JOHANNESBURG (miningweekly.com) – Platinum provides an exponential improvement in the performance of electrolysers used to produce green hydrogen, says Hydrox Holdings CEO Corrie de Jager, who describes platinum’s uplift as being “amazing”.
“We tried a smattering of only 9% platinum and it provided a tremendous improvement in the electrolytic performance of the system,” De Jager told Mining Weekly. (Also watch attached Creamer Media video.)
“Suddenly, you get much higher current density when using platinum, which is what you want, a small unit with high current densities, so that you can lower your capital costs further.
“You can build a smaller system and bring the costs down. That’s on the capital side. On the operational side, the closer your electrodes can be, the higher the efficiency, and the less power they will consume, and that’s why we’re excited about the whole process.
“If you go from 1.7 V to say 2 V, it’s exponential. It’s just amazing how the platinum suddenly increases efficiency. It’s just ‘wow’. It’s mind-blowing,” De Jager added.
As reported by Mining Weekly in March, Hydrox, which is sponsored by Shell Energy, achieved a Proudly South African world first by building a hydrogen electrolyser at its Strydompark, Randburg, Johannesburg, premises, using its homegrown divergent electrode flow through (DEFT ™) technology, which allows electrolysers to operate without membranes at higher temperatures. This results in greatly improved electrical efficiencies, and promises to lower the production price of clean hydrogen, demand for which is growing by leaps and bounds globally.
A stroke of Hydrox genius was to innovate by perforating its electrodes, without any membrane or diaphragm in between. The flow of hydrogen and oxygen through the two perforated electrodes separates the hydrogen and oxygen gases from migrating or crossing over.
Nickel, not platinum, has been the main electrode metal used: “We really couldn’t afford the platinum. I must say, when we tested with platinum, we had to send our electrodes over to America and the guys plated the platinum on for us and sent it back, and it didn't really last.
“But in the short spell of time, we got the reports back that were just amazing. We got over an amp back, 1 100 milliamps per square centimetre…normally you work at 200 milliamps, and we got a 1 100 milliamps per square centimetre back, on the performance level, from a little bit of platinum. And this is what we’re going to look at. What is the optimum. Platinum is obviously expensive so you’ve got to look at what’s the least you can use, and there are other metals associated with platinum that can actually tie in with platinum. Molybdenum is one and there are a couple of others, not expensive, but they can all play a part. Iron can play a part, but it’s got to be worked out, it’s got to be experimented.
“We know how to do it, and we know how to get it to last, and how to get it attached to our electrodes. Also, we’re looking at different kinds of electrodes now, more surface area. It’s just amazing what we can do with our flow through system now, and if we can get the catalyst on there, boy, we’re going to blow them away. It’s going to be mind-boggling, and then we’ll have efficiency second to none,” De Jager enthused.
Electrolysis electrochemically splits water into hydrogen and oxygen and for more than a century, electrolysers have been limited to lower temperatures and pressures, with electrolysis basically being undertaken using some or other form of membrane to keep the gases separate.
Now the world has a new local system, which has been achieved with the financial support of the Gamechanger programme of petroleum giant Shell, which provides businesses with seed funding to advance unproven early-stage ideas that have the potential to enhance the future of energy.
Support from Shell has been vital to Hydrox, which is a recipient of South Africa’s National Science and Technology Forum Award for Innovation.
DEFT ™ can use fluctuating currents: “Apparently, no other electrolyser can do that. We’ve tested from, say, 200 milliamps to 20 000 milliamps, 20 amps, per square centimetre, and we still get separation, obviously, we don't go that high, because it will break the system apart, with all the shocking effects, but we can use the fluctuating currents in our system, and we’ve tested it now as part of our Shell project. We’ve tested that so we can use the fluctuating currents from renewables.
