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Unit 1
Unit-I provides an introduction to renewable energy. It defines renewable energy as energy from natural resources that regenerate over human timescales, such as sunlight, wind, rain, tides, and geothermal heat. Renewable energy technologies harness these resources to generate electricity and fuels. The document then discusses the need for renewable energy due to limitations of conventional sources. It outlines various renewable energy types, including solar, wind, biomass, hydropower, geothermal, and ocean energy. Storage devices like capacitors and batteries are also introduced. The document concludes with sections on photocatalytic water splitting, microgrids, and references.
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Unit 1
- 1. Unit-I Introduction of RenewableEnergy BY R.ARULJOTHI M.Tech( 2nd YEAR) 15EE302 Under the guidance of DR. N.P. SUBRAMANIAM, M.E.,Ph.D., ASSISTANT PROFESSOR DEPARTMENT OF ELECTRICALAND ELECTRONICS ENGINEERING PONDICHERRY ENGINEERING COLLEGE
- 2. Overview • Introduction • Needof Renewable Energy • Types of Renewable Energy • Storage Devices • Photocatalysis via Water Splitting • Microgrid
- 3. Renewable Energy-Introduction • Renewableenergy is generally defined as energy that is collected from resources which are naturally replenished on a human timescale. • The source of energy which is freely available from nature and never exhausting and continuous renewed are called Renewable Energy Sources. • Renewable energy is energy generated from natural resources such as sunlight, wind, rain, tides and geothermal heat ,which are renewable (naturally replenished). • Renewable energy technologies range from solar power, wind power, hydroelectricity/micro hydro, biomass and biofuels for transportation. • Renewable energy is energy that is generated from natural processes that are continuously replenished. This includes sunlight, geothermal heat, wind, tides, water, and various forms of biomass. This energy cannot be exhausted and is constantly renewed.
- 4. Need of RenewableEnergy • Conventional energy sources fixed and limited • Cost, Demand and Supply increase • Conventional energy sources can’t be regenerated • Transportation of coal, petroleum difficult and costly • Associated with hazards and fire • Transmission and Distribution costly of Conventional energy sources • Conventional energy sources produces pollution • Conventional energy sources are owned by few country • Energy security of conventional energy sources very less.
- 5. Types of RenewableEnergy • Solar Energy • Wind Energy • Biomass • Hydropower • Nuclear power • Geothermal energy • Ocean energy
- 6. Solar Energy • Solarpower is the conversion of sunlight into electricity either directly by using photo voltaic or concentrated solar power. • A solar cell, or photovoltaic cell (PV), is a device that converts light into electric current using the photoelectric effect. Advantages • Non-polluting: Solar energy is an alternative for fossil fuels as it is non- polluting, clean and reliable • Solar energy is a renewable source of energy as it can be used to produce electricity as long as the sun exists. Dis-Advantages • The primary disadvantage of solar power is that it obviously cannot be created during the night. • The power generated is also reduced during times of cloud cover (although energy is still produced on a cloudy day). Applications • Solar water heater • Solar water pump • Solar furnaces • Traffic light, Street light and railways signal • Solar cooker
- 7. Wind Energy • Windenergy is a form of solar energy. • Wind energy(or wind power) describes the process by which wind is used to generate electricity. • Wind turbines convert the kinetic energy in the wind into mechanical power. • A generator can convert mechanical power into electricity. Advantages • It's a clean fuel source. • Wind energy doesn't pollute the air like power plants that rely on combustion of fossil fuels, such as coal or natural gas. Dis-Advantages • Direction and motion of wind not continuous • Unpredictable • In interior region not suitable • Uneven speed cause difficulty to generate Electrical Energy Applications • Generate Electrical energy by wind mill • Water pump for irrigation • Flour mill • Run machine without electric power
- 8. Biomass • Biomass isorganic matter derived from living, or recently living organisms. • Biomass power is carbon neutral electricity generated from renewable organic waste that would otherwise be dumped in landfills, openly burned, or left as fodder for forest fires. • In biomass power plants, wood waste or other waste is burned to produce steam that runs a turbine to make electricity, or that provides heat to industries and homes. Advantages • Biomass used as a fuel reduces need for fossil fuels for the production of heat, steam, and electricity for residential, industrial and agricultural use. • Biomass fuel from agriculture wastes maybe a secondary product that adds value to agricultural crop. Dis-advantages • Research is needed to reduce the costs of production of Biomass based fuels. • Expensive • Require More Land
- 9. Geothermal Energy • Geothermalenergy is the energy obtained from the earth(geo) from the hot rocks present inside the earth. • It is produced due to the fission of radioactive materials in the earth’s core and some places inside the earth become very hot. These are called hot spots. • They cause water deep inside the earth to form steam. • As more steam is formed, it gets compressed at high pressure and comes out in the form of hot springs which produces geothermal power. Advantages • Maintenance cost of geothermal power plants is very less. • Geothermal power plants don't occupy too much space. • Unlike solar energy, it is not dependent on the weather conditions. • It is non-polluting and environment friendly. Dis-advantages • Total generation potential of this source is too small. • There is always a danger of eruption of volcano. • Installation cost of steam power plant is very high.
- 10. Nuclear Energy • Nuclearpower is the use of nuclear reactions that release nuclear energy to generate heat, which most frequently is then used in steam turbines to produce electricity in a nuclear power plant. • The term includes nuclear fission, nuclear decay and nuclear fusion. • Nuclear energy is a powerful source of energy, generated during a nuclear reaction, by change in the nucleus of an atom. The source of nuclear energy is the mass of the nucleus and energy generated during a nuclear reaction is due to conversion of mass into energy. Advantages • Nuclear power produces very less amount of pollution. • Very small amount of raw material is required. • It is a very reliable source of energy Dis-advantages • The danger of accidental discharge of radio activity also exists. • Nuclear power stations are always at the risk from terrorist attack. • Proliferation of nuclear technology increases the risk of nuclear war too.
- 11. Tidal Energy • Tidesare the waves caused due to the gravitational pull of the moon and also sun(though its pull is very low). The rise is called high tide and fall is called low tide. • During high tide, the water flows into the dam and during low tide, water flows out which result in turning the turbine. Advantages • It is an inexhaustible source of energy. • Tidal energy is environment friendly energy and doesn't produce greenhouse gases. • As 71% of Earth’s surface is covered by water, there is scope to generate this energy on large scale. • Maintenance costs are relatively low. • The life of tidal energy power plant is very long. • The energy density of tidal energy is relatively higher than other renewable energy sources. Dis-Advantages • Cost of construction of tidal power plant is high. • The actual generation is for a short period of time. • There are very few ideal locations for construction of plant and they too are localized to coastal regions only.
- 12. Storage Devices • Energystorage is the capture of energy produced at one time for use at a later time. • A device that stores energy is sometimes called an accumulator. • There are two types of storage devices in Electrical Method Capacitor Battery • A capacitor (originally known as a 'condenser') is a passive two-terminal electrical component used to store energy electrostatically. • Practical capacitors vary widely, but all contain at least two electrical conductors (plates) separated by a dielectric (i.e., insulator). • A capacitor can store electric energy when disconnected from its charging circuit, so it can be used like a temporary battery, or like other types of rechargeable energy storage system. • Capacitors are commonly used in electronic devices to maintain power supply while batteries change.
- 13. • An electricbattery is a device consisting of one or more electrochemical cells with external connections provided to power electrical devices such as flashlights, smartphones, and electric cars. • The range and diversity of batteries used as a source of electrical power is truly enormous, reflecting the immense range of uses of electrical power. They range in size from tiny button cells storing milliwatthours of energy and delivering microwatts of power to giant load levelling batteries, the size of buildings, storing megawatthours and delivering megawatts. Application / Requirement Battery type Low power, low cost consumer applications Low power Primary and Secondary cells. Leclanché, Alkaline, NiCad, NiMH, Lithium primary, Lithium secondary. Power tools, cordless equipment NiCad, NiMH, Lithium Ion Small devices, hearing aids, watches, calculators, memory back up, wireless peripherals. Primary button and coin cells, Zinc air, Silver oxide, Lithium Thyonyl Chloride and other Lithium primaries Industrial traction batteries Lead acid, Nickel Iron Other traction batteries, robots, bicycles, scooters, wheelchairs, lawnmowers Lead acid, Nickel Zinc, NiMH, Lithium Ion Very high power, load levelling. Pumped, renewable electrolyte Flow batteries
- 14. Photocatalysis via WaterSplitting • Photocatalytic water splitting is an artificial photosynthesis process with photocatalysis in a photoelectrochemical cell used for the dissociation of water into its constituent parts, hydrogen and oxygen , using either artificial or natural light. Theoretically, only solar energy (photons), water, and a catalyst are needed. • Most of the energy that we use comes from fossil fuels, • Problem with fossil fuel: A. Production of greenhouse gases B. The amount of fossil fuel on the Earth is limited • To replace or reduce the use of fossil fuels, several alternative energies have been developed. • These energy sources include A. wind. B. hydropower. C. solar. D. geothermal.
