The world we live in revolves around the culmination
of various energy sources to operate the daily necessities of living, such as
food, shelter, electricity, transportation and much more. The following paper will evaluate the
conventional energy technologies used as well as alternative energy sources and
their impact on Earth. Furthermore, the
chemistry behind the functionality of the energy sources will be analyzed.
One of the largest environment-impacting energy
sources used involves fossil fuel burning.
Fossil fuels are hydrocarbons that are formed from the remains of dead
animals and plants. Coal, fuel oil, and
natural gas are common examples of fossil fuels. A hydrocarbon is an organic compound that
consists of hydrogen and carbon. When
decomposed, hydrocarbons provide an abundance of carbon and hydrogen which,
when bonded, can form chains. The
primary use of hydrocarbons is as a combustible fuel source. Chemistry principles can be used to describe
the burning of methane or the carbon in coal.
The reaction: C+ O2 -> CO2 is the basic reaction of the burning of
carbon which provides the largest energy source. This reaction is what happens in coal,
natural gas, and oil, all of which are fossil fuels. Energy within this reaction is only present
because of the solar energy within the plants, which are then processed for
millions of years under the pressure in the Earth. Carbon molecules in coal are bound, thus,
there is only one C-C bond for every C atom.
To determine the efficiency of this mechanism, one must calculate the
energy release from creating CO2. Carnegie
Mellon University states that the net release is 152 kcal/mole of carbon. Therefore, 1 kg of carbon gives approximately
11000 kcal. The university also states
that 44g of CO2 is produced for every 12g of carbon burnt. The contribution that carbon dioxide has to
global climate change is substantial and is one of the major problems of fossil
fuel economy. To put the environmental impact in perspective, power plants that
burn coal produce more harmful carbon dioxide than all cars, trucks, planes, and
other forms of transportation combined (Fossil Fuels Affect the Environment,”
2018). Greenhouse gases are contributing to global warming as the sun’s energy
is trapped in the Earth’s atmosphere.
The remainder of this paper will examine the
alternative energy sources from the sun, wind and ocean as these modes can help
reduce the use of fossil fuels. These
renewable energy sources do not emit carbon dioxide into the atmosphere, which
is an imperative step towards helping the planet.
The Sun, which will provide at least another 4 billion
years of solar energy striking Earth daily, harnesses a powerful energy source
for electricity and can be one of the best options to combat global warming. However, for solar panels to be efficient, a
variety of factors must be met. Majority
of solar panels are made with a layer of protective glass over the cells which
sunlight must pass through. Reflection
of the glass is to be minimal, as well, the amount of energy harnessed depends
on the angle of which light is passing through.
The user also must be aware of the positioning and angle of the panel
upon installation. The panel should be
placed so that the maximum amount of sunlight is shining on it to maximize
efficiency. This would include avoiding
shade and finding the optimal position on a roof (Empire
Renewable Energy, 2018). Solar panels function through solar cells
within the panels. A single solar cell
is made of two types of semiconductors called p-type and n-type silicon. Boron or gallium are p-type silicon and is
produced by adding atoms as they have one less electron in the outer energy
level. Since boron has one less electron than necessary to form bonds with
silicon atoms, an electron hole is created.
This is perfect because in an n-type silicon there is one more electron
in the outer level, i.e., phosphorus. Therefore, binding with surrounding atoms
can occur, however, one electron is not involved in bonding. The electron is instead allowed to freely
move inside the silicon structure. Thus,
within a solar cell there is a p-type silicon placed in conjunction to a layer
of n-type silicon. The n-type layer has extra electrons, whereas the p-type
layer is excessively charged with positive holes. Between the layers, the electrons on one side
move into the holes of the other side. A
junction is created known as the depletion zone. Once the holes are filled in this zone, the
p-type now contains negatively charged ions, and the n-type side contains
positively charged ions. With this oppositely charged ions created, an electric
field will prevent electrons in the n-type layer to fill the holes in the
p-type layer. Upon sunlight striking a
solar cell, electrons in the silicon are released, which results in the
formation of holes. Having this occur in
an electric field will move the electrons from n-type to p-type. Solar panels are built with metallic wires
which will allow the electrons to travel from n-type to p-type by crossing the
depletion zone previously discussed; this creates the flow of electricity (American Chemical Society, 2017).
As the main goal is to reduce global warming
emissions, solar panels do a relatively good job compared to natural gas and
coal. It is estimated that solar power
ranges from 0.08-0.2 pounds of carbon dioxide per kilowatt-hour. This is far less than its counterpart of coal
at 1.4-3.6 pounds of carbon dioxide per kilowatt-hour (Union
of Concerned Scientists, 2013).
Apart from solar energy, hydro is also one of the best
methods of energy source because of its ability to use waves and water currents
to produce electricity. Hydroelectric
power plants use a dam on a river to store water in a reservoir. The flow of
water once the reservoir is released spins a turbine which then activates a
power generator to produce electricity. There are power lines that are
connected to the generator that bring electricity produced to homes. Moreover, hydropower is quite efficient as
there are power plants that can store power, called a ‘pumped storage plant’. Power is sent from a power grid into the
electric generators. When generators
spin the turbines backwards, it causes the turbines to pump water from the
river or lower reservoir to an upper reservoir.
This is where the power is stored.
To use that stored energy, the water is released from the upper
reservoir back into the river or lower reservoir, causing forward spinning of
the turbines and ultimately activating the generators to produce electricity
(Renewable Energy World, 2018).
The movement of water does not negatively affect the
environment; it is safe and clean, which is why it is the world’s leading
source of renewable energy. Since water
is a sustainable source, it will not run out and can be used over and
over. By using water as energy, there is
no decrease in the volume of water.
However, speeds, flow of water, and sometimes temperature, are changed. To
put in perspective how beneficial hydropower really is, Wisconsin Valley
Improvement Company’s website has some staggering facts. Hydropower prevents the burning of 22 billion
gallons of oil and 120 million tonnes of coal each year. Hydropower is such an
efficient way to generate electricity as turbines can convert the 90% of
potential energy of water and gravity into electricity. On the other hand, even the best of fossil
fuel power plants are only 50% energy efficient.
As discussed in this paper, fossil fuels are not a top
choice for energy production. With the
modern development of solar panels and hydroelectric power, it eliminates the
need for other energy production methods that produce harmful greenhouse gases. It is imperative for everyone to promote
renewable energy as it could one day be the sole factor to whether the Earth is
habitable for mankind or not.