Calling at Ivotuk (Part 1)

Ivotuk, AK, is a small research site at the southeastern edge of the National Petroleum Reserve on the North Slope of Alaska’s interior. The station supports autonomous instrumentation that requires electrical power 24 hours a day, 365 days a year to transfer scientific data to researchers at their home institutions in near real-ime. Scientists who rely on the data from Ivotuk include Dr. Walter Oechel, director of the Global Change Research Group at San Diego State University, and Dr. Larry Hinzman of the Water and Environmental Research Center of the University of Alaska, Fairbanks (WERC), among others. Providing this data requires a reliable, consistent power source. Enter Tracy Dahl, our renewable energy specialist. Since 2003, he has worked full time for Polar Field Services to integrate renewable energy technology in some of the world’s most inhospitable environments, such as Ivotuk. Last week Dahl and his team did some critical maintenance at the remote station. Here’s what they did, in his own words.

Work at Ivotuk is progressing on schedule. The damaged wind turbine was replaced with our last good re-built spare unit. A potential vendor in Colorado has been located that may be able to help us keep these machines in service longer. It will be more fully investigated upon return.

The team raises the new wind tower. All photos: Tracy Dahl

Much of the generator maintenance has been accomplished, with Brad Whelchel performing the majority of the labor. About 40’ of coolant hose has been replaced along with complete fluid change out. The leaking radiator on Gen A was replaced at this time as well.

The re-worked PV charge controllers and monitoring system. Controlling each array independently overcomes problems with differential voltages and increases system efficiency.

We finally experienced a Gen A fail to start and lock-out while on site. This is an intermittent problem that has occurred for a couple of years now, but we could never get it to replicate while on site. The engine also failed to crank in manual mode, which narrowed the possible causes. We have replaced the ECU (engine control unit), and so far it seems to be working properly.

Ivotuk PV. The new array is on the right and is rated at 1kW maximum output. The three arrays are set up with a moderate multi-azimuth orientation to produce the maximum amount of power on a year-round basis while hopefully offsetting diesel generator runs almost entirely in the warm summer months. This should correct the problem we have experienced in recent years with a positive feedback loop as the module tries to cool itself off.

The new 1kW PV array has been installed and even in generally gray solar conditions is proving to add greatly to the overall energy balance of the system. The control architecture has been reworked, with each of the three arrays feeding in through a separate charge controller. This significantly increases the overall output. A new AXS Port allows for high resolution remote system monitoring.

The back of the new PV array showing additional bracing and tie downs. The array is set at a steep 80 degree angle to maximize power production in the shoulder seasons. The black color and angle should minimize snow accumulation. The bottom of the panels is located 40” above grade to prevent being buried in snow drift. All of this produces a significant sail effect, so it is important to hold it down well. We use a combination of pinning with re-bar, ballast and guy cables. Two more side guys are yet to be installed.

The system for jacking and re-levelling the module has been set up and a pre-task safety meeting conducted. We will not raise the module until SRI staff is on site to re-point the satellite dish, as we expect to lose connectivity at that time.

New array from the front. To a solar geek, it is a beautiful thing.

PV arrays and wind turbine tower have had their earth grounding systems updated, with more current technology lightning arresters added as a precaution.

The landform has changed over the past ten years, so the module must be re-levelled. Here is the set-up with two Hi-Lift jacks and spreader bases.

Things are going to plan and we are on schedule. SRIU and NOAA staff are expected to arrive Sunday, June 15. We are ready.