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Imnavait Creek, Alaska - Autonomous Power and Communications Systems
Tracy Dahl
Polar Field Services
Partner in CH2M Hill Polar Services

Imnavait Creek Ridge Station
Imnavait Creek Ridge Station
(click on image for larger version)
Power System panel
Power System panel
(click on image for larger version)
System Solar icon Wind turbine icon Battery iconSolar and Wind as renewable energy sources to a sealed lead-acid battery bank.
Location Two sites are located on the North Slope of Alaska approximately 8 miles NE of Toolik Field Station and 2 miles from the Dalton Highway.   (68° 36' N, 149° 18' W)
Description Overview

Two autonomous power and communications systems in support of separate instrument towers measuring gases and meteorological data.

These autonomous power and communications systems were developed by ABS Alaskan in support of the NSF supported Brett-Harte/Shaver project, part of the more encompassing AON (Arctic Observing Network) initiative. These units were originally intended as temporary support infrastructure, while a long-term solution could be developed. Due to budget constraints, the original project scope and requirements have been reduced, and no longer include provision for more power consumptive winter time instrument de-icing.

These skid mounted units are capable of being transported by sling load from a large helicopter, but must be disassembled for transport by smaller aircraft. Power generation is provided by a 650 Watt PV array and a 900 Watt rated wind turbine. Energy storage is provided by an AGM type battery bank rated at 43,000 Watt-hours at the 24 hour rate. This provides for a 15 day period of autonomy with no energy input from sun or wind, not dropping below a 65% state of charge.

The PV array and wind turbine are supported by a tilt-up, guyed lattice tower, attached at the base to the skid unit. An insulated fiberglass enclosure is also mounted to the skid, and houses the batteries and all electronics.
The system operates at 48VDC nominal, obviating the need for power inverters for transmission to the instrument towers, located approximately 100' distant from the systems. Efficient DC/DC converters reduce the voltage to 12VDC to power instrumentation at the towers, as well as the communications equipment within the modules.

Iridium modems at the power modules are intended to relay power system status and a daily photo from the webcam, located at the ridge site. Similar modems at the towers are intended to relay science data to the researchers home institution.

  • PV array: Five Kyocera KC130, 12 volt, 130 Watt panels in series for 650 Watts at 60VDC. Array angle set at 85 degrees to maximize winter and shoulder season production.
  • PV charge control by Outback MX60 
  • Wind turbine: Southwest Windpower "Whisper 200". Rated at 900 Watts maximum output.
  • Wind charge control is diversion type, currently via a Power IO HDD series solid state relay that is controlled by the  AUX relay circuit of the MX60. 
  • Energy storage: AGM battery bank consisting of 32 each, Concorde PVX-2240T, 6-volt batteries. Arranged in series/parallel configuration for 48-volt nominal in four strings.
  • Power transmission via #8 MC cable, laid across the tundra.
  • Instrument tower Tyco DC/DC converter from SRI International.
  • Circuit protection provided by Square D, QOU series breakers and Blue Seas fuse block.
  • Power system data acquisition accomplished by discrete sensors and an SRI developed single board computer (SBC/DAQ).
  • Webcam: Sony SNC-RZ30N in external enclosure
  • Communications:  Iridium using DoD RUDICS with NAL Research A3LA-D transceivers
Detailed report by Tracy Dahl (3.0 MB)  PDF icon