Pros And Cons Of Electric Power Engineering Environmental Sciences Essay

Electric power has becoming a necessity in our daily lives. As the use of fossil fuels are slowly running out and phasing out, the use of environmentally friendly energy is now becoming popular and cheaper too. Electrical power is then transmitted after an electric charge has been generated and converted into electricity. It is then distributed to substations then to the homes at a level of voltage, which is safe for us to use. And that is how scientists and engineers have made electricity such as a success to date.

Electric power is the use of electric energy to do work. Through electric power, machines are run, and through the running of machines electricity can be generated. Electric power is used in all industries and therefore become an essential tool in our lives. No-one is certain as to where the future of transmission and distribution of electric power lies, but scientists are certain that the energy sources of the future definitely lie in the emission-free sources.

Over the years of electric power production various energy sources have been used to produce electric power across the world. These energy sources have been used according to its availability in that specific area, the cost to build and maintain the station, how it will be transmitted and distributed and lastly its affect on the environment. Engineers are trying to find an alternative of clean and cost effective energy to produce electric power. These are some of the electric power used from the past, to date.

Hydro-electric power

Hydroelectric power is the conversion of energy from free falling water into electrical energy. It uses the water stored in dams. The water flows through a tunnel pipe to the power plants hydraulic turbine. As water rushes through the turbine, it spins the turbine, which drives the electric generator.[1,2] [see figure 3.1 and 3.2].

Pro:

It costs less to operate than fossil-fueled stations.

There are no emissions produced.

Cons:

There is generally a deterioration of fish spawning in the areas when dams are used.

This process of producing hydro electric power is limited to availability of water and suitable locations for dams and reservoirs [1,2,3]

Nuclear power

Nuclear power uses a device called nuclear reactor to produce enormous amount of heat by fissioning the nuclei of atoms of a heavy element like Uranium. The heat converts water into steam, which drives the turbine that runs the electric generator. After the steam has turned the turbine, it is left to be condensed in the cooling towers and then later recycled in the plant [4].

Pros:

It is carbon-free electricity as it hardly emits any carbon dioxide.

It requires much less fuel than fossil-fueled stations to produce an equal amount of electricity.

Cons:

It produces tons of radioactive waste annually, which is a health hazard to all living organisms.

Uranium mining scars the land and pollutes the water supplies as all types of mining do [4,5,6].

Geothermal power

Geothermal energy is generated wherever water comes into contact with hot rocks below the Earth’s surface. The rocks give off heat that makes the water hot enough to turn it into steam. The energy is captured by tapping into earth’s crust through a process called hydrothermal convection, where a cooler water seeps into the Earth’s crust, is heated up and then rises to the surfaces. When the water is heated it turns into steam. The steam is then captured and used to drive electric generators [7].

Pros:

It releases no harmful emissions as it is a natural source of energy.

It is far more efficient than heating and cooling and can move 3-5 times more energy

Cons:

Geothermal heat pumps have higher up-front costs.

There’s a risk that while trying to drill into earth’s crust, it might trigger seismic activity fracture rock stability, thus resulting in the collapsing of infrastructures.[7,8]

And now it is rumored that the use of biofuels might be the energy source for the future as they are the third generation biofuels (made from algae and other microbes).

Despite the type of energy source used, the bottom line is they all have to create enough force to turbine a turn a turbine that will then run a generator. The generator has a rotating electromagnet called a rotor and a stator. A separate generator called an excitor powers the rotor creating a magnetic field that produces an electric charge in the stator. The charge is transmitted as electricity [1,7].[see Figure 3.3 and figure 3.4]

Electric power transmission

There are mainly two ways electric power can be transmitted either overhead or underground.

As electric current moves along transmission lines, the lines resist the current flow. The resistance within the lines causes the current to lose energy. Power stations therefore limit energy losses by transmitting electricity at high voltages. As the voltage is increased, the amount of current needed to transmit a particular amount of electric power decreases. Because there is less energy lost due to the resistance. Electric current may either be DC or AC. Direct current flows in only one direction. Alternating current is therefore easier to transmit than direct current [1].[see Figure 5].

The history behind the way electric power is transmitted today.

