Energy Resources
Intended Learning Outcomes
At the end of this session, students will be able to
• Explain Energy Resources
• Discuss increasing energy needs
• Describe the renewable/ non renewable
• Explain the use of alternate energy sources
Energy Resources
• Energy is defined by physicists as the capacity to do work
• Sun is the primary energy source in our lives, we use it directly for its warmth and through various natural processes that provide us with food, water, fuel and shelter
• Sun’s rays power the growth of plants, which form our food material, give off oxygen which we breathe in and take up carbon dioxide that we breathe out
• Energy from the sun evaporates water from oceans, rivers and lakes, to form clouds that turn into rain
• Today’s fossil fuels were once the forests that grew in prehistoric times due to the energy of the sun
• In India, manual labour is still extensively used to get work done in agricultural systems and domestic animals used to pull carts and ploughs
• Electrical energy produced in several ways, powers transport, artificial lighting, agriculture and industry
• Nuclear energy is held in the nucleus of an atom and is now harnessed to develop electrical energy
• We use energy for household use, agriculture, production of industrial goods and for running transport
• Modern agriculture uses chemical fertilizers, which require large amounts of energy during their manufacture
• Industry uses energy to power manufacturing units and the urban complexes that support it
• Energy-demanding roads and railway lines are built to transport products from place to place and to reach raw materials in mines and forests
• No energy related technology is completely ‘risk free’ and unlimited demands on energy increase this risk factor many fold
• All energy use creates heat and contributes to atmospheric temperature
• Many forms of energy release carbon dioxide and lead to global warming
• Nuclear energy plants have caused enormous losses to the environment due to the leakage of nuclear material
• The inability to effectively manage and safely dispose of nuclear waste is a serious global concern
• At present almost 2 billion people worldwide have no access to electricity at all
• While more people will require electrical energy, those who do have
• In addition, a large proportion of energy from electricity is wasted during transmission as well as at the user level
• It is estimated that the currently used methods of using renewable energy and non-renewable fossil fuel sources together will be insufficient to meet foreseeable global demands for power generation beyond the next 50 to 100 years
• Thus when we use energy wastefully, we are contributing to a major environmental disaster for our earth
• We all need to become responsible energy users
Types of energy
• There are three main types of energy; those classified as Non-renewable; Renewable
Non-renewable energy
• To produce electricity from non-renewable resources the material must be ignited
• The fuel is placed in a well contained area and set on fire
• The heat generated turns water to steam, which moves through pipes, to turn the blades of a turbine
• This converts magnetism into electricity, which we use in various appliances
• Non-Renewable Energy Sources: These consist of the mineral based hydrocarbon fuels coal, oil and natural gas, etc.
• These are called ‘fossil fuels’ because they are formed after plant life is fossilized
• At the present rate of extraction there is enough coal for a long time to come
• Oil and gas resources however are likely to be used up within the next 50 years
• When these fuels are burnt, they produce waste products that are released into the atmosphere as gases such as carbon dioxide, oxides of sulphur, nitrogen, and carbon monoxide, all causes of air pollution
• These have led to health problems in an enormous number of people all over the world and have also affected buildings like the Taj Mahal and killed many forests and lakes due to acid rain
• Warming the seas also leads to the death of sensitive organisms such as coral
Oil and its environmental impacts
• India’s oil reserves which are being used at present lie off the coast of Mumbai and in Assam
• Most of our natural gas is linked to oil and because there is no distribution system, it is just burnt off, this wastes nearly 40% of available gas
• The processes of oil and natural gas drilling, processing, transport and utilisation have serious environmental consequences, such as leaks in which air and water are polluted and accidental fires that may go on burning for days or weeks before the fire can be controlled
Coal and its environmental impacts
• Coal is the world’s single largest contributor of greenhouse gases and is one of the most important causes of global warming
