Energy Sources: Renewable and Non-Renewable - PDF

Energy Sources Core Case Study: How Long W i l l Supplies of Conventional Oil Last? Oil Major energy supplier How much is left? When will we run out? Three options Look for more Reduce oil use Use other energy sources ...

Energy Sources Core Case Study: How Long W i l l Supplies of Conventional Oil Last? Oil Major energy supplier How much is left? When will we run out? Three options Look for more Reduce oil use Use other energy sources  "The world will run out of oil in 10 years." - U.S. Bureau of Mines (1914) "The world will run out of oil in 13 years." - U.S. Department of the Interior (1939 and 1950) "The world will run out of oil and other fossil fuels by 1990." Almost ran - Paul Erlich, Limits to Growth (1973) out of oil? "The world will run out of oil in 2030, and other fossil fuels in 2050." - Paul Erlich, Beyond the Limit (2002) “The world's oil supply will continue to meet the growing global energy demand until at least 2050“ International Energy Outlook (2021) Major Sources of Energy  ENERGY SOURCES Non Conventional Energy Sources Resources which are yet in the process development over past few years: Solar, Wind, Tidal, Biogas, Biomass, Geothermal.... Conventional Energy Sources The sources of energy which have been in use at present for a long time: Coal, Petroleum, Natural Gas, Nuclear and Water power (Hydropower)... Conventional v/s Non-Conventional Sources of Energy Conventional Sources of Non-Conventional Sources of Energy Energy Coal, Petroleum, Natural Gas And Solar, Wind, Tidal, Biogas, And Water Power. Biomass, Geothermal. Exhaustable except water. NOT exhaustable Environment pollution like smoke, Pollution free ash, chemicals... Power transmission is expensive Local power generation and use. Waste Disposal Problems Environment friendly waste Planet Heat imbalance Balanced Heat NON Renewable Renewable Energy Energy Source Source Natural Capital: important nonrenewable energy resources Important that ca n be removed from the earth’s crust Nonrenewable Coal Oil Energy Resources natural gas some forms of geothermal energy Nonrenewable uranium ore Global Energy Systems Transition, (% of market) 100 Wood Coal 80 Solids Gases 60 Hydrogen 40 Liquids 20 Oil 0 Natural Gas 1850 1900 1950 2000 2050 2100 2150 Advantages and Disadvantages of Oil? Heavy oils from oil sand and Conventional oil oil shale currently abundant exist in potentially large high net energy yield supplies relatively inexpensive have low net energy yields but using it causes air and higher environmental water pollution and impacts than conventional releases greenhouse gases oil has. to the atmosphere. W e Depend Greatly on Oil Fossil fuels: crude oil and natural gas Found deep within the earth’s crust on land or under the seafloor. dispersed in pores and cracks in underground rock formations Oil extraction and refining drill a well vertically or horizontally into the deposit oil, drawn by gravity (pressure difference) out of the rock pores flows into the bottom of the well and is pumped takes energy and money to find, drill and pump Petrochemicals products of oil distillation raw materials  Oil extraction and recovery Primary recovery underground pressure in the oil reservoir is sufficient to force the oil and gas to the surface Secondary recovery Over the lifetime of a well, the pressure falls When there is insufficient underground pressure to force the oil to the surface, external energy is supplied by injecting fluids to increase reservoir pressure by water and gas injection Enhanced recovery Steam is injected where the oil is thicker and heavier than normal crude oil to increase the mobility of the oil in order to increase extraction. Light oil Petroleum, or crude oil conventional, or light oil 30% of the world’s estimated supply of oil. heavy oil unconventional heavy oil Thick 70%of the world’s estimated supply of oil Some of thick oil left behind in wells some is extracted from deposits of tar sands and oil shale rock takes considerable energy and money to extract which reduces its net energy yield.  