The Dutch electrical engineer Cees van Nimwegen (75) had sold his business and had some money left, he invested in a seasonal heat storage project. The idea is very simple: store electricity from 150 solar panels as heat in cheap basalt and withdraw it again as electricity. The difference with basalt as compared to water as storage medium is that you can achieve much higher storage temperatures than 100 C, like 500 C; basalt doesn’t boil (that easy). On the other hand, the capacity of water to store heat is 5 times higher than basalt:
Specific heat basalt: 0,84 kJ/(kg*K)
Specific heat water: 4,19 kJ/(kg*K)
So the heat storage capacity of a standard volume of water between 20-100 C is comparable to that of the same standard volume of basalt over a temperature range 20-500 C. Van Nimwegen stresses that basalt is available in virtually unlimited quantities and that recycling is a non-issue. This “battery” goes on for ever and ever.
Storage volume: 200-250 kWh/m3
Storage cost: 2 cent/kWh
Storage leak: 80% energy still present after 6 months
The claim is that with a storage volume of at least 100,000 m3 50% of the original electricity input can be recovered.
[cesar-energystorage.com] – Project site – basalt battery
[trouw.nl] – Uitvinder Cees van Nimwegen bouwde een ‘zonne-accu’ van basalt.
[ed.nl] – Misschien wel een steengoed idee: energieopslag in basalt
[bjmgerard.nl] – Warmteopslag in basalt voor het ECOdorp in Boekel
[duurzaambedrijfsleven.nl] – BOM and EU invest in basalt battery
In parallel has Siemens in Hamburg-Germany built a storage facility according to the same principles.
[welt.de] – Auf der Suche nach dem Superspeicher