• Many coal-based power generation plants are not fitted with devices such as electrostatic precipitators to reduce emissions of suspended particulate matter (SPM) which is a major contributor to air pollution
• Thermal power stations that use coal produce waste in the form of ‘fly ash’
• Large dumps are required to dispose off this waste material, while efforts have been made to use it for making bricks
• The transport of large quantities of fly ash and its eventual dumping are costs that have to be included in calculating the cost-benefits of thermal power
Renewable energy
• Renewable energy systems use resources that are constantly replaced and are usually less polluting
• Examples include hydropower, solar, wind and geothermal (energy from the heat inside the earth)
• We also get renewable energy from burning trees and even garbage as fuel and processing other plants into biofuels
• One day, all our homes may get their energy from the sun or the wind
• Your car’s gas tank will use biofuel
• Your garbage might contribute to your city’s energy supply
• Renewable energy technologies will improve the efficiency and cost of energy systems
Hydroelectric Power
• This uses water flowing down a natural gradient to turn turbines to generate electricity known as ‘hydroelectric power’ by constructing dams across rivers
• Between 1950 and 1970, Hydropower generation worldwide increased seven times
Drawbacks
• Although hydroelectric power has led to economic progress around the world, it has created serious ecological problems
• To produce hydroelectric power, large areas of forest and agricultural lands are submerged.
• Silting of the reservoirs (especially as a result of deforestation) reduces the life of the hydroelectric power installations
• Water is required for many other purposes besides power generation.
• The use of rivers for navigation and fisheries becomes difficult once the water is dammed for generation of electricity
• Resettlement of displaced persons is a problem for which there is no ready solution.
• In certain regions large dams can induce seismic activity which will result in earthquakes. There is a great possibility of this occurring around the Tehri dam in the Himalayan foothills. Shri Sunderlal Bahuguna, the initiator of the Chipko Movement has fought against the Tehri Dam for several years
Solar energy
Energy Resources
• In one hour, the sun pours as much energy onto the earth as we use in a whole year
• Today we have developed several methods of collecting this energy for heating water and generating electricity
• Solar heating for homes: Modern housing that uses air conditioning and/ or heating are extremely energy dependant
• A passive solar home or building is designed to collect the sun’s heat through large, south-facing glass windows
• In solar heated buildings, sunspaces are built on the south side of the structure which act as large heat absorbers
• The floors of sunspaces are usually made of tiles or bricks that absorb heat throughout the day, then release heat at night when it’s cold
• Solar water heating: Most solar water-heating systems have two main parts: the solar collector and the storage tank
• The solar energy collector heats the water, which then flows to a well-insulated storage tank
• Solar water-heating systems cannot heat water when the sun is not shining. Thus homes must also have a conventional backup system
• Solar cookers: The heat produced by the sun can be directly used for cooking using solar cookers
• A solar cooker is a metal box which is black on the inside to absorb and retain heat
• The lid has a reflective surface to reflect the heat from the sun into the box
• The box contains black vessels in which the food to be cooked is placed
• Other Solar-Powered Devices: Solar desalination systems (for converting saline or brackish water into pure distilled water) have been developed
• Photovoltaic energy: The solar technology which has the greatest potential for use throughout the world is that of solar photo voltaic cells which directly produce electricity from sunlight using photovoltaic (PV) (also called solar) cells
• Solar thermal electric power: Solar radiation can produce high temperatures, which can generate electricity. Areas with low cloud levels of cover with little scattered radiation as in the desert are considered the most suitable sites
• Solar thermal systems change sunlight into electricity, by focusing sunlight to boil water to make steam
• Biomass energy: When a log is burned we are using biomass energy
• Biomass energy is a form of stored solar energy
• Although wood is the largest source of biomass energy, we also use agricultural waste, sugarcane wastes and other farm by-products to make energy
• Ways to use biomass;
• It can be burned to produce heat and electricity
• Changed to a gas-like fuel such as methane or changed to a liquid fuel.
