Wind Energy
Wind is nothing other than sunlight in motion. The sun heats the air unevenly, and off it blows.
The wind is among the oldest servants of humankind. Long before anyone spoke of electricity, it drove ships across the seas and mills on the fields. And at bottom wind energy is only a disguised form of solar energy: the sun warms land and water to different degrees, warm air rises, cool air flows in after it, and this balancing movement is what we call wind.
A bit of history
Sailing boats existed more than 5000 years ago, windmills for about a thousand years, first in Persia, then across Europe. They ground grain and pumped water; the Netherlands drained whole stretches of land with their help. The windmill was for centuries the strongest machine a village possessed. At the end of the 19th century the first wind turbines were built that, instead of millstones, drove an electricity generator. The great breakthrough, however, came only with the oil crises of the 1970s, when suddenly everyone was searching for domestic energy sources.1
How it works
The principle is astonishingly simple: the wind presses against the rotor blades, they turn, and this rotation drives a generator that produces electricity. Modern installations, however, are high-tech. Their blades are longer than a football field is wide, turn seemingly leisurely and yet capture enormous forces. For the power grows rapidly with the wind speed: twice as much wind means not twice but about eight times as much energy. That is why every metre of height counts, where it blows stronger and more evenly.
Today: on land, at sea and in the waves
One distinguishes two worlds. Onshore, that is, on land, stand most installations; they are cheap and quick to build, but run up against limited space and against residents who do not want them on their doorstep. Offshore, on the sea, the wind blows stronger and steadier, which is why huge wind farms arise there. They deliver a lot and reliably, but are expensive to build and maintain, for salt water and storm are merciless opponents.
A third idea is wave energy. Because the wind piles up the waves, wind power is stored in them too, only time-shifted. Installations that win electricity from the movement of the waves have so far hardly gone beyond the experimental stage: the sea destroys the technology faster than it pays off. A good example of the fact that a physically possible energy source is by no means yet a practical one.
Advantages
Wind is free, inexhaustible and in operation free of exhaust fumes and CO₂. A large wind turbine produces the energy needed for its construction back within a few months. And it complements the sun superbly: in winter and at night, when photovoltaics weakens, it often blows most strongly. Together the two cover a far larger part of the year than either on its own.
Disadvantages
The obvious catch: the wind, too, comes and goes as it pleases. On still days the rotors stand idle, and electricity cannot be produced in advance for storage. As with the sun, it therefore takes storage, grids and flexible backup power plants.
Added to this are tangible conflicts on the ground. Wind turbines are visible from afar and change landscapes, they produce a quiet but steady sound, and their rotors can become dangerous to birds and bats. These objections are to be taken seriously, but are also often politically inflated: bird protection turns up in the debate conspicuously often exactly where someone simply does not want to see the installation, while far deadlier dangers to birds, such as glass panes and cats, upset no one.
The critical look
Hardly any energy source is as contested as the wind, because you can see it. A gas power plant at the edge of town is barely noticed, a wind turbine on the horizon by everyone. That is exactly what makes the debate instructive: it shows that it is rarely only about technology, but about aesthetics, habit and the question of who bears the burdens and who has the benefit.
Whoever wants to judge in a self-determined way therefore asks: who owns the wind farm, a distant fund or a citizens' cooperative from the village? Do the profits flow away or stay in the region? Experience shows: where the people on the ground are involved and earn along with it, resistance drops astonishingly fast. The wind itself is neutral. Whether it is experienced as an imposition or as a shared gain is decided not by the technology but by how fairly we organize it.