EnergyIn physics, energy is an indirectly observed quantity that is often understood as the ability of a physical system to do work on other physical systems.Since work is defined as a force acting through a distance (a length of space), energy is always equivalent to the ability to exert pulls or pushes against the basic forces of nature, along a path of a certain length. The total energy contained in an object is identified with its mass, and energy cannot be created or destroyed.Energy Technology refers to the knowledge, skills, and equipment required for the production, conversion, transference, distribution, and utilization of energy. This leads to the mastering of technology based on the laws of nature, as a result of which different forms of energy can be used to serve the needs of mankind in such a way that nature is spared and the economic resources of society are taken into consideration. Energy engineering is a broad field of engineering dealing with energy efficiency, energy services, facility management, plant engineering, environmental compliance and alternative energy technologies. Domain of Energy Engineering expertise combines selective subjects from the fields Chemical, Mechanical and Electrical Engineering. It is an interdisciplinary program, which has relativity with electrical, mechanical and chemical engineering.Forms of EnergyEnergy can be found in many different forms which can generally be divided into two categories: kinetic or movement energy; it encompasses forms of energy which are generated by motion potential energy; it is also known as stored energy and is released by energy conversion1. Kinetic EnergyForms of kinetic energy include: Electrical energy. It is one of the most commonly used forms of energy which is created by movement of electrical charges. An example is lightning and electrical charges travelling through the wire. Electrical energy, however, can also be a form of potential energy. In this case, it is known as electrical potential energy. Radiant energy or electromagnetic radiation. It refers to energy of electromagnetic waves. Examples include radio waves, ultraviolet radiation, microwaves, gama rays, infra-red radiation and visible light. Thermal energy. The term describes the internal heat that is generated by movement of atoms and molecules. Examples of thermal energy include geothermal energy and heat that is radiated by the sun or solar radiation although the latter is usually classified as radiant energy. Sound energy. It is released by vibrating objects and travels in waves through a medium. The amount of energy that is gained from vibrating objects does not have any major value for humans such as generating electricity for instance. But it can be more powerful than most people think. Sometimes it is classified as a form of mechanical energy.2. Potential EnergyForms of potential energy include: Nuclear energy. It refers to energy which is stored in a nucleus of an atom which is converted into electricity by splitting of the nuclei by a process known as fission. But it is also released by radioactive decay, a process in which the nuclei of an atom spontaneously release energy that is known as ionizing radiation. Chemical energy. The term describes energy that is stored in the bonds between molecules and atoms which is released only through chemical reaction. The best example of chemical energy are fossil fuels and biomass that release energy when burned. Mechanical energy. Sometimes also known as elastic energy, mechanical energy refers to energy that is released by application of force. It is used to generate electricity (generator) but usually, other forms of energy are used to generate mechanical energy. The best example is internal combustion engine that converts chemical energy (burning fuel) into mechanical energy. Magnetic energy. It is a potential energy of a magnet that can be used to convert electrical energy into mechanical and mechanical into electrical. Gravitational energy. It is the energy that attracts objects to the ground. An example of gravitational energy is hydroelectricity that uses the gravitational force of falling to generate electricity.

Energy resources

For all practical purposes energy supplies can be divided into two classes Renewable and Non-renewable energy

Renewable energyRenewable energyis classified as energy that comes from resources like sun light (known as solar), wind, geothermal heat and rain that are constantly replenished. Renewable energy can serve as a replacement to electricity, motor fuels, rural energy and heating. Many people might discount renewable energy sources right off the bat just by looking at the definition. They wouldnt hesitate to question why it is necessary to switch to sources like sunlight,wind, or rain. The way they see it, these are not very reliable sources of energy. This is why the question can only be begged: what are the real benefits of renewable energy sources? While there are certainly advantages and disadvantages to switching to renewable energy, it is quite arguable that the benefits of using such sources outweigh the shortcomings of it, especially in the future. Of course, theshortcomings are all things that can, with time and money, be fixed due to the rapid technological advancements our country makes on a nearly annual scale. The benefits of renewable energy sources are breathtaking, and while we may not quite be in a position to fully switch over to renewable energy sources just quite yet (requiring a balance ofrenewable energyand other sources for now), it is imperative that we look ahead to the future..

Non-renewable energyIs energy obtained from static stores of energy that remain underground unless released by human interaction. Examples are nuclear fuels and fossil fuels of coal, oil and natural gas. that the energy is initially an isolated energy potential, and external action is required to initiate the supply of energy for practical purposes. To avoid using the ungainly word nonrenewable, such energy supplies are called finite supplies Energy. Figure1.1 Shows Contrast between renewable and finite energy supplies.Physical laws state that energy can neither be produced nor destroyed or lost. Never the less, many people talk about energy losses or energy gains, although the law of energy conservation states:The energy content of an isolated system remains constant. Energy can neither be destroyed nor be created from nothing; energy can transform to other types of energy or can be exchanged between different parts of the system..

