Interesting point about Vanadium Redox batteries - I though they needed a lot of maintenance due to the membrane needing constant change and were a very low power density - will have to read up more - have you got a good reference (maybe Tonise?)? Most references on batteries for "smoothing" renewables appear to be Li On which according to Tesla are about 800 cycles and have a 10 year life with only 60% of the capacity after 10 years - so they need continuous upgrades to maintain capacity (usually rated a about 4 hours) for continuous sunny/windy days (which over course does not happen in the real world) - the issue is that 4 hours is inadequate for a stable grid and 8+ hours is probably unaffordable and still inadequate to cope with relatively minor disruptions (i.e one dull day). I recall that Redflow had a zinc-bromine flow battery which was good for ~2,000 cycles but had a poor input/output efficiency (~70%) - I don't know if they are still in business.
Picked up a good youtube video (HERE) on Solid Oxide fuel cells (SOFC) and electrolisers (SOEC) and their ability to provide hydrogen efficiently when operating with nuclear energy (or something like WPL is exploring for Heliogen's concentrated solar) and to also be "reversible" and operate in fuel cell mode to generate electricity from the hydrogen it produced whilst there was a surplus of electricity (i.e during a renewables "curtailment") or to avoid ramping down a nuclear reactor when renewables were going full bore (i.e 11.00 am - 2.00pm on a summer sunny day). It appears that Bloom Energy (as in the video) is only one of a number of companies working on SOFC and SOE and "reversibility" as below (impressive efficiencies but these are a high steam temperatures (600C too 800C) and thus unsuitable for renewables):
Also the IRENA report (HERE) discusses pyrolysis and says "Low-carbon hydrogen can also be produced from methane pyrolysis, where the carbon ends up as solid rather than as CO2, with 4-5 times lower electricity consumption than electrolysis and potentially lower hydrogen production cost" - IMO this is that way forward for WPL - the low capacity factors (particularly from curtailed electricity) and poor thermal efficiency of cold water electrolysis will in my view make them non-viable without massive subsides (i.e uneconomic feed in tariffs and selling renewable certificates to allow polluters to "green wash"). If a reasonable carbon tax ever comes in (and modern SMR nuclear(ref: Frazer Nash) lives up to its promise of an LCOE of ~USS$64 - US$77) then with a 90% capacity factor for nuclear) IMO renewables for producing hydrogen looks a shaky economic proposition without subsidy
WPL Price at posting:
$22.77 Sentiment: Hold Disclosure: Held
(20min delay)