Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
MSE0290 – SUSTAINABLE ENERGY TECHNOLOGIES Hydro Power Büsra Yilmaz Rafael Osorio Holger Part Nature of the Hydro Power • Hydropower or water power (from the Greek: ύδωρ, "water") is power derived from the energy of falling water or fast running water, which may be harnessed for useful purposes. • Since ancient times, hydropower from many kinds of watermills has been used as a renewable energy source for irrigation and the operation of various mechanical devices, such as gristmills, sawmills, textile mills, trip hammers, dock cranes, domestic lifts, and ore mills. History behind the Hydro Power • In Imperial Rome, water powered mills produced flour from grain, and were also used for sawing timber and stone; in China, watermills were widely used since the Han dynasty. • In China and the rest of the Far East, hydraulically operated "pot wheel" pumps raised water into crop or irrigation canals. • The power of a wave of water released from a tank was used for extraction of metal ores. The method was first used in Wales from 75 AD onwards, but had been developed in Spain, Britain in the Medieval and later periods to extract lead and tin ores. It later evolved into hydraulic mining when used during the California Gold Rush. History behind the Hydro Power • Technological advances had moved the open water wheel into an enclosed turbine or water motor. • In 1848 James B. Francis, while working as head engineer of Lowell's Locks and Canals company, improved on these designs to create a turbine with 90% efficiency. He applied scientific principles and testing methods to the problem of turbine design. His mathematical and graphical calculation methods allowed confident design of high efficiency turbines to exactly match a site's specific flow conditions. The Francis reaction turbine is still in wide use today. • In the 1870s, deriving from uses in the California mining industry, Lester Allan Pelton developed the high efficiency Pelton wheel impulse