Hydropower study notes


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Hydropower study notes

  1. 1. What is Hydropower?  1882, the transmission of surface is runoff, which empties into lakes, large pipe called a penstock. This boosts the directly at the intake to prevent the debris from hydroelectric power was demonstrated rivers and streams and is carried back to the power generation capabilities of the dam. The going in to the take. Debris cleaning devicesHydropower, hydraulic power or water at the Exposition in Munich with oceans, where the cycle begins again. penstock feeds water into a turbine which should also be fitted on the trash-racks. Intakepower is power that is derived from the force or direct current of 2400 volts The first Advantages: structures can be classified in toenergy of moving water, which may be central hydroelectric station of a high pressure intakes used in caseharnessed for useful purposes. capacity of 250 lights was installed in • Emissions-free, with virtually no of large storage reservoirs and Appleton, Wisconsin. CO2,NOx, SOx, hydrocarbons, or low pressure intakes used in case  1883, a hydro-electric plant was particulates. of small ponds. The use ofPrior to the widespread availability of developed at Portrush in Ireland. • Renewable resource with high providing these structures at thecommercial electric power, hydropower was  1885, also in Ireland, a 65 intake is, water only enters and conversion efficiency to electricityused for irrigation, and operation of various horsepower turbine was opened for ( 80+ %). flows through the penstock whichmachines, such as watermills, textile machines, the Bessbrook and Newry railway. strikes the turbine. • Dispatchable with storage capability.sawmills, dock cranes, and domestic lifts.  1900, Oliver Evans developed a • Usable for base load, peaking, and completely water powered mill that pumped storage applications Control gates arrangement is“is power that is derived from the force or handled everything from unloading • Scalable from 10 kWe to 10,000 provided with Spillways.energy of moving water.” sacks of grain to packing flour in MWe Spillway is constructed to act as a turbines. • Low operating and maintenance costs safety valve. It discharges the  2000, water power is becoming • Long lifetime – 50+ years typical overflow water to the downHistory… highly implemented and extremely powers a generator. stream side when the reservoir is utilized. full. These are generally constructed of concrete  Saqia - a wheel used by the Persians Disadvantages: The dam is usually built on a large river that has and provided with water discharge opening, shut to a drop in elevation, so as to use the forces of off by metal control gates. By changing the raise water from a river to higher place. gravity to aid in the process of creating degree to which the gates are opened, the A renewable ENERGY source • Frequently involves impoundment of  250 BC, water power was used as a large amounts of water with loss of electricity. A dam is built to trap water, usually discharge of the head water to the tail race can in a valley where there is an existing lake. be regulated inorder to maintain water level in clock. Hydropower is the leading source of renewable habitat due to land inundation reservoir.  80 BC, the Antipater of Thessalonica energy. It provides more than 97% of all • Variable output – dependent on wrote, "Cease your work, ye maids electricity generated by renewable sources. rainfall and snowfall Reservoir - area behind the dam where water is stored, the water there is called gravitational The penstock is a long shaft that carries the who labour at the mill . . . for Ceres • Impacts on river flows and aquatic potential energy. The water is in a stored water towards the turbines where the kinetic has commanded the water-nymphs to Why is it renewables? ecology, including fish migration and perform your task." The work of oxygen depletion position above the rest of the dam facility so as energy becomes mechanical energy. The force to allow gravity to carry the water down to the of the water is used to turn the turbines that turn grinding grains such as corn was • The sun provides the water by • Social impacts of displacing automated by water power. evaporation from the sea, and will turbines. Because this higher altitude is different the generator shaft. The turning of this shaft is indigenous people known as rotational kinetic energy because the  762 AD, water mills became popular keep on doing so. than where the water would naturally be, the • Health impacts in developing energy of the moving water is used to rotate the by the Saxons in England. A • The water on the earth is continuously water is considered to be at an altered countries generator shaft. The work that is done by the millwright traveled the countryside replenished by precipitation. equilibrium. • High initial capital costs water to turn the turbines is mechanical energy. and fixed broken mills. • The fall and movement of water is • Long lead time in construction of Gravity will force the water to fall to a lower This energy powers the generators, which are  1086 AD, the Domesday survey found part of a continuous natural cycle mega-sized projects position through the intake and the control very important parts of the hydroelectric power that there were more than 5000 mills. called the hydrologic cycle. gate. They are built on the inside of the dam. plant; they convert the energy of water into  1400 –1500, iron works exploited the When the gate is opened, the water from the electricity. power of the water to cool the blast Hydrologic Cycle: furnace. In Sheffield and Sussex, How Hydropower Works reservoir goes through the intake and becomes translational kinetic energy as it falls through The generators are comprised of four