Household Utilities: Sustainable Energy: Wind.

Wind energy systems convert kinetic energy (the moving air) into electricity by turning a turbine that turns a rotor to turn a generator. The amount of energy generated depends upon the swept rotor diameter and the average wind speed of the site. As wind supply tends to be intermittent on most sites, a household may also require a backup source of energy.

Large-scale grid-connected wind farms, consisting of multiple wind turbine generator units, typically rated at between 300kW to 1.5MW each, are making an important contribution to the electricity supply mix in many countries around the world.

Small wind generators producing a few tens of Watts can be used to provide top-up power for a single 12V battery system. Mechanical wind power systems, which generally convert rotary motion into reciprocating shaft power, are ideally suited for water pumping and hence are known as wind pumps.

Unlike solar power, wind power can be generated at any time of the day or night. Output from a wind generator is dependent on wind speed and design characteristics of the turbine. Before selecting wind power as a major source of power supply, site-specific anemometer readings should be logged to show annual wind averages and seasonal variations. The wind turbine selected needs to be matched to the site's wind characteristics.

Selecting a site for a wind generator will be dependent on:

1. Height - any wind generator under 10m from the ground is unpredictable. Wind speed increases with height. Small-scale obstacles, trees and buildings, disturb the airflow. The wind generator should be situated at least twice the height of the obstacle upwind or 20 times the height downwind, or 2 - 3 times the height above the obstacle.

2. Topography - the ideal spot would be on the crest of a low, smoothly rounded ridge running at right angles to the prevailing wind or slightly below the crest, on the windward ridge.

3. Local climate and local microclimate. Data collection and analysing of wind patterns at various heights would be required before a decision can be made to implement a wind power system. TimeStudio has been used to collect and analyse this data.

The TimeStudio software system has been developed by Hydro Tasmania for the acquisition, management, analysis and presentation of hydrometric and other time dependent data.

4. Local authority requirements pertaining to visual and noise pollution limits.

Newton House - Wind Option

Visual observations of wind on the Newton's site indicate that this may be a suitable power option as part of a hybrid power system. Concerns about implementation include turbulence created by trees on the property and the height required for the windmill to clear this.

Links

http://www.greenhouse.gov.au/renewable/technologies/wind/index.html
http://www.windpower.dk/core.htm