ENERGY

10.4.1 Energy Basics

All organisms on earth require energy to live. Energy is considered as one of the most important resources on earth. It actually comes from the sun. Sun is consist of hydrogen and helium gases which produces tremendous amount of energy in a form of electromagnetic radiation . Only small amount of it is being radiated to Earth. Most of it is being dissipated back to space. Energy sources may be classified as renewable and non-renewable. Renewable sources are those which may be inexhaustible or may be replaced. During Industrial period, energy is being produced by humans in form of fossil fuel, either as coal, oil or natural gas. However, such is non-renewable which means would last for only some period of

time.

Energy is defined as the capacity to do work. It is divided into two types : potential and kinetic energy . Potential energy is energy which is being stored or at rest and available for use, while kinetic energy is energy in motion or working energy. Thermodynamics is the study of energy transformations. There are two laws concerning energy. The first law of energy is the law of conservation of energy which states that “ energy is neither created nor being destroyed but is converted from one form to another. The second law of energy which is the law of entrophy, states that energy when being transformed is converted to low -quality energy in a form of heat. When energy is changed from one form to another, a more useful is converted to a less useful form.

10.4.2 Energy Consumption and Resources

Everything on earth utilize energy. All organisms which include human, plants and animals need energy to live. The buildings that humans live, car, factories and the world economy relies on energy. Energy that heats up the earth comes from the sun and is considered to be inexhaustible . After industrialization , about 80% of the world’s energy sources comes from extraction and burning of minerals which are obtained from earth’s crust. These are commercial energy or being sold in the marketplace as fossil fuels such as coal, oil and natural gas. Fossil fuels were formed hundreds of million years ago from remains of plants and animals. However, the rate of consumption of fossil fuels is faster that its production and such sources are known as non-renewable energy sources. On the other hand, there are energy sources which are continuously present and can be replenished , these are known as renewable energy sources. Some of these renewable sources are solar, geothermal , wind , moving water and biomass.

10.4.3 Non-renewable Energy Sources

Fossil fuels are non-renewable sources which comes from remains of organisms, compressed in oxygen free environment. Fossil fuels are being formed million years ago as product of photosynthesis with the aid of solar energy. Although photosynthesis is a natural process , formation of fossil fuels is slower than it is being used. It is being formed after dead plants are being decomposed by bacteria and fungi. It include petroleum, natural gas and coal. Petroleum or crude oil is considered as the largest source of commercial energy in the world. It is known as “light oil“ which comes form the ground as black colored liquid which is consist of hundreds of different combustible hydrocarbons along with small amounts of sulfur, oxygen and nitrogen impurities. Crude oil is being deposited within the earth’s crust or under the sea floor. In order to extract the oil, developers tend to drill wells in the deposit and is drawn out of rock pores, flows into the bottom of the well and is pumped into the surface. After it is being extracted, oil is not ready for use, it has to be transported to a refinery to be heated in a process known as refining. Some of the products of crude oil distillation are called petrochemicals such as gasoline, diesel fuel and furnace oils. It has been projected by geologists that crude oil will be depleted sometime in 2050 and 2100 depending on humans consumption rates.

One of the major problem associated with crude oil is with regards to its transportation. Usually oil is being transported throughout the globe through supertankers and sometimes results to leaks and spills. Oil spills result to water pollution just like what happened in Guimaras which resulted to death of phytoplankton, corals and fishes. Oil spills on land can contaminate the soil and underground water. Evaporation of oil products and incomplete combustion of oil fuels results to air pollution.

Natural gas like coal and oil forms from fossil remains. It is a mixture of gases of which 50-90% is methane (CH4) and contains small amount of hyrodrocarbons such as propane and butane. Natural gas lies above most reservoirs of crude oil in the earth’s crust or in the deep sea. The extraction process to yield natural gas is similar to oil . When natural gas is being tapped, propane and butane gases are liquefied and removed as liquefied petroleum gas (LPG).

Natural gas when being burned produces carbondioxide and water. Carbondioxide is one of the greenhouse gases which in high levels results to global warming. However, as compared to coal and oil, it produces less carbondioxide. Accidents which may result to explosion or fire when being transported by ships or tankers is one of the common problem.

