$3.(15$pts$)$ According to MIT Technology Review $"$an energy startup called Stem has developed a battery for commercial buildings that's clever enough to predict $-$ based on the price of electricity $-$ when to store power and when to release it$.$ The batteries are not just intended as backup power. Instead, in concert with software, they're part of a system designed to allow a building to use the cheapest form of power available at any given moment, whether that power comes from Stem's batteries or from the grid."

a$.$ Name the system elements implemented by the startup and outline the rest of the system $($Tool$,$ Source, Distribution, Packaged Payload, Control$/$Interface$).$

b$.$ Which system elements would you ask your engineers to invent or improve for the long$-$term benefit of the company and its customers.