“We’ve still got to link it to a wind farm or a solar plant and see exactly what it does, but in theory, where we’ve tested it with the on computer, this is what’s exciting and it’s another possibility, because we don’t have the membranes. Our gas bubbles travel over a very short distance. This is what’s so exciting about our technology. It’s so simple. It works so well; it’s got lots of potential. So, yes, fluctuating currents, renewables, it’s a great match,” said De Jager.
Standard electrolysers use a heat exchanger system to remove excess heat so that it does not supersede the maximum operating temperature of the membrane. But with DEFT ™, this excess temperature can be ‘locked’ into the system to improve system efficiencies, resulting in lower operating expenditure and hydrogen costs. The new system can also handle fluctuating currents, which makes it ideal for renewable energy and ‘green’ hydrogen.
These are the written replies that Hydrox gave to questions put to it by Mining Weekly:
Why has Hydrox been so obsessed about creating membraneless electrolysers?
Membraneless electrolysis has for many years been attempted by many scientists as it opens the way to lowering the cost of electrolysis. Eliminating the membrane and its associated supporting components not only allows for a capital cost reduction but also for greater operational flexibility. Membranes/diaphragms have a limited operating temperature. Going beyond this setpoint has an effect on the lifespan of the electrolyser and on the purity of the gas it produces. Membraneless operation does away with these limitations, giving rise to the potential to operate at more efficient operating conditions, such as high temperatures. Some conventional units can waste up to 40% of the electrical input owing to heat production/removal. Our passion for membraneless systems stems from the fact that our unique patented approach resulted in the development of the world’s first fully functional membraneless electrolyser. All other kinds of membraneless technologies are still in the experimental stage. It is pleasing to note that our technology is being referenced in scientific publications. We are currently working on optimising our unit to surpass the performance of conventional systems as it is our aim to be a leading hydrogen solutions company that can unlock green hydrogen.
How does Hydrox’s technology work and who will buy it?
All electrolysers use two electrodes, oxygen is produced on one and hydrogen is produced on the other. In order to keep the oxygen and hydrogen gases separated some kind of membrane or diaphragm is required. These membranes/diaphragms, however, are not very conductive and hence add to the resistance of the cell. Hydrox has gone against the conventional way of thinking by employing diverging electrolyte flows exclusively through perforated electrodes. Injection into the centre of the electrode gap has allowed us to keep the produced hydrogen and oxygen gases separate and essentially the gases are swept away from one another employing liquid flow. This allows for the operation of an electrolyser that does not make use of a separating membrane/diaphragm without a large increase in cell resistances. The target market is any industry/sector that can benefit from low-cost decentralised hydrogen production. This could include production as a feedstock into industries such as refineries or petrochemical producers, production for the mobility market, fuel cell vehicles, such as trucks, industrial vehicles for mines, or high capacity flexible energy storage for renewable energy farms. We are even getting enquiries from the farming sector to replace their current unreliable energy provider.
Why is the world moving towards the use of hydrogen?
Hydrogen has always been an important building block in chemistry. Almost every organic molecule contains hydrogen thus forming an important part of organic chemistry. Most of the fuels we use are organic and thus contain hydrogen. This is important as hydrogen can be used to manipulate and change fuel types. With hydrogen as a building block, reactions with available carbon and oxygen can form many of the fuels we use today. Hydrogenation reactions (reactions with hydrogen) are important to industry, often used to form valuable products from process byproducts. Hydrogen is widely used to form ammonia ,which is vital to the agricultural industry. In the mining sector, it can be used as a reducing agent in refineries to extraction metals from their oxide forms. There are several important hydrogen-related processes which form part in the manufacturing of many of the chemicals and materials today. Beyond the use as an industrial feedstock, hydrogen is one of the most energy-dense fuels by mass, carrying an energy density of 39.4 kWh/kg. With the combustion of hydrogen, or its use in a fuel cell, the only emission that results is that of water. Hydrogen produced from a renewable energy source results in an energy-dense carbon-free fuel with the potential of zero-emissions upon use.
