Electrical energy

Electrical energy is the term given to energy that has been converted from electric potential energy. This electric potential energy has usually been in turn converted from another source of energy, through a process known as generation.

Electrical energy is supplied by a voltage (or electrical potential) delivered via an electric current.

Electrical power is defined as the rate at which electrical energy is transferred via an electrical circuit over a given amount of time. It is therefore the rate of ‘doing work’. The SI unit of electrical power is the watt, which equates to an energy transfer rate of 1 joule per second.

In the context of buildings, electrical energy is typically converted into other forms of energy, to serve useful purposes such as heating, lighting, motion or other forms of electrical power conversion.

Electrical energy for use in buildings is often supplied via a grid connection, and typically originates at a power station, where it has been generated by electro-mechanical generators. Electrical energy can by generated by many means, such as chemical combustion, nuclear fission, or renewable means such as flowing water, wind, geothermal heat and solar voltaic.

Equally, electrical energy may be generated at the building itself, typically either via solar voltaic, localised electromechanical generators or other renewable sources. Such energy may be used locally within the building or may be exported back into the grid for use by other consumers. Where this latter facility exists, the building and its system are referred to as a ‘prosumer’ – i.e. a simultaneous producer and consumer of electrical energy.