WTF, page-168

what I’m trying to get my head around is whether the economics turn in RFX’s favour after 4-6 hr, or whether it’s actually 4-6 weeks. ZBM has a lower round trip efficiency by about 10%, and lower power, so for frequent charge/discharge cycles, lithium is better. At what point does ZBM deliver a better technical outcome? It seems to me that if lithium loses 5% in 24h from full, and then much smaller after that, it must be a few weeks before ZBM makes up for its lower RTE. A lower technical return means that you need a much lower price to make a business case - there’s a step change in the price you can charge if ZBM a technical advantage in the 4h-24h timeframe, but not in the 4week timeframe.