Coal is a hard black mineral consisting mainly of carbon. It comes from remains of plants and animals that were buried million years ago . It is burned in power plants to generate about 40% of the world’s electricity. It is the world’s most abundant fossil fuel . There are two ways in which coal is being extracted : either through surface mining or underground mining. It is consist of large percentage of carbon, small amounts of sulfur which upon combustion is being released as sulfur dioxide (SO2) in the atmosphere. Burning of coal also releases particulates or soot. Coal burning power and industrial plants are major emitters of greenhouse gases such as carbondioxide (CO2). Burning of coal also emits trace amount of toxic and indestructible mercury and radioactive materials in the air which contributes to acid rain and human health diseases.

Mining as a method of extraction of coal results to several environmental problems such air, water, noise and land pollution. Large waste such as acid mine tailings are being disposed into bodies of water such as rivers and streams. Large amount of coal dusts are being released into the air and can cause health problems not only to the miners but also to other people when being inhaled. Many miners suffers from respiratory diseases or black lung diseases that results from accumulation of fine coal-dust particles in the lungs. Burning of coal also results to acid rain due to sulfur dioxide since coal as fossil fuel contains sulfur. Carbon dioxide and sulfur dioxide that are being released into the air contributes to global warming.

10.4.4 Renewable Energy Sources

Solar energy

Energy from the sun is an inexhaustible source of energy. Sun which is a star is composed of 72% of hydrogen and 28% of helium gases which upon nuclear fission will emit an enormous amount of energy known as electromagnetic radiation. Only 66% of its total emission is capable of reaching the earth’s surface, while the remaining 34% is being dissipated to space.

Solar energy comes directly from the sun. Solar energy can be converted to electrical energy by photovoltaic (PV) cells, or commonly termed as solar cells. Usually solar cells are made up of thin silicon with trace amount of metals that allows them to act as semiconductors to generate electricity. When sunlight strikes the solar cells, electrons will be emitted and many cells that are wired together in a panel can produce electrical power. The cells can be connected to electrical grid systems or batteries that store the electrical energy until its usage. Solar cells produce no pollution or greenhouse gases when being used. However, solar panels are quite expensive.

Wind energy

Wind is produced by uneven heating of earth’s surface and earth’s rotation. Radiant energy from the sun is converted to mechanical energy which is the movement of air molecules. Wind turbines tend to capture the wind on land and at sea and convert into electrical energy. Since wind varies, so is the amount of electricity that is generated by each wind turbine. Usually wind turbines are installed on rural areas with continual wind scuh as coastal areas, islands, mountain passes or grasslands. Wind energy produce very low environmental impact, no emissions of waste and is a clean source of energy. It produces no emissions of carbondioxide (CO2), ,sulfur dioxide (SO2) and nitrogen oxides (NO2). It has low electricity cost and moderate capital cost. However, wind turbines can kill birds and bats , interfere with flights of migratory birds, and require large areas with steady winds.

Nuclear energy

Nuclear energy is considered to be one of the most cheapest sources of electricity.It involves changes in the nucleus of the atoms. Atoms are smallest component of non-living matter . An atom is composed of positively charged protons, negatively charged electrons , electrically neutral neutrons and a central region called the nucleus. There are two nuclear reactions which take place to release energy : these are fission and fusion. During fission, larger atoms of certain elements are split into two smaller atoms of different elements. During fusion, two smaller atoms are combined to make one larger atom of different element. The nuclear reactions produce smaller amounts of energy in the form of heat which is converted to electricity.

The problem with nuclear energy are accidents at nuclear facilities, terrorist use of nuclear materials, safety concern among worker and public exposure to radiation and nuclear waste disposal. One of the accident occurred on nuclear plant was the Chernobyl nuclear accident which happened in 1986. The nuclear power plant explode and it took 10 days to control the burning reactor. Several people were affected with radiation related diseases such as thyroid cancer and abnormalities among developing babies.

Hydropower energy

Hydropower uses kinetic energy of flowing and falling water to produce electricity. The most common approach in utilizing hydropower is to build high dam across a large river or reservoir. The potential energy of held back by the dam is converted to kinetic energy as the water falls down as penstock where it turns turbines that generate electricity. Building of dam can cause flooding of large areas of land and destroy organisms such as plants and animals. Dams may also disrupt the migration of spawning fishes . Waterborne diseases may also result from construction of dams.

