In your blog, describe the four types of marine renewable energy and discuss which (if any) are most feasible for Australia.
Wave energy – Wind waves and long period swell. Wind waves are created by winds pushing the surface of the ocean to create waves. These waves are not incredibly powerful. Long period swell entails waves created by storms, these waves are often much more powerful and can travel much further distances.
Tidal energy – Is based on the tides. Tides are based on the force of gravity from the moon and sun reacting and manipulating the earth and oceans. This type of force causes the oceans to “bulge”, this in turn creates long waves. There are two main types of tidal energy (Tidal barrage and tidal current).
Heating from the sun. The temperature difference in warmer surface waters and cooler deeper waters.
Energy from ocean currents from such currents as the EAC produce energy in their movement.
The most feasible for Australia would be Tidal energy. Wave energy requires wind or storm activity to create the waves required to produce the energy. Unfortunately as Australia’s climate is so diverse and weather so unpredictable it cannot be guaranteed that there would ALWAYS be wind to produce the waves. In some parts of Australia (Southern Australia & Northern Australia) strong winds and tropical cyclones may be more feasible however this is only in certain locations throughout the country and at certain times during the year.
However with the tidal energy, as the Earth is constantly under the influence of gravity tides will always occur at most marine – meets – land locations (beaches, rivers, etc) This suggests that tidal energy would always be constant and therefore a more feasible source of energy that wave energy, which cannot be counted on to always be able to be produced.
In your blog, discuss how energy can be harvested from waves.
Wave energy is all about creating a rotation – this in turn creates electricity. The energy itself comes from the movement of the wave, not the wave itself. As the wave moves, a certain point (vertical) will rise and fall with the wave motion. As this movement occurs it can push a wheel causing it to rotate and produce energy. The vertical movement will produce the rotational movement. – Produces electricity.
Two floating objects (connected via connector in the middle) as the waves rise and fall, so will the objects causing the connector to flex with the motion. This will cause it to again have a rotational movement producing energy.
Research how each of these three main forms of tidal power generation work, and summarise each in your blog.
- A tidal stream generator – Can also be referred to as a TEC (tidal energy converter). It is a machine used for removing energy from tides (moving masses of water). These machines work a lot like a wind turbine in the way that they take the energy from currents in the water like wind turbines collect energy from the air. The water flow creates a rotational movement in the tidal stream generator which produces the energy. It is advised that this is the cheapest and least economically damaging of the three main forms of tidal power generation.
- A tidal barrage – Acts a lot like a dam. It captures the energy from the water as it moves in and out of the area during high and low tides. However instead of damming water like a normal dam would a tidal barrage collects the water as the tide pushes in it in and releases the water as the tide goes out again. This is monitored by someone who measures the flow of the tides and controls the sluice gates when it is required at certain points during the tides. This is one of this oldest methods of tidal power generation.
- Dynamic tidal power – Has yet to be tried and tested, however it involves a dam like structure (much like tidal barrage) however much longer the is built perpendicular to the coastline – It leaves an option for a coast parallel barrier at its far end which would form a T shape, however this is not compulsory for it to work. It produces energy in the way that the dam would interfere with the tides creating different water levels on each side of the structure. These different water levels would drive a number of bi-directional turbines (Like tidal stream generators) which would produce the energy.
In your blog, summarise the costs and benefits of offshore wind farms
- Hypothetically a 500MW wind farm, consisting of 100x, 5MV turbines – in shallow water 15miles from the coastline would cost an estimate of $340 million for the turbines, $100 million for the foundations for the turbines, $60 million for all of the electrical connections. This gives an estimate of the total construction cost being $1200/kW and energy costing $54/MW h.
- Other costs include annual expenses of land rent – $12,000.00, maintenance – $215,000/year, Replacement & overhaul costs – $55,000/year.
- As they are positioned in the ocean, it may be harder to access and complete repairs maintenance etc on them due to their location.
- Wind power has low carbon emissions over its life cycle. Meaning that it appears to be environmentally friendly and has little negative impact on the environment (No toxic emissions etc).
- Wind power does not require fuel to operate. Meaning there is no fuel costs to run this machinery.
- There is no dependency on freshwater to power the machinery which other conventional sources do require.
- Offshore wind power has the benefit of location – its structures are not taking up land space that could be used for farming ect but are placed in the ocean where winds are more and space is less usable.