basic England iron works were employed The hydrologic cycle begins with the next to the water. evaporation of water from the surface of the  Hydropower plants capture the energy the next main part of the system: the penstock. components: the shaft, the excitor, the rotor,  1581, Peter Morise installed a water of falling water to generate electricity. Translational kinetic energy is the energy due to and the stator. The turning of the turbines ocean. As moist air is lifted, it cools and water wheel under the old London Bridge. It vapor condenses to form clouds. Moisture is A dam impounds water to form a motion from one location to another. The water powers the excitor to send an electrical current reservoir and raises the water level to is falling (moving) from the reservoir towards to the rotor. The rotor is a series of large worked on the ebb and flood tides, transported around the globe until it returns to create head. Water from the reservoir the turbines through the penstock. electromagnets that spins inside a tightly wound meaning it was reversible. the surface as precipitation. Once the water flows due to gravity to drive the coil of copper wire, called the stator. “A voltage  1824, the Catrine cotton mill used a reaches the ground, one of two processes may turbine. Turbine is connected to a The intake includes the head works which are is induced in the moving conductors by an effect water wheel and through gearing occur; 1) some of the water may evaporate back generator. Power generated is the structures at the intake of conduits, tunnels called electromagnetic induction.” The shafting and belting achieved 9000 into the atmosphere or 2) the water may transmitted over power lines. or flumes. These structures include blooms, electromagnetic induction caused by the rev/s. penetrate the surface and become groundwater. screens or trash - racks, sluices to divert and spinning electromagnets inside the wires causes  1838, 28 Tide mills existed in Groundwater either seeps its way to into the England even though the era of steam oceans, rivers, and streams, or is released back In other words, it uses a reservoir to create prevent entry of debris and ice in to the turbines. electrons to move, creating electricity. The potential energy from the dammed water. Booms prevent the ice and floating logs from kinetic/mechanical energy in the spinning engines was beckoning. into the atmosphere through transpiration. The This water flows through an intake and into a going in to the intake by diverting them to a turbines turns into electrical energy as the balance of water that remains on the earths generators function. bypass chute. Screens or trash-racks are fitted
  2. 2. The transformer, another component, takes the systems, tides and oceans without the use of temperature difference. This temperature each bucket on the runner. There is no suction • Bulb turbine. The turbine andalternating current and converts it into higher- dams difference generally increases with decreasing on the down side of the turbine, and the water generator are a sealed unit placedvoltage current. The electrical current generated latitude, i.e. near the equator, in the tropics. flows out the bottom of the turbine housing after directly in the water stream.in the generators is sent to a wire coil in the Vortex power, which creates vortices which hitting the runner. An impulse turbine istransformer. This is electrical energy. Another can then be tapped for energy generally suitable for high head, low flow • Straflo. The generator is attachedcoil is located very close to first one and the is a form of hydro power which generates Sizes: applications. directly to the perimeter of the turbine.fluctuating magnetic field in the first coil will energy by placing obstacles in rivers/oceans in • A pelton turbine has one or more • Tube turbine. The penstock bendscut through the air to the second coil without the order to cause the formation of vortices which Large HP - More than 100 MW feeding into a free jets discharging water into an just before or after the runner,current. The amount of turns in the second coil can then be tapped to a usable form of energy large electricity grid aerated space and impinging on the allowing a straight line connection tois proportional to the amount of voltage that is such as electricity. Medium - 15 - 100 MW usually feeding a grid buckets of a runner. Draft tubes are the generator.created. That current is then sent by means of Vortex-induced vibrations (VIV) are motions Mini HP - Capacity above 1MWpower lines to the public as electricity induced on bodies facing an external flow by Small HP - Capacity 300kW to 1MW not required for impulse turbine since • Kaplan. Both the blades and the the runner must be located above the wicket gates are adjustable, allowing periodical irregularities on this flow. Vortices Micro HP - Capacity 0kW to 300kW maximum tailwater to permit are then formed changing the pressure for a wider range of operation.Now, the water that turned the turbines flows Pico HP - Up to 10kW, remote areas away from operation at atmospheric pressure.through the pipelines (translational kinetic distribution along the surface. the grid • Francis turbine has a runner with • A cross-flow turbine is drum-shaped fixed buckets (vanes), usually nine orenergy, because the energy in the water is being Tidal power, which captures energy from the and uses an elongated, rectangular- more. Water is introduced just abovemoved,) called tailraces and enters the river tides in horizontal direction section nozzle directed against curved the runner and all around it and thenthrough the outflow. The water is back to being Types Of HP: Tidal power is the only form of energy which vanes on a cylindrically shaped falls through, causing it to spin.kinetic/mechanical/potential