The advantage and disadvantage of renewable and non-renewable energy.

Advantages of Renewable Energy1. Renewable energy is, well, renewable:This means it has infinity of sustainability and we will never run out of it. Other sources of energy likecoal,oil andgasare limited and will run out some day.Renewable energy canreduce our dependence on fuels and energy from foreign governments. Strong winds,heat within earth, moving water, shining sun can provide a vast and constant energy resource supply.

2. Environmental Benefits:It is clean and results in little to no greenhouse and net carbon emissions. It will not deplete our natural resources and have minimal, if any, negativeimpacts on the environment, with nowaste productsof Co2 and other, more toxic take with different sources of energy. The environmental benefits of renewable energy are innovative in that they will dramatically scale back on the amount oftoxic air pollutionreleased into the atmosphere by other methods. Enables us to protect the environment from toxic pollutions, which in turn keep people healthier.

3. Reliable Energy Source:Our dependence onfossil fuelshas increased considerably in last few decades.The result is that our national security continues to be threatened by our dependence on fossil fuels which are vulnerable to political instabilities, trade disputes, wars, and high prices. This impacts more than just our national energy policy. Also, solar and wind plants are distributed over large geographical area and weather disruptions in one area wontcut off powerto an entire region.

4. Economic Benefits:Renewable energy is also cheaper and more economically sound than other sources of generated energy. It is estimated that as a result of renewable energy manufacturing, hundreds of thousands of stable jobs will be created. Thousands of jobs have already been created in numerous European countries like the United Kingdom and Germany, who have adopted measures to manufacture renewable energy. Renewable energy amenities require a less amount of maintenance, which reduces the costs. Switching to renewable energy sources also means that the future of our energy is returned back to the people: to communities, families, farmers, and individuals.

5. Stabilize Energy Prices:Switching to renewable energy sources also means steady pricing on energy. Since the cost of renewable energy is dependent on the invested money and not the increasing or decreasing or inflated cost of the natural resource, governments would only pay a small amount in comparison to the needlessly heavy pricing of the energy prices we are witnessing currently.The United States of America has the best wind resources in the entire world. Now that wind energy is the most cost effective source of energy, and the technology of wind turbines has improved as well as the cost has gone down. This permits more manufacturing plants that are cost effective. Wind is a reliable source ofelectricity, as is solar power for similar reasons.

Disadvantages of Renewable Energy1. Reliability of Supply:One shortcoming is that renewable energy relies heavily upon the weather for sources of supply:rain, wind, and sunshine. In the event of weather that doesnt produce these kinds of climate conditions renewable energy sources lack the capacity to make energy. Since it may be difficult the generate the necessary energy due to the unpredictable weather patterns, we may need to reduce the amount of energy we use.

2. Difficult to Generate in Large Quantity:Another disadvantage of renewable energy is that it is difficult to generate large amount ofenergy as those produced by coal powered plants. This means that either we need to set up more such facilities to match up with the growing demand or look out for ways to reduce our energy consumption.

3. Large Capital Cost:Initial investments are quite high in case of building renewable energy plants. These plantsrequire upfront investments to build, have high maintenance expenses and require careful planning and implementation.

4. Large Tracts of Land Required:To meet up with thelarge quantities of electricityproduced byfossil fuels, large amount of solar panels and wind farms need to be set up. For this, large tracts of land is requiredto produce energy quantities competitive with fossil fuel burning.

Advantages of Non-Renewable Energy

Because non-renewable energies seem abundant, like oil, gas and coal, some experts believe if channeled correctly, our supplies will be safe for future generations. Non-renewable energy sources include oil and petroleum products, gasoline, diesel fuel, and propane, natural gas, coal, and uranium used for nuclear energy. Some environmentalists include our forests, trees, and plant life as a non-renewable energy source as well especially due to the deforestation of our forests. One advantage of non-renewable energies is that right now, they seem widely available and affordable. Oil and diesel are still good choices for powering vehicles. They are cost effective and much easier to produce and use. Non-renewable energy also has market value where a supplier or manufacturerMAKES MONEYand pays workers enhancing economies. Although governments struggle with fair trade practices, many countries have a non-renewable energy source which can used as a bargaining tool to help their economy stay afloat.