Biomass energy

Biomass is consist of plant materials and animal waste that can be burned directly as a solid fuel or converted into gaseous or liquid biofuels. Biomass may come from plant materials such as sawdust, wood chips or firewood, charcoal and animal waste such as dung. It is possible to convert biomass particularly animal waste into biogas. Biogas is usually composed of mixture of gases (mostly methane) which is stored and transported like a natural gas. Biogas may be used for lighting and cooking. Solid remains from a biogas digester may also be used as fertilizer. Biomass may also be converted to liquid fuels such as methanol and ethanol. Biodiesel is made from plant and animal oils which can be used as an alternative fuel for vehicles. Biodiesel is more clean upon combustion as compared to an ordinary diesel.

Biomass reduce burning of fossil fuels that emit huge amount of carbon dioxide in the atmosphere. However, it requires land, water and energy. Crop residues which comes from cornstalks, wheat stalks and wood waste from paper mills and saw mills may turned into waste materials which will eventually decompose. Another issue related to biomass is the loss of biodiversity. Whenever natural ecosystems are transformed into single-species energy plantations, biodiversity is being reduced making ecosystems more susceptible to disease or pest attacked.

Geothermal energy

The natural heat within the Earth’s core where continental plates slide over one another and from the decay of radioactive elements is the primary source of geothermal energy. The heat comes from the Earth’s core and from the decay of radioactive elements. Countries which are located around the Pacific plate or “Ring of Fire” shave high geothermal source. It is usually associated wth volcanoes containing large underground heat reservoirs. Geothermal energy is tapped by drilling wellls to obtain the steam which is then used to power electrical generators. As compared to combustion of fossil fuels as source of electricity, it emits small fraction of air pollutants. Its common disadvantage is with regards to the steam that contains hydrogen sulfide gas (H2S) that has a rotten egg smell and is a source of air pollution. The minerals in the steam also corrode pipes and equipment and is toxic to fishes.

Tidal energy

Tides which refers to the daily rise and fall of the ocean levels are produced from gravitational pull of the moon and the sun. In coastal areas with high tides contains enormous amounts of potential energy as compared to low tide. Since 11th century, Englishmen use tides to turn waterwheels producing mechanical power. The energy is usually being captured with a dam across a bay or a turbine and is converted to electricity. Despite that tidal energy is considered renewable source of energy, tidal power is expensive. Dams needed to generate electricity may have negative impacts on aquatic organisms.

10.4.5 Energy Conservation

Energy conservation is not a method of producing energy but rather reducing the need of additional energy and saving money. There are techniques and technologies at present which can reduce energy consumption. More efficient and less energy-intensive industry , automobiles, buildings and household practices can help in reducing energy consumption.

Improved automobile efficiency, better mass transit and increased railroads are means of transport energy conservation. In industry and household, the use of compact fluorescents (CFLs) bulbs instead of incandescent bulbs as source of lightings conserves energy. CFL’s utilize four times less energy and last eight times longer than incandescent light bulbs. The compact fluorescent will be more expensive to buy it will use less electricity.

The National Appliance Energy Conservation Act ( NAECA) set national efficiency standards for appliances such as refrigerators, freezers, washing machines and clothes dryers to save energy and money. In many countries, efficiency rating labels are mandatory on most appliances. These are are also high quality products that last longer, needless repairing and generate less noise. The use of renewable energy sources such as wind, solar, geothermal, biofuel can reduce energy and cost , utilization , pollution and greenhouses gases as compared with non-renewable sources.

10.5 Key Takeaways

• Energy is the capacity to do work. These are potential energy which is at rest and kinetic energy which is at motion. Energy sources may be categorized into renewable and non -renewable energy. Renewable energy which can be replenished while non-renewable energy sources are those which requires several years to be replaced.

• Non-renewables sources include fossil fuels such as petroleum or crude oil, coal and natural gas. Fossil fuels comes from remains of plants which are compressed in oxygen free environment.

• Renewable sources of energy include solar energy, wind, hydropower, nuclear, geothermal, biomass and geothermal. Solar energy comes from the sun and is considered inexhaustible source of energy.

• Wind energy is produced by turbines converting wind energy to electrical energy. Nuclear energy is generated through fission of atoms which generates heat and is converted to electricity.

• Hydropower utilizes running or falling water to generate electricity through dams in rivers or water reservoir. Geothermal energy derives its heat from the Earth’s core and decay of radioactive elements that is converted to electricity.

• Biomass comes from plant materials and animal waste which can be burned directly as solid fuel or converted to gaseous or liquid fuel.

• Tidal energy comes from tidal waves brought by gravitational pull of moon and sun to generate electricity.