Refining Crude Oil Fractional distillation process by which oil refineries separate crude oil into different, more useful hydrocarbon products Separation is based on differences in molecular weight of different components of the crude oil Different molecular weights → different boiling points lighter components boil at lower temperatures As weight increases, boiling point increases, and thus compounds that are heavier are separated later during the process Heavy Oil from Sand Oil sand, tar sand mixture of sand, clay, water, and bitumen Bitumen: a thick, sticky, tarlike heavy oil with a high sulfur content. Extraction Serious environmental impact: air, water, wildlife, and climate Low net energy yield: Is it cost effective? oil sand is mixed with hot water and steam to extract the bitumen  Oil Shales: heavy oil from oily rocks Oil shales (Oily rocks) must be heated to increase its flow rate contain kerogen; a solid processed to remove sulfur, combustible mixture of nitrogen, and other hydrocarbons impurities. Low net energy yield Natural Gas Conventional natural gas more plentiful than oil high net energy yield fairly low cost lowest environmental impact of all fossil fuels Natural gas: mixture of gases More than half is CH4 (50-90%) Liquefied petroleum gas (LPG) propane and butane gases are liquefied under high pressure Liquefied natural gas (LNG) low net energy yield natural gas that has been cooled down to liquid form for ease and safety of non- pressurized storage or transport. about –162 ºC Refrigerated tanker ships Natural Gas Has M o r e Will natural gas be the bridge fuel Advantages helping us make the transition to a more sustainable energy future? Than Disadvantages Advantages and Disadvantages of Coal? Conventional coal very plentiful high net energy yield low cost but it has a very high environmental impact. severely degrade land and pollute water and air. When burned it severely pollutes the air Stages in Coal Formation over Millions of Years  Science: Coal-Burning Power Plant Coal-fired plants produce electricity by burning coal in a boiler to produce steam. The steam produced, under tremendous pressure, flows into a turbine, which spins a generator to create electricity. The steam is then cooled, condensed back into water and returned to the boiler to start the process over.  E n vironmental impacts of coal mining Surfac e mining of c oal completely eliminates existing vegetation destroys the genetic soil profile displaces or destroys wildlife and habitat degrades air quality alters c urrent land uses scarred landscape with no scenic value movement, storage, and redistribution of soil during mining disrupt the c ommunity of soil microorganisms  Coal Is a Plentiful but Dirty Fuel World’s most abundant fossil fuel Environmental costs of burning coal Severe air pollution Sulfur released as SO2 Large amount of Soot (black powdery substance consisting largely of amorphous carbon) CO 2 Trace amounts of mercury (Hg) and radioactive materials Group Work List down the top 3 countries that have: 1. Coal 2. Natural gas 3. Light oil 4. Tar sands 5. Oil shale Recent estimation Fall 2024 Top 3 countries Coal Natural Gas Light Oil Tar Sands Oil Shale  low environmental impact very low accident risk Nuclear high costs E n ergy? low net energy yield long-lived radioactive wastes vulnerability to sabotage, and the potential for spreading nuclear weapons technology have limited its use How Does a Nuclear Fission Reactor Work? Controlled nuclear fission reaction in a reactor Fueled by uranium ore and packed as pellets in fuel rods and fuel assemblies Water is the usual coolant Containment shell around the core for protection Water-filled pools or dry casks for storage of radioactive spent fuel rod assemblies  After 3 or 4 Years in a Reactor, Spent Fue l Rods A r e Removed and Stored in Water Radioactivity of nuclear waste A major environmental concern related to nuclear power is the creation of radioactive wastes such as spent (used) reactor fuel. These materials can remain radioactive and dangerous to human health for thousands of years. Diminishes with time - Waste must be isolated for sufficient time to reduce radioactivity below acceptable limits - Days to years Spent fuel rods from nuclear powerplants - 5 years of cooling (up to 10 years in some cases) - wastes must be stored safely for thousands of years E x a m p l e of nuclear waste storage Dry cask storage is a method of storing high-level radioactive waste, such as spent nuclear fuel (after the spent rods have cooled already)  W h a t Is the Nuclear F u el Cycle? 