Professor Sir Chris Llewellyn Smith (Emeritus Professor of Physics at University of Oxford)              ESE0074

Supplementary written evidence from Professor Sir Chris Llewellyn Smith (Emeritus Professor of Physics at University of Oxford)

 

Dear Philip,

 

Testifying yesterday was an interesting experience: thanks for inviting me. You and your colleagues did an excellent job probing the witnesses. There are, however, three important points that I somehow failed to make, which I would like to bring to your attention:

 

  1. GB will need tens of TWh of hydrogen storage. The scale (which I think may not have come across) is over 1,000 times that currently provided by pumped hydro. With just wind, hydrogen and some batteries, we find a need to store 95 TWh, including 20 % contingency (95 TWh is the lower heating value of the energy in the hydrogen, not the electricity it can deliver).  By adding other things (such as a lot of nuclear baseload, and other types of store), I can get the hydrogen capacity down to 40 TWh, but not much less (some of it could be replaced by ammonia: a bit more expensive than hydrogen, but it can be located anywhere).

 

  1. Our modelling of 2050 finds that in high wind, solar and storage systems, the cost/MWh of electricity will be higher than in the last decade, but less that it has been in recent months, and much less than it was in 2022.

 

  1. On the realism of making large hydrogen storage systems: i) Centrica is ‘confident’ that they can store 17 TWh in the depleted Rough gas field and say they will do so with the right government support (although more tests may be needed first), while Bute Energy will shortly be announcing (under a new name) plans to build almost as much capacity in solution-mined salt caverns, which they plan to use to store electricity, relying on high capacity payments.  If I implied that hydrogen storage may not be viable, I meant that it won’t be commercially viable without government support: it will be technically viable.

 

I would be happy to provide any more information that you would find valuable, or answer further questions.

 

February 2024