eng paper

ABSTRACT

Energy can neither be created nor destroyed, that is what scientists have concluded from their researches on energy, however, energy conservation and management remains a priority issue to all nations. Posterity of energy is a growing concern, and several states, are critically considering measures that will ensure energy availability and sustainability. This has elicited researches into various energy related fields in a bid to ensure availability prioritized. This report will therefore explore matters as pertaining to energy availability. Prospects of energy sources, reliability, depletion, and recovery techniques will be a priority. Intensive research in the later named fields will be pivotal in ensuring energy is Available for use today and tomorrow, for the world needs efficient energy transformations.

Energy availability

Introduction

Advancement in civilization and science can be attributed to the availability of energy. Over the past years, energy has been the driving force behind various sectors of the economy, such as transport, manufacturing and processing, agriculture, etc. Great scientific explorations have also been enabled by the progress made in energy production systems that power space vehicles and satellites. Owing to its importance, human beings have always, both in the past and in the present times, sought for methods of exploiting energy resources to obtain maximum benefits. The increased use of coal during the industrial revolution enhanced industrial growth and mechanization in the production of goods. Coal exploitation also changed the transport sector with invention of locomotives and steam powered engines that required coal. Advancement in technology led to exploitation of petroleum, thereby replacing coal as the main source of energy. Petroleum has been widely used in power generators and as fuel for engines. Concerns have however been raised on the durability of the available energy resources since most coal and petroleum deposits are getting depleted and may not be available in the future [3]. This has led to research and development on alternative energy sources such as solar, wind, hydro, geothermal and even tidal energy. In addition, the use of various forms of energy in homes, places of work and industries has undergone major transformations in a bid to minimize energy wastage and lower pollution levels arising from the production of greenhouse gasses. Scientists have also come up with methods of making the use of energy more convenient and reliable. More power stations are also being built in an attempt to meet the ever growing power demands by the human population. All these efforts are driven by the concern that the world may, in the future, experience energy shortages and blackouts due to energy unavailability [6]

Energy Sources

Energy can derived from different sources and is usually transformed into various forms that make it usable for various purposes such as for manufacture of goods, for transport, for lighting and heat in homes and places of work. Energy sources may be classified as primary or secondary. Primary energy sources may include sources that occur naturally like hydropower, geothermal, fossil fuels and nuclear energy. Secondary sources on the other hand, are obtained from the conversion of primary sources, and may include electricity generated from different primary sources. The primary sources can also be classified as either renewable or nonrenewable sources. Renewable sources have reserves which are always replenished. Examples in this category include: wind, solar, hydro and geothermal energy sources [5]. Nonrenewable sources on the other hand come from limited sources. Examples in this category include: fossil fuels and earth minerals such as uranium.

Energy reliability

Energy reliability refers to the capacity of an energy source or system of energy production to continuously produce the anticipated levels of energy over a given period of time [1] To achieve this many factors interplay different roles to ensure that there is always a continuous and steady supply of power. Having numerous sources of that generate electricity provides a diversified input to the grid. This prevents power shortages or blackouts that may result from storms or breakdowns in power generation plants. Energy reliability also depends on the availability of base load power plants that are able to constantly generate power to meet the minimal demands of an electrical grid. Majority of base load power plants generate power from coal or nuclear reactions. In contrast, peaking power plants supply power only occasionally, when there is peak demand for electricity. Many peak power plants rely on gas or petroleum powered turbines that generate power from combustion of natural gas or petroleum. In some cases, water may be pumped into reservoirs, and released to flow into turbines to generate extra power if demands increase [1] intermittent energy sources have variable outputs which are subject to uncontrollably factors. Solar and wind energy are classified as intermittent since their output is subject to environmental conditions such as wind speed and sunlight intensity and duration. Power output from intermittent energy sources is difficult to control or predict, and is thus problematic when used to meet consumer demands. Even though electricity generation from renewable sources of energy likes wind or solar help to minimize emission of greenhouse gasses, their power output is not reliable in meeting consumer power demands. Nuclear power plants have the capacity to generate sufficient amount of electricity over long periods of time and are thus considered reliable [4].

Renewable energy

Renewable energy refers to energy that is obtained from sources that are naturally regenerated and replenished over a period of time. Renewable energy can be obtained from natural sources such as wind, sunlight, geothermal heat, tides and waves [5].

