American Samoa Power Authority

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1 American Samoa Power Authority 1.75MW Photovoltaic Solar Power System March 2013 American Samoa Delegation 1

AMERICAN SAMOA POWER AUTHORITY GRID-TIED PHOTOVOLTAIC POWER SYSTEM PROJECT Introduction American Samoa is a group of five inhabited islands and is a US territory located in the South Pacific.

American Samoa has a semiautonomous utility called the American Samoa Power Authority (ASPA) that provides Electric, Water, Waste Water, and Solid Waste utility service to its entire population.

2 AMERICAN SAMOA POWER AUTHORITY GRID-TIED PHOTOVOLTAIC POWER SYSTEM PROJECT Introduction American Samoa is a group of five inhabited islands and is a US territory located in the South Pacific. It has a population of approximately 55,000, with over 90% of its population residing on the main island of Tutuila. American Samoa has a semiautonomous utility called the American Samoa Power Authority (ASPA) that provides Electric, Water, Waste Water, and Solid Waste utility service to its entire population. For the main island of Tutuila, ASPA provides power from two power plants, the Satala and Tafuna Power Plant. The total peak for the island is around 23MW. The two power plants operated in parallel until September 29, 2009, when a devastating tsunami destroyed the Satala power plant located inside Pago Pago harbor, taking out about 60% of ASPA s generation capacity. A temporary power station is now in place at Satala providing power from containerized generators. The ASPA through assistance from FEMA is planning the construction of a new replacement Satala power plant. The Tafuna plant and the temporary Satala plant are still operating independently until a planned Tie-line system for Satala is installed; this will allow the two plants to once again operate in parallel. In April 2012, ASPA commissioned its Photovoltaic (PV) Solar Powered Systems located at two sites at the Pago Pago International Airport. The total PV system capacity is 1.754MW-DC, or 1.527MW-AC. The total project cost was $9M USD, and was fully funded from the American Recovery and Reinvestment Act (ARRA) of The PV system is expected to generate about 2% of ASPA s annual energy. The PV system is connected to the Tafuna Power Plant Grid System, which supplies power from the Central district to the Western district of Tutuila island. 2

Tutuila Island Grid Layout TAFUNA POWER PLANT GRID: Supplies Central to West Side, Peak: 11MW Feeder 5 Feeder 7 (Connected to PV Site 1.5, 362kW-DC) Feeder 6 Feeder 9 (Connected to PV Site 1.

3 Tutuila Island Grid Layout TAFUNA POWER PLANT GRID: Supplies Central to West Side, Peak: 11MW Feeder 5 Feeder 7 (Connected to PV Site 1.5, 362kW-DC) Feeder 6 Feeder 9 (Connected to PV Site 1.0, 1,391kW-DC) Feeder 10 Feeder 11 PV Site Location. * Tutuila System Peak: 22MW SATALA POWER PLANT GRID: Supplies Central to East Side, Peak: 11MW Feeder 8 Feeder 3 Feeder 4 Feeder SP (Tuna Cannery) Feeder SK (Tuna Cannery) Feeder 1 3

Overview The American Samoa Power Authority Photovoltaic solar farm project consists of two sites, the Main Site 1.0 has a capacity of 1,391kW-DC (1,217kW-AC) ground mount array on 3.

