In the past, electrical and magnetic phenomena have been known and observed as natural occurrences. Such phenomena have been essentially extended over thousands of years of human interest and inquiry, creating the electro-technology industry that we have today.
It is impossible to store large quantities of electrical energy. Therefore, the consumer gets electricity energy through a transmission and distribution system from bulk supplies of electrical energy fed directly from the generating station. This need led to the growth and development of the electricity supply industry.
Just after the results of Faraday’s famous 1831 experiments were published, various inventors built many practical generators. Their goal was to create a direct current supply that would replace the battery as an electric power source.
The first D.C. Generators also known as dynamos, were designed for experimental purposes. Later on, dynamos were improved and produced for supplying the arc lamp and for electroplating. The arc lamp which is used for lighting produces a sharp light from an arc formed between two carbon electrodes. Out of the first machines designed in Britain, some of them were specially designed to provide the energy required for the arc lamps in lighthouses. It didn’t, however, take long before the arc lamp was used for illuminating public places.
As time passed, the design of bigger and more efficient dynamos progressed. To emphasize more on the size, the famous 1881 Jumbo dynamo of Thomas Edison was rated at 1500 light 110 volt, driven by a 150 horsepower engine equivalent to approximately 112kW. In comparison, today’s larger generators are rated at up to 650,000kW in a base-load power station.
Before the inception of more efficient dynamos (before 1880), the primary purpose of the majority of electrical sources was to supply the electrical energy for arc lamps. Although, there was a need for regular maintenance for the open arc of these lamps (because they produced gases that can cause a fire hazard), control gear and arc carbons.
The eventual invention of the incandescent lamp required a growing public supply. However, almost all early public supply systems were direct current. They were small and often owned by private companies. Fortunately, the government became involved because of their desire to get lights on public streets. Therefore, they took over many private supply companies. Large supply areas came under the control of electricity companies after some years, and they are formed mainly for the purpose of distributing electricity.
Gradually, as alternators (generators that produce alternating current), engines, transformers and equipment gradually improved, the generation, transmission and distribution of three-phase a.c. was adopted worldwide.
Some scientists that contributed to the utilization of electricity are:
- Thomas Edison (1847-1931): He was an inventor and successful entrepreneur. He invented the first commercial incandescent lamp and developed the first major direct current-based electrical distribution system.
- Nikola Tesla (1856-1943): He was a great engineer. Tesla’s inventions and theoretical research shape the basis of the modern alternating electricity system we have today. He invented the a.c. motor (also known as an inductor motor), which is probably the single most important invention in the industrial use of electricity.
- George Westinghouse (1846-1914): He was a businessman and entrepreneur. George converted great inventors and engineers like Tesla’s inventions into commercial reality. These included the transformer and induction motor, heralding today’s a.c. supply system.
- Mikhail Dolivo-Dobrovolsky (1862-1919): He is an engineer, electrician, and inventor. Mikhail was accredited with developing the three-phase a.c. system.
The first commercial use of an arc lamp was in a lighthouse at Dungeness, England in 1857. Also, the first sales of electricity to the public was made in the USA in 1879.
Modern Electricity Generation Methods
A great percentage of electrical energy generated today is obtained from a rotating turbine connected to an electrical generator. The energy used in driving turbines in sourced from flowing water, steam, dam, wind, and hot gases. In most countries, the major source for creating steam to drive turbines is coal. Some other sources of steam production are petroleum, natural gas and concentrated sunlight (solar energy).
Hydroelectric Power Energy Systems is using controlled water flow from dams to power turbine generators. The energy from the tidal flows is another source used to power turbine generators in some appropriate coastal locations.
The hot gases produced by burning natural gas or oil are utilized in gas turbine generators to directly drive the turbine. Recently, these sources are supplemented with some couples of the renewable energy sources.
Modern electricity generation systems fall into the groups below:
- Power stations which use thermal energy released by a nuclear reaction, known as nuclear power stations.
- Power stations which use thermal energy released from burning coal, oil or natural gas to generate steam or hot gases, known as thermal stations.
- Power stations that use the kinetic energy of moving water, also known as hydroelectric stations (the most common form of renewable energy).
- Other renewable energy sources are biogas (from landfill), solar energy (from the sun), geothermal, kinetic energy (from wind) and wave movement.
For areas which are remote from the main power network, small diesel-engine driven generators are used for their electricity supply. They are becoming more and more common in those areas as their standby power supply.
Thermal power plants use the heat gotten from burning coal, oil or natural gas to transform water to steam, and the steam is used at high pressure to drive a turbine that is directly connected to an electrical generating alternator.
Though coal and nuclear thermal power plants can take hours, even days, to achieve a stable state power output. Since they take a long time to heat up to operating temperature, these plants are used to supply large amounts of base-load demand.
The voltage (V) or pressure at which the current is produced varies from 11000 Volts to 23000 Volts. For the transmission of electricity, we have step-up transformers and we also have step down transformers which helps consumers to utilize the electrical energy. One of the major advantages of using A.C. is that its voltage can be easily converted.
How Electricity Generation is Contaminating the Environment
The Intergovernmental Panel on Climate Change (IPCC) – a top scientific body of the United Nations, made a conclusion in their Fourth Assessment Report. They reported that our climate is warming due to greenhouse gases produced from gas emissions into the atmosphere from burning fossil fuels such as coal.
Coal is used to generate 41% of the world’s electricity. But burning them results in the conversion of carbon to carbon dioxide, which is later released into the atmosphere. It is estimated that the world’s electrical power industry emits 10 billion tonnes of CO2 yearly. This causes the earth’s levels of atmospheric carbon dioxide to increase significantly. Hence, the promotion of the greenhouse effect and global warming.
