John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
Let's take a look back at the ambitious 1930s plan to erect this monstrosity over the city.
Berlin rests in the shadow of a monstrously tall steel tower with a hydra head of spinning fans, each about 500 feet in diameter. A medium-sized town's population climbs over the 1,400-foot-high structure, noshing in a cavernous cafeteria and peering off a cloud-shrouded viewing deck. The city is aglow with great gouts of energy pouring out of the windmill – as much as 130,000,000 kilowatt hours a year – illuminating the anguished faces of once-profitable oil barons now crying into their beer.
This was the ambitious 1930s-era vision of Hermann Honnef, a German engineer with a lifelong obsession with high towers and wind power. Honnef took a known fact, that there were steady, strong currents of air flowing high above the surface of earth, and ran with it to the limits of the human imagination. As you can see in this page from a 1932 copy of Science And Mechanics, dug out of a musty box by the ceaselessly entertaining blog Modern Mechanix, the multifanned windmill would've loom far above any building in existence at the time. Just imagine the bloody mincemeat it would make out of migrating birds, not to mention any unfortunate dirigible pilot sucked into its flailing blade-field.
The world was alerted to Honnef's startling plans for the future when he approached the German government in 1931, prompting a "storm of Indignation" from petroleum manufacturers who "saw themselves threatened by a competitor," according to a NASA translation of a German article on wind power. Nevertheless, the engineer was able to test prototypes in wind tunnels with promising results; he later built a larger-scale version in an experimental site outside Berlin, where it whirled successfully for a full year.
The crucial element of Honnef's giant windmill was the placement of three turbines at the top, each one serving as its own 30,000-horsepower electrical generator. Here's how Science And Mechanics describes it working:
The surveys which have been made in Germany show that, with little variation, wind velocities of 22 miles an hour are quite constant at the height illustrated. To utilize this most effectively, instead of small wheels, it is proposed to erect on each wind-turbine tower three power wheels, each 530 feet in diameter. The whole weight is so counterbalanced on bearings that it faces the wind; while the angle at which the wheels encounter the air currents is depending upon the velocity of the wind. If this is very high, as in a storm, they present their edges only; if the currents of air are light, the wheels take a vertical position, as illustrated in the detail at the lower right of our illustration. The wheel will begin to rotate in a breeze of but 4 miles an hour and, because of its great inertia, will turn steadily.
For an appetizer to the main event, Honnef wanted to erect a 665-foot-tall wind turbine near Berlin with fans 200 feet wide. This plan was endlessly delayed. However, a German company did construct a power plant based on his designs during World War II. Finished in 1944, the plant "could not be put into operation because of the air raids and was lost because of Germany's collapse," according to the NASA document.
Though Honnef was without a doubt brilliant and in possession of workable schemes – he turned down large amounts of money offered for his wind-based patents – the Godzilla-sized turbine attracted its fair share of doubters. Some worried that frozen buildups in the structure's canopy would send massive blocks of ice crashing onto horrified citizens. And The New York Times noted other potential problems:
Engineers who have built skyscrapers will readily concede that the construction of a steel, latticed tower 1,000 feet high presents no technical difficulties. But they are not so sure of the frame that tilts automatically in all directions. There are no precedents for such a structure. No one knows how it will behave in so fickle a medium as the wind, which may vary from a zephyr to a howling gale. Vibrations may be set up in the frame as a whole and jam the rather nicely balanced windwheel-frame.
In Honnef's defense, his idea to have the turbines go flat in the event of powerful winds was pretty smart. That way they avoided flying apart in a terrible explosion of fire and debris, like what happened to this British turbine in 2011 but on the apocalyptic scale: