Your Questions About Wind Turbine Generators Australia

admin answers:

I think with any system if energy is removed then the ‘natural’ state of the system must be disrupted somehow. With wind we must consider how much we are taking out of the overall system. The first thing to note is that the winds are largely driven by solar heating – causing high and low pressures to form through air density differences which act to even out by transporting air between them. The sheer scale of the energy and the vertical distribution of the wind means that even with our best efforts we can currently only harvest a small amount of the wind energy at surface level, let alone for the whole 10km of the troposphere. The effect that this will have is for the wind farm to be ‘seen’ by the lower winds as an area of increased surface friction, in a similar way to a large tree might be seen. This might lead to local effects close to the turbines but I don’t think it would be noticeable without high-tech equipment. As for global effects like El Nino then we would have to be seriously affecting the upper controlling winds (like the jet stream) and global circulation cells.
I would say that if the entire globe was covered in wind turbines then I would expect some dampening of the atmospheric circulation system, but since this is unlikely and we currently (key word!) extract a tiny percentage of the available energy then it is not of concern.

According to Greenpeace, we currently extract 6.0xE4 MW per year in the world. The total energy in the global wind is estimated at 3.6xE9 MW. With five orders of magnitude difference we have a long way to go before we impact on the wind in the atmosphere. Also there is a limit of 59% (called Betz limit) on how much we could extract.

To be green I think we should reduce our energy consumption, be efficient, and use the whole set of renewable available to “play with a full set of clubs”. In addition, I think we should return to this issue if wind power begins to extract a more significant amount of energy from the atmosphere.

admin answers:

Tidal power is a means of electricity generation achieved by capturing the energy contained in moving water mass due to tides. Two types of tidal energy can be extracted: kinetic energy of currents due the tides and potential energy from the difference in height (or head) between high and low tides.
The extraction of potential energy involves building a barrage. The barrage traps a water level inside a basin. Head is created when the water level outside of the basin changes relative to the water level inside. The head is used to drive turbines. In any design this leads to a decrease of tidal range inside the basin, implying a reduced transfer of water between the basin and the sea. This reduced transfer of water accounts for the energy produced by the scheme.

Tidal power is classified as a renewable energy source, because tides are caused by the orbital mechanics of the solar system and are considered inexhaustible within a human timeframe. The root source of the energy comes from the slow deceleration orbit of the moon around the Earth, and the deceleration of the Earth’s rotation. Tidal power has great potential for future power and electricity generation because of the total amount of energy contained in this rotation. Tidal power is reliably predictable (unlike wind energy and solar power).

The efficiency of tidal power generation largely depends on the amplitude of the tidal swell, which can be up to 10 m (33 ft) where the periodic tidal waves funnel into rivers and fjords. Amplitudes of up to 17 m (56 ft) occur for example in the Bay of Fundy, where tidal resonance amplifies the tidal waves.

As with wind power, selection of location is critical for a tidal power generator. The potential energy contained in a volume of water is

E = xMg
where x is the height of the tide, M is the mass of water and g is the acceleration due to gravity. Therefore, a tidal energy generator must be placed in a location with very high-amplitude tides. Suitable locations are found in the former USSR, USA, Canada, Australia, Korea, the UK and other countries (see below).
Several smaller tidal power plants have recently started generating electricity in Norway. They all exploit the strong periodic tidal currents in narrow fjords using sub-surface water turbines.____For more information go to the site below.