ALASKA VILLAGE ELECTRIC COOPERATIVE

Transcription

1 ALASKA VILLAGE ELECTRIC COOPERATIVE Energizing Rural Alaska since 1968 ARCTIC RENEWABLE ENERGY SUMMIT September 15-17, 2016 Iqaluit, nu, canada Willliam Thomson PE, PENG Operations Manager Alaska Village Electric Cooperative

2 Who (or What) is AVEC A non-profit member-owned electric cooperative providing electric service to 56 communities. Combined population 30,000 Smallest village 80 Largest village 1,200 Bethel (added 2014) 6,300 Alaska 738,000 Anchorage 299,000 2

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4 System Information 90 full time employees 95 village plant operators 10,800 services 48 power plants 170 diesel generators 500+ fuel tanks 8.5 million gallons of diesel Two tug and barge sets 34 wind turbines serving 15 villages 4

5 kwh Sales 6 55 Villages 72,000,000 kwh Average per village 1,310,000 kwh Average load 150 kw Bethel Sales 40,000,000 kwh Average load 4,500 kw Anchorage Grocery Store 2,700,000 kwh

6 What Electricity Costs in Cents/kWh 7 Fuel Power Production 9.97 Admin and General 2.97 Depreciation 2.91 Consumer Accounts 2.39 Distribution 1.19 Interest 1.11 Taxes 0.44 Total 49.56

7 Capital Costs in Rural Alaska 8 1,500 kw diesel plant 4.5 million 150,000 gallon tank farm 3.0 million Local distribution system 1.0 million 100 kw wind turbine 1.0 million Electronic control/dispatch 1.0 million Tieline to connect villages 500k/mile Hydropower 500 kw 8.5 million

8 Many of AVEC s villages are in Western Alaska have Class 4 or better wind regimes Alaska Wind Map

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10 AVEC Wind Projects 2003 Selawik 260kW 2006 Kasigluk 300kW with tie line to Nunapitchuk 2006 Toksook Bay 400kW - with tie lines to Tununak and Nightmute 2008 Hooper Bay 300kW Savoonga 200kW 2009 Gambell 300kW 2010 Chevak 400kW Mekoryuk 200kW Quinhagak 300kW 2011 Shaktoolik 200kW Emmonak/Alakanuk 400kW 2016 St. Mary s 900 kw 2017 Bethel 900 kw Kasigluk #11

11 A Snapshot of Wind Production in 2014 Community Pop. mwh 12 Sales Average kw load kw Wind Installed Wind Percent Selawik 876 2, % Kasigluk +1 1,163 2, % Toksook Bay +2 1,288 3, % Hooper Bay 1,178 3, % Savoonga 718 2, % Gambell 713 1, % Chevak 989 2, % Mekoryuk % Quinhagak 724 2, % Shaktoolik 282 1, % Emmonak 1,571 3, %

12 AVEC Current Major Projects New Stuyahok Ekwok Intertie Emmonak Tank Farm and Power Plant Wind Studies Stebbins, Eek, Elim, Mt. Village, St. Mary s, Teller, Bethel 900 kw Wind Design and Construction St. Marys, Bethel, Stebbins Wind to Heat Chevak, Gambell, Mekoryuk, Shaktoolik Heat Recovery New Stuyahok, Noorvik, Stebbins Old Harbor Hydro FERC license imminent 13

13 AVEC SOLAR In 2012 AVEC installed a 10 kw stationary PV array at latitude 64.3 degrees. Electrically it feeds into a single string 3 phase inverter. The angle of the panels is changed seasonally. In winter these panels are vertical. Capital cost was $120K, and some reliability cost a bit to sort out. Attended to acquire PV experience, it has a 60 year payback Kaltag #14

14 Cloudless September Day

15 The Effect of Partial Clouds

16 Northern SOLAR Issues Winter sun is of short duration and is low to the horizon. Summer sun lasts a long time but goes in a circle. Access to the sun with non-tracking arrays is limited. BUT - Tracking solar arrays are unreliable when subjected to cold temperatures and high winds. BUT if the cost is low enough, stationary arrays will be cost effective. AND Not just utilities will be installing them. Are you ready? Technically? Tarriffs? #17

17 Picture of Drying Salmon Bleeding Edge Technology in a Subsistence 18 Environment How do you structure tariffs when the value of renewable energy can vary from high (directly avoiding diesel fuel consumption) to zero (there are more renewables than we know what to do with)

18 Arctic Alaska Sustainability Issues Small systems that do not economically support large utility infrastructure Overly-optimistic life-cycle costs Lack of well trained local operators Lack of well trained maintenance personnel Complex inter-dependent systems Lack of system redundancies Continual obsolescence of

19 Arctic Alaska Sustainability Depends Upon Connecting communities with interties Continuing Vendor-Client relationships Standardizations of design and operation Design and maintain for long term pay back Cooperative Operator and Technical training Continual Operational Logging Remote Operational Monitoring