4 Overview The American Samoa Power Authority Photovoltaic solar farm project consists of two sites, the Main Site 1.0 has a capacity of 1,391kW-DC (1,217kW-AC) ground mount array on 3.93 Acres of land located just north of the southwest end of the airport runway and Overflow Site 1.5 with a capacity of 363kW-DC (310kW-AC) ground mount array situated on 1.88 Acres of land located approximately 0.60 mi to the NE for a total power capacity of MW-DC or 1.527MW-AC. Site kW 1.88 Acres Site 1.0 1,391kW 3.9 Acres 3,397 feet Apart The total Airport land Acreage used for this project is 5.81 Acres, however, for the smaller PV site 1.5, only 1.3 Acres was used up; there is still 0.58 Acres of available land. ASPA plans to add an additional 218kW-DC for this site in the near future. The PV systems are connected to the ASPA Tafuna electrical grid and converts solar energy into electricity using 7,308 Sharp PV modules that are mounted using galvanized steel pipe structure. There are also roof mounted PV systems on island, totaling approximately 630kW-DC owned by Government offices, private business and residents. On Site 1.0, the 1,391kW array connects to five (5) 260kW PV Powered inverters. The inverters are housed in two different Power Vault enclosures. Power Vault-1contains 3 inverters with a combined output of 780kW. Power Vault-2 contains 2 inverters with combined output of 580kW. Within each Power Vault, the 480VAC outputs of each inverter are combined and connected to a 750kVA transformer with a primary voltage of 13.2kV. The 363kW array connects to (1) 260kW and (1) 50kW PV Powered inverter. Both inverters are housed in Power Vault- 3 with a combined output of 310kW AC. The 4

5 480VAC output of the Power Vault is then connected to a separate MV transformer (provided by ASPA) which steps the voltage up to 13.2kV. 260kW Inverter Unit inside Ventilated Power Vault Enclosure These are utility-scale, grid-interactive systems. In this configuration, the PV system operates to provide power to the utility grid during the daylight hours (there is no provision for energy storage such as a battery bank). The system does not have standalone capability, since it must be connected to AC power from the utility grid in order for the inverters to function. In the event of a utility loss of phase or complete power outage the inverter shuts down to ensure the safety of utility line workers. Upon restoration of utility grid power the inverter will automatically resume operation after a 5-10 minute delay. The inverter operation is completely automatic. The inverter wakes up and begins to deliver power as the sun rises and sleeps as the sun sets. The inverter electronics monitor and match utility voltage, frequency and phase angles and deliver current as sunlight is available. Upon detection of abnormal conditions such as over/under frequency or over/under voltage the inverter disconnects itself from the utility grid and goes into a standby mode, awaiting restoration of normal utility conditions. PV System Design Selection On January 2011, ASPA issued out an RFP for a PV Solar System; unlike past RFP s, ASPA made known the funding amount of $9M for the PV project, and required the offerors to provide a system with the best energy output from the available funding. Other main requirements included hardening against tropical cyclone wind strength of 150mph, and marine environment. The ASPA also had to comply with funding source (ARRA) regulations, which required ASPA to follow the Buy America requirements for materials and equipment for the project. 5

6 Out of five proposals, the ASPA engineers selected Sunwize (SW) Technologies to design and build its PV Solar System. The PV system was designed with six 260kW inverters and one 50kW inverter which provided ASPA with the flexibility to sectionalize the PV system with the fewest number of inverters. Other proposals offered a system with numerous inverters, and a smaller PV system output compared to SW. Project Challenges Locating flat land on a volcanic mountainous island, which are scarce on small islands Logistics, storage and movement of materials, staging area. Some heavy equipment required for movement of equipment Drill rig for drilling volcanic rock required for footing installation, had to be shipped from NZ, very expensive to rent Obtaining FAA clearance and Govt. permits takes time Vandalism after installation of PV s panels Coordinating between contractor, government agencies and other project workers Very high profile project for a small island Tropical environment and high rainfall, requires more frequent weed control Additional Fixed Operating Costs due to monthly lease of $9,493 for the fair market value of Airport Land of 5.81 Acres Grid Stability Issues Inverter Frequency is set to trip the inverters at 59.3 Hz and 60.5 Hz The PV is installed on the Tafuna grid with a penetration level of 20% during weekends (including privately owned PV systems) ASPA requires extra spinning reserve to make up for the PV output drop during cloud cover. Need to run extra gensets to adjust frequency as clouds cover the PV panels, output can drop by 70% Other Project Information Contractor: Sunwize Technologies 111 W. St. John St. Suite 1200 San Jose, CA TEL: Funding: American Recovery and Reinvestment Act (ARRA) of 2009 grant funding Project Cost: $9M USD System Monitoring: Draker Laboratories provides the PV Data Acquisition System through their monitoring equipment. System data and reports are accessed on a web interface called Sentalist4 by Drakers Laboratories. Solar, Temperature and Wind instruments are also installed on 6