In 1878, Thomas Edison [see Figure 6:] developed and sold commercially viable replacement for gas lighting and heating locally generated and generated direct current electricity. He opened the world’s first public electricity supply in the late 1881.this system was powered from a water wheel , which drove a Siemens alternator that supplied a number of arc lamps with electricity within the town as well as shops and premises. As the years went by Edison opened more power stations in various parts o the world. All his methods of supplying electricity were using direct current (DC). Later on that year it was discovered that there was a demand for electricity, so Edison decided to increase the voltage so that the high demand for electricity could be supplied, and also because the increase in voltage reduced the resistive losses in the cable. But it was after a series of fatal accidents that he also realized that increasing the voltage increases the danger from direct contact and also increases the required insulation thickness. Furthermore some loads were difficult or impossible to make for higher voltages. Nikola Tesla, who worked for Edison for a short period of time and appreciated electricity in a way that Edison did not, devised a alternative system using alternating current. Tesla realized that while doubling the voltage would halve the current and reduce losses by three quarters, only an alternating current system allowed the transformation between voltage levels in different part of the systems. This allowed efficient high voltages for distribution where their risks could be easily migrated by good design while still allowing fairly safe voltages to be supplied to the loads. He went on to develop alternative for DC appliances. In 1888, Tesla worked with George Westinghouse, who owned a patent for type of transformer that could deal with high voltages and was easy to make. They both built a power system for a gold mine in Colorado. Almarian Decker finally invented the whole system of the three-power generating in California. Edison was force to sell his deal with General Electric to Tesla’s new system.

Thus Tesla’s alternating current system remains the primary means of delivering electric power to consumers throughout the world. While high-voltage direct current is increasingly being used to transmit large quantities of electricity over long distances.[9]

Electrical power distribution

Some large industries require high voltage current and receive it directly from transmission lines. But high voltages are unsafe in homes, offices and most factories. The voltage must therefore be decreased before the electricity is distributed to them. High voltages are carried by the transmission line to sub transmission substations near the substations to 12500 to 138000 volts. The voltage is then further reduced at the distribution substations to 2,000 to 34,000 volts. Distribution lines may carry this medium voltage current voltage to commercial, industrial or institutional users. Distribution lines may also carry electric power to distribution transformers on poles , on the grounds , or in under ground vaults. Distribution transformers are what reduce the voltage to the levels needed by most users. Wires from the transformers run to homes, stores, offices, and other users. Nearly all consumers receive electric power at a level of 110-240 volts. And we use it to run our daily lives [1] [see Figure 7:] .

Conclusion

Electricity has evolved over the years for it to be where it is today. The electric power demand continues to grow. Power companies as well as engineers must plan carefully for expansion to meet the ever-increasing demand. However, construction of new power plants is costly and takes several years. Many planned nuclear power have been cancelled due to the soaring construction costs and public concern over safety and nuclear waste [see Figure 8 ] :. Extensive research is being carried out into nuclear fusion, but it may take decades to succeed. If the consumption of fossil fuels continues as at present, then the supply will eventually run out. However, many scientists believe that energy from the sun, earth, wind and oceans can be used more extensively to produce electric power cheaply and efficiently in the future [1].

References :

“electric power.” The World Book Encyclopedia. International edition. 6th vol. 1995, 1994, 1993, 1992 pp 159.

” Hydro electric power.” The World Book Encyclopedia. International Edition. 6th vol. 1995,1994,1993,1992 .pp 159.

United States geological Survey. (n.d.). Retrieved 11 09,2010, from Water Science for Schools: http://ga.water.usgs.gov/edu/hyhowworks.html

“nuclear power stations.” The World Book Encyclopedia. International edition. 6th vol.1995,1994,1993,1992.pp159.

Pro’s and Con’s of nuclear power http://www.greenenergyhelpfiles.com

Pro’s and Con’s of nuclear power http:// timeforchange.org.

“Geothermal energy.” The World Book Encyclopedia. International edition. 6th vol.1995, 1994, 1993,1992.pp 245.

Department of energy-Oak Ridge National Laboratory (ORNL).2008. Geothermal (Ground-Source) Heat Pumps: Market status, Barriers to Adoption, and Actions to Overcome Barrers. Report ORNL/TM-2008/232.

http://en.wikipedia.org./wiki/electric_power_industry.