Electricity without a power line
For most of the early twentieth century, the electric grid was a city affair. Utilities built lines where there were many customers, and farms and remote homes were often left out because the cost of stringing wire to a few households was too high. In the United States, a large fraction of farms had no central-station electric service into the 1930s. A small wind generator was one of the few ways to get electric light, and it was often the cheapest.
How a farm wind generator worked
The idea was simple. A propeller of two or three blades mounted on a tower was turned by the wind and drove a small generator directly or through a light gear. The generator produced direct current, usually at low voltage such as 32 volts, which charged a bank of batteries in a shed or cellar. A household drew its power from the batteries, not from the turbine itself, which meant lights could come on at night or in calm weather.
A tail vane pointed the propeller into the wind, and the blades were designed to regulate their own speed in strong gusts by changing pitch or by turning out of the wind. This mattered because a farm generator had to run without a technician. Systems were sized for a modest household load: a few lights, a radio and sometimes a small appliance, and electric motors for small tasks such as a cream separator or a water pump. Devices drawing heavy current, such as a stove or household refrigerators, were beyond what most of these installations could run.
Makers and the Midwestern market
Some firms made a business of wind chargers. In the United States, Marcellus Jacobs and his brother Joe began building wind-electric plants in Montana in the 1920s and sold them widely over the following decades, and several other companies sold propeller-type chargers, many of them to farms and ranches in the Midwest and the Great Plains. Machines were also made and used in Denmark, Australia, Canada, Argentina and elsewhere. Exact production numbers are uncertain, but accounts of the period describe large numbers of units, which indicates a real market and not a hobby.
One of the first things many families did with a wind charger was to run a radio. Radio broadcasting reached rural areas in the 1920s and 1930s, bringing weather reports, farm markets and entertainment, and a battery that could be recharged by wind made listening practical on a farm without any wires. Electric lighting in barns and houses also replaced kerosene lamps, which cut the fire risk and the work of trimming wicks, though it is hard to measure how much safer homes became.
Limits of the small generator
These machines had shortcomings. The output depended on the wind, and in calm periods the battery could run low, so many users kept a gasoline engine generator as backup. A lead-acid battery needed regular attention and could wear out quickly if abused. Because the supply was low-voltage direct current, wiring losses were high over any distance and standard appliances were not designed for it, so users bought special 32-volt bulbs and equipment, which cost more. Installing a tower was not cheap either.
Rural electrification and the decline
The turning point came when central-station power reached the countryside. In the United States, the Rural Electrification Administration, created in 1935, lent money to cooperatives that built lines to farms. The same kind of public effort took place in many other countries, at different times. A household connected to the grid got alternating current at ordinary appliance voltages, power in any weather, and no batteries to maintain. Within a few years, wind chargers lost most of their market in places the lines had reached, and many manufacturers shifted to other products or stopped production.
Not all wind generators vanished. They continued to serve places that remained off the grid, such as remote ranches, island stations, mountain huts and boats. In the later twentieth century, a revival of interest brought small turbines back for cabins and homes as the cost of power lines grew, and as battery technology improved and solar panels and wind were paired to cover each other’s gaps.
Why the farm generators mattered
The small wind generator did not alter national electricity supplies, but it left useful marks. It gave a generation of rural users first-hand experience with electricity and showed how much they valued it, which supported the political case for extending the grid. For engineers, it demonstrated that automatic, self-regulating wind machines could survive in the field for years, a lesson that carried into later, larger turbines. The Danish and American tradition of building reliable, simple propeller machines for ordinary customers is part of the lineage of today’s commercial turbines, though the commercial machines of today connect to the grid and are a very different scale.