energy as it is in derives directly from the relative motions of the runner. It resembles a "squirrel cage" Besides the runner, the other majorthe river and has to potential to have the energy Hydro plants can be classified according to Earth–Moon system, and to a lesser extent from blower. The cross-flow turbine allows components are the scroll case, wicketharnessed for use as it flows along (movement.) water flow/storage characteristics the Earth–Sun system. The tidal forces produced the water to flow through the blades gates, and draft tube. by the Moon and Sun, in combination with twice. The first pass is when the water Earths rotation, are responsible for the Impoundment. The most common type of flows from the outside of the blades to generation of the tides. hydroelectric power plant is an impoundment the inside; the second pass is from the facility. An impoundment facility, typically a Hydro Turbine ParametersForms Of Hydropower: inside back out. A guide vane at the (Power, discharge, Efficiency, Head, specific Wave power, is the transport of energy by large hydropower system, uses a dam to store entrance to the turbine directs the flowWaterwheels, used for hundreds of years to Speed) i.e, P = n x g x Q x H ocean surface waves, river water in a reservoir. Water released from to a limited portion of the runner. Thepower mills and machinery Waves are generated by wind passing over the the reservoir flows through a turbine, spinning cross-flow was developed toA water wheel consists of a large wooden or sea surface. As long as the waves propagate it, which in turn activates a generator to produce accommodate larger water flows andmetal wheel, with a number of blades or buckets Escudero Hydroelectric Power Plant slower than the wind speed just above the electricity. The water may be released either to lower heads than the Pelton.arranged on the outside rim forming the driving o It was built in 1937. located at Villasurface. Most commonly, the wheel is mounted waves, there is an energy transfer from the wind meet changing electricity needs or to maintain a constant reservoir level. Reaction Turbine Escudero Tiaong, Quezon,vertically on a horizontal axle, but the tub or to the waves. Both air pressure differences A reaction turbine develops power from the Philippines.Norse wheel is mounted horizontally on a between the upwind and the lee side of a wave crest, as well as friction on the water surface by Diversion, sometimes called run-of-river, combined action of pressure and moving water. o it generated power for the Escuderovertical shaft. Vertical wheels can transmitpower either through the axle or via a ring gear the wind shear stress causes the growth of the facility channels a portion of a river through a The runner is placed directly in the water stream coconut plantation.and typically drive belts or gears; horizontal waves. canal or penstock. It may not require the use of flowing over the blades rather than striking each o composed of 2 hydro units; a 75wheels usually directly drive their load. a dam. individually. Reaction turbines are generally kW(located below the 1937 unit) and Osmotic power, which channels river water used for sites with lower head and higher flows a 37.5 kW plant (located 700metersHydroelectricity, usually referring to into a container separated from sea water by a than compared with the impulse turbines. down river). Pumped Storage. When the demand forhydroelectric dams, or run-of-the-river setups semi permeable membrane. electricity is low, a pumped storage facility(eg hydroelectric-powered watermills) is the energy retrieved from the difference in the stores energy by pumping water from a lower • A propeller turbine generally has a Costis electricity generated by hydropower, i.e., the salt concentration between seawater and river reservoir to an upper reservoir. During periods runner with three to six blades in Hydropower is an efficient way to generateproduction of power through use of the water. of high electrical demand, the water is released which the water contacts all of the electricity.gravitational force of falling or flowing water. It back to the lower reservoir to generate blades constantly. Picture a boat  Modern hydro turbines can convert asis the most widely used form of renewable Marine current power, which captures the electricity. propeller running in a pipe. Through much as 90% of the available energyenergy. Once a hydroelectric complex is kinetic energy from marine currents. the pipe, the pressure is constant; if it into electricity.constructed, the project produces no direct isnt, the runner would be out of  The best fossil fuel plants are onlywaste, and has a considerably lower output level Ocean thermal energy conversion, which balance. The pitch of the blades may about 50% efficient. exploits the temperature difference betweenof the greenhouse gas carbon dioxide (CO2) than deep and shallow waters. be fixed or adjustable. The major  25% the cost of natural gasfossil fuel powered energy plants. Types of Hydro plant TURBINES components besides the runner are a is hydro energy conversion system which uses scroll case, wicket gates, and a draft  40% the cost of fossil fuelDamless hydro, is a renewable technology the temperature difference that exists between Impulse Turbine tube. There are several different types  50% the cost of nuclearbased on capturing the kinetic energy of rivers, deep and shallow waters to run a heat engine. The impulse turbine generally uses the velocity of propeller turbines:channels of chutes, spillways, irrigation As with any heat engine, the greatest efficiency of the water to move the runner and discharges and power is produced with the largest to atmospheric pressure. The water stream hits “Hydropower makes us wet”
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