Self-sustaining energy: GKN explores residential hydrogen storage
Last week Dr. Nils Bornemann introduced us to the demonstrator project in the Alps, where GKN is building a zero emission, integrated power and heat supply station based on metal hydride hydrogen storage sourced from a small river.
Based on GKN’s PM technology, the team can make small storage vessels and operate them at lower pressure conditions, creating opportunities for seasonal energy buffering.
In the second half of our interview with Nils we spoke about conversion losses, the next steps in the demonstrator project, and if metal hydride hydrogen storage would also be suitable for mobile applications.
GKN’s concept includes two conversion processes. How does the system combat energy losses through conversions?
The overall efficiency may be an initial drawback one would identify compared to the 90 percent roundtrip efficiency of battery systems. The hydrogen generation commonly exhibits 50 percent utilization, and the fuel cell converts hydrogen to electricity with 50 percent efficiency. So, our electric roundtrip efficiency for a hydrogen system is only 25 percent.
The main energy demand is not electric - it is thermal energy for heating. If you consider the thermal energy generation of the hydrogen system and assume full utilization for hot water and heating, the roundtrip efficiency of our system increases up to 90 percent.
We are using this free of charge, zero emission renewable resource that generates a permanent excess of power for many hours per day. This is one of the principles of changing grids and value chains in power supply: it is built on local production from renewable sources and using storage capabilities.
What are the next steps for GKN?
We are currently in the building phase. This includes the small shed next to the house which will host our system and all the manufacturing of our subsystems required for the demonstrator. We have just met with our partners to discuss and align all modules. We are the first company to develop such a complex management system for the two transformation processes plus the heat management in a residential application with metal hydrides. This results in high requirements for safety, comfort and stability of the system.
On another spectrum, we are looking at other applications like mobile industrial vehicles for constrained conditions. Underground mining, for example, faces strict regulations on emissions and atmospheric conditions don´t allow reliable, battery-driven vehicles.
Hydrogen-driven engines could also be an answer for vessels in harbors to reduce the high emission levels for the last mile and running the systems during loading. Our PM-based technology would significantly reduce the required size for the tanks whilst the higher weight would be an advantage.
What will be the key challenges?
Homeowners don’t want to control the shed every day to start or stop certain processes - they want to switch on or off any electrical device, like the oven to cook a meal. This sounds simple but it exhibits dozens of sensors and data with numerous lines of coding.
Once we understand all the interdependencies and reactions, we can start looking at functional optimization, downsizing and cost optimization with a perspective toward midsize units for residential housing.
We will be sharing updates on the hydrogen storage project regularly, so stay tuned for further communication.