Clean energy is represented today by the energy sources that generate electricity without polluting the environment, and also refers to the energy saved through energy efficiency measures.
What is Clean Energy? – Definition
Clean energy is the energy produced today by renewable energy sources with zero-emission and also represents the energy saved through energy efficiency measures.
Renewable energy is produced today using renewable resources such as the sunlight, wind, geothermal heat, water, tidal, wave and biomass.
These resources are considered renewable because they are constantly “renewed” by nature, so we can use them as sources of clean electricity for several billions of years from now on.
The energy efficiency measures restrain the energy consumption, which lowers the energy bills and saves energy.
The energy saved through energy efficiency measures is also considered clean energy because it doesn’t have to be produced, so will never pollute the environment.
The economy of the U.S. can become cleaner and more sustainable only if we combine renewable energy sources with energy efficiency measures.
Because renewable energy has a tiny share in the energy mix of the U.S. (only 11% in 2017), some sources have included in the term ‘clean energy’ also the sources of power that are nonrenewable, but are cleaner, such as nuclear power, natural gas and ‘clean coal’.
Sources of Renewable Energy Considered Clean
Not all the renewable energy sources available today are considered 100% green in terms of harmful emissions.
1. Solar Energy
Today, we are using the sunlight to generate clean electricity directly using solar panels, to heat water (solar water heaters) and to heat an agent (molten salt is used by solar thermal power plants) that will produce steam to spin a turbine and generate clean power.
The sunlight is also used to heat passive homes, which will lower the energy bills pretty much.
Passive homes are considered clean homes because they save large amounts of energy every year and they also have a very small carbon footprint.
The sunlight is produced by the Sun. so is a renewable energy source that is also clean (zero emissions).
2. Wind Energy
The kinetic energy of the wind is used today to spin horizontal axis and vertical axis turbines that are producing clean electricity.
Wind on our planet is produced by the Sun due to the fact that the sunlight heats the air layers in an uneven way, which makes the layers of warm air to go up in the atmosphere and the layers of cooler air to go down.
This movement of the air layers up and down in the atmosphere represents the wind and is generated by the Sun.
Being produced by the Sun, we can consider wind power as a renewable and clean source of electricity, which is also 100% green (no emissions).
3. Geothermal Energy
Geothermal power is a source of renewable energy provided by the Earth’s core.
The core of our planet is very hot (was named ‘the inner sun’ because is hotter than the surface of the Sun), and this thermal heat reaches the surface under the form of steam and hot water.
We are using the geothermal resource available today to heat and cool homes and business for free.
The hot steam is also used to spin a turbine and generate clean electricity.
Being produced by a natural resource (the hot core of our planet) we consider geothermal power as a renewable energy resource which is also green if the electricity consumed to extract the resource from the underground is also clean (produced by renewable energy not by burning fossil fuels).
4. Water Energy
Water is the source of life on planet Earth, and is also a clean source of free power.
The kinetic energy of the falling or fast moving water (streams) is used by hydroelectric power plants to spin underwater turbines that generate clean electricity with the help of very powerful generators.
Hydroelectricity or simply the power of the water is considered a renewable energy source because water is a renewable resource on our planet being renewed every day by the water cycle in nature.
Hydroelectricity is the most developed renewable energy source in the energy mix of the U.S. and is also clean because is an energy source with zero emissions.
5. Tidal Power
The tides on our planet are generated by the gravitational forces of the Earth, Moon and Sun combined.
There are two tides per day, the high tide and the low tide.
We can generate clean electricity using the kinetic energy of the tides using powerful underwater turbines.
Tidal energy is a renewable and very predictable power source.
At the same time tidal power is a clean source of electricity with zero emissions.
6. Wave Energy
Waves in our oceans are generated by the wind, which means that wave energy is a renewable energy source.
We are generating clean electricity today using buoys that oscillate in resonance with the incoming waves.
The oscillating movement of the buoys strongly amplifies the motion and allows a large amount of energy to be absorbed.
This way the linear motion is converted into clean electricity using a new type of mechanical drive line, which is located inside the buoy.
Being generated by the wind, wave energy is a renewable energy source and also a clean source of power with zero emissions.
7. Biomass
Biomass is another form of renewable energy available today that can replace the fossil fuels for electricity and heat production.
Biomass mostly consists today of wood and plant waste, energy crops, human and animal organic waste and of course trash.
