Buffalo Gap Wind Farm

Buffalo Gap Wind Farm

September 10, 2014

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The AES Corporation (NYSE: AES) is a global power company that owns and operates a diverse and growing portfolio of electricity generation and distribution businesses, which provide reliable, affordable energy to customers in 20 countries. AES understands that a reliable, affordable supply of electricity is essential to human progress, economic growth, public health and security.

Our power plants encompass a broad range of technologies and fuel types, including coal, diesel, hydropower, gas, oil, wind and biomass. Our utilities power several diverse markets, from São Paulo, Brazil to Indianapolis, Indiana.

Combining deep local insight with a global presence and more than 30 years of experience, AES has a proven commitment to ensuring operational excellence in providing electricity to its customers.

Overview

September 10, 2014

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Buffalo Gap Wind Farm Ranked the 7th largest wind farm in the United States by AWEA statistics

(2012)Located in Taylor and Nolan Counties of West Texas.

-3.5 hours west of Dallas-30 miles SW of Abilene-30 miles SE of Sweetwater.

Consists of three projects totalling 524 MW-Buffalo Gap 1: 67 Vestas 1.8 MW turbines-Buffalo Gap 2: 155 GE 1.5 MW turbines-Buffalo Gap 3: 74 Siemens 2.3 MW turbines

Introduction

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Buffalo Gap Wind Farm 1 General Manager, 3 Operations Managers, 1 High Voltage engineer, 1

performance engineer, 25 wind turbine technicians.28,000 acres of leased property in which our staff maintains roads, gates,

fences and cattle guards.37 Land-owner relationships. 296 wind turbine generators.14 miles of 138kv transmission line.175 miles of 34.5kv collection line.

Responsibilities

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Buffalo Gap Wind Farm Buffalo Gap 1 has a 15 year 100% PPA (Power Purchase Agreement).Buffalo Gap 2 has a 10 year PPA covering 80% of production with the

remaining 20% going merchant. Buffalo Gap 3 has a 7 year PPA covering 80% of production with the

remaining 20% going merchant.Direct Energy is the QSE (Qualified Scheduling Entity) for all of Buffalo Gap

Wind Farm.

Accountabilities

September 10, 2014

Preparation for Cold Weather

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Buffalo Gap Wind Farm…Objectives

Preventative Maintenance Schedule

Emergency Action Plan

Communication

Buffalo Gap Wind Farm seeks to provide timely, efficient and cost effective winter maintenance, snow removal, and ice control for the wind turbine generators and the surrounding site areas.

Buffalo Gap Wind Farm seeks to prevent unexpected functional failure by maintaining proper operations- replacing necessary parts when they show wear, lubricating on schedule and cleaning on schedule.

Buffalo Gap Wind Farm seeks to prevent fatalities and injuries; reduce damage to wind turbine generators, facility structures and other equipment; Protect our environment and community; accelerate the resumption of normal operations.

Buffalo Gap Wind Farm seeks to ensure that communications between the QSE, Remote Operations Center and Site personnel are well coordinated, effectively managed and responsive to the diverse information needs of ERCOT.

September 10, 2014

Inclement Weather Plan

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Buffalo Gap Wind Farm…Inclement Weather Plan

ScopeIntended as a guide for safe work procedures during the event of inclement weather. Considering the different variables in forecasting weather, safe work practices will be determined by Buffalo Gap leadership in cooperation with the Safety Coordinator. Also, the ability for all AES personnel and contractors to identify unsafe conditions and report them accordingly to the leadership team to determine the safest approach for field personnel to work safely outside the confines of the shop/warehouse area.

Road ConditionsIce & Snow

– Buffalo Gap Wind Farm inquires with the TxDOT to determine the availability of roads.

– If roads are deemed unpassable by TxDOT, all work activity is cancelled.

Field WorkIce on Equipment

– Visual inspection of equipment.– If ice is spotted, all field work activity is

cancelled.– Extreme caution is observed during the melting

period.

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Buffalo Gap Wind Farm…Preventative Maintenance Schedule

ScopeBi-annually, the PM schedule is intended as a guide for inspecting and cleaning the condenser coil for its heat transfer and dust accumulation, and fans and blowers to insure proper air delivery to system; Inspecting and testing the amperage of the motors for maximum productivity. Check exposed ducting for leaks and proper insulation. Lubricate motors and bearings to avoid friction losses. Test controls and safety switches. Test the heating system for proper operation. Inspect all relays and contacts where possible.

Summer PrepDON’T FORGET YOUR FANS!

– Fans and blowers are key to ensuring your equipment is being cooled properly during normal operations in high ambient temperature.

Winter PrepDON’T FORGET YOUR HEATERS!

– Cabinet Heaters are key to ensuring your equipment is being cooled properly during normal operations in low ambient temperature.

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Buffalo Gap Wind Farm…Emergency Action Plan

ScopeIt is our policy that if all safety criteria are not met, work will not begin or continue unless all safety procedures can be followed and materials that will be needed to render personnel safe from the elements are available.

If any element on this plan or procedure is not available when conditions warrant, then all operations which may put personnel at risk will stop immediately until the criteria are met.

Extreme ColdAll personnel work in groups of two or more.All personnel in the working in the field will receive

clearance from site leadership prior to entering the field.

All personnel on site will have communication devices on their person at all times.

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Buffalo Gap Wind Farm…Communications

ScopeThe Buffalo Gap Wind Farm takes communications seriously; from the technician in the field having a radio and cellular phone (email and text capable), to the operator at the 24-7 desk having LAN line telephone, cellular phone and e-mail capabilities - communications are always the forefront of our operations.

