Reactive power control in Wind Farms by using the capability of wind generators: real experience and results Milan, May 9 th, 2007 Emilio Fernández-Antón Technical Services Iberdrola Renewables Energies

May 9th, 2007 IBERDROLA RENEWABLES ENERGIES : IBERDROLA’s renewable capacity will reach over 7.000MW as established by the Strategic Plan International Capacity National Capacity These figures imply an average annual growth of over 850 MW International capacity will reach a significant importance with over 20% of total capacity New technologies will add power: TermoSolar, PV, Wave Energy and Bio-mass

May 9th, 2007 IBERDROLA RENEWABLES ENERGIES3 Iberdrola is applying its own professional production management model to wind energy Maximize economic performance of every wind farm during the extension of its lifetime Starting point Production Management Model Main goal Iberdrola’s 100 years utility culture Wide O&M expertise:  Hydroelectric  Gas combine cycles  Nuclear  Renewables  Fuel oil  Coal  Cogeneration Iberdrola doesn’t develop a wind farm to sell it Iberdrola develops to create value Systems and procedures Strategy Organization & functions “Dominate technology and key management factors”

May 9th, 2007 IBERDROLA RENEWABLES ENERGIES4 Wind in the Grid. Iberdrola’s position Large scale integration on the grid may be one of most important barriers for the development of wind energy. Will we reach the EU on wind energy generation if we do not find the way of solving these problems? Iberdrola has got a valuable experience in the Spanish case: wind energy must be quite alike conventional plants. Additionally, the grid must be able to feed in as much as wind energy be possible. Iberdrola, as one of the main player of the world market, is using its position in the wind sector to… –propose technical improvements to manufacturers, pushing the market to give solutions to these new requirements –define and install new solutions for wind energy management, showing they are useful and feasible –cooperate with the OS and the sector to achieve realistic solutions

May 9th, 2007 IBERDROLA RENEWABLES ENERGIES5 Reactive Power Requirements. The Spanish case. During the last two years, these requirements had to be fulfilled in Spain: Bonus (%) Power FactorHigh LoadMedium LoadLow Load Lagging <0, <0,96 & ≥ 0, <0,97 & ≥ 0, <0,98 & ≥ 0,9702 <1 & ≥ 0, Leading <1 & ≥ 0,98020 <0,98 & ≥ 0,9720 <0,97 & ≥ 0, <0,96 & ≥ 0, <0,958-4

May 9th, 2007 IBERDROLA RENEWABLES ENERGIES6 Iberdrola’s Results (I) Each Iberdrola’s turbine regulates reactive power. Each Iberdrola’s wind farm regulates reactive power in the connection point. Additionally, Iberdrola’s wind farms follow special requirements from the System Operator (REE) when the grid needs it. Results have been achieved exclusively based on the wind turbine regulation capability, no capacitors or similar solutions at the substation have been used.

May 9th, 2007 IBERDROLA RENEWABLES ENERGIES7 Iberdrola’s Results (II). Fulfilling regulation [PE] BORDECOREX NORTE From: 01/01/2007 To: 31/01/2007 DateTimeP(kWh)Q2(kWh)Q3(kWh) Cos Phi Lag/LeadPeriodBonus Total ,12% 01/01/20070: ,88INDValle8,00% 01/01/20070: ,92INDValle8,00% 01/01/20070: ,91INDValle8,00% 01/01/20071: ,91INDValle8,00% 01/01/20071: ,92INDValle8,00% 01/01/20071: ,91INDValle8,00% 01/01/20071: ,91INDValle8,00% 01/01/20072: ,92INDValle8,00% 01/01/20072: ,92INDValle8,00% 01/01/20072: ,92INDValle8,00% 01/01/20072: ,92INDValle8,00% 01/01/20073: ,93INDValle8,00% 01/01/20073: ,93INDValle8,00% 01/01/20073: ,91INDValle8,00% 01/01/20073: ,91INDValle8,00% 01/01/20074: ,91INDValle8,00%

May 9th, 2007 IBERDROLA RENEWABLES ENERGIES8 Iberdrola’s Results (III). Fulfilling TSO requirements During the day 15/02/2007, (01:32 a.m.), REE asked for a reduction of the consumed reactive power in Pedregal Wind Farm, due to the low voltage level. Thanks to its centralized Renewable Energies Control Centre (CORE), Iberdrola reduced the reactive power absorbed by the Wind Farm, going to fdp=1. Consequently, the voltage level grew, reaching stable levels.

May 9th, 2007 IBERDROLA RENEWABLES ENERGIES9 Iberdrola’s Results (IV). Fulfilling TSO requirements. Active Power.

May 9th, 2007 IBERDROLA RENEWABLES ENERGIES10 Iberdrola’s Results (V). Fulfilling TSO requirements.Reactive Power.

May 9th, 2007 IBERDROLA RENEWABLES ENERGIES11 Iberdrola’s Results (VI). Fulfilling TSO requirements. Voltage Level.

May 9th, 2007 IBERDROLA RENEWABLES ENERGIES12 Conclusions Iberdrola’s wind farms are able to regulate reactive power and voltage level, cooperating with TSOs in order to assure the grid stability. The obtained results shows that wind farms can cooperate with the grid stability in a similar way that conventional power plants do.