Field Notes: The Polar Field Services Newsletter

Postcard from the Field

Building the ‘Solar Chalet’ at Toolik Field Station

The building site for the Solar Chalet. All photos: Tracy Dahl

The building site for the Solar Chalet. All photos: Tracy Dahl

Recently, PFS renewable energy expert Tracy Dahl spent a few days at Toolik Field Station, Alaska. He and associate “Solar” Joe Yarkin worked at a nearby field site where Jeff Welker (University of Alaska, Anchorage) will mount a new NSF-funded research project. Below, Tracy takes us through the process of building a solar array durable enough to withstand extreme temperatures and the elements, demonstrating yet again that polar research (and research support) is not for delicate flowers.

Step one: Find the ground. Not only did almost three feet of snow have to be removed from a 15’ x 25’ space—it had to be removed from the site entirely. We shoveled it onto a sled and drug it 300-feet away.

Then we shoveled it off again. Repeat, repeat, repeat, ad nauseum. Everything had to be snowmobiled into the site. Here Joe shows off our tools, while postholing for the 10,000th time that day.

Keeping it clean: Joe finishes covering tools for the day.

Keeping it clean: Joe finishes covering tools for the day.

We hauled 16 batteries in by sled.

Each battery is 305 Amp hours and weighs approximately 100 lbs.

Each battery is 305 Amp hours and weighs approximately 100 lbs.

We hauled many many loads.

This load contained the power electronics enclosure and some of the 24 solar panels.

This load contained the power electronics enclosure and some of the 24 solar panels.

Once we situated all of the gear, materials, and components on site, began constructing the power system.

We had to erect a platform on spongy tundra that can hold a couple of tons of weight.

We had to erect a platform on spongy tundra that can hold a couple of tons of weight.

Cribbing is stout, inexpensive and creates a well dispersed footer.

Cribbing is stout, inexpensive and creates a well dispersed footer.

The structure begins to take shape.

The structure begins to take shape.

Once we completed the platform, we built an A-frame for the solar arrays, which face east and west. A second array will face south.

The solar array system will harvest solar power 20 hours a day in the high arctic summer.

The solar array system will harvest solar power 20 hours a day in the high arctic summer.

The complete (and very strong) structure with one of the two polycarbonate skylights in place. The structure's strength is achieved with the A-frame design, PV panels, and the diagonal cross bracing.

The complete (and very strong) structure with one of the two polycarbonate skylights in place. The structure’s strength is achieved with the A-frame design, PV panels, and the diagonal cross bracing.

Everything was made as small as physically possible to minimize snow drifting in the research area, while still getting the job done.

Tight quarters.

Tight quarters.

We built in rain protection for the equipment in the summer, while allowing snow to scour through in the winter.

This shot shows the polycarbonate “double bubble.”

This shot shows the polycarbonate “double bubble.”

Like everything else in the system, the batteries were a precision fit, with no extra room to spare.

This represents 30kWh of energy storage, enough for 24 hours of autonomy (no power generation).

This represents 30kWh of energy storage, enough for 24 hours of autonomy (no power generation).

We also installed a back-up generator and power electronics enclosure. If necessary, this generator can completely recharge the batteries in about four hours. The backup generator is a shared asset with the Shaver/Bret-Harte AON project, which uses it in the winter.

With the multi-faceted PV arrays, we do not expect to run the backup generator much—if at all—during the Welker EAGER summer project.

With the multi-faceted PV arrays, we do not expect to run the backup generator much—if at all—during the Welker EAGER summer project.

Tracy Dahl

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