Solar energy comes in the form of radiant heat and light from the sun, which is harvested using solar panels or solar heaters. Energy trapped from the sun can either be active or passive depending on how it is captured, transformed and distributed for use in various purposes. Active harnessing of solar energy involves the use of solar panels and thermal collectors. Solar panels are made from photovoltaic cells that convert radiations from the sun into direct current electricity. Passive methods involve solar architecture whereby selective materials, with convenient thermal and light scattering properties are used in construction of buildings. It may also involve orienting or designing a building to maximize on the use of sunlight for lighting and air circulation [4]

Wind energy is obtained by using wind turbines that have blades propelled by wind. Wind turbines in turn rotate generators to produce electricity. Wind towers are usually erected in wind farms which may either be offshore or onshore. Wind power is widely distributed in Asia, Europe and the United States. The world’s largest onshore wind farms are found in China, United States and India, whereas the largest offshore wind farms are found in Germany, Denmark and the United Kingdom [4]

Walney offshore wind-farm, UK. Image source: www.cleanenergyworldnews.com

Hydroelectricity refers to electricity generated by the use of gravitational force produced by flowing or falling water (hydropower). Hydropower is used to turn generators which convert the kinetic energy into electricity. Hydroelectricity is a source of power for most towns and cities; and is also the most commonly used renewable energy. Hydroelectricity is very flexible since power plants are easily erected to meet the power demands of various places. It also has a lower output of waste as compared to power plants that generate electricity from fossil fuels. The construction of dams, however, interferes with the natural courses of rivers and may also result in displacement of populations. China is the world’s largest producer of hydropower, with the Three Gorges Dam being the largest hydroelectric power station [5]

Three Gorges Dam, China. Image source: newamericamedia.org

Tidal energy is a form of hydropower captured from the rise and fall of tides. Tides are produced as a result of gravitational interaction between the earth, moon and sun, which cause motion in the ocean. This results in periodic rise in water levels, which move back and forth. A tidal generator is used to transform the energy from tidal flows to electricity. Tides are more predictable, unlike wind and solar which keep varying. Generation of energy through tides however is limited to coastal areas and also relatively expensive [4].

Geothermal energy refers to thermal energy stored beneath the earth. Geothermal energy originates from the slow decay of radioactive materials in the earth’s crust. Some of this energy is also attributed to heat losses coming from the initial processes during the formation of the earth. The high temperatures in the earth’s crust heat the rocks below the surface, which in turn heat the underground water to produce steam, under high pressure. The steam is harnessed for rotating turbines in power generators, which produce electricity. Power generated from geothermal energy can be used for both domestic and industrial purposes. Geothermal power is clean, sustainable, cost effective and environmentally friendly. The cost of exploration and setting up geothermal power plants is however, expansive. Geothermal energy is also limited to areas close to tectonic plate boundaries [5]

Nesjavellir geothermal power station, Iceland. Image source: www.ucsusa.org

Biofuels are fuels produced from living organisms. This energy comes from carbon fixation that occurs in microalgae and plants. Biomass energy comes from conversion of organic material by chemical, biochemical or thermal processes resulting into fuel. This form of energy generally comes from plant and animal waste, and is used for cooking and heating in homes as well as fuel for transport and industries. Its main drawback, however results from high emission of carbon dioxide into the atmosphere.

Non-renewable energies

Nonrenewable energy refers to energy drawn from sources that are not replenished and can thus be exhausted. Nonrenewable energy sources include fossil fuels (petroleum, coal and natural gas) and nuclear energy. Fossil fuels are the major source of the world’s primary energy sources and are widely used because there is technology and infrastructure for their exploitation [3]

Coal is formed from decayed plants and comprises of carbon combined with organic or inorganic compounds. It is the most abundant fossil fuel on the earth. Coal is mostly found lodged between rock layers beneath the earth’s surface from where it is mined. Coal is usually burnt to provide heat which may be used to generate electricity. In coal powered plants, coal is used to heat water into steam, which is channeled to rotate turbines that generate electricity. Coal is relatively cheaper to mine and has more reserves as compared to other fossil fuels like petroleum or natural gas. The use of coal for heating however results into emission of high levels of carbon dioxide which is responsible for global warming. High amounts of coal used in power plants have also led to excessive mining which has caused significant environmental degradation.

Petroleum (crude oil) is a carbon based viscous liquid that is formed from fossilized remains of animals. Most oil deposits are found underground between rock seams, on land or under the ocean floor. Oil may however emerge to the surface from the ground below and form large pools of oil, as in the LaBrea Tar Pits found in California. Crude oil is abundant in Middle East countries such as Iraq, Iran, Kuwait, Saudi Arabia, and United Arab Emirates (UAE). A few oil wells are also found in North America and Canada [3]. Crude oil is mined by sinking drill rigs into the reservoirs and pumping the oil out through pipes. Crude oil is refined to make a wide range of products with different uses. Oil products such as gasoline is widely used in the transport sector and in industries. Even though it is relatively inexpensive to extract and use as a source of energy, petroleum extraction, transport and use, pose a major threat to the environment. Combustion of oil leads to emission of greenhouse gasses and other atmospheric pollutants. Oil spills during drilling and transport may also result in death of both land and sea organisms.

