Hydrogen is the simplest, lightest and most abundant element in the universe. It is the first element on the periodic table, with an atomic number of one and a relative atomic mass of 1,00797 (in comparison, the second-most abundant element, and second on the periodic table, helium, has atomic number 2 and a relative atomic mass of 4,0026).

Normally a colourless, odourless gas, hydrogen becomes a solid – with metallic properties – when subjected to pressures 500 000 times greater than that of the earth’s atmosphere at sea level.

A standard hydrogen atom comprises one proton and one electron, although the element has two isotopes, deuterium and tritium. Deuterium is a naturally occurring isotope, composed of one proton, one neutron, and one electron – about one in every 6 500 hydrogen atoms is deuterium. Tritium is radioactive, with a half life of only 12,5 years, and is made up of one proton, two neutrons and one electron.

Hydrogen accounts for 93% of the total number of atoms, and 76% of the total mass of normal matter, in the universe. It is the fuel for most stars, including the sun – the huge temperatures and pressures in the heart of these stars cause hydrogen atoms to fuse together, creating helium and releasing heat and light. On earth, hydrogen occurs mostly in combination with oxygen, as water. And water covers some 70% of the planet’s surface. (Free hydrogen accounts for a mere 0,00005% of the earth’s atmosphere.)

Hydrogen is also the basis of a major South African science and technology research, development and innovation strategy, Hydrogen South Africa, or HySA, that was launched late last year, as the outcome of a process that started in 2005.

MORE BOUNCE TO THE OUNCE

Hydrogen burns, a fact spectacularly and tragically illustrated by the destruction of the German airship Hindenburg, at Lakenhurst, New Jersey, in the US on May 6, 1937.

(Theories first floated in the late 1990s that the airship was destroyed by the burning of its fabric covering have been refuted by experimentation.)

It is this flammability that makes hydrogen a fuel. Indeed, liquid hydrogen is one of the two elements that form cryogenic rocket fuels, the other being liquid oxygen. Technically, liquid hydrogen is the fuel while the liquid oxygen is the oxidiser. They are designated cryogenic because they must be kept very cold to remain in liquid form – in the case of hydrogen, at least at –253 ˚C, and in the case of oxygen, at least at –183 ˚C. This liquid hydrogen/liquid- oxygen combination forms the most efficient liquid rocket fuel. In the words of an information sheet issued by the US National Aeronautics and Space Administration’s (Nasa’s) John F Kennedy Space Centre (at Cape Canaveral, Florida), hydrogen “has about 40% more ‘bounce to the ounce’ than other rocket fuels”.

Such cryogenic fuels powered the RL-10 engines on the US Centaur rockets, and the J-2 engines employed by the second stage of the Saturn 1B and by the second and third stages of the Saturn V rockets. (The Saturn Vs were the rockets that launched the American Apollo missions to the moon). The liquid hydrogen/ liquid oxygen combination also powers the main engines of Nasa’s space shuttle (known simply as the space shuttle main engine or, SSME, although apparently meant to be designated RS-24 or RS-25), which is the most reliable large rocket engine ever developed.

Back on earth, gaseous hydrogen can be used as a fuel in internal combustion engines. In fact, it is not difficult to run an internal combustion engine on hydrogen. And, again, hydrogen has a superior energy-to-weight ratio to that of alternative fuels. What is difficult is to get such an engine to run well on hydrogen. For example, hydrogen requires very low energy to achieve ignition – much lower than for petrol – but this means it suffers from problems such as premature ignition and flashback, caused by hot spots on, or hot gases in, a cylinder. This is why, although hydrogen was used as a fuel in early experiments in the development of the internal combustion engine in the second half of the nineteenth century, it was replaced by petrol once the carburettor was invented. Still, the desire to achieve clean energy for transport has led in recent years to several motor companies developing prototype cars fuelled by gaseous hydrogen.

But there is another way in which hydrogen can be used as an energy source, for both transport and fixed applications. It is this alter- native which has led South Africa, a country which neither makes space rockets not has a significant automotive design sector, to launch the HySA strategy.

The alternative is fuel cells. Fuels cells directly convert chemical energy into electrical energy. Because they have no moving parts, fuel cells are quiet and reliable. They usually employ hydrogen as their fuel, and, what attracted South Africa, most fuel cells use platinum group metals (PGMs) in their construction.

FUEL CELLS

“An important component of most types of fuel cells is a PGM-based electrocatalyst. Proudly, within our borders we have more than 75% of the world’s known platinum reserves,” explained then Science and Technology Minister Mosibudi Magena at the launch of HySA on September 16 last year.

“With the global emergence of the ‘hydrogen economy’, it is envisaged the demand for PGMs will increase. Participation in the emerging hydrogen economy will enable South Africa to develop PGM-based manu-facturing activities, and create numerous socioeconomic opportunities for the country.”

In a typical fuel cell, gaseous hydrogen passes over a platinum electrode which contains a catalyst. This strips the electrons off the hydrogen atoms, turning the latter into hydrogen ions. These free electrons then travel along an external circuit while the ions proceed through an electrolyte (usually a solution) to another electrode. Oxygen is passed over this second electrode, and a chemical reaction involving the oxygen atoms, hydrogen ions, and free electrons takes place at this electrode. Electricity and heat are generated, and the waste produced is water (in vapour form). If the heat produced as well as the electricity is harnessed, a fuel cell in a static installation can achieve a fuel efficiency of 80%.

