Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. GVEA BESS Expected and Actual Performance Dan Bishop Golden Valley Electric Assoc Fairbanks, Alaska USA

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. Table of Contents BESS Background BESS 18 Month Availability Guarantee BESS Hardware Issues BESS Lessons Learned Actual Performance Future Uses

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS - BACKGROUND GVEA - RUS CO-OP in Alaska Typical Short on Real Spinning Reserves Power Supply Outages Shed Customers to Stabilize System BESS Conceived as Part of a New Intertie Project 1993 Project Delayed Due to EIS Process on Intertie 2000 Selected a Consortium of ABB and Saft $30.3M

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS - BACKGROUND Project Started October MW for 15 Minutes ABB Converter Technology (46 MVA) Saft Liquid Filled Ni-Cd Technology 4 Strings (13,760 total cells) 5kV DC Link Voltage Commercial Startup in September 2003 Begin 18 Month 98% Availability Period Project Completed December 2003

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS BACKGROUND – Operating Modes Spinning Reserve Automatic Scheduling AGC Support for Scheduled Load Increases PSS Charging Primary Use is Voltage Support (VAr) Converter is capable of full power circle output

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS – BACKGROUND - OPERATING MODES

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS – BACKGROUND - OPERATING MODES Spinning Reserve Mode Critical due to nature of electrical system Lack of “Real” Spinning Reserve due to cost of oil-fired generation GVEA Purchases Non-Firm Energy from Anchorage Utilities We are Responsible for the Spinning Reserves if Unit(s) Trips SCADA Loads BESS table with Spinning Reserve Obligation Operates as part of SILOS (25%, 25%, 50%)

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS – BACKGROUND - OPERATING MODES Automatic Scheduling Mode For Problems Internal to the GVEA Transmission System Monitors Generator & Remote Transmission Substation Breakers Power Flow thru Breaker, Trip Circuit Current & Breaker Status

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS - 18 MONTH AVAILABILITY GUARANTEE 98% Availability for 18 Months Hours September 19, Start Diode Failure(s) October 21, 2003 – BESS Offline for 70 Hours June 2004 – Converter Maintenance July 2004 – Two Separate PSR Board Failures March 18, 2005 – Successful Completion Down Time = 111 Hours 99.2 % Availability

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS – HARDWARE ISSUES Diode Failures Board Failures Losing Air Pressure in the Cooling System Sentry (BMS Modules) Battery Cells

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS – HARDWARE ISSUES - Sentry Device

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS - HARDWARE ISSUES - Sentry Device 344 Sentries/ String; 1376 Total String would Fail to Complete Sentry Logging Process Individual Sentry Failures Turned out to be an ESD Issue Low Voltage Communication Wire Extended over the High Voltage Side of the PCB.

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS – HARDWARE ISSUES - Sentry ESD Solution

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS – HARDWARE ISSUES – Battery Cells December 2003; Initial Installation Transit or Other Damage – 15 Cells Low Voltage Problems – 7 Cells Rejected June 2004 Leaking Due to Transit Damage – 3 Cells Rejected Severe Reversal / Electrolyte Ejection – 3 Cells Rejected April 2005 Severe Reversal / Low Capacity – 4 Cells Rejected 2008 SOH Issue Warranty replacement of two strings with improved cells.

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS – LESSONS LEARNED - SPINNING RESERVES

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS - LESSONS LEARNED Run Time Predictor Functionality Originally Fixed MW Values that showed Runtime (Minutes) AGC and Load Shed Applications Needed a 15 Minute MW Value. Charge Mode Modification – Modify Auto Start & Add Ability to Turn On/Off From Dispatch Q (VAr)-Oscillations – 20 Hz Software Filter Ramp Standard VS Ramp Fast Transition Between Modes 4 MW/Minute VS 2500 MW/Minute

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS – Actual Performance BESS Statistics 388 Events to Date (November 2003 – June 2012) Recent Event - May 26, MW for 9 minutes, then ramped down at 4MW/minute due to a fault on the Alaska Intertie 651 MW-hrs Availability 99.14% 9/1/2010-6/19/2012

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS - Actual Performance Customer Outages avoided as of 6/19/2012 1,621,712

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS Performance – RESPONSE TO EVENTS/OUTAGES BESS Event Response (November 2003 – April 2005) Projected Performance

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS Performance – RESPONSE TO EVENTS/OUTAGES BESS Event Response [MWHrs] (November 2003 – April 2005)

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS Performance – RESPONSE TO EVENTS/OUTAGES BESS Event Response (January 2009 – December 2011) Projected Performance

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS – Future Application Renewable Mode GVEA is working with SAFT and ABB Optimize for use with the Eva Creek Project Ramp rate relief Determine if improved batteries could reduce CT backup req’s Rapidly responding spinning reserve The BESS response faster than conventional generation. As Railbelt generation is upgraded to more efficient Aeroderivative units this is expected to become a more important factor in controlling UF loadshed.

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. BESS – World Records Most Powerful BESS 46 MW for 5 Minutes; Guiness World Record 34 MW for 15 Minutes 27 MW for 24 Minutes Maximum Output of 46 MVA Highest Voltage Battery >5 kV DC Also a -46/+46 MVAR SVC

June Golden Valley Electric Assoc. Inc © 2012 GVEA. All rights reserved. Thank you!