GE has announced a new grid-scale battery storage offering, called Reservoir, which it hopes will let it catch up with the likes of Tesla’s record-breaking batteries deployed in South Australia. This market for megawatt-class batteries is heating up, but there is lots of action at much smaller scales – with home battery startup ElectrIQ Power winning a deal with Mattany Homes to install its units in new builds. There will be a complex balancing act for utilities when it comes to integrating storage into their grids. For most, batteries are an enabling technology that allows them to leverage renewables like solar and wind, which can be purchased for less than gas or coal in many markets but need to have…