I like these presentations, different perspectives and great ideas.
They fit some applications really well due to the higher energy density and peak current capacities, but not grid scalability.
27:45 - coal stations do not take 15 minutes to chaneg 5% he has zero clue as to what he is talking about. Coal stations can offer up around 5% as spinning reserve (up or down) that can react within about 2-4 seconds, granted not for long initially. The longer term ramp rate of coal is typically around 20-50MW/minute per unit or 100-200MW per station. Grids operate by balancing all the stations together and at times the partly self governed state requires no intervention at all, this is how grids work.. It is unfortunate when the power system is badly misrepresented and poorly understood. Efficiency plays critically into the economics.
Unfortunately 75% efficiency range is a non starter if charging from fossul fuels due to the way that CCGT (gas) units operate and the economics of startup, shutdown and part loading. Coal stations have different issue due to the very high stat cost. I know because I used to work this out and switch a CCGT station on/off/part in the UK for a couple of years. The efficiency is key for any energy storage system with scale.
There is nowehere near enough renewables in the system at the moment to make this level of efficiency viable because the higher level of renewables will increase the pricing separation between fossil and renewable (much cheaper renewables price $/kWh).
28:20 - no, it looks horrendous as it is still way more (multiples) expensive than current lithium cells, excluding future scaling of lithium. That is on a $/kWh basis only. Density basis it is different.
At the moment I still believe that metal flow (non molten liquids) is the future, not molten because of the efficiency, scalability and no storage losses. Molten cells still have their valid applications, like helping powering rail guns on warships.... Airplane with molten metal battery ?? Shipping is not so critical of energy density, lower cost beats density, hence lithium in near term for short routes.