During cold weather events, site personnel stay in constant contact with the operations center and the QSE via phone and email, giving updates on the hour and as needed.

Operating in an Inclement Weather EventDesignated personnel will remain on-site during

event.Ensure local SCADA control can be achieved.Make contact with Operations Center and QSE at

least hourly or when conditions change.

September 10, 2014

Preventative Measures

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Blade Coatings

Cold Weather Packages

Drive trains

Buffalo Gap currently uses two types of anemometers; a 3-cup non-heated and an ultrasonic.

Ice-phobic blade coatings are designed to wick moisture off of the blades negating ice build-up.

Certain wind turbine generator manufacturers offer cold weather packages for wind farm located in arctic climates.

Protecting your drive train equipment from damage due to ice.

September 10, 2014

Anemometers

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Buffalo Gap Wind Farm…Anemometers

ScopeBuffalo Gap Wind Farm currently operates with two different styles of anemometers. One is a 3-cup mechanical type, the other is an ultrasonic electrical type. Both style of anemometers typically work well in the West Texas environment; however, if an icing event occurs, the 3-cup mechanical anemometer is susceptible to icing over which will cause the wind turbine to fault.

3-cup mechanical Pro’s

– Cheap– Easy to replace– Works well in normal conditions.

Con’s– Susceptible to ice

UltrasonicPro’s

– Will operate in any condition– Easy to replace

Con’s– Expensive

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Buffalo Gap Wind Farm…Blade Coatings

ScopeBuffalo Gap Wind Farm currently operates with Leading Edge Protection blade coating on 1/3 of Buffalo Gap 1 wind farm. The coating is rolled at 5-8 mils thickness (2-3 business cards), this coating is designed to protect the blades from external damage in the air and can also act as an ice-phobic agent with the proper material. Buffalo Gap 1 is trialing 1/3 of the turbines to see how it will perform during arctic climate.

Pros– Protect blade

materials– Wick away moisture

Cons– Expensive– Not enough data to

prove success/fail– Can cause rotor

imbalance if not placed equally

September 10, 2014

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Buffalo Gap Wind Farm…Cold Weather Packages

ScopeBuffalo Gap Wind Farm currently does not have cold weather packages for their wind turbine generators; however, some wind generation sites in West Texas do have the cold weather packages. The jury is still out on how cost effective these packages would be.

Cold weather packages include nacelle space heaters; heaters in the yaw drive and pitch motors; gearbox oil heating; slip ring heaters in the generator; controller and control cabinet heating as well as battery heaters.

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Buffalo Gap Wind Farm…Drive trains

ScopeThe heart of the wind turbine is its electricity generating system. Inside the nacelle of a typical wind turbine, the rotor drives a large shaft into a gearbox, which steps up the revolutions per minute to a speed suitable for the electrical generator. A wind turbine gearbox must be robust enough to handle the frequent changes in torque caused by changes in the wind speed. The gearbox requires a lubrication system to minimize wear.

September 10, 2014

January 6, 2014 Event

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ERCOT EEA 2

ERCOT EEA 1

ERCOT EEA Cancelled

At 1000 on January 5, 2014 ERCOT Operator Ed Self issued an Advisory for an expected hard freeze for the night and following morning with temperatures in the teens and twenties across the State.

At 0659 on January 6, 2014 ERCOT Operator Jerry Douglass issued an Emergency Energy Alert Level 2.

At 0755 on January 6, 2014 ERCOT Operator Jerry Douglass issued an Emergency Energy Alert Level 1.

At 0916 on January 6, 2014 ERCOT Operator Jerry Douglass Cancelled the Emergency Energy Alert Level 1.

September 10, 2014

ERCOT Advisory

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Buffalo Gap Wind Farm…Operations during the advisory

10:00 January 5, 2014The wind turbines had been producing between 100mw and 450mw; Temperatures ranged from 24 degrees to 34 degrees F within a 12-hour span prior to the event.

The staff knew that as long as the turbines were online and producing, the chances of the turbines tripping due to weather/temperature would be low.

Buffalo Gap Wind Farm was producing around 300mw with 8.5m/s wind speeds. The temperature was at 25 degrees F.

September 10, 2014

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Buffalo Gap Wind Farm…Operations during the EEA2


The staff knew that as long as the turbines were online and producing, the chances of the turbines tripping due to weather/temperature would be moderate due to the temperature dropping and ice accumulation was imminent.


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Buffalo Gap Wind Farm…Operations during the EEA1


The staff knew that as long as the turbines were online and producing, the chances of the turbines tripping due to weather/temperature would be moderate due to the temperature dropping and ice accumulation was imminent.


September 10, 2014

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Buffalo Gap Wind Farm…Operations during the EEA cancellation


The staff knew that as soon as the turbines stopped turning and producing, the chances of the turbines tripping due to weather/temperature would be high due to the temperature dropping and ice accumulating.

Buffalo Gap Wind Farm was producing around 0mw with 2m/s wind speeds. The temperature was at 12 degrees F.

September 10, 2014

Lessons Learned

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Buffalo Gap Wind Farm…Lessons Learned

Cold Weather EventsBuffalo Gap Wind Farm learned that during cold weather events, the turbine could operate when the temperatures were below the specified temperature cut-out recommended by the manufacturer as long as the technicians could keep the wind turbine in operation, barring wind resource.

September 10, 2014

Questions?

Documents

Buffalo Gap Wind Farm