A brief history of hydroelectric power

Water is by no means a new form of energy. Here's a brief history on hydroelectric power that might help you decide if it's the right power source for your home.

• The use of waterwheels to free humans from heavy labour is almost as ancient as the use of beasts of burden. Some of the earliest applications of such wheels were to raise water from wells and to turn millstones to grind grain. Later, waterwheels were adapted to provide power for processes demanding a slow, ponderous, unceasing rotary motion.
• In Europe and North America, textile factories and sawmills were generally built on riverbanks to take advantage of water power.
• Individuality and variety marked the waterwheels of the past. The most efficient type was the overshot wheel, but if the water source was not high enough, a breast wheel or undershot wheel was employed.
• A typical wheel made 10 to 20 revolutions per minute; with wooden gearings this could be stepped up to 10 times that rate.

• Old-fashioned gristmills could grind a quarter of a tonne of grain an hour. The miller poured the grain into a hopper from which it trickled down through the eye of the upper millstone onto a bed stone.
• As the half-tonne upper stone rumbled over the bed stone, it scraped off the husks and pulverized the grain. The husks were then separated with a sieve, leaving flour.
• A number of traditional waterwheels are still in operation in Europe and North America, turning out the stoneground meal that is so highly prized by many home bakers.
• With the introduction of steam power in the early nineteenth century, waterwheel technology became obsolete.
• Water did not compete as a power source again until the invention of the high-speed turbine for generating electricity. Turbines led not only to huge hydroelectric installations but, in time, also made modest private hydropower schemes possible.

The only practical way to make efficient use of a creek or river is to employ a modern turbine system.

• Using a turbine eliminates the gearing problems associated with a waterwheel. Turbines convert water flow directly into high-speed turning motion. Little in the way of supplementary gearing is needed to achieve generator speeds.
• In addition, turbines are much smaller than waterwheels of the same power output but only slightly larger than the generators with which they are coupled.
• Turbines run with a high-pitched whine — not as soothing as the rumble and splash of the old mill wheel — and some suffer from cavitation (wear caused by air bubbles).

Water is an old but powerful source of energy. Consider this quick history and decide whether water-sourced energy is the right choice for your home.