Of Hydropower and Water Wheels @museum.de

Since ancient times, water wheels have been used to generate energy and power a wide range of different mills. Of course, they basically have a very simple mechanical structure, refined over time. Water hits the plates of the water wheel, setting it in motion. The force is transferred to the individual machines by a system of pulleys and transmission belts.

The water wheel at Leustetten’s Bark Mill is again operational and powers the machinery in the museum.

It’s what’s known as an “overshot” water wheel. That means the water from the village stream is introduced to the wheel from above. So in addition to the kinetic energy of the running water, the system also benefits from the energy of the water’s drop. That way, the energy gain is higher than with a "breast-shot" wheel, where the water meets the water wheel’s plates near the centre.

That’s probably why the original breast-shot water wheel on the side of the building facing the road was abandoned and a larger, overshot replacement was built on the gable side facing the town. The higher energy yield meant that more machines could run simultaneously.

But perhaps you’re wondering if there’s a third type of waterwheel besides the overshot and the breast-shot varieties.

The answer is yes. If the running water hits the plates at ground level, it is called an "undershot" water wheel. In that case, only the flow velocity of the water has an effect, and the water wheel is powered by the kinetic energy alone.

When you talk about mills, people generally think of flour mills. But until the industrial revolution and the invention of the steam engine, there were many other important types of mills. Hammer mills powered the blacksmiths' hammers; in the mining industry, pumps and conveyors used in mines were powered by hydro energy; there were saw mills and, of course, bark mills.

Actually, this type of energy generation complies with all the principles of a renewable energy strategy, and in that respect, it’s absolutely "cutting edge"!