Just looking at table 2 from the article you link, it looks like lithium ion has the following advantages over lead acid for this application: * Greater energy

Just looking at table 2 from the article you link, it looks like lithium ion has the following advantages over lead acid for this application: * Greater energy density, which means you need to carve less space out of your existing floor plan to make room for batteries. * About twice the cycle life, so batteries need replacement less often. * Can discharge more deeply without harming cycle life, so for applications where discharging happens frequently that means either the effective energy density or the effective cycle life is even greater. * Better efficiency for <24h charge-discharge cycles. These are all things that are more advantageous in this kind of application, where you can expect to see a lot of repeated cycling during hot summer months. For a telco application, where you're presumably only expecting infrequent use during occasional power outages, they'd be of negligible value. Keep on reading to figures 5 and 6, where they look in more detail at cycle life, and the lead acid batteries start to look like a straight-up bad choice for this kind of application.