1 2 3 4 5 Mine the Process the Use it in the Safely store Decommissi uranium uranium to reactor the on the make the radioactive reactor fuel waste Nuclear Power Plants, 1960-2002 (in gigawatts) 400 35 350 30 300 25 250 Construction 20 Capacity 200 15 150 10 100 50 5 0 0 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 00 02 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 20 20 Capacity Decommissioned Construction  What Happened to Nuclear Power? Slowest-growing energy source expected to decline more Why? Economics Poor management Low net yield of energy of the nuclear fuel cycle Safety concerns Need for greater government subsidies Concerns of transporting uranium Case Study: Worst March 29, 1979 Commercial Nuclear Power Plant Accident in Near Harrisburg, PA, U.S. the U.S.: Three M i l e Island Nuclear reactor lost its coolant Led to a partial uncovering and melting of the radioactive core Unknown amounts of radioactivity escaped People fled the area Increased public concerns for safety Led to improved safety regulations in the U.S. Case Study: Worst Nuclear Power Plant Accident in the World: Chernobyl April 26, 1986 In Chernobyl, Ukraine Series of explosions caused the roof of a reactor building to blow off Partial meltdown and fire for 10 days Huge radioa ctive cloud spread over many countries and eventually the world 350,000 people left their homes Effects on human health, water supply, and agriculture Remains of a Nuclear Reactor at the Chernobyl Nuclear Power Plant Radioactive Wastes Dealing with Radioactive Wastes Produced by Nuclear Power Difficult Problem High-level radioactive wastes Must be stored safely for 10,000– 240,000 years Where to store it Deep burial: safest and cheapest option Would any method of burial last long enough? There is still no facility  Nuclear fusion power of the future? Still in the laboratory phase after 50 years of research and $34 billion dollars 2006: U.S., China, Russia, Japan, South Korea, and European Union Will build a large-scale experimental nuclear fusion reactor by 2040 Group Work 1. List down the top 3 countries that have nuclear energy. 2. Check the location of these sites and comment on how far they are from commercial areas. (What is the minimum required distance between Nuclear power plants and commercial areas?) Recent estimation Fall 2024 Top 3 countries Nuclear Energy Site 1 Location + Distance to commercial areas Site 2 Location + Distance to commercial areas Site 2 Location + Distance to commercial areas energy produced from sources that do not deplete or can be replenished within a human’s lifetime most common examples Wind Solar Geothermal Biomass Hydropower E fficiency is an Important Energy Resource  W e Waste Huge Amounts of Energy Advantages of reducing energy waste Quick and clean cheapest way to provide more energy Reduce pollution and degradation Slow global warming Increase economic and national security  Superefficient and ultralight cars M o r e Energy- Gasoline-electric hybrid Efficient car Plug-in hybrid electric Vehicles A r e vehicle Energy-efficient diesel c ar on the W a y Electric vehicle with a fuel cell (Hydrogen Power)  W e Can Save Energy and M o n e y in Existing Buildings Insulate Insulate and plug leaks and plug one-third of heated air in typical homes escapes: air leaks, and sealing Use energy-efficient windows Use highly efficient super-windows that have the insulating effect of a window with 3 to 20 panes cut expensive heat losses Stop other heating and cooling losses Stop Leaky heating and cooling ducts; white or light- colored roofing or living roofs Heat houses more efficiently Heat superinsulation  Heat water Use Use more energy- energy- efficiently efficient efficient Existing Solar heaters appliances lighting B uildings Refrigerators Electric stoves A Thermogram Showing Heat Loss A r o u n d Houses and Stores  Renewable Energy: Is it a solution? W e Can Use Renewable Energy in Place of Nonrenewable Energy Sources Renewable energy Solar energy Geothermal energy Benefits of shifting toward a variety of locally available renewable energy resources Any suggestions  SOLAR ENERGY “Solar” is the Latin word for sun and solar power is the energy from the sun. Solar energy technology comprises of two different categories, thermal conversion and photo-conversion. Photovoltaic: Sunlight directly converts into electrical energy. Thermal Energy: Sunlight focuses to thermal receptors and converts water to steam then turbines rotary power produces electricity.  SOLAR ENERGY There are number of solar techniques which provides a broad number of applications, of which some of them are listed below. Solar water heating Solar air conditioning Solar drying Solar green-house Solar desalination Solar refrigeration Solar cooking Solar furnace Solar electricity (Photovoltaic) Solar electricity (Thermal)  SOLAR ENERGY Advantages of Solar Energy Solar energy is free Solar energy does not cause pollution It can be used in remote areas where it is too expensive to extend electricity power grid. Calculators and other low power consuming devices can be powered by solar energy effectively.  Advantages and Disadvantages of Solar Energy? Passive and active solar heating systems heat water and buildings effectively costs of using direct sunlight to produce high-temperature heat and electricity are coming down Rooftop Solar Hot Water on Apartment Buildings in Kunming, China Sunlight to Produce High-Temperature Heat and Electricity? Solar thermal systems Central receiver system for widespread use High cost Low net energy yields Limited suitable sites Sunny, desert sites Solutions: W o m a n in India Uses a Solar Cooker W e Can Use Solar Cells to Produce Electricity Photovoltaic (PV) cells (solar cells) Convert solar energy to electric energy Thin wafers of silicon (Si) or with trace amounts of metals that allow them to produce electric ity Free energy? Solar-cell power plants Many examples around the world Key problem High cost of producing electric ity Will the cost drop with? Mass production New designs Nanotechnology  PHOTOVOLTAIC Photovoltaic: Photovoltaics is the direct conversion of light into electricity at the atomic level. Some materials exhibit a property known as the photoelectric effect that causes them to absorb photons of light and release electrons. When these free electrons are captured, an electric current results that can be used as electricity.  PHOTOVOLTAIC Silicon is a material known as a ‘semiconductor’ as it conducts electricity and it is the main material for photovoltaic cells. Impurities such as boron or phosphorus are added to this base material. These impurities create the environment for electrons to be freed when sunlight hits the photovoltaic panel. The freeing of electrons leads to the production of electricity. The diagram above shows a basic photovoltaic cell. The blue represents the main material, silicon. The black round and irregular shapes represent the impurities of boron or phosphorous. As the sun/light strikes the cell the impurities free up electrons which ‘bounce’ around at incredible speeds. This creates an electrical charge.  Solutions? Solar Cells Used to Provide Electricity for Solar-Cell Power Plant in Arizona, U.S., a Remote Village Is the Largest Solar-Cell Power Plant  Group Work 1. List down the top 3 countries that rely on Solar energy. 2. Check whether it is possible to use Solar energy in Lebanon. 3. If yes specify 3 locations in Lebanon that it could be used in small scale and in large scale. Every group should select one governorate and make the study based on it. A group representative will present the work and try to show exact locations using the Lebanese map shown in the right! Recent estimation Fall 2024 Top 3 countries Solar Energy Site 1 Location in Lebanon Site 2 Location in Lebanon Site 3 Location in Lebanon  HYDRO-ELECTRIC POWER Hydroelectricity is the term referring to electricity generated by hydropower ; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy, accounting for 16 percent of global electricity generation.  Electricity from the Water Cycle over dams Water tidal flows flowing ocean waves environmental concerns used to limited availability of generate suitable sites electricity limited use of these energy resources World’s leading renewable energy source used to produce electric ity Hydropower Hydroelectric power Micro-hydropower generators HYDRO-ELECTRIC POWER  SMALL HYDRO POWER (SHP) Small hydropower can provide clean, renewable and relatively inexpensive energy. Unlike large hydropower schemes, small hydropower does not necessitate a reservoir. They can be constructed in any location where there is e n o u g h wate r f l o w a n d h e a d to m a ke e n e rg y generation viable. Since, no reservoir is created on the upstream, there is minimal impact on nearby communities with respect to displacement.  ADVANTAGES OF SHP SHP is a clean energy source, producing no water or air pollution As a non-consumptive water use, small hydropower is a renewable energy source. There is minimal impact on the environment. Long useful life and low running cost  DISADVANTAGES OF SHP To be economical, energy consumers need to be located near the hydropower scheme. Seasonal variation in stream flow causes variation and disturbance in energy supply. The stream flow limits the power generation’  ENERGY DERIVED FROM OCEANS Marine energy refers to the energy carried by ocean w a v e s , t i d e s , s a l i n i t y, a n d o c e a n t e m p e r a t u r e differences. The movement of water in the world’s oceans creates a vast store of kinetic energy, or energy in motion. This energy can be harnessed to generate electricity to power homes, transport and industries.  Tides and Waves Can B e Used to Produce Electricity Produce electricity from flowing water O cean tides and waves So far, power systems are limited Disadvantages Few suitable sites High costs Equipment damaged by storms and corrosion  Group Work 1. List down the top 3 countries that rely on Hydropower energy. 2. Check whether it is possible to use Hydropower energy in Lebanon. 3. If yes specify the locations where it could be used in small scale and in large scale. Every group should select one governorate and make the study based on it. A group representative will present the work and try to show exact locations using the Lebanese map shown in the right. This activity counts towards your Participation grade! Recent estimation Fall 2024 Top 3 countries Hydropower Site 1 Location in Lebanon Site 2 Location in Lebanon Site 3 Location in Lebanon  Producing Electricity from Wind: Using W i n d to Produce Electricity Is an Important Step toward Sustainability Wind: indirect form of solar energy Captured by turbines Converted into electric al energy Wind farms on land and offshore If environmental costs of energy resources are included in market prices wind energy is the leastexpensive and least polluting way to produce electric ity  WIND ENERGY We can use the energy in the wind by building a tall tower, with large propeller on the top. The wind blows the propeller round, which turns a generator to produce electricity.  WIND ENERGY Refers to production of electricity from wind using wind turbines. When wind flows through the blades of a turbine, they rotate and spin powering a rotor inside the generator, produce electricity. Multiple turbines are working independently. The electricity from each turbine flows through cables and combines with energy from other turbines , power conditioned and then distributed.  ADVANTAGES OF WIND ENERGY Wind energy is a renewable resource, so it will never run out Has little direct effect on the environment as there has NO green house gas (GHG) problems Modern turbines available upto 1MW and wind farms of 100 to 150 MW installed. Individual turbines are repairable and no need of farm shutdown. The farm land can be used for agriculture or farming activities – means ecofriendly and promotes tourism.  DISADVANTAGES OF WIND ENERGY It cover large areas usually on ridges and hill tops. They are noisy. Need huge am ount of cabling and com plex Electrical Engineering technology. Generation of waste materials from damaged wind mills. Regular monitoring and recurring repair of electronics.  Group Work 1. List down the top 3 countries that have Wind energy. 2. Check whether it is possible to use Wind energy in Lebanon. 3. If yes specify the areas where it can be used and suggest the best location where a wind farm can be built to provide electricity to more people. Every group should select one governorate and make the study based on it. A group representative will present the work and try to show exact locations using the Lebanese map shown in the right. This activity counts towards your Participation grade! Recent estimation Fall 2024 Top 3 countries Wind Energy Site 1 Location in Lebanon Site 2 Location in Lebanon Site 3 Location in Lebanon  BIOMASS Biomass fuels come from things that once lived: wood products, dried vegetation, crop residues, aquatic plants and even garbage. Plants used up a lot of the sun's energy to make their own food ( photosysnthesis ). They stored the foods in the plants in the form of chemical energy. As the plants died, the energy is trapped in the residue.  BIOMASS 1.Energy from the sun is transferred and stored in plants. When the plants are cut or die, wood chips, straw and other plant matter is delivered to the bunker. 2.This is burned to heat water in a boiler to release heat energy (steam). 3.The energy/power from the steam is directed to turbines with pipes. 4. The steam turns a number of blades in the turbine and generators, which are made of coils and magnets. 5.The charged magnetic fields produce electricity, which is sent to homes by cables.  BIOMASS Biomass falls into three categories Biomass in traditional form (Wood and Agricultural residue is burnt to produce energy) Biomass in non-traditional form (Biomass converted to ethyl alcohol and methyl alcohol to be used as liquid fuels in engine.) Biomass for domestic use: Organic waste is decomposed anaerobically to produce a mixture of gases (Biogas) namely methane, Carbondioxide, Hydrogen Sulphide etc. Biogas is a good biofuel used for cooking and lighting) METHODS TO CONVERTING BIOMASS TO ENERGY Burning:- Direct burning of biomass is the simple method of energy production. Wood and other forms of biomass burned for thousand years, to warm, to cook food, and other tools. Alcohol Fermentation:- In alcohol fermentation, the starch in organic matter is converted to sugar. This sugar is then fermented by yeast. The resulting ethanol is distilled and then blended with another fuel. The end product “Gasohol” has been used successful in various countries as an alternative to regular gasoline. Gasohol A fuel consisting of a blend of ethanol and unleaded gasoline, especially a blend of 10 percent ethanol and 90 percent gasoline. Thailand  W e Can Convert Plants and Plant Wastes to Liquid Biofuels Liquid biofuels Biodiesel (From Vegetable oil) Bio-Ethanol (from agricultural and vegetable waste) Major advantages over gasoline and diesel fuel produced from oil Biofuel crops c an be grown almost anywhere No net inc rease in CO 2 emissionsif managed properly Biggest producers of biofuel Brazil The United States The European Union China METHODS TO CONVERTING BIOMASS TO ENERGY A n a e r o b ic D ig e s t io n : - Anaerobic digestion converts biomass, especially waste products, into methane and carbon dioxide. The biomass is mixed with water and stored in an airtight tank. Pyrolysis:- Pyrolysis involes the heating of biomass in the absence of oxygen. Biomass such as wood or agriculture waste is heated at or above 500oC and allowed to decompose into gas and charcoal. The major advantage of p y r o l y s i s i s t h a t c a r b on dioxide is not produced. Produces ethylene, many forms of carbon, and other chemicals from petroleum, coal, and even wood.  BIOGAS Biogas typically refers to a mixture of different gases produced by the breakdown of organic matter such as garbage and sewage by anaerobic bacteria. Biogas is a fuel gas, consisting of 65% methane and about 30-35% CO2 and 2% other gases. It is a renewable resource of energy resulting from biomass.  Biomass as an Energy Source Solid biomass a renewable resource burning it faster than it is replenished net gain in atmospheric greenhouse gases creating biomass plantations degrade soil biodiversity Liquid biofuels (Example: Bio-Ethanol) derived from biomass c an be used in place of gasoline and diesel fuels creating biofuel plantations c ould degrade soil and biodiversity and increase food prices and greenhouse gas emissions Production of solid mass fuel fast-growing trees Biomass plantations crop residues and animal manure  can be made from plants such as sugarca ne, corn, and Ethanol switchgrass, and from agricultural, forestry, and municipal wastes Converting plant This starches into simple sugars process Then sugars are involves processed to produce ethanol  Group Work 1. List down the top 3 countries that have Biomass energy. 2. Check whether it is possible to use Biomass energy in Lebanon. 