Abstract: Provided in some embodiments is an uninterruptable electrical power supply system. The system includes an electrical power distribution network (having a consumer side network coupled to one or more electrical loads that consume electrical power and a utility side network that supplies electrical power to the consumer side network), a primary power source (coupled to the utility side network, and that supplies electrical power to the utility side network for supply to the consumer side network), a secondary power source coupled to the utility side network, and a terminal between the consumer side network and the utility side network. The secondary power source supplies backup power to the utility side network (in response to a power shortage on the utility side network) and sinks surplus power from the utility side network (in response to a power surplus on the utility side network).