What are the factors leading to the demand for green hydrogen?
Renewable energy sources, such as solar, wind, geothermal, and hydropower represent a promising alternative approach to energy production amidst growing concerns about diminishing fossil fuel reserves and harmful emissions contributing to global warming. Renewable energy sources are unfortunately intermittent, therefore, for renewable energy to re-shape the energy sector, effective energy storage mechanisms need to be in place. For widespread adoption of renewable energy sources, energy storage methods need to offer more flexibility and higher storage capacities. For renewable energy to reshape the transportation sector, long haul modes of transportation require an energy storage mechanism that has a superior power-to-weight ratio compared to what is offered in existing storage methods. Decentralised green hydrogen production is a viable solution. Low-cost decentralised hydrogen will benefit wider society by unlocking renewable energy, allowing for the transformation of industries which currently contribute to global emissions and accelerate the rate of global warming. Decentralised electrolysers, operating off renewables are the answer to a cleaner and more sustainable future. It is the key to unlocking a world that is not reliant on carbonaceous fossil fuel. Hydrogen can be utilised for remote/rural energy storage, high capacity energy storage from renewable energy farms, as a means of transporting renewable energy, and in turn, fuelling different modes of transportation. Additionally, hydrogen is a reactant in producing carbon-neutral conventional fuels and high energy density liquids. Electrolytic hydrogen can be combined with carbon dioxide extracted from the air or point sources to produce methanol and other fuels through the Fischer Tropsch process.
Water is a scarce commodity. Where does Hydrox envisage sourcing it to produce hydrogen from it?
Electrolysis does use water as a feedstock, however not as much as one may think. Nine litres (L) of water are capable of producing 1 kg of hydrogen, which has an energy density of 39.4 kWh/kg. For example, assuming South Africa dedicates its entire 52 GW of power-producing capacity to hydrogen production leaving no power for anything else. The system would consume roughly just over 200 ML of water. It is estimated that irrigated agriculture utilises 28 000 ML of water per day. Even in the extreme case of consuming all of South Africa’s power, the water consumption of electrolysis systems seems very manageable. It is estimated that a single person in South Africa consumes roughly 230 L of water per day. This amount of water could produce 25 kg of hydrogen with an energy capacity of 985 kWh, which could very well power their household for a month. Further to this, if there is a need for it, water feeds can come from grey water or saltwater sources with simple and energy-efficient water purifications systems installed in conjunction with the electrolysis system. Once hydrogen is used in a fuel cell, it recombines with oxygen to become water again.
Why not just burn coal to get the hydrogen, as Sasol has been doing since 1950?
Coal’s single big advantage is its abundance making it also the most cost effective form of energy but the downside is that coal is also the worst polluter of all. Even if the hydrogen is extracted from it, vast quantities of carbon dioxide are still realised. It makes more sense to rather use the coal directly for power production, as is currently the case.
Hydrogen fuel cell technology is being held back by a lack of hydrogen. How can Hydrox Holdings help to solve that problem?
Hydrogen production needs to be decentralised in order to solve the distribution problem and its cost needs to become competitive to that of fossil fuels for the hydrogen economy to succeed. Currently the vast bulk of hydrogen is derived from fossil fuels and produced in centralised plants situated close to the natural gas sources. Although hydrogen is one of the most energy-dense fuels by mass, it is not very energy-dense by volume. As it is so light, a small mass occupies a large volume. This makes the transportation of hydrogen difficult and cost-intensive as large tankers, carrying hydrogen at high pressure, are required to distribute the hydrogen from the centralised plants. Water electrolysis offers the cleaner onsite, decentralised and on-demand production and feed solution which other means of production cannot. Ideally the power for this needs to come from renewable energy sources making it pollution-free green hydrogen. Onsite electrolytic hydrogen production also lends itself well to applications such as grid balancing and high capacity energy storage for intermittent systems. In the past electrolytic hydrogen production came at a high cost, hence, slowing its uptake in the replacement of existing technologies. The electrolysis market has developed rapidly over the past years and is at a point where applications exist that show favourable use cases and economics for the uptake of electrolytic hydrogen generation. Hydrox is actively working to drive the uptake of hydrogen by not only working to develop systems, such as membraneless systems to further reduce the cost associated with electrolytic hydrogen, but to become a hydrogen solution provider.
