Wind Farm Curtailment Logic

Golden Spread Panhandle Wind Ranch

• Golden Spread Panhandle Wind Ranch (GS PWR) – 78.2 MW – – 34 Turbines Located just East of Amarillo TX in the TX Panhandle – Commercial Operations Date September 2011 • Capacity Factor: 48.59% • Effective Factor: 50.84% • Highest Monthly Capacity Factor: 60.89% • • Lowest Monthly Capacity Factor: 36.57% Average LMP: $23.29/MWh • • Max LMP: $408.28/MWh Min LMP: $-561.03/MWh

Curtailment

• • • EIS Market - Intermittent Status GSEC imports the (LIP) into SCADA from the XML Listener data stream (We hope to be able to get market prices from SPP via ICCP in the future).

A short program is written within SCADA to evaluate the LIP prices and send a base point to the wind farm control system if the criteria is met.

Curtailment Continued….

• • • The logic will Curtail the wind farm (reduce output close to zero without opening the breaker) if the instantaneous price is less than or equal to a certain “extreme” price point or if the average price for two consecutive intervals are less than or equal to a “less extreme” dollar amount.

The logic will Release the wind farm (increase based on actual capability of production) if the instantaneous price is greater than or equal a certain “extreme” price point or if the average price for two consecutive intervals are greater than or equal to a “less extreme” dollar amount.

The logic will ignore any price change for 20 minutes after each Curtailment or Release operation.

– Safety – Oscillation

Curtailment Continued….

• • • The wind farm has local/remote control capability, which allows the wind farm to ignore the SCADA signal if needed.

An email is automatically sent to the local BA for notification of when the wind farm will be curtailed and also when it will be released from curtailment as a result of the “logic”.

This email is sent 1 minute prior to being curtailed or released.