Wind energy is touted as so environmentally friendly that it deserves cross-subsidy from other energy production. If it actually was environmentally friendly, that argument might be valid. Sadly, wind energy is the opposite of friendly - it makes things worse, it would be better for the environment to take that subsidy money and burn it. Windmills are a statement: "look at ME! I'm GREENER than you are!" Someday, they may come to symbolize thoughtless consumption.
Electricity does not store. In some parts of the world, Norway for example, there are high mountain valleys not far from low valleys, and lots of water, which can be used for pumped hydro energy storage. This is not true of most of the world.
Here in the Pacific Northwest, the Columbia river is used for hydro-power, but it is a running river system. Once a bolus of water is released from giant reservoirs in British Columbia, the water inexorably heads downhill though a series of shallow reservoirs and dams until it reaches the sea. The heights of the reservoirs is limited - the channel is only so deep. It cannot be used for pumped storage. The dams are spaced to maximize power production for peak usage times on the west coast, and the water boluses are released to match expected demand many days hence. But there is little room for water flow adjustment, especially given the primary missions of the Bonneville Power Administration - wildlife, fish runs, navigation, and irrigation. Power production is relatively low on the list. Perhaps the Norwegians have different priorities.
The wind blows erratically. Power production is proportional to the cube of the wind speed. If the wind is blowing at half of peak design speed, the power production is 12% of peak production. If the wind is blowing faster than peak design speed, the generators and power systems can't handle the load; the turbine blades are pitched down and power is limited to peak power. If the wind is blowing much faster than peak design speed, the blades are "feathered" and the generator stops. If the wind is blowing at category 5 hurricane force, the whole turbine topples to the ground. Wind is not an easy power source to manage.
The power is not only erratic, it tends to peak at night, when the demand is minimum. There are potential customers for that power - electric car recharging, irrigation water pumping in Southern California.
However, wind farms are scattered and cover large areas. Aggregating that power and feeding it to the grid requires lots of power transmission lines. The existing transmission lines are inadequate, and because of the glacial pace of site studies and regulatory approval, as much as 15 years is needed from proposal to operation. Because of this, there is no way to get power from most wind farms to most customers - the transmission lines (even at night) are saturated. So much of the power is thrown away, heating resistors in the desert.
Wind generators must be light to operate on top of tall pylons, yet they are subjected to enormous buffeting wind forces. This wears them out quickly - generators in Europe typically last 7 years. When they fail, they must be lowered back down the pylons and taken back to the factory for re-manufacture. A construction and a reverse construction every 7 years is not compatible with a 10 year economic payback time for a single construction event. If the generators are imported, or if the designs change over time, the repair process becomes even more expensive. Even so, 7 years - 60,000 hours - is a pretty good operating life. That is like getting 2 million miles on a car engine. Airplane jet engines typically run for 5000 hours before replacement.
Generators use a lot of rare earth metals such as neodymium in their high-tech magnets. Most of these materials are single-sourced from China. There are other ore deposits, such as the Mountain Pass mine owned by Molycorp in southern California, but most of the world's rare earth mines have been shut down because of they are incredibly toxic in operation. The rare earths are typically associated with thorium and other radioactive elements. Safely operating these mines is difficult. Only in China are these kinds of dangerous operations permitted.
Other materials needed for wind turbine deployment are less toxic, but are still energy intensive. Many tons of aluminum, steel, and concrete must be manufactured and assembled on the site.
I won't dwell on bird strikes, noise, and appearance. The death count for bird strikes is secret. Noise and unsightliness is in the mind of the beholder, and if it drives some of the looky-loos out of the country and back to the city, the environment will benefit.
Like many alternative energy sources, wind turbines are a dead-end scale-up of technologies that make sense only when the scale is small and the energy is used as it is generated. The old farmer's well pump made sense. Wind farms do not. And the only way to know is to run the numbers based on realistic measured data. "I wish it were so" doesn't power modern civilization.
The Europeans are figuring this out. The massive push to build wind farms is petering out, as the stark realities of counter-cyclic mismatches between demand and load, and the horrendous recurring maintenance costs, become impossible to ignore. Most of Europe can't use Norwegian pumped storage, so they must fill in the dips in wind production with quick-start natural gas generators. The natural gas comes from Russia. Electric motor magnets and car battery materials come from China. Rather than create energy independence, the Europeans are trapped by the geopolitical agendas of these sole-source material producers.
Guess why natural gas tycoon T. Boone Pickens is promoting wind energy in the U.S.?
It was a worthwhile experiment to build a few wind turbines and gather that data. Now it is time to stop, and spread the data far and wide. And work on many other alternatives, such as advanced fuel cycle nuclear, and Server Sky. It is too early to pick winners. We don't know enough. But we do know enough to stop major investments in losers, and invest in more research instead.