7 site to monitor ambient weather conditions for PV output forecasting and performance monitoring. PV Power System Performance Graphs & Tables 18% Max Tafuna Grid Penetration % 15% % w.r.t. Tafuna Grid 14% 12% 10% 8% 6% 9% 10% 12% 13% 12% 12% 11% 14% 12% 12% 4% 2% 0% March April May Total Tafuna Grid Penetration June July August September October November December January PV Penetration Data (kw) 2012 PV TAFUNA Penetration (ASPA System Only) Mar 897 9,650 9% Apr 1,197 10,425 10% May 1,319 9,900 12% Jun 1,313 8,625 13% July 1,327 10,025 12% Aug 1,429 10,200 12% Sept 1,459 12,075 11% Oct 1,483 9,350 14% Nov 1,493 10,550 12% Dec 1,484 8,150 15% 7

8 Power Output on Typical Scattered Cloud Day 8

9 PV System Capacity: 1,754kW-DC, 1,527kW-AC 2012 to Date Monthly kwh Capacity Factor Days in Operation March April 164,411 19% 23 May 170,987 15% 31 June 158,615 14% 30 July 152,056 14% 31 August 225,740 20% 31 September 191,375 17% 30 October 230,857 20% 31 November 229,931 21% 30 December 219,228 19% 31 January 182,193 16% 31 February 222,066 22% 28 Total 2,147, % 327 Financial Performance Mar to Feb Per Day Per Month Gallons avoided 151, ,067 Average Fuel cost $3.76 per gal Avoided Diesel Costs Estimated $568,623 $1,739 $52,892 *Based on System Fuel Efficiency of 14.2kWh/Gal 9

10 Typical PV Power Output on a Day with Scattered Clouds (Site 1.0) PV Site 1.0, Capacity: 1.37MW DC, 1.2MW AC Land Area: 3.9 Acres Site 1.5 Overflow, Capacity: 362kW DC, 315kW AC 10

11 Land Area: 1.3 Acres Power Vault Enclosure at Overflow Site 1.5 PV Footings Installation 11

12 Damaged PV Panel from Vandalism Inverter AC Output Readings Draker Lab Instrument Pole 12

13 PV System Technical Information The photovoltaic (PV) modules are attached to ground mounted array racking system at a 10 tilt at a 329 azimuth angle. The main site has 5,796 PV modules feeding two (2) Advanced Energy Power Vaults. Within the first Power Vault (PV-1) there are three (3) PV Powered PVP- 260 kw 480V inverters. In PV-2 there are an additional two (2) PVP-260 kw 480V inverters. The inverters feed through a medium voltage transformer to raise the voltage to 13.2 kv for interconnection to the utility service. Similarly the overflow site has 1,512 PV modules with one PVP-260KW 480V & one 50 KW 480V inverters fed through medium voltage transformer to the grid. This system has been designed for unattended operation and should present no danger to personnel during normal daily operation. Table below is an analogue view of the entire system. Site 1 Power Vault 1 2 Inverter Inverter Size KW AC String Size Size Qty Module Qty Array Size KW-DC A B C D E SITE-1 Total: F G Site 1.5 Total: System Total: TECHNICAL DETAILS OF COMPONENTS ARE GIVEN BELOW: Photovoltaic Modules Manufacturer: Sharp Model: ND-240QCJ Rated power, at STC 240 watts DC Rated power, at PTC watts DC 13

