The economic case for a smart metering roll-out was based mainly on the environmental efficiency gains that a better awareness of the costs of electricity at any time would bring to the customer. This presentation explores how further benefits might be derived by utilising smart metering to marshal a demand side response from residential and SME customers that will provide the reserve and response requirements of an electricity system that is reliant on an increasing proportion of intermittent low carbon generation, and resolve the associated network congestion without substantial new network investment. Such a response is likely to be dependent upon technology that will also make buildings 'smart'.