Renewable energy is not necessarily free, as it does come with some costs, in terms of money spent for equipment, and other environmental costs. For example, windmills do not operate at 100 percent efficiency, because the windmill structure itself blocks the movement of the wind, and the moving parts are subject to aerodynamic drag and friction. In theory, a windmill can generate up to 59 percent maximum efficiency, which goes down through time due to wear and tear.

And then there?s the turbine noise, which may not be ideal in a residential setting.

A new windmill design loosely based on Archimedes?s screw principle, aims to change this, however. A Dutch startup aptly named The Archimedes has re-worked the concept of the windmill to move away from the traditional concept of using the pressure differential between the front and rear of the device to move the rotors.

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The Liam F1 Urban Wind Turbine, modeled after a Nautilus shell, measures about 1.5 meters wide and weighs 75 Kg ? an ideal size for installation in a residential setting. The turbine is rated to achieve an efficiency ?80 percent of the maximum that is theoretically feasible.?

According to the creators, the device is designed to provide enough electricity to power an apartment or small home. ?The Liam F1 generates an average of 1,500 kilowatt-hours of energy [per year] at a wind-speed of 5 m/s [16.4 ft/s], which resembles half of the power consumption of a common household.? The Liam can even adjust to wind direction, which enables it to maximize power generation even with changing conditions.

The Liam is priced at Eur 3,999 or about US$ 5,450 and will start retailing by July 1st. The Archimedes says it has sold 7,000 units in 14 countries so far. The company says it has undertaken field tests for efficiency and power generation ?over 50 times,? in which it has achieved its rated output and efficiency.

At this price and projected efficiency, will The Archimedes? Liam help address the need for better renewable energy sources?