This way, biomass is considered a renewable energy source due to the fact that until mankind will live on this planet, trash and waste will be always produced, which means that the fuel for biomass power plants will be always available.
Exactly like coal, biomass is used today to generate low-carbon electricity and residential heating.
Biogas and biofuels are produced today from organic waste and different types of plants.
Biomass represents a renewable energy source, and also a clean source of energy, but is not 100% green because some emissions are released into the atmosphere while burning wood for heating and biofuels in engines.
Non-renewable Sources of Energy Considered Cleaner
The nonrenewable sources of energy considered cleaner or low-carbon energy sources consist of nuclear energy, natural gas and ‘clean coal’.
1. Nuclear Energy
The power of the atom is used by mankind to generate clean electricity without releasing harmful emissions in the atmosphere.
However, the nuclear fuels used today in the nuclear reactors (uranium and plutonium) produce beside clean electricity also nuclear waste during the nuclear fission reaction.
The nuclear waste is very harmful for the environment and also for any living being, and this is the reason why is very expensive to dispose it and require military protection.
Nuclear waste is the major issue of nuclear power
Being such a risky and dangerous material, nuclear waste needs to be heavily guarded by military personnel to avoid being stolen by terrorist organizations.
Nuclear power cannot be considered a renewable energy source today because the nuclear fission reaction used today in the nuclear power plants relies on fossil fuels such as uranium and plutonium, which are limited resources.
At the same time, the nuclear power plants are producing clean electricity, but also dangerous nuclear waste, and this is the reason why nuclear power has no future for mankind under this form.
The nuclear fusion reaction is another form of nuclear reaction that can use hydrogen (a clean and very abundant element on the planet and in the universe) as nuclear fuel.
The thermonuclear reaction (nuclear fusion) is also the nuclear reaction used by the Sun to produce energy under the form of heat and light.
Nuclear power will become renewable only when mankind will use the nuclear fusion reaction to generate unlimited amounts of clean electricity.
2. Natural Gas
Natural gas is the ‘cleanest’ fossil fuel used today by mankind to produce electricity, residential heat and for cooking.
Natural gas is a fossil fuel like coal and oil, but because it burns cleaner than the other two fossil fuels, it is considered a low-carbon energy source that can help us make the transition from the dirty fossil fuels to an economy powered only by renewable energy sources.
3. Clean Coal
Of course that there is no clean coal, there is only coal, which is a cheap and very efficient source of electricity for mankind.
Coal is considered the dirtiest among all fossil fuels because while burning, it releases into the atmosphere sulfur dioxide, nitrogen oxides, carbon dioxide, some mercury and particulate matter.
These harmful emissions reach the air that we breathe, and also the water resources, causing smog, soot, acid rains, global warming and climate change.
The particulate matter causes dangerous diseases such as asthma, lung cancer, several types of heart diseases and many other health issues.
The concept of ‘clean coal’ only refers to the technology used to produce energy from coal.
One such technology is called carbon capture and storage and refers to the fact that carbon dioxide is captured and separated from the air that leaves the power plant and reaches the atmosphere (the process is called carbon absorption or carbon scrubbing).
Chemicals called amines are used to bind to the carbon dioxide and pull it out of the air that leaves the power plant.
The captured carbon dioxide is then piped underground (sequestered) to avoid a leak into the atmosphere.
Another way to make coal cleaner, is to wash the sulphur out of coal before entering the power plant.
Clean coal is coal that produces less emissions when burning
The ‘washed coal’ will produce less emissions while burning.
A third technology used to make coal cleaner is called “oxy-fuel combustion”, and refers to the fact that the technology reroutes the flue gas back into the power plant where is paired with pure oxygen and reused to burn more coal.
The oxy-fuel combustion technology allows hotter temperatures to be reached in the power plant, which will generate more energy and less emissions.
However, all these technologies used to make coal cleaner are not solving the real problem caused by the fact that we are still using coal for energy production.
The actual problem with the ‘clean coal’ technology is the fact that all these harmful byproducts are not eliminated entirely they are only moved elsewhere.
These technologies are not helping the environment, they are only moving the carbon dioxide in a different place, causing environmental issues in time.
Final conclusion
Mankind and the environment on our planet need to suffer a few more decades until the global economy will mostly rely on renewable energy and only a tiny amount of fossil fuels.
By then, we need to protect the environment and reduce our carbon footprint as much as we can, and we also need to teach the young generation, how important is to keep the environment clean for a healthy and happy life here on the planet.
