Grid balancing ensures that electricity consumption matches electricity production of an

electrical grid An electrical grid (or electricity network) is an interconnected network for electricity delivery from producers to consumers. Electrical grids consist of power stations, electrical substations to step voltage up or down, electric power tran ...

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 is responsible for the balancing (in the US electric system smaller entities, so called balancing authorities, are in charge, overseen by reliability coordinators). In a wide area synchronous grid the short-term balancing is coupled with frequency control: as long as the balance is maintained, the frequency stays constant (at the ''scheduled frequency''), whenever a small mismatch between aggregate demand and aggregate supply occurs, it is restored due to both supply and demand being frequency-sensitive: lower frequency increases the supply, and higher frequency increases the demand. 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 inertial response provided by the

kinetic energy In physics, the kinetic energy of an object is the form of energy that it possesses due to its motion. In classical mechanics, the kinetic energy of a non-rotating object of mass ''m'' traveling at a speed ''v'' is \fracmv^2.Resnick, Rober ...

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), often described as being equivalent to one event (or Cycle per second, cycle) per second. The hertz is an SI derived unit whose formal expression in ter ...

) 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 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 the energy transferred as electric charges move between points with different electric potential, that is, as they move across a potential difference. As electric potential is lost or gained, work is done changing the energy o ...

could alternatively be used in

electrolysis of water Electrolysis of water is using electricity to Water splitting, split water into oxygen () and hydrogen () gas by electrolysis. Hydrogen gas released in this way can be used as hydrogen fuel, but must be kept apart from the oxygen as the mixture ...

to make high purity hydrogen fuel used in

fuel cell A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen fuel, hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most bat ...

s. 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 A breast pump is a mechanical device that Lactation, lactating women use to milking, extract milk from their breasts. They ...

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 Peaking power plants, also known as peaker plants, and occasionally just "peakers", are power plants that generally run only when there is a high demand, known as peak demand, for electricity. Because they supply power only occasionally, the powe ...

References

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* * * {{Electricity delivery Electrical grid Renewable energy

See also

References

Sources