Grid balancing ensures that electricity consumption matches electricity production of an electrical grid at any moment. Electricity is by its nature difficult to store and has to be available on demand, so the supply shall match the demand very closely at any time despite the continuous variations of both. In a deregulated grid, a

transmission system operator File:Electricity grid simple- North America.svg, 380px, Simplified diagram of AC electricity grid from generation stations to consumers rect 2 243 235 438 Power station rect 276 317 412 556 Transformer rect 412 121 781 400 Electric power transmis ...

is responsible for the balancing (in the US electric system smaller entities, so called balancing authorities, are in charge, overseen by reliability coordinators). As of the beginning of 2020s, the actual balancing service was provided primarily by the conventional power stations: frequently, the only quick-response safety margin is the

operating reserve In electricity networks, the operating reserve is the generating capacity available to the system operator within a short interval of time to meet demand in case a generator goes down or there is another disruption to the supply. Most power sys ...

provided by the

kinetic energy In physics, the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acc ...

of the physically rotating machinery ( synchronous generators and turbines). If there is a mismatch between supply and demand the generators absorb extra energy by speeding up or produce more power by slowing down causing the

utility frequency The utility frequency, (power) line frequency (American English) or mains frequency (British English) is the nominal frequency of the oscillations of alternating current (AC) in a wide area synchronous grid transmitted from a power station to t ...

(either 50 or 60

hertz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that o ...

) to increase or decrease. However, the frequency cannot deviate too much from the target: many units of the electrical equipment can be destroyed by the out-of-bounds frequency and thus will automatically disconnect from the grid to protect themselves, potentially triggering a blackout. Since the 20th century grid balancing has become less predictable with more

variable renewable energy Variable renewable energy (VRE) or intermittent renewable energy sources (IRES) are renewable energy sources that are not dispatchable due to their fluctuating nature, such as wind power and solar power, as opposed to controllable renewable ener ...

being installed into the grid. This has resulted in

wind farms Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few h ...

being turned off at night time, when wind is high and demand for power is low. In Scotland this has resulted in payouts, most recently over £6m in 33 days has been paid by the grid to wind farms to not generate electricity. Constraint payments are made to other electricity suppliers as well as wind. In 2011/2012, payments by the National Grid in the UK totaled £324 million of which £31 million went to wind. In 2012/2013, thanks to improved transmission capability, they were £130 million of which only £7 million were for wind. This temporary excess of

electric energy Electrical energy is energy related to forces on electrically charged particles and the movement of electrically charged particles (often electrons in wires, but not always). This energy is supplied by the combination of electric current and electr ...

could alternatively be used in

electrolysis of water Electrolysis of water, also known as electrochemical water splitting, is the process of using electricity to decompose water into oxygen and hydrogen gas by electrolysis. Hydrogen gas released in this way can be used as hydrogen fuel, or remi ...

to make high purity

hydrogen fuel Hydrogen fuel refers to hydrogen which is burned as fuel with oxygen. It is zero-carbon, provided that it is created in a process that does not involve carbon. It can be used in fuel cells or internal combustion engines (see HICEV). Regarding hydr ...

used in fuel cells. In areas with little hydroelectricity,

pumped storage Pumping may refer to: * The operation of a pump, for moving a liquid from one location to another **The use of a breast pump for extraction of milk * Pumping (audio), a creative misuse of dynamic range compression * Pumping (computer systems), th ...

systems such as the Dinorwig Power Station can allow the energy to be used for operational reserve or at times of peak demand rather than run a natural gas peaking power plant.

References

Sources

* * * {{electric-power-stub Electrical grid Renewable energy

See also

References

Sources