Disadvantages of Non-Renewable Energy

On the other side, there are many disadvantages to non-renewable energy. Because non-renewable energies come from sources on our planet, once they are gone they can't be replaced or revitalized Pollution grows greater through the by-products they leave behind and mining of non-renewable energy is causing damage to our environment. There is no doubt that fossil fuels contribute to global warming and to break humans of their habit to lean on non-renewable energy sources remains a challenge. As countries disagree through wars and differences, the prices of non-renewable energies such as oil has become a commodity where price fluctuation is always eminent. The burning of fossil fuels continues to rise producing high levels of carbon dioxide (CO2) which climatologists believe is amajor cause of global warming.

Renewable Energy Introduction The concept of renewable versus nonrenewable resources provides the cornerstone of sustainability. Renewable resources are replaced by natural processes over time, but even these must be conserved so that they are not used up faster than nature can replace them. Conversely, nonrenewable resources such as oil or minerals are formed in the Earth over millions of years. Earth can replenish nonrenewable resources, but this occurs over eons such as the millions of years needed to transform organic matter into fossil fuels. Uses of Renewable Energy1. Renewable energy has many uses and it can support small as well large applications. Renewable energy from wind, sun and geothermal is used to produce electricity and heat for use. The solar power plants are used to generate electricity and steam for industrial projects.. Thus the renewable energy sources can viably help users to their heat homes. 1. Some other applications of renewable energy sources include heating space, day lighting, space cooling, water heating, mechanical energy to cut woods and grinding grains.

Reduced Dependence on Fossil Fuels Solar energy production does not require fossil fuels and is therefore less dependent on this limited and expensive natural resource. Although there is variability in the amount and timing of sunlight over the day, season and year, a properly sized and configured system can be designed to be highly reliable while providing long-term, fixed price electricity supply.2.4. Global warming and solar energy The use of fuels like oil and gas in homes, cars and industry has brought us to the problem of global warming. The extreme production of harmful gases like carbon monoxide has destroyed the ozone layer hence we receive both the harmful and harmless sunrays. The use of sun to support industrial processes can help us overcome the worst situation of global warming.2.5. Forms and types of renewable energy2.5.1. Wind and tidal powerThe first major form of renewable energy is wind power. Wind has been an energy source for a very long time. It was the first major form of renewable energy.

The traditional methods of producing electricity have resulted in climate changes because of high rate pollution it discharges. Wind power turbines can provide clean electricity which can cover its cost in 5 to 6 months easily.

2.5.2. Geothermal and Hydropower energy1. Hydropower is the power derived from the energy of falling water and running water. it comprises total 88% of the renewable energy sources. Hydroelectricity come from the water stored in dams; these dams convert the potential energy present in the water to the electricity with the support of generators. The amount of energy which can be pulled out from water depends upon the working of Head (difference of height between the source and water flow).

Fig. (2-4). Hydropower from Dams

1. Geothermal energy is the thermal energy generated and stored in the earth because of the sun that is why it falls under the renewable energy and it is used for producing electricity. Geothermal electric energy can be extracted from the earth by installing heat exchangers into the earth.The energy for the geothermal heat pumps can be pulled out by earth tubes and heat exchangers. Heat from the earth can be directly transferred to the radiators for heating homes. Fig. (2-5). Geothermal energy

Advantages and disadvantages of hydropower and geothermal energy

Table. (2.1). Hydropower and Geothermal advantages and disadvantages

2.5.3. Biomass energy It is another form of renewable energy source and it is derived from living or dead organisms like plants, waste and alcohol mostly. Biomass energy source is most often derived from plants either to generate electricity or to produce heat.

Fig. (2-6). Biomass

Sources of Biomass Energy

1. Biomass energy is derived form various sources which help in generating sufficient energy for use. The various source of generating energy from biomass are wood, waste, alcohol, garbage, landfill gases. Wood is either taken from trees or from the waste of industrial processes.

1. The second major source of deriving biomass energy is from the solid waste. This solid waste is either provided by municipality waste or industrial waste. When energy is extracted either from alcohol or from the fiber present in the corn, it is termed as ethanol fuel.

Advantages and disadvantages of Biomass energy

Table. (2.2). Advantages and Disadvantages of Biomass

2.5.4. Renewable energy from wastes : It is energy comes from food, oxygen in the air and water. After consuming these resources there is a lot more production of waste material. This waste material if not disposed properly would surely harm the environment which ultimately is dangerous for human beings. With the ever growing population, there is need to not only disposed this waste rather by taking some advantage out of waste renewable energy.

Fig. (2.7). Waste energy

2.5.5. Solar Energy Solar Energy is the energy we derive from rays and heat of sun. The energy from the sun can be used to overcome the energy crisis generated by using fossil fuel so That is why now more and more countries have switched to processes which help them conserve the heat and light from sun. Applications of solar energy