Erecting a wind turbine in permafrost may be a little more difficult than you think. There are a lot of factors to consider. As the ground softens in the warmer months, the tower may experience a shift in lateral support, changing the relative center of gravity. Turbines cannot settle or tilt in any way or they will first lose efficiency. After that, the equipment will begin to break. The permafrost layer of the earth is constantly fluctuating in depth and distance to the surface. This not only affects the tower itself, but also the construction of the tower. The cranes used to hoist the tower up onto its foundation require leverage, which is sometimes difficult to acquire because of the unstable ground.
The logistics of transporting a crane to a construction site are substantial. Barging a crane to and from a project site is an alternative, but also demands waiting on the weather. Winter sea ice often makes the ocean impassible. To avoid driving on sensitive tundra lands during summer months, cranes used to lift a tower up onto its foundation are often stuck in rural Alaska for the duration of the winter, waiting to drive on the frozen landscape when the light returns. The need for a quick turn around on the crane rental is important for saving money.
There are a few ways to combat these issues. Small-scale “tilt-up” wind towers are available. These do not require a crane at all. Instead, tilt-up towers can be erected with the use of motor/hydraulic equipment or even a four-wheel drive vehicle.
To combat the foundational problems of permafrost, six or more pilings between one-third and two-thirds of the height of the tower may be driven into the ground. To avoid heating the earth, the foundation is generally elevated, allowing cold air to pass over the ground to keep it frozen. All of these solutions work well but are expensive, driving up the cost to erect a wind turbine in remote locations. Wind peaks daily at night and seasonally in the winter. Having a turbine up and ready to produce energy as soon as possible in project development is important in maximizing the return.