South Africa positions itself to go green using platinum group metals
Hydrogen and fuel cell technologies (HFCT) have received considerable attention in South Africa from a mineral beneficiation perspective. Platinum group metals (PGMs) are the key catalytic materials used in most fuel cells and, with more than 75% of the world’s known platinum reserves located in South Africa, there is great potential for socioeconomic advantages from beneficiating the country’s PGM resources.
The Cabinet-approved National Hydrogen and Fuel Cell Technologies Research, Development and Innovation Strategy (HySA strategy) is at the core of fuel cell technology development in South Africa. The strategy is intended to stimulate and guide innovation along the HFCT value chain, positioning the country to supply high-value-added products to both the domestic and international markets.
The three centres of competence established by the department of science and technology (DST) to implement the HySA strategy have made considerable progress in developing technology, human capital, and knowledge products such as publications and patents. The centres have also formed strategic partnerships with end users in the deployment of technology products. The partnerships provide a platform for technology testing and validation, in line with the second five-year phase (2014/15 to 2018/19) of the HySA programme. Technology demonstration is critical in the process of translating research and development outcomes from the laboratory into socially beneficial products and services, and in creating early markets.
Recently, a number of technologies in the HySA portfolio have gained prominence at a global level. Renewable hydrogen production from water through electrolysis, metal hydride hydrogen storage material, and liquid organic hydrogen carriers are potential game-changers in the area of hydrogen production, storage and distribution. This is a clear indication that the HySA programme is developing globally relevant technologies.
The use of renewable hydrogen and fuel cell technology to produce electricity has been demonstrated at Poelano Secondary School in Evaton. The 2.5kW HySA-developed fuel cell system, with renewable hydrogen production and storage on site, was launched by Minister of Science and Technology Mmamoloko Kubayi-Ngubane on April 13 2018, and is now a reliable source of power for the rural school. It is estimated that more 5 000 schools and clinics across the country have little or no access to reliable electricity. The 2.5kW fuel cell system will be capable of powering classroom lights and some computers in rural schools.
It should be noted that the modular nature of fuel cells makes it possible to combine similar units, with minimum changes to the balance of the plant, to make 5kW, 7.5kW or larger systems, as required. Given that many such facilities are located more than 20km from the Eskom grid, and that installing the required transmission infrastructure to some of these areas would be extremely costly, distributed generation is the most feasible way to provide power to many communities.
Globally, wind and solar photovoltaic energy are being used to power megawatt electrolysers to produce hydrogen as a viable way of decarbonising sectors, using hydrogen as an input chemical. The Hydrogen Council, a global initiative of leading energy, transport and industry companies that seehydrogen as a key solution in transitioning to a low-carbon, sustainable economy, envisages that by 2050 hydrogen will be able to convert and store hundreds of terawatt hours of solar and wind power. This will enable the deployment of green energy that might otherwise be lost, and allow international distribution from regions where renewable resources are abundant to regions that need to import energy. Given its abundant renewable resources and the success of the Renewable Energy Independent Power Producer Procurement Programme, South Africa could position itself to be a significant exporter of renewable hydrogen.
The 2015 Paris Agreement by the Conference of the Parties to the 1992 United Nations Framework Convention on Climate Change brought to the fore the role that hydrogen and fuel cell technologies could play in the decarbonisation of the energy and transport sectors in order to limit global warming. If the world’s temperature is not to exceed the agreed two-degree increase, energy-related carbon dioxide emissions will have to be reduced drastically (by 60% in 2050). The Hydrogen Council estimates that in 2050, hydrogen could power 25% of passenger ships and 20% of locomotives on non-electrified tracks, in addition to powering about 400 million cars, 15 to 20 million trucks and five million buses.
For this to be achieved, there will need to be significant technological advances in hydrogen production, storage and distribution. Hydrogen storage poses challenges to researchers owing to the size of the molecule. Significant quantities of hydrogen gas can be put in a container at high pressures or cryogenic temperatures in liquid form, but these are energy-intensive processes. Solid-state hydrogen storage using metal hydrides or hydrogen-absorbing materials has benefits in applications where weight is not an issue. A collaboration between the HySA Systems centre of competence at the University of the Western Cape and Impala Platinum has demonstrated that metal hydride hydrogen storage can enable a fuel-cell-powered forklift to operate at a pressure 150 bars lower than conventional systems. However, the need for reduced weight, and the challenges related to using high-pressure hydrogen underground, has mining companies looking at alternative methods of transporting hydrogen.
HySA Infrastructure, at North-West University in Potchefstroom, is pursuing the use of liquid organic hydrogen carriers (LOHC) as a safe way of using hydrogen in underground mining equipment. Under appropriate conditions, the carriers absorb hydrogen, allow it to be transported in liquid form at room temperature, and release it at the point of use. In a recent announcement, Anglo American Platinum (Amplats) chief executive Chris Griffith indicated that a fuel cell dozer that runs on hydrogen using the LOHC technology is expected in 2019. Such technology has the potential to reduce the cost associated with extracting diesel fumes from underground. Furthermore, LOHC technology could play a leading role in the renewable hydrogen export market.
Significant progress has also been made in applications where hydrogen compression is still a requirement. Electrochemical hydrogen compression, with no moving parts, is more efficient and cleaner than conventional mechanical compression. HySA Infrastructure has been at the forefront of developing this technology, both for compression and hydrogen separation from mixtures with other gases. In April 2018, Amplats entered into a strategic partnership on electrochemical hydrogen compression and purification technology with Shell Technology Ventures BV and the Netherlands-based HyET Hydrogen. The partners believe that the technology can reduce costs and increase the reliability of the production and storage of high-pressure hydrogen, which could lead to the wider deployment of public hydrogen refuelling stations for automotive applications.
Through the HySA programme, know-how and capabilities in game-changing technologies have been acquired and developed so that South Africa can be a significant player in the HFCT sector. However, there is still plenty of scope for further innovation to develop better performing materials in the form of PGM-based catalysts for fuel cells and electrolysers and LOHC technology, in line with the country’s beneficiation strategy. This is the domain of HySA Catalysis, based at the University of Cape Town and Mintek in Randburg.
The shift towards a less carbon-intensive energy mix is not unique to South Africa, but is a global phenomenon that South Africa has to accept and innovate towards in order to remain globally competitive. The country is fortunate to have the resources (both renewable and mineral) that are the essential components of these low-carbon technologies, and government’s foresight in establishing the HySA programme should be applauded.
Dr Cosmas Chiteme is the director: hydrogen and energy, at the department of science and technology