So what’s the current situation with the use of electricity from renewables in Germany?
Christopher Knoch: At the moment, electricity from wind and solar power is fed directly into the grid whenever the sun is shining or there’s wind. This electricity has priority under the German Renewable Energy Act. Consequently, when conditions are good, 100 percent of our electricity comes from renewables – and Germany even exports clean electricity. But in the so-called “dark doldrums”, when there’s no wind and it’s dark, our electricity must continue to come from other power sources such as coal or nuclear. If we could store clean electricity over long periods, however, the power of the sun would also be available to us at night.
How does your energy storage system, Aurora, work?
Justin Scholz: Our system uses the established process of air liquefaction to store energy. Electricity from renewables is used to cool air down to around minus 200 degrees Celsius, so that it becomes liquid. The heat produced during charging is stored, so that it can later help the discharging process when the liquid air reverts to its gaseous state and releases energy. The cold that is in turn generated during discharging is also stored, in order to liquefy air again and re-charge the storage unit.
What have been the most important milestones so far?
Christopher Knoch: The idea that we currently have on paper looks easy, but it’s been a long haul. We made the biggest step forward when we realised that we didn’t have to build the most efficient storage unit, but rather the cheapest and most useful. For it costs so little to generate clean electricity that it’s no problem having a slightly less efficient storage unit, as long as it’s cheap, mobile and flexible to use and lasts a long time. So we came up with the idea of putting the storage units in containers. This makes it possible to combine storage units in a modular way and use them in quite different areas of application – for example, right next to a wind power plant or an electric vehicle charging station.
How do you benefit from the EIT Climate KIC programme and the support of ERGO and Munich Re?
Justin Scholz: Other storage unit manufacturers give guarantees for their systems. As a young start-up in the sector, it’s a big help for us to be able talk to experts about this at an early stage. For the possibility of also being able to give our customers guarantees and being insured against possible breakdowns will help us to market our system.
Christopher Knoch: EIT Climate KIC is also helping us to quantify the long-term impact of our storage system. This is so valuable because many potential investors are already watching out for these key figures and waiting for certifications. We’re expecting this trend to continue.
And what are the next steps for your team?
Christopher Knoch: In the course of this year, we want to be able to show the complete system to potential customers and hopefully accept advance orders. To this end, we’re currently finalising a number of simulations, after which we’ll concentrate more on the hardware.