Introduction
Everything on Earth runs on energy because energy is the power to do work. To harvest energy there are many sources that we can use they are categorised as renewable and non renewable. The key source of our energy today comes from burning fossil fuel which is a nonrenewable source of energy meaning that it will run out eventually. Burning fossil fuels is harmful and destroys our environment.
Earth is bombarded by the sun’s radiation at every moment. Thirty percent is reflected back into space off shiny surfaces, such as metals and glass. The remaining seventy percent of this radiation is absorbed by the oceans, atmosphere and the ground (mostly by the atmosphere). When the Earth starts warming up the stored radiation is released in the form of Infrared (IR) radiation which will move into space through the atmosphere. This natural exchange process between outgoing and incoming radiation that keeps our planet warm is called the Greenhouse effect. The greenhouse effect keeps the Earth’s overall temperature at about 15 degrees Celsius.
A diagram showing how tidal stream generators work
(http://www.alternative-energy-tutorials.com/tidal-energy/tidal-stream.html)
Gases in the atmosphere that absorb incoming radiation are called Greenhouse gases (GHG’s). Some examples of GHG’s are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) and Fluorinated gases (hydrofluorocarbons, perfluorocarbons and Sulphur hexafluoride).
Unregulated human activities have increased the abundance of greenhouse gases in the atmosphere. This has led to more radiation being stored, heating up the earth. This effect is called the “accelerated greenhouse effect”. This increased emission of greenhouse gases is one of the key causes of global warming.
Burning fossil fuels is one of the biggest emitters of GHG’s. Since the start of the industrial revolution the rate at which humans have been burning fossil fuels has been ever increasing. For example in the US it is believed the over 70% of electricity is produced in plants that burn fossil fuels. Transportation also produces a lot of GHG’s from burning fossil fuels.
To save our environment we have to switch from using fossil fuels for energy to other alternative forms of energy production that are not as harmful and which are renewable. One of the best alternative sources of energy are from renewable sources. Renewable energy sources are those energy sources that will never run out and usually do not have a very high if any negative impact upon our environment. One such renewable source of energy are the tides in the oceans(tidal energy). Tides are formed as a result of the gravitational pull the moon has on Earth. They also have to do with the relative position of the moon to that of the body of water being considered. Energy from the tides are harvested through various technologies that turn the kinetic energy in the waves into electricity.
The potential to harness Tidal energy is present with any large body of water, although this potential does vary with the size and location of the body of water. According to “Energy.gov” for tidal energies to be harnessed into a considerable amount of power the difference between high and low tides must be at least five meters.
Tidal energy harvesting technologies turn the kinetic energy in the tides into electricity. They do this by placing turbines in the stream of water and the kinetic energy in the water rotates the turbines. These turbines are connected to electric motors that create electricity from the movement of the turbines. Some of these technologies are Tidal Stream Generators and Tidal Barrages.
Tidal Stream Generators
Tidal Stream Generators make use of the kinetic energy in waves to convert them to electricity by making use of turbines - they work similarly to wind turbines. According to”Energy.gov” the best place to have a tidal stream generator is close to shore at a depth between twenty and thirty meters
Tidal Barrages
Tidal barrages work similarly to a hydroelectric dam. Barrages have two gates; the first one that has an underwater turbine and the second gate which doesn’t. When high tide comes in water rises to the level of the second gate and it is opened letting all the water in. When low tide comes in the water stored in the barrage is let out through the second gate which has a turbine. When the water flows past the turbine fans which are connected to a electric generator the kinetic energy in the water is converted to electric energy.
Earth is bombarded by the sun’s radiation at every moment. Thirty percent is reflected back into space off shiny surfaces, such as metals and glass. The remaining seventy percent of this radiation is absorbed by the oceans, atmosphere and the ground (mostly by the atmosphere). When the Earth starts warming up the stored radiation is released in the form of Infrared (IR) radiation which will move into space through the atmosphere. This natural exchange process between outgoing and incoming radiation that keeps our planet warm is called the Greenhouse effect. The greenhouse effect keeps the Earth’s overall temperature at about 15 degrees Celsius.
A diagram showing how tidal stream generators work
(http://www.alternative-energy-tutorials.com/tidal-energy/tidal-stream.html)
Gases in the atmosphere that absorb incoming radiation are called Greenhouse gases (GHG’s). Some examples of GHG’s are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) and Fluorinated gases (hydrofluorocarbons, perfluorocarbons and Sulphur hexafluoride).
