Yes, good articles. Thanks for posting!
China certainly is doing major environmental damage to this planet and we continue to encourage it by sending all our manufacturing there.
I think they are stretching a bit to come to the conclusion that off-grid solar with Li-ion batteries is slightly more sustainable than current grid electricity (which, BTW, is not sustainable). They use the following assumption to get there:
Assuming a lifespan of 20 years for the solar PV system and a DoD of 80%, the lithium-ion batteries will last as long as the PV panels.
While I do think Li-ion batteries will eventually get there, they are not that reliable today. Tesla warrants their Powerwall for 10 years if you use it in float service, but only for 7 if you cycle it. The Enphase AC Batteries come closest, being warranted for 10 years with two very deep cycles each day. OTOH, no one really knows how long PV panels last. I have 2.88 kW of PV still in service after 16 years with no failures and almost zero loss of production. Simply put, PV could last 40, 50 or even more years. Li-ion batteries cycled 80% daily have no chance to last that long.
In other words, the authors assume Li-ion batteries last much longer than they actually do while simultaneously assuming PV modules die much quicker than they do.
At the end of the day, grid-tied PV in sunny regions is the most sustainable approach. Don't add batteries into the mix unless you're somewhere that grid-tie is no longer allowed or is actively discouraged.