Why would competitively priced, accessible hydrogen open the way for fuel cell vehicles?
The world is moving towards a cleaner, more sustainable environment and the switch to fuel cell vehicles is hampered by the price and availability of hydrogen. Both fuel cell vehicles and battery-powered vehicles can reduce carbon emissions by offering higher efficiencies than combustion engines, and if connected to renewable energy sources, a fairly carbon neutral means of operation can be achieved. The public and industrial sector would only adopt this technology if it came at a cost comparable to their current means of transportation. The switch by mining houses to large fuel cell vehicles trucks is a boost to the hydrogen economy as a whole.
Could renewable hydrogen be used to turn Eskom green?
For Eskom to be entirely green it would need to abandon its coal-fired power stations and focus purely on renewable energy. Electrolytic hydrogen production can certainly help Eskom in carrying out its operations by assisting in grid balancing, which would result in less energy wastage and reduced emissions etc. Hydrogen does, however, lend itself to high capacity and flexible energy storage which is ideal for renewable energy producers as they are often intermittent, especially in the case of wind and solar. If Eskom were to turn its attention to the development of large-scale renewable energy production, hydrogen could provide a means of high capacity energy storage to make up for any power production shortfalls. This source of hydrogen may even be used directly in the conversion of coal-fired power stations to operate directly off hydrogen by generating high-temperature steam from specialised catalysts under development.
Could renewable hydrogen turn Sasol green?
The electrolytic production of renewable hydrogen allows for the formation of cleaner, carbon-neutral fuels. Carbon dioxide, extracted from the air or captured from point sources, can be reacted with electrolytic hydrogen to produce liquid fuels. The carbon dioxide can be reacted to form liquids such as methanol or conventional hydrocarbons through the Fischer Tropsch process. If Sasol were to adopt this technology, it would be able to produce many of their current chemicals products with a massive reduction, if not elimination, in emissions. Producing carbon-neutral fuels by this means is still, however, more costly. To be cost-competitive, a reduction in production costs of electrolytic hydrogen is required. Once this has been achieved, and due to the pressure provided by carbon taxes, companies such as Sasol are more likely to adopt this technology.
How is Hydrox funded?
Hydrox is a registered public company and its activities are funded by its directors and shareholders. Research and Development costs are extremely high and we are grateful to Shell Energy through its Game Changer Programme for providing the funding to complete our 5 kg unit. The next phase, to upscale and to commercialise, is going to be very cost intensive as we need to increase our capacities and we will be looking at equity investors to help us to raise the required funding.
What are your immediate goals after the success of the 5 kg unit?
Hydrox’s short-term goals are:
- the optimisation of the system to be much more efficient by improving the catalytic properties of the electrodes. Even a small addition of platinum is known to drastically increase the efficiency of the system and this needs to be balanced out with the overall capital costs. The much higher current densities will result in a smaller stack with a positive reduction in costs. The 5 Kg unit will then be ready for commercialisation; and
- our other immediate priority is the scaling up of our system to 100 kg/day as the cost of hydrogen can be further reduced through the economies of scale principle. There is a huge demand for these sized units and commercialisation is a high priority.
Our longer term goals are to develop the higher temperature properties of our membraneless technology in conjunction with an international consortium of scientists headed by the University of Iceland. This will open up the prospect of really cheap hydrogen as the electricity requirements will be drastically reduced through the improved kinetics associated with higher temperatures.
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