Reserve Services and Frequency Response
National Grid is responsible for contracting short term generating provision to cover demand prediction errors and sudden failures at power stations. This covers a few hours of operation giving time for market contracts to be established to cover longer term balancing.
Frequency-response reserve acts to keep the system AC frequency within 1% of 50 Hz, except in exceptional circumstances. This acts on a second by second basis to adjust demand and provide some extra generation.
Reserve services are a range of services on differing response times:
- Fast Reserve: rapid delivery within two minutes of increased generation or reduced demand, sustained for a minimum of 15 minutes.
- Fast Start: units that start from standstill to deliver power within five minutes automatically, or seven minutes of a manual instruction, maintained for a minimum of four hours.
- Demand Management: reduction of demand of at least 25MW from large users of power, for at least an hour.
- Short Term Operating Reserve (STOR): generation of at least 3MW, from a single or aggregation of sites, within four hours of instruction and maintained for at least two hours.
- BM Start-Up: mainstream major generation units maintained in either an energy readiness or hot standby state.
These reserves are sized according to three factors:
- The largest credible single generation failure, which is currently either Sizewell B nuclear power station (1,260 MW) or one cable of the HVDC Cross-Channel interconnector (1,000 MW)
- The general anticipated availability of all generation plants
- Anticipated demand prediction errors
Read more about this topic: National Grid (Great Britain)
Famous quotes containing the words reserve, services, frequency and/or response:
“In a democracy—even if it is a so-called democracy like our white-élitist one—the greatest veneration one can show the rule of law is to keep a watch on it, and to reserve the right to judge unjust laws and the subversion of the function of the law by the power of the state. That vigilance is the most important proof of respect for the law.”
—Nadine Gordimer (b. 1923)
“Those services which the community will most readily pay for, it is most disagreeable to render.”
—Henry David Thoreau (1817–1862)
“The frequency of personal questions grows in direct proportion to your increasing girth. . . . No one would ask a man such a personally invasive question as “Is your wife having natural childbirth or is she planning to be knocked out?” But someone might ask that of you. No matter how much you wish for privacy, your pregnancy is a public event to which everyone feels invited.”
—Jean Marzollo (20th century)
“... the most extreme conditions require the most extreme response, and for some individuals, the call to that response is vitality itself.... The integrity and self-esteem gained from winning the battle against extremity are the richest treasures in my life.”
—Diana Nyad (b. 1949)