- 15. • Hydrogen isthe ideal fuel for the future. • it is clean, energy efficient, and abundant in nature. • While various technologies can be used to generate hydrogen, only some of them can be considered environmentally friendly. • solar hydrogen generated via photocatalytic water splitting A. low-cost B. clean hydrogen production. • Photocatalytic water splitting is another promising technology to produce “clean” hydrogen. • Compared with thermochemical and photobiological water-splitting techniques, it has the following advantages: • Reasonable solar-to-hydrogen efficiency; • Low process cost; • Small reactor systems suitable for household applications, thus providing for a huge market potential. Mechanism of photocatalytic water splitting
- 16. Types of PhotocatalyticWater-Splitting Reaction (1) Photochemical-cell reaction. (2) Photoelectrochemical-cell reaction. The mechanism basically involves 4 major steps: (1)generation of electron-hole pairs. (2)oxidation of water by photo-generated holes (3)transfer of photo-generated electrons (4) reduction of H+ by photo-generated electrons.
- 18. • Pt/SrTiO3:Rh andWO3, used as H2-photocatalyst and O2-photocatalyst, respectively • ion-exchange membrane allows the transport of protons, As well as the exchange of the mediator ions (Fe2+/Fe3+) in solution
- 19. Future Prospects ofPhotocatalytic Water Splitting • Over the past few decades, several semiconductor materials and photocatalytic systems have been developed for the water-splitting reaction under UV and visible-light irradiation. • It has been observed that photo-generated charge separation, prevention of water-splitting backward reaction • utilization of a large fraction of the incident energy are the essential requirements for achieving high photo-conversion efficiency. • The development of new technologies requires collaboration of many streams with a strong theoretical background for a better understanding of the hydrogen production mechanism in order to come up with a low-cost and environmentally friendly water- splitting process for hydrogen production.
- 20. Microgrid • It isa small-scale power supply network that is designed to provide power for a small community. • It enables local power generation for local loads. • It comprises of various small power generating sources that makes it highly flexible and efficient. • It is connected to both the local generating units and the utility grid thus preventing power outages. • Excess power can be sold to the utility grid. • Size of the Microgrid may range from housing estate to municipal regions. Microgrid Components • Distributed Generation • Loads • Immediate storage • Controller • Point of Common Coupling
- 21. Typical Microgrid isshown below:
- 22. Microgrid Operating Modes GridConnected Mode: • Utility grid is active. • Static switch is closed • All the feeders are being • supplied by utility grid.
- 23. Microgrid Operating Modes IslandMode: Utility grid is not supplying power Static switch is open. Feeder A, B, C are being supplied by Microsources. Feeder D (not sensitive ) is dead.
- 24. Conventional Grid vs.Microgrid Efficiency of conventional grid is very low as compared to Microgrid. Large amount of energy in the form of heat is wasted in conventional grid. Power sources in case of Microgrid (often referred to as Microsources) are small and are located in close proximity to load. • Microgrid encourages the use of the renewable energy sources. • Large land use impacts are avoided. • CO2 Emissions are reduced. Environmental Aspects
- 25. Advantages & Disadvantages Advantages •A major advantage of a Microgrid, is its ability, during a utility grid disturbance, to separate and isolate itself from the utility seamlessly with little or no disruption to the loads within the Microgrid. • In peak load periods it prevents utility grid failure by reducing the load on the grid. • Significant environmental benefits made possible by the use of low or zero emission generators. • The use of both electricity and heat permitted by the close proximity of the generator to the user, thereby increasing the overall energy efficiency. • Microgrid can act to mitigate the electricity costs to its users by generating some or all of its electricity needs. Dis-Advantages • Voltage, frequency and power quality are three main parameters that must be considered and controlled to acceptable standards whilst the power and energy balance is maintained. • Electrical energy needs to be stored in battery banks thus requiring more space and maintenance. • Resynchronization with the utility grid is difficult.
- 26. References • Chi-Hung Liao,Chao-Wei Huang, and Jeffrey C. S. Wu. Hydrogen Production from Semiconductor-based Photocatalysis via Water Splitting. Catalysts 2012, 2, 490-516. • Midilli, A.; Ay, M.; Dincer, I.; Rosen, M.A. On hydrogen and hydrogen energy strategies I: • Current status and needs. Renew. Sustain. Energy Rev. 2005, 9, 255– 271. • Parida, B.; Iniyan, S.; Goic, R. A review of solar photovoltaic technologies. Renew. Sustain.Energy Rev. 2011, 15, 1625–1636. • Kishore VVN, Renewable Energy Engineering and Technology, Teri Press, New Delhi, 2009. • John Twidell, Anthony D. Weir, A., Renewable Energy Sources, EFN Spon Ltd, 2nd edition, 2006.