Other emissions and contaminants may also be produced depending on the fossil fuel and the method of burning. These contaminants are Ozone, Nitrogen dioxide, Sulfur dioxide, and other gases as well. Nitrogen and Sulfur oxides contribute to acid rain and smog.
Coal also contains dilute radioactive material and when it is burnt in large quantities, it releases this harmful radioactive substance into the environment and thus causing global radioactive contamination.
Another way by which coal affects the environment is through mining. Coal mining practices have now involved removing mountain tops and other methods causing environmental pollution (air and water pollution).
The usage of water is also one of the environmental impacts of electricity generation. Coal, natural gas, geothermal, biomass and nuclear cycles all use water as a cooling solvent to drive the thermodynamic cycles that enhance electricity to be extracted from heat energy. Other energy sources such as wind and solar make use of water for equipment cleaning. Also, hydroelectricity uses water from evaporation from the reservoirs. The amount of water used in the process of electricity generation is a great concern as the population of the world continues to increase and chances of droughts getting higher. In the process of electricity generation, some harmful effluents are released into the water sources thereby causing pollution.
The solutions to these environmental contamination is by practicing renewable and sustainable energy generation.
Renewable and Sustainable Energy Generation
Although, greenhouse gases occur naturally in the atmosphere, human activities that include burning of fossil fuels and land clearing increase the concentration of these gases. After recognizing this problem, there are joint efforts made internationally to put an end to greenhouse gas emissions across all sectors of the economy.
What does sustainable energy means? Sustainable energy is a term that means both an efficient use of energy from any source (which means, using less energy to provide the same service) and energy from renewable sources such as solar, wind, geothermal, and hydro. Don’t mistake renewable energy with energy extracted from materials such as fossil fuels. Renewable energy is the conversion of energy already existing naturally to other beneficial sources such as electricity.
Wind power makes use of mechanical energy from the periodical flow of air over the surface of the earth. Wind power plants generally consist of wind farms, fields of wind turbines in areas with very high winds. The disadvantage of wind power is the issue of noise thereby making it unattractive to the society.
When a modern wind farm is installed on agricultural land, it has a very low environmental impact:
- It is compatible with growing crops and also occupies less land area per kilowatt-hour (kWh) of electricity.
- Its operation does not produce greenhouse gas. However, during its construction the greenhouse gas emissions and air pollution are minimal.
- It produces the energy used during its construction in just a few months of operation.
- Modern wind turbines does not rotate so fast in terms of revolutions per minute. Therefore, they’re rarely a threat to birds.
Solar power works by converting the sun’s energy (radiation) into direct current (DC) power through photovoltaic cells. This power can then be further converted into the common AC power and released to the power grid.
Solar photovoltaic power provides a good alternative to fossil fuels for its supply and cleanliness. However, the cost of production is very high. There are promising future technological innovations currently in place to reduce the cost to a more encouraging range.
The negative impacts of solar power on the environment can be seen in the building of solar cells which are made majorly from silica. During the extraction of silicon from silica, fossil fuels are required. This then brings about the production of CO2 gas, however, newer production processes have been employed in eliminating the production of CO2.
With Solar and Wind Power offering a significant amount of electricity generation, they, however, cannot produce enough energy to meet the world’s demand in the nearest future. This is because their cost of production is too high.
The best alternative for the generation of massive electricity that will be more than sufficient and sustainable for the World’s population is Nuclear Power.
Nuclear power plants do not make use of fossil fuels and thus do not directly emit carbon dioxide. However, due to the high energy yield of nuclear fuels, nuclear power produces carbon dioxide but in relatively small amounts when compared with carbon dioxide emitted by fossil fuels of similar energy yield.
With new developments in technology, the newest nuclear plants produce clean energy that does not produce greenhouse gas emissions. Nuclear power provides power for 24 hours in a day, therefore, it is a crucial part of the energy to mix necessary electricity demands. Electricity generated from nuclear plants is the lowest-cost provider of large-scale electricity. This means their production is much cheaper compared to wind and solar power production.
Nuclear energy can be derived from the splitting of uranium atoms. The process is known as Nuclear Fission. This process generates heat to produce steam, which is harnessed by a turbine generator to generate electricity.
How Nuclear Fission Produces Electrical Energy
For hundreds of years, the power which can be generated by water expanding into steam has been regulated and used. This reaction in a nuclear reactor is triggered by the heat generated during the nuclear fission process. Enriched uranium, by nuclear fission, provides energy. This energy is regulated at a nuclear power plant in a process that converts the heat generated by nuclear fission into electrical energy.
The uranium is stored in bundles within the reactor core. Uranium pellets are arranged in rods of the same length and diameter, and these rods are gathered into bundles. The bundles of uranium are placed in a container and submerged as a coolant in water. The heat of the bundles of uranium in the core of the reactor must be managed to prevent overheating which could cause the reactor to melt. Control rods are raised and lowered in the uranium bundle to control the core temperature, as required. The rods can also be lowered all the way down, stopping heat generation and shutting down the reactor in the event of an emergency or changing fuel.
The first move in the production of electrical energy is to allow water to expand into steam in the reactor core containing the uranium bundle. The steam leaves the container in the next step to power the turbine. The turbine spins a generator, and the generator ends up generating electricity.
Some nuclear plants add another stage to the process that produces a second loop that converts water back to steam before driving the turbine. This prevents direct contact of contaminated water and steam with the turbine. To enable operation at higher temperatures, reactors can be filled with various types of coolant.
Article author: shineguru (Fiverr.com)