Liquid fuels, also called biofuels, include two forms of alcohol: ethanol and Methanol
• Biomass can be changed directly into liquid fuel, it could someday supply much of our transportation fuel needs for cars, trucks, buses, airplanes and trains with diesel fuel replaced by ‘biodiesel’ made from vegetable oils
• Organic municipal solid waste includes paper, food wastes and other organic non-fossil-fuel derived materials such as textiles, natural rubber, and leather can be converted into electricity by combustion boilers or steam turbines
• Biogas: Biogas is produced from plant material and animal waste, garbage, waste from households and some types of industrial wastes, such as fish processing, dairies and sewage treatment plants
• It is a mixture of gases which includes methane, carbon dioxide, hydrogen, sulphide and water vapour
• Once used the residue is used as an agricultural fertilizer
• Biogas plants have become increasingly popular in India in the rural sector
• The biogas plants use cow-dung, which is converted into a gas which is used as a fuel
• National Project on Biogas Development (NPBD) and Community / Institutional Biogas Plant Program promote various biogas projects
Energy Resources
• Wind Power: Wind was the earliest energy source used for transportation by sailing ships
• Some 2000 years ago, windmills were developed in China, Afghanistan and Persia to draw water for irrigation and grinding grain
• In Tamil Nadu, there are large wind farms producing 850 megawatts of electricity
• At present, India is the third largest wind energy producer in the world
• Power in wind is a function of the wind speed and therefore the average wind speed of an area is an important determinant of economically
• Over the past two decades, a great deal of technical progress has been made in the design, siting, installation, operation and maintenance of power-producing wind mills (turbines)
• These improvements have led to higher wind conversion efficiencies and lower electricity production costs
• Geothermal energy: is the energy stored within the earth (“geo” for earth and “thermal” for heat)
• Geothermal energy starts with hot, molten rock (called magma) deep inside the earth which surfaces at some parts of the earth’s crust
• The heat rising from the magma warms underground pools of water
• If there is an opening, hot underground water comes to the surface and forms hot springs, or it may boil to form geysers
• With modern technology, wells are drilled deep below the surface of the earth to tap into geothermal reservoirs, known as direct use of geothermal energy and it provides a steady stream of hot water that is pumped to the earth’s surface
• Geothermal energy is nearly as cheap as hydropower and will thus be increasingly utilised in future
Nuclear Power
• In 1938 two German scientists Otto Hahn and Fritz Strass man demonstrated nuclear fission
• They found they could split the nucleus of a uranium atom by bombarding it with neutrons
• As the nucleus split, some mass was converted to energy
• Nuclear power industry however was born in the late 1950s
• First large-scale nuclear power plant in the world became operational in 1957 in Pennsylvania, US
• Dr. Homi Bhabha was the father of Nuclear Power development in India
• The Bhabha Atomic Research Center in Mumbai studies and develops modern nuclear technology
• India has 10 nuclear reactors at 5 nuclear power stations that produce 2% of India’s electricity
• These are located in Maharashtra (Tarapur), Rajasthan, Tamil Nadu, Uttar Pradesh and Gujrat
• The nuclear reactors use Uranium 235 to produce electricity
• Energy released from 1kg of Uranium 235 is equivalent to that produced by burning 3,000 tons of coal
• Heat energy produced in the reaction is used to heat water and produce steam, which drives turbines that produce electricity
• The drawback is that the rods need to be changed periodically, this has impacts on the environment due to disposal of nuclear waste cause to aquatic ecosystems, even though it is cooled by a water system before it is released
• Land, water, vegetation are destroyed for long periods of time
• Management, storage and disposal of radioactive wastes resulting from nuclear power generation are the biggest expenses of the nuclear power industry
Summary
• Energy is defined by physicists as the capacity to do work
• Energy has always been closely linked to man’s economic growth and development
• 3 main types of energy; Non-renewable, Renewable and Nuclear energy
• Coal is the world’s single largest contributor of green-house gases and is one of the most important causes of global warming
• Energy released from 1kg of Uranium 235 is equivalent to that produced by burning 3,000 tons of coal
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