Offshore petroleum extraction, Canada. Image source: oil-canadasnaturalresource.weebly.com

Natural gas refers to a mixture of many gasses (methane, butane, propane and ethane) that is trapped beneath the earth’s surface. Natural gas is extracted by drilling into rocks beneath the surface. Hydraulic fracturing may be used to split the rocks to release the trapped gasses under high pressure. Middle East countries have high amounts of natural gas reserves. Natural gas is a cleaner fossil fuel as compared to coal or oil, and its extraction is also relatively inexpensive. Its extraction may however pose a threat to the environment and cause minor earthquakes when rocks are split under great pressure [1].

Nuclear energy is generated from nuclear processes (nuclear fission or nuclear fusion) that are exothermic. Many nuclear power plants use nuclear fission to produce energy. Nuclear fission involves splitting of atoms to release energy stored in elements. Uranium 235 is used in most nuclear power plants and electricity is normally generated from the resultant energy produced by these reactions. Nuclear energy is clean since it does not emit greenhouse gasses. It also requires small amounts of raw materials to produce high amounts of energy, making it very efficient. It is however expensive to set up and run a nuclear power plant. The radioactive materials produced as a waste of the reactions may be toxic and carcinogenic. Nuclear disasters and leakage of nuclear materials may also be very difficult to contain, and can result into devastating effects both to the human beings and the environment. Examples of such disasters have occurred in Chernobyl, Ukraine and Fukushima Daiichi, Japan, in 1986 and 2011 [2].

TVA Watts Bar Nuclear Power Plant | Photo courtesy of Tennessee Valley Authority

New energy recovery techniques

To ensure energy availability, new techniques are being employed to enhance efficiency by the use of new energy recovery techniques. Some of the methods convert waste into energy that can be used for various purposes in homes and industries [2]

Anaerobic digestion of organic waste by bacteria in biogas digesters results in the production of biogas which is rich in methane. The biogas is normally used in homes for cooking and heating. Biogas is also used in power generation by gas powered turbines. The sludge from the digesters may be used as manure or soil conditioner depending on the composition of the waste used.

Waste may also be incinerated in combustion chambers to produce heat energy. The resultant heat energy may be used to produce steam for steam turbines or even industrial processes that require heating. Waste that is dumped in landfills usually undergo decomposition over a period of time to produce landfill gas, which has high percentages of methane. Recovery of landfill gasses can provide useful energy for cooking or heating or even power generation [3]

Many efforts have also been made in attempts to create systems that consume less energy. Such advancements can be seen in the design of modern engines that consume less fuel but have grater output. Energy saving devices have also been designed in an attempt to minimize power wastage. Modern architecture has also been involved by designing of energy efficient buildings that use renewable solar energy for lighting and heating. This has not only lad to minimal production of greenhouse gasses but also minimized overreliance on other sources of power [6]

Recommendations

In as much as great strides have been made to harness energy from various sources, the issue of energy availability, for present and future uses, has not been adequately tackled. The consumption of fossil fuels, especially coal and petroleum, still remains high despite prospects to cleaner and renewable energy sources. It is recommended that industries that depend on fossil fuels should make investments aimed at replacing their energy sources with renewable ones since the energy deposits are fast getting depleted and may not be available in the future. Even though the costs of setting up and running nuclear power plants may be high, their power supply is very reliable to meet the increased demands of power in various states. It is therefore recommended that investments should be made to build more nuclear based power plants to meet the current energy demands which keep escalating. It is also recommended that buildings should be fitted with solar panels and solar heaters if possible to help supplement power demands. Modern building designers should also incorporate necessary designs that enable the use of sunlight for lighting and air circulation. This would help in minimizing the use of electricity, thereby lowering power demands. More research and exploitation is also recommended in the prospect for tidal energy which is still rather unpopular in many countries.

Conclusion

Since energy is the driving factor behind civilization and scientific advancements, its conservation and management remains a top priority for all nations. Availability of sustainable energy is an important factor for all countries that plan for continuous survival of the present and future generations. The shift from reliance on fossil fuels to cleaner and renewable energy sources still remains a major challenge owing to unpredictability of conditions that generate clean energy such as sunlight and wind. The use of renewable energy can be considered as the future of energy availability since coal and petroleum deposits, which are the current major sources of energy in various countries in the world, are getting depleted.

References

[1]Beggs, C. 2009.” Energy: Management, supply and conservation. Amsterdam: Elsevier Butterworth-Heinemann.” P. 123-456

[2]Duncan, T. 2011. “Energy Recovery. New Delhi: World Technologies.” P. 45

[3]Evans, R. L. 2007. “Fueling our future: An introduction to sustainable energy. Cambridge: Cambridge University Press”. P. 32

[4]Khaligh, A., and Onar, O. C. 2010. “Energy harvesting: Solar, wind, and ocean energy conversion systems.” Boca Raton: CRC Press. P. 12

[5]Langwith, J. 2009.” Renewable energy. Detroit” Greenhaven Press. P. 67

[6]Orme, H. 2008. “Energy for the future.” New York, NY: Bearport Pub. P.112