Making Wind Work for Alaska: Supporting the Development of Sustainable, Resilient, Cost-Effective Wind-Diesel Syst

1. Making Wind Work for Alaska: Supporting the Development of Sustainable, Resilient, Cost-Effective Wind-Diesel Systems for Isolated Communities TASK AREA II.1: High Penetration Operation of Hybrid Power Systems REAP/Wind Working Group Meeting, Nome, AK Nov. 11~12, 2010 Billy MUHANDO, ACEP

2. EPSCoR Project Research Components and Budget Overview University of Alaska Task 1: Development of Statewide Wind Energy Database G. Fay – UAA ISER (lead) K. Keith – UAF ACEP J. Jensen - Alaska Energy Authority Task 2: Technical Issues Associated with High Penetration of Wind G. Holdmann – UAF ACEP (lead) R. Wies - UAF INE R Peterson-- UAF INE B. Muhando – UAF ACEP Task 3: Cold Climate Operation M. Cullin – UAA SOE (lead) K. Keith – UAF ACEP Joey Yang – UAA SOE Task 4: Social, Economic, and Political Challenges G. Fay – UAA ISER (lead) M. Berman – UAA SER S. Colt – UAA ISER State Agencies and Outreach Alaska Energy Authority Renewable Energy Alaska Project UAF Cooperative Ext. Services Rural Campuses Utility Partners TDX Power Kotzebue Electric Ass. Kodiak Electric Ass. Alaska Village Electric Coop, Etc. Industry Partners Northern Power Systems Sustainable Automation PowerCorp Prudent Energy HOMER Energy, Etc. World Class Laboratories NREL SNL Other Labs Other Universities

3. 1. Overview of Task II • The Task: • Address technical issues associated with high penetration of wind. • Research Components: • 1. Develop transformative and efficient energy technologies to address high wind penetration challenges in Alaska: • a) Operation in diesel-off mode, b) Advanced energy storage • 2. Wind power for space heating and transportation applications (smart grid applications, hybrid/electric transportation) • 3. Advanced modeling - wind analysis, design, and integrated modeling by an objective third party.  

4. 1.1 High Wind Penetration in AK Isolated communities utilizing commercial wind-diesel hybrid systems in Alaska New State Energy Plan released in January 2009 shows strong wind potential in 116 communities (http://www.aidea.org/aea/)

5. 1.2 Challenges to HP Systems Deployment in AK Technical • Lack of dispatchable load and controllers to allow higher-penetration systems • Lack of an established technology track record • High and undocumented installation and operation expenses • Limited capacity of the grid Policy • High capital cost and general discounting of sustainability • Perceived risk and associated higher financial costs • Limited funding to support the development of diesel alternative systems Institutional • Lack of trained personnel and the ability to keep trained personnel in communities • Environmental, siting, or other development concerns.

6. 1.3 Technical Solutions to High Penetration Challenges • Innovative technologies for grid-forming • Power electronic converters and other devices to enhance participation of the systems in voltage management and frequency control • Additional reactive power control and fault-ride-through capability, etc • Advanced energy storage • Batteries provide two specific advantages:  • Frequency stabilization (ms to seconds) • Load shifting (minutes to hours) • 3. Diesel-off mode operation

7. 2. Implementation of Task II.1 • Approach: • 1. Installation of a test bed to assess options for wind-diesel hybrid power systems in Alaska to operate in a diesel-off mode by testing state-of-art power electronics devices. • 2. Design control strategies, and identify suitable power electronic components and advanced storage technologies for wind-diesel systems in AK.

8. 2.1 Test Bed for Diesel-off Mode Operation • Test Bed Equipment • 1. Wind Turbine Simulator, 100 kW, induction generator, 3-phase 480 VAC • 2. Lead-Acid Battery Bank, 336 VDC, 896 Ah nominal capacity • 3. Grid-Forming Power Converter, 200 kVA, 480 VAC, 60 Hz • 4. Transformer, Isolation, 225 kVA, 480/277 V.

9. Test Bed (cont’d)

10. Diesel-off Mode Operation (cont’d) • Converter control algorithms are designed for operation under the following conditions: • Diesel OFF state — no diesel gensets online, the converter has to establish the grid frequency; the voltage regulator on the converter controls the field current so as to maintain the desired AC bus voltage. • Diesel-ON state — inverter operates in parallel with diesel gen-sets and the WT. The energy produced from the WTs acts as a negative load, the diesel gen-sets follow the load, and any excess power is used to charge batteries, if present, or is dissipated by the dump load.

11. 2.2 Energy Storage Options by Time Scale and Complexity Viable technologies for Alaska:

12. Flow Battery Storage Testing @ACEP +ve Electrolyte: Vanadyl/vanadium sulphate -ve Electrolyte: HypovanadousVII/Vanadous VIIISulphate Electrolyte operating temp. range: 10 to 35 degC Allowable storage temp. range: -25 to 75 degC

13. 3. Recap • Advanced Storage Analysis: • Battery performance testing involves characterization in relation to manufacturer’s specifications. Aim is to verify suitability for AK climate • Cycle life • Discharge rate • Duty cycle • Environmental conditions (temp., pressure, vibration, etc) • Battery qualification will be based on • Satndby losses (if any) • Capacity • Accelerated life and storage analysis • Diesel-off Mode Analysis: • Short term Analysis: • Grid-forming: Over voltage, under voltage, over frequency, under-frequency, trip tests, harmonics, DC current injection, unintentional islanding, synchronization • Real and reactive load sharing • Long term research will be defined based on additional equipment, personnel, funding: • Grid simulation, • Low load operation, secondary load management and prioritization, etc. • Controlled battery charging/discharging • Emission issues, etc 1. Adoption and field trials 2. Reduction in cost of energy