It’s not a scam, it’s a battery. And yes, it’s a net energy consumer because all forms of storing and transferring power are lossy.
The reason rates are higher during the day is because of demand. The whole point of a “battery” system like this is be able to supply additional power during peak demand periods without having to increase the generating capacity of power plants.
The current green movement possibly started with the defeat of ConEd’s application to build a pump storage system above the Hudson River on Storm King mountain. In the 70’s the Federal Power commission denied them a license to build after being sued by Historic Hudson Society and others. This one project could have offered relief to millions of users in the East and reduced their electric bills..