In the last 5 years at least residential energy storage technology has grown substantially. With revelations of add on systems from the likes of SolarEdge, Enphase Energy, with stand alone options from the likes of GENERAC in their PwrCell offering, to Briggs & Stratton offerings, then there are some companies like Sonnen looking at the advanced “smart home” system, being followed by Schneider Home product. One is getting a premium system with a lot of programming control to address TOU rate spiking periods, the capability to design a system that can charge the battery pack from solar PV during the day then use grid off peak power at night to permit arbitrage of buy low, store energy, then suppliment the home load needs with lower cost stored energy while the sun is not high enough in the sky for substantial power generation during the early mornings and evenings as the sun sets, then after peak solar PV in TOU rate spiking periods that seem to be from 4 PM to 9 PM daily.

A substantial event occurred in Australia in 2017 when TESLA installed the so called “Big Battery” across a wind farm there. This site has proven that the “big battery” used for several grid services, stacked different use case grid services into one (asset) which paid for the cost of the original TESLA BESS with 2.5 years of use. It was then ‘enhanced’ from 129MWh to 194MWh for better capture and grid services function from then on. Most typical electric generation plants are on an amortization schedule of 20 to 50 years, this particular site amortized in 2.5 years then expanded in capacity and is probably today fully amortized again. With pilot programs creating distributed VPP grid services in some areas, it is also very possible to have one’s home BESS provide grid services that help pay off one’s investment of the BESS sooner than later.