There are many factors but, for both redox flow batteries and water electrolysis, cost and efficiency key. This means in the first place economies-of-scale. Both technologies are based on our large cell design and on our electrolysis technologies proven in over 600 plants worldwide. This makes our solutions the right choice for large-scale projects. And we know how to build these plants very well.
In fact, all chlor-alkali plants produce hydrogen, so we are the world’s No. 1 supplier for electrolytic hydrogen production. This differentiates us clearly from small start-ups and shows that we know how to handle hydrogen as well as high currents, or the grid connections of large-scale energy consumers.
They address different demands. The redox flow batteries are extremely flexible. In contrast to conventional batteries, they can be scaled independently in terms of power and storage time. This is ideal, e.g. for transferring solar power to nighttime, balancing out wind energy, but also for stabilizing the energy grid and many other applications for storage times of 4–10 hours. But this is just pure storage and release of energy. When power has to be stored for longer or if “green” hydrogen made from renewable energy is needed for sustainable chemicals, water electrolysis is the better option.
Hydrogen is a basic feedstock for many chemical “routes” that lead to products we all need and use: fuels or fertilizers are good examples. thyssenkrupp Industrial Solutions can offer complete process chains from a single source, e.g. for ammonia and subsequent fertilizer production. With solar power, hydrogen from water electrolysis, and nitrogen from the atmosphere, we can produce ammonia out of sunlight, air, and water. This eliminates the CO2 emissions that would occur in the standard process, which uses natural gas as a feedstock.
There we have many advantages, not only through the scale effects I mentioned, but also by providing our customers with additional revenue streams. It does not stop at renewable energy production, where you can fill the gaps between production and demand, or use the otherwise curtailed energy from a wind farm for hydrogen production. You can easily use the same solutions to reduce costs in energy-intensive industries like steelworks just by “shaving off” your peak energy demands and smoothening out your demand curve. You can operate micro grids in remote locations such as mines. There are many possibilities.
They are very good, especially if you look at the complete life cycle of our solutions. Both the redox flow batteries and the water electrolysis plants are expected to have a lifespan of at least two decades, with low maintenance efforts. And after that, the majority of the materials and components can be recycled very easily. Other battery solutions are much more problematic in this respect. In our redox flow batteries, even the vanadium electrolyte, which accounts for a large part of all the materials, is nearly 100% reusable.