The cost savings described in that article compare the cost of covering peaks above our contractually agreed capacity from HydroQuebec with Powerwalls versus needing to purchase the difference at the variable market rates from ISONE when they’re at their absolute highest due to demand.

They are not comparing against the cost of covering that shortfall with local GMP owned gas or even fuel oil fired peakers.

Of course, a site focusing on green energy isn’t going to make that type of comparison in a situation where fossil fuels might provide a cheaper solution.