Some may use these but a simple check on the web brings up:
No need for rare earths
No Need for gear boxes
No need to synchronise rotors to grid frequency:
as used by Ecotricity
as stolen by the US
Enercon 7.5MWAmongst other features, the annular generator is a key component in ENERCON’s gearless wind generator design. This low-speed synchronous generator is directly connected to the rotor. Generator output voltage and frequency vary with the speed and are converted via the ENERCON Grid Management System to be fed into the grid.This allows rotational speed control to be optimised; the annular generator is thus perfectly independent of the grid. By adjusting or ‘pitching’ the blades and through electrical excitation via the turbine control system, rotational speed and power output are constantly checked and optimised. The electrical power produced by the annular generator passes into the ENERCON Grid Management System which comprises a rectifier, the so-called DC Link and a modular inverter system. The inverter system defines the essential performance characteristics for output to the grid and ensures that the power output corresponds to grid specifications. Here in the inverter system, voltage, frequency and power are converted accordingly. Via the transformer, inverter voltage (400 V) is stepped up to the appropriate medium voltage required by the grid or the wind farm network.
ENERCON wind turbines are equipped with a Grid Management System designed to meet the latest grid connection requirements. This facilitates integration in any transmission and distribution network. The Grid Management System offers numerous performance features e. g. reactive power management and optimum contribution to maintaining voltage levels. Essentially, ENERCON wind farms behave very much like power stations or in some aspects even exceed their performance.
Intermittency of windpower
there are many different stages of operation of power stations. From wiki:
There is generally about 1.5 GW of so called spinning reserve—this is typically a large power station paid to produce at less than full output. So, a typical power station, which might have 4 generating sets each of 660 MW, giving a total output of 2.64 GW, might only be operating at 2 GW, with the steam boiler full, but with the steam valve not fully open. At the request from National Grid control centre, or under command from the generator governor this valve can open up and deliver an extra 640 MW in 20 to 30 seconds. This requires the boiler air fans and the coal feeders to increase output accordingly. The greater the total load on the system, and/or the greater the expectation of large demand fluctuations (at the end of popular TV programmes for example) the larger the proportion of spinning reserve set by National Grid plc.
NG pays to have up to 8.5 GW of additional capacity available to start immediately but not running, referred to as warming or hot standby, that is ready to be used at short notice which could take half an hour to 2 hours to bring on line. Generally, there will be more of such hot standby capacity whenever there is a large amount of expected disturbance on the system. The cost of fuel or tonne of CO2 emitted by keeping such plant warm is tiny in comparison with the amount of fuel used to generate power, maybe equivalent to the fuel used to produce a quarter of a MW compared to a full load fuel demand for a large set of 1.8 GW. Often quoted talk about the high costs of standby spinning reserve are misleading.
A similar amount of power stations (8–10 GW by capacity) are operable from a cold start in about 12 hours for coal burning stations, and 2 hours for gas fired stations.
...Other stations are mothballed or deep-mothballed which means they cannot be readily called upon; even in an emergency it may take several months to de-mothball. In Summer 2006, Fawley Power Station near Southampton was de-mothballed to cope with anticipated power capacity shortages for winter 2006/07
Not mentioned is the short term 2GW available in seconds from pumped storage Dinorwig can provide full output within 65secs from startup and 16 second if spinning.
As I mentioned the grid HAS to have spinning reserve to cope with current generator failures Building large Nuclear stations of over 1.5GW capacity will require an increase in the spinning reserve to allow for failure.
Unpredictable wind turbine trip will remove perhaps 3MW from the system. Predictable loss of wind (an increasing loss because wind does not stop instantly over the whole country) can be handled by the warm reserve or even cold start gas turbines (I acknowledge that the combined cycle gas turbines - 60% efficient - should only be brought online if prolonged windlessness were predicted, however the standard GT - 30% efficient - would only be required for short interruptions.
Every watt that the wind generates in electricity is equivalent to preserving up to 3 watts equivalent in gas/oil/coal for the future!
Some predictable surge levels