14 Performance Specifications Conditions: STC1, PTC2 Module power, watts: STC: 240W-DC PTC: 216.4W Module efficiency 14.7% max power (Vmp), volts: 29.3 max power (Imp), amps: 8.19 Open circuit voltage (Voc), volts: 37.5 Short circuit current (Isc), amps: 8.75 Max system voltage, volts DC 600 Max series fuse rating, amps: STC: 1,000 W/m2, 25 ºC cell temperature, 1.5 air mass spectrum. 2. PTC: 1,000 W/m2, 20 ºC ambient temperature, 1.0 m/sec wind speed. Module Physical Specifications Length: 64.6 in. Width: 39.1 in. Overall area: ft2 Depth: 1.81 in. Weight: 41.9 lb. DC Distribution DC Combiner Boxes - String Combiners Manufacturer: Bentek Solar Model: BTK D400 Quantity: Installed 24, Spares 3 Enclosure rating: NEMA 4X Overcurrent protection: 15A, 600 VDC (KLKD-15), Spares 30 Output connection rating: 400A Integrated DC Disconnect: Yes Array Combiners Manufacturer: Bentek Solar Model: BTK Quantity: Installed 6, Enclosure rating: NEMA 4X Overcurrent protection: 350 A, 600 VDC, Output connection rating: 1600A 14

15 DC Disconnect Switches DC disconnects integrated into String Combiners and Inverters Power Conditioning System Inverter (Inverters A-F) Manufacturer: PVPowered Inverter Model: PVP260KW (480Vac) Inverter Quantity: 6 Inverter Rating: 260 kw Input Voltage (MPPT): 295 to 600 VDC Maximum Input Isc: 925 ADC Nominal AC Line Voltage: 480 VAC (422 VAC to 528 VAC) Nominal Line frequency: 60 Hz Maximum output current/phase: 316 AAC (continuous) Enclosure: NEMA 3R with environmentally enclosed electronics Cooling: Forced air Max. Ambient Temperature: 50º C (122º F) Safety: UL 1741, IEEE 1547, CSA , IEEE C Inverter Enclosure (Power Vault 1 & 2 - Main Site) Manufacturer: PVPowered Model: PVP780KW Rating: 780 kw Inverters A, B & C power vault-1 & inverters D & E power vault-2 Nominal AC Line Voltage: 13.2 kv Nominal Line frequency: 60 Hz Maximum output current/phase: 34.1 AAC 13.2kV) Enclosure: NEMA 3R Cooling: Forced air Inverter Enclosure (Power Vault 3, Overflow Site) Manufacturer: PVPowered Model: PVP310KW Rating: 310 kw Inverters F & G 15

16 Nominal AC Line Voltage: 480 V Nominal Line frequency: 60 Hz Maximum output current/phase: 377 AAC 480V) Enclosure: NEMA 3R Cooling: Forced air AC Disconnect Switches The AC Disconnecting means for each inverter is the inverter output breaker located in the main switchboard of the Power Vault. Each breaker is labeled with the appropriate with the inverter it services. The primary disconnecting means for each Power Vault is the main breaker for the main switchboard. Point of Common Coupling Power Vault 1: Primary side of transformer Power Vault 2: Primary side of transformer Power vault 3 : Primary side of Transformer PV System and Weather Monitoring System Manufacturer: Draker Laboratories Model: System Manager & Weather Station DC Grounding PV module frame interconnect to combiner boxes: 10 AWG & 6 AWG bare Source circuit combiner boxes to re-combiner ground: 2 AWG THWN-2 Re-combiner to inverter: 3/0 AWG THWN-2 Ground fault detection and interruption: By PV Powered inverters 16

17 AC Grounding Both Power Vaults are grounded to a 250kcmil ground loop with eight (8) ground rods distributed around the Power Vaults. Data Acquisition System (DAS-1) The DAS-1 Sentalis 1000 PV base station is the central point for collecting data from site instrumentation, and gateway for data transmission to Draker hosted data server. The system includes a Campbell Scientific CR1000 data logger, NEMA 4X Stainless Steel enclosure, 37-Ahr battery backup. PV production details and data are available on line for tracking and reporting. 17

18 Typical Schematic of PV System Connection 18

19 19

SunSwitch setting requirements min. 15 % Daily output in average month 154 m³

SunSwitch setting requirements min. 15 % Daily output in average month 154 m³ Parameter Location: Nigeria, Bonny (4 North; 7 East) Total dynamic head: 20 m Required daily output: 70 m³; Sizing for average month Motor cable: 25 m Dirt loss: 5.0 % Pipeline: - Products Quantity Details