Power System Requirements for Wind Power

The power system requirements for wind power mainly depend on the power system configuration, the installed wind power capacity, and how the wind power production varies. Wind resources vary on every time scale: seconds, minutes, hours, days, months and years. On all these time scales, the varying wind resources affect the power system. An analysis of this impact will be based on the geographical area that is of interest. The relevant wind power production to analyse is that of larger areas, like synchronously operated power systems, comprising several countries or states. The integration of wind power into regional power systems is mainly studied on a theoretical level, as wind power penetration is still rather limited. Even though the average annual wind power penetration in some island systems (e.g. Crete in Greece) or countries (e.g. Denmark) is already high, on average wind power generation represents only 1–2 % of the total power generation in the Scandinavian power system (Nordel) or the Central European system (UCTE). And the penetration levels in the USA (NERC regions) are even lower. Most examples in this chapter come from Central and Northern Europe, as there is already some experience with large-scale integration of wind power, and there are farreaching targets for wind power. In Central Europe, power production is mostly based on thermal production, whereas in the Nordic countries thermal production is mixed with a large share of hydro power. We will refer to the energy penetration when we use the term wind power penetration in the system. The energy penetration is the energy produced by wind power (annually) as a percentage of the gross electricity consumption. Low penetration means that less than 5 % of gross demand is covered by wind power production, high penetration is more than 10 %. First, this chapter will describe the power system and large-scale wind power production. We will then look at the effects of wind power production on power system operation as well as present results from studies in order to quantify these effects.