Regarding vehicles, Japanese carmaker Honda claims that its FCX Clarity hydrogen-fuel-cell-powered car has an energy efficiency of 55%. (The Clarity is being produced in small numbers and is only available in Japan and in southern California, in the US, and only on lease, owing to a lack of hydrogen infrastructure; it won the 2009 Green Car Award last month at the New York International Auto Show.) According to Honda, petrol-fuelled internal-combustion-engine-powered compact cars have an average efficiency of just under 20%, while the figure for compact hybrid cars is 30%.

Unfortunately, currently, fuel cells are expensive to produce.

And then there is the awkward question of how to obtain the hydrogen. It has to be separated out from other compounds, such as hydrocarbons – especially natural gas – or water. Various options are available, but all require energy, and that energy has itself to be generated. It is hardly progress if one has to use dirty sources of energy to produce hydrogen – under these circumstances, hydrogen can hardly be regarded as a clean and green fuel.

SA STRATEGY

HySA’s long-term aims are to create wealth for the country by developing high value- added manufacturing of PGM catalysts for the world fuel cell market, with a target of 25% of this market by 2020; to locally develop competitive processes for the production of hydrogen, using already existing South African expertise; and to increase local content in finished products, thereby increasing equity and inclusion with regard to the benefits provided by the country’s resources.

“This is a very significant programme,” Mangena told Engineering News last year.

“We don’t just want to dig holes in the ground and give the metals to other people. We’re looking at adding value.”

“What are the challenges regarding hydrogen?” asks Department of Science and Technology (DST) director-general Dr Phil Mjwara.

“They are the production of the hydrogen, the storage of the hydrogen, its delivery, and the manufacture of membrane electrode assemblies (MEAs).” (MEAs are key components of fuel cells).

These challenges are not going to be met quickly. “Our time horizon for HySA is 15 years,” he points out.

“HySA is still in its early days. In its first phase, we are considering three main issues. First, what competitive advantage does South Africa have? We can’t match US or Japanese investments in hydrogen. Second, what strategic partners can we find? We can’t go it alone. Third, we need to develop human capital in South Africa.”

The DST has already identified two very important competitive advantages possessed or already being developed by this country. Fuel cells operate through catalysis. And South African petrochemicals giant Sasol invests heavily in research and development (R&D) regarding catalysis.

“Catalysis is essential for Sasol,” highlights Mjwara.

“So, in South Africa, we have good expertise regarding catalysis.” Then there is the fact that South Africa holds 75% of the globe’s PGM reserves. (South Africa may possess a third competitive advantage – its pebble-bed modular reactor, or PBMR, nuclear energy programme. The PBMR will be able to be used in process heat applications, and process heat can be used to produce hydrogen. This would provide a nongreenhouse-gas-emitting hydrogen production capability.)

To build on, and further develop, this expertise, three centres of competence have been set up. These are the Centre for Competence for Catalysis, jointly hosted by minerals beneficiation research council Mintek and the University of Cape Town; the Hydrogen Infrastructure Centre of Competence, also jointly hosted, by the Council for Scienctific and Industrial Research and the North West University; and the Centre for Systems Integration and Validation, hosted by the University of the Western Cape.
The last named will seek to create small fuel cells using local materials and components.

“We hope to develop this expertise and capability over the next five to seven years,” says Mjwara.

The three centres will receive total funding of R15-million annually over the next three years in order to set themselves up – to recruit staff, obtain equipment, and set up infrastructure.

Each was asked last year to develop a long-term business plan, and all did so. These plans were then reviewed by a panel of overseas experts, who considered them fine, but lacking in coordination, and urged that they should be coordinated. The three centres have since revised their plans in order to achieve this coordination. The DST has approved R52-million for all three centres to service their business plans.

The DST is also in talks with companies in the platinum sector to set up a Catalysis Research Centre. This will involve cooperation between these companies and the Centre for Competence for Catalysis.

Meanwhile, the country is already developing international cooperation and partnerships to advance HySA. The head of the Centre for Systems Integration and Validation is internationally renowned Norwegian scientist Dr Oystein Ulleberg, who has been granted two years leave (from September 2008) by Norway’s Institute for Energy Technology to get the South African centre up and running. “A German company has already agreed to transfer technologies concerning MEAs to South Africa and to allow their manufacture here,” reveals Mjwara.

The DST is also actively seeking partnerships with institutions, agencies and companies in the US, Europe, and Japan. “In the US, the states of California and Massachusetts are investing a lot in alternative energy. President Barack Obama wants investment in alternative energy. Japan is spending a lot on fuel cells. The EU is also keen on fuel cells and is eager for South African researchers to participate in related research Framework Programme 7 projects,” he reports. “So we’re hopeful that the capabilities we are developing will fit into the US, Japanese, and EU programmes.”

The short- to medium-term intent of HySA is to develop and demonstrate technologies.

Only once this is done will major investments take place, to scale up to commercial size and production. Consequently, the current global recession is unlikely to have any damaging affect on HySA.

“HySA is going to boost science and technology in South Africa a great deal,” said Mangena last September. “It’s going to produce a lot of doctorates and master’s degrees. It is already exciting our scientists and researchers a heck of a lot. You can only train people by doing science – by having projects people can take part in.”