, has set a price level for that hydrogen of ¥30/m3, which translates into about $3/kg. From 2040, Japan wants the hydrogen it imports to be carbon free.
Council for Scientific and Industrial Research (CSIR) senior research engineer Thomas Roos calculates that South Africa has the potential to meet Japan’s 2030 price date and beat its carbon-free deadline by ten years.
Currently, South Africa earns a lot by exporting its energy coal, but this is projected to decline as the world opts for cleaner energy solutions to mitigate climate change. India, which accounts for more than 50% of South Africa’s current coal exports, has stated publicly that it is targeting coal self-sufficiency, which would mean that South Africa stands to earn less from coal exports in the future.
If South Africa could capture a 25% share of the estimated 800 000 t/y hydrogen demand from Japan, this would be a $600-million-a-year chance for South Africa to offset the decline in coal export earnings.
Although modelling shows that Argentina’s wind-intensive Patagonia region can produce hydrogen cheaper than South Africa, the shipping distance from Argentina to Japan is greater than the distance from South Africa and preliminary assessments indicate that South Africa’s combined generation and transport costs would be lower.
A study is under way under the auspices of Hydrogen South Africa (HySA) Infrastructure to determine the cost of transporting hydrogen by land and sea. The HySA programme falls under the Department of Science and Innovation, which provides funding and direction.
HySA Infrastructure comprises teams at North West University and the CSIR. HySA’s two other hubs are HySA Systems, at the University of the Western Cape, and HySA Catalysis, which is shared between the University of Cape Town and the State-owned minerals research organisation Mintek, in Randburg. Under scrutiny is hydrogen generation, hydrogen transport using carriers such as methanol, ammonia, liquid organic hydrogen carrier technology, cryogenically liquefied hydrogen, hydrogen storage and codes and standards.
When President Cyril Ramaphosa went to Japan as Deputy President in 2015, he drove a hydrogen-fuelled, platinum-catalysed Toyota Mirai fuel cell electric vehicle. At the time, Ramaphosa and Naledi Pandor, the then Science and Technology Minister, were attending the Japan South Africa hydrogen and fuel cell symposium.
Pandor, when subsequently launching a fuel cell forklift and hydrogen refuelling station at the Impala Platinum refinery, in South Africa, described the issue of hydrogen distribution from highly dispersed sources of production as being one of the bigger challenges facing South Africa in its development of a local hydrogen economy.
The main focus of innovative South African company Hydrox Holdings is to produce pure hydrogen from demineralised water at a price competitive with petrol, using membraneless technology.
Electricity consumption of 70 kW/h per kilogram of hydrogen needs to be reduced to below 60 kW/h. Energy from renewables will be of benefit, as will operating at higher temperatures and pressures.
Membrane-using electrolysers are limited to lower temperatures and pressures and an international consortium has approached Hydrox to explore the potential of high temperatures and pressures reducing hydrogen cost significantly. Hydrox’s membraneless divergent electrodeflow-through electrolyser technology faclitates operation at temperatures greater than conventional systems.
Initial testing indicates that costs of using brine and AMD are unlikely to deviate much from the costs of using demineralised water. Upscaling is the company’s priority at this stage, states Hydrox CEO Corrie de Jager in a note to Mining Weekly.