Can geothermal heat pumps really work in the harshest of climates?

How about wintertime in Alaska, where temperatures can drop to a bone chilling -40°F? - Scientists Skeptical of Anthropogenic Global Warming - Gus Mahlr 

The goal of the research project—which replaced the 77,000 Btu/hr oil-fired condensing boiler that had been heating the 5,000 square foot office space—was to monitor the system for 10 years to better understand the performance of geothermal heat pumps in sites with permafrost and high heat needs, helping to inform future designs.

• Researchers at the National Renewable Energy Laboratory in Alaska put this idea to the test, and their results were nothing short of impressive!
• With over 700 gallons of fuel oil saved per year ..., it's clear that geothermal is the most efficient and cost-effective way to heat any size of space.

To read the full article, click the link below:
https://www.energy.gov/.../geothermal-heat-pump-case...?
Mike Austin - Two points, needs a heat source, like warm volcanic rock, as that will allow the heat cool cycle to work in areas like Alaska. In the lower 48 states, the deap ground is warm enough naturally. Permafrost will not work...