Battery storage power stations use rechargeable batteries for load-leveling (storing electric energy at times of low demand for use during peak periods) and for renewable energy uses (such as storing power generated from photovoltaic arrays during the day to be used at night).
Definition of dray. : a vehicle used to haul goods; especially : a strong cart or wagon without sides.
a group of flying squirrels is called a dray or a scurry. Mensan, woodworker, building electronics projects since age 12, taught electronics, am in ham radio, very good at biology/astronomy/physics.