Hot Rocks in a Box: The Rise of Thermal Batteries - Ep168: Anand Gopal 

Thanks to Anand Gopal for joining us on this week's episode of Cleaning Up. For more, sign up to our newsletter at cleaninguppod.substack.com

Hi Bryony and Michael, I really love your podcasts as they align almost perfectly with all my hobby-horses (my part two options were 'second-hand car salesman': thermodynamics, power plants, materials and economics). I started doing calculations on thermal storage in rocks or sand a few years ago before I discovered that my conclusions had been 'pre-discovered' by Seimens. With one major difference. I don't believe the hot rocks need to be in a box - thus reducing the cost of thermal batteries massively. I quickly found that sand requires much too high pumping costs and causes problematic pressure differentials. I then found that quartz rich rocks have issues with a a phase change at 573C causing them to possibly crumble to sand with repeated heating and cooling. So the optimal rock is a basic one such as basalt. I then went through a series of simplifications and ended up with a pile of rocks forming the structure of the 'building' with insulation and weatherproofing just laid on top. The issues is that stream raising temperature rocks will expand about 0.005 (50mm over a 10m wide heap) and the force this would generate if confined would crush the contact points to sand (400MPa if solid, less with void ratio but obv higher pressure at contact points) Lots of other issues with buoyancy, convection etc etc but all soluble IMO if the simple heap design is followed. What's needed is for somebody with influence (hint, hint) to get some action started at Drax, say. Spare thermal power station available from September, ideal position to get N Sea curtailed capacity while freeing some of the main north-south wires for Scottish.

MIn. 32:30: 6$ per MWh corresponds to 0.6 cents/kWh not 6 cents/kWh :)

@CleaningUpPod I used to listen to your podcast on Google Podcast which has been retired in favour of Google Music. Could you make your episodes available on Google Music? This way it will allow me to listen to the adio only, as before My battery would thank you for this! 😂

Whenever I hear the word "thermal" I expect to hear it followed by the word "runaway".

Just the first 60 seconds of introduction was a litany of fabrications and nonsense.