Unregulated human activities have increased the abundance of greenhouse gases in the atmosphere. This has led to more radiation being stored, heating up the earth. This effect is called the “accelerated greenhouse effect”. This increased emission of greenhouse gases is one of the key causes of global warming.
Burning fossil fuels is one of the biggest emitters of GHG’s. Since the start of the industrial revolution the rate at which humans have been burning fossil fuels has been ever increasing. For example in the US it is believed the over 70% of electricity is produced in plants that burn fossil fuels. Transportation also produces a lot of GHG’s from burning fossil fuels.
To save our environment we have to switch from using fossil fuels for energy to other alternative forms of energy production that are not as harmful and which are renewable. One of the best alternative sources of energy are from renewable sources. Renewable energy sources are those energy sources that will never run out and usually do not have a very high if any negative impact upon our environment. One such renewable source of energy are the tides in the oceans(tidal energy). Tides are formed as a result of the gravitational pull the moon has on Earth. They also have to do with the relative position of the moon to that of the body of water being considered. Energy from the tides are harvested through various technologies that turn the kinetic energy in the waves into electricity.
The potential to harness Tidal energy is present with any large body of water, although this potential does vary with the size and location of the body of water. According to “Energy.gov” for tidal energies to be harnessed into a considerable amount of power the difference between high and low tides must be at least five meters.
Tidal energy harvesting technologies turn the kinetic energy in the tides into electricity. They do this by placing turbines in the stream of water and the kinetic energy in the water rotates the turbines. These turbines are connected to electric motors that create electricity from the movement of the turbines. Some of these technologies are Tidal Stream Generators and Tidal Barrages.
Tidal Stream Generators
Tidal Stream Generators make use of the kinetic energy in waves to convert them to electricity by making use of turbines - they work similarly to wind turbines. According to”Energy.gov” the best place to have a tidal stream generator is close to shore at a depth between twenty and thirty meters
Tidal Barrages
Tidal barrages work similarly to a hydroelectric dam. Barrages have two gates; the first one that has an underwater turbine and the second gate which doesn’t. When high tide comes in water rises to the level of the second gate and it is opened letting all the water in. When low tide comes in the water stored in the barrage is let out through the second gate which has a turbine. When the water flows past the turbine fans which are connected to a electric generator the kinetic energy in the water is converted to electric energy.
Advantages and Disadvantages
One of the advantages of tidal energy is that it is a completely consistent and predictable source of clean energy. Tides are formed as a result of the gravitational pull the moon has on Earth.Just as we can predict the position and rotations of the moon, months or even years in advance we can predict tides to a similar level of accuracy. This makes it easy to maintain and harvest tidal energy.This predictability allows us timely maintenance of facilities that are built to harvest tidal energy. It is very important that we are able to maintain these facilities as they are constantly exposed to harsh underwater conditions that can lead to damages like corrosion.
To harvest a substantial amount of power through tidal energy the difference in depth between tides needs to be a minimum of five meters. According to “triple pundit.org” there are only twenty sites that have been located around the world that have a high potential to capitalize on tidal energy. Thus there are limited locations from where tidal energy can be harvested and this is insufficient to meet global demand.
To harvest a substantial amount of power through tidal energy the difference in depth between tides needs to be a minimum of five meters. According to “triple pundit.org” there are only twenty sites that have been located around the world that have a high potential to capitalize on tidal energy. Thus there are limited locations from where tidal energy can be harvested and this is insufficient to meet global demand.
Economic factor
Infrastructure required to harvest tidal energy it very expensive to build. For example according to “education-portal.com” the cost to generate energy by capitalizing on tidal can be more than $400 per Megawatt Hour(MWH). However the same cost for other clean energy sources such as biofuels and geothermal energy is around $150 per MWH. Because of the large costs tidal energy does not seem like a sensible alternative of clean energy compared to other clean energy sources.On the other hand the cost of producing the infrastructure required to harvest tidal energy is set to come down substantially in the future. The amount of energy technologies can harvest out of our tides is also set to increase in the future. For example according to”thinkglobalgreen.org” by 2020 tidal energy is expected to be more compeditive than wind energy. Thus as a result of more advanced technology in the future tidal energy will be a more practical choice of clean energy.
Personal opinion and conclusion
I think we need to switch from our dependency on fossil fuels for energy to renewable energy sources. Tidal Energy should be one of the renewable energy sources that we switch to, because although Tidal Energy may be very expensive it is a very reliable and easy to maintain source of Energy. In conclusion i think Tidal energy is surely a energy resource for the future but we must take risks and try out tidal energy now.