3. If yes specify the areas where it can be used and suggest the best location where it can be implemented as a small scale and a large scale project. Every group should select one governorate and make the study based on it. A group representative will present the work and try to show exact locations using the Lebanese map shown in the right. This activity counts towards your Participation grade! Recent estimation Fall 2024 Top 3 countries Biomass Energy Site 1 Location in Lebanon Site 2 Location in Lebanon Site 3 Location in Lebanon  W e Can Cool Buildings Naturally Technologies available Superinsulation and high- effic ienc y windows Light-c olored roof Reflective insulating foil in an attic Geothermal pumps Plastic earth tubes underground  GEOTHERMAL ENERGY The term Geothermal originates from two Geek words 'GEO' and 'THERM'. The Greek word ‘geo’ means the earth and ‘thermal’ means heat. Hot water trapped below the surface acts as a geothermal reservoir  GEOTHERMAL ELECTRICITY One way of producing electricity from geothermal energy is by drilling wells into the geothermal reservoirs. The hot water that rises emerges at the surface as steam. The steam is used to drive turbines producing electricity. If the water is not hot enough to produce steam, it can still be used to heat homes and businesses, saving gas/electricity. A GEOTHERMAL ELECTRICITY PLANT IN ICELAND Geothermal T energy Station  heat stored in Soil Geothermal Underground rocks energy: Fluids in the earth’s mantle Advantages great potential for and supplying many areas Disadvantag with heat and electric ity es of low environmental Geothermal impact Energy? locations are limited. Geotherma High cost of tapping l energy: large-scale hydrothermal reservoirs two geothermal reservoirs problems could be depleted Hot, dry another potential source rock of geothermal energy? Geothermal energy requires pumps to move the water that provides the heating and cooling which means that some noise pollution may be generated in nearby spaces (when used in a residence there is no noise pollution outside the residence.) Group Work 1. List down the top 3 countries that have Geothermal energy. 2. Check whether it is possible to use geothermal energy in Lebanon. If yes specify the locations where it could be used. Recent estimation Fall 2024 Top 3 countries Geothermal Energy Site 1 Location in Lebanon Site 2 Location in Lebanon Site 3 Location in Lebanon  FUEL CELLS A fuel cell is a device that generates electricity by chemical reaction. For any type of fuel cell, there are mainly three segments Anode Cathode Electrolyte and catalyst Every fuel cell has two electrodes, one positive (Anode) and the other negative (Cathode). Every fuel cell also has an electrolyte, which carries electrically charged particles from electrode to the other, and Catalyst, which speeds the reactions at electrodes FUEL CELLS Hydrogen atoms enter a fuel cell at the anode where a chemical reaction strips them of their electrons. The hydrogen atoms are now "ionized," and carry a positive electrical charge. The negatively charged electrons provide the current through wires to do work. If alternating current (AC) is needed, the DC output of the fuel cell must be routed through a conversion device called an inverter. FUEL CELLS Oxygen enters the fuel cell at the cathode and, in some cell types, combines with electrons returning from the electrical circuit and hydrogen ions that traveled through the electrolyte from the anode. In other cell types the oxygen picks up electrons and then travels through the electrolyte to the anode, where it combines with hydrogen ions. Whether they combine at anode or cathode, together hydrogen and oxygen form water, which drains from the cell. As long as a fuel cell is supplied with hydrogen and oxygen, it will generate electricity.  FUEL CELLS OVER HEAT ENGINES High Efficiency. Virtually silent. No Pollutant emissions Power plants located near the consumer Provides electric power and heat as by-product. Heat is transferred to Heat Exchanger w h i c h provides hotwater supply or for desalination of sea water. Electric transmission lines are not required and hence reduces transmission loss.  Hydrogen fuel fuel c ells:2H2+O2→2H2O great promise powering c ars and generating electricity Eliminate most air pollution problems Reduce threats of global warming to be environmentally benefic ial it would have to be produced without the use of fossil fuels Some challenges CO 2 levels dependent on method of hydrogen production Under development Hydrogen-powered vehicles: prototypes available Larger fuel c ells  Solutions: Decentralized Power System electricity is produced by a large number of dispersed, small- scale micropower systems