20 Grid Bridging Systems - Similar to this one by ABB (Kotzebue AK)

21 What is a Grid Bridging System? The GBS is comprised of three essential elements and two optional ones. The essential ones are: Essential requirement #1: A fully grid-forming inverter (programmed to simulate a rotary generator) The simulation should include speed droop, VAR droop and frequency adjustment capabilities. They should act just like a gen-set, not an inverter. This may be new territory for many inverter suppliers, but it is essential to provide an always-on system that plays well with others. Because it is always on, quiescent power consumption by the inverter should be minimized. #22

22 What is a Grid Bridging System? Essential requirement #2: A high power energy storage element. Ultracapacitors are recommended due to their long cycle life, high efficiency, safe maintenance, and low risk. Once again, using ultracapacitors may stretch the capabilities of some suppliers, but it is essential for fulfillment of the GBS s goals. #23

23 What is a Grid Bridging System? Essential requirement #3: A system controller, which can monitor the state of charge of the energy storage and choose to start/load-up the most efficient generation source or stop/unload the least efficient one. Typically these would be diesels, but curtailing wind output with pitch control is another possibility. When controlling multiple diesels, the system control will need to know the efficiency curves for each gen-set, at least sufficiently to know when to switch to a different unit or combination. The system controller may be the only source of rate information - how much value should be given to customer generated renewables? #24

24 Optional GBS Elements 4: If economically justified, then an energy storage array, typically a chemical battery. The cost to operate is the charge-discharge life cycle cost. The advantage is to take advantage of times of low marginal cost power (such as wind turbines in high wind) by charging, and then discharging during high marginal cost power, typically offsetting diesel fuel. If you don t have times of low marginal cost power, then you don t need this. 5: A load of last resort. This is typically a resistance element dumping surplus energy into a heat recovery system. You need this if your un-controlled renewable energy sources exceed your system load. Future consumer installations of PV arrays may require this! Containerized Lithium Battery #25

25 Why a Grid Bridging System? They Perform two essential functions on micro grids, these become more important as the penetration of renewables increases. 1: They provide spinning reserve seconds of full power reserve is sufficient time to bring another diesel engine on line. Not having to run an oversized diesel to provide spinning reserve is a huge advantage - run the most efficient diesel instead. Even when there are no renewable sources, this provides a large increase in efficiency. Spinning reserve will also prevent outages from diesel gen-set faults. Overall system reliability increases. #26

26 Why a Grid Bridging System? Spinning reserve is absolutely critical with large wind turbines, which can shut-down without warning during high winds and maximum output. Larger wind turbines provide much better cost per installed capacity, but are harder for micro grids to digest, and without spinning reserve, will cause outages when the turbine faults. #27

27 Why a Grid Bridging System? 2. They provide stability. Renewable sources (especially wind) are notoriously power noisy. The ultracapacitors soak up the noise by acting as a large power shock absorber. Larger turbines generally produce more noise, despite pitch control of output. Instead of having to reduce the output of a pitch control wind turbine to provide a more steady output, the GBS allows the turbine to produce as much as possible, even though there will be constant wind induced power fluctuations. #28

28 Why Ultracapacitors? 1: They can be discharged before servicing. So elaborate safety procedures by trained personnel are not necessary. 2: They don t catch fire, so elaborate segregation into fire-wall separated racks is unnecessary. Worse case is reduced. 3: When pumping power in and out of capacitors, only ohmic losses occur. Charging voltage is essentially the same as Discharge voltage. 4: They are not chemical energy storage devices, they store energy by electrostatic fields, so they are able to be cycled millions of times. This is particularly important when providing second by second system stability. Xtreme Power was contracted to provide battery systems at First Wind s Kaheawa I and Kahuku wind energy projects, the Kauai Island Utility s Koloa solar energy project, and Castle & Cooke s La Ola solar energy project. The Kahuku battery was destroyed by a fire in #29

29 GBSs can change the game. 1: Currently renewables are the bane of micro system operators because of their uncontrolled nature, and the future potential for customer owned PV arrays just makes it worse. A GBS provides enough time to make intelligent dispatch decisions. 2. They must be based on a common specification across all manufacturers. This will make operation, troubleshooting, training, and long term maintenance and component replacement possible. We MUST get away from one-off, customized solutions to make renewables work. It should be like a Model T, any color as long as it s black. Only then can these devices supply the system backbone to hang renewables on. #30

30 Arctic Alaska Sustainability Depends Upon Connecting communities with interties Continuing Vendor-Client relationships Standardization of system design and operation Design and maintain for long term pay back Cooperative Operator and Technical training Continual Operational Logging Remote Operational

31 Thank You! William Thomson PE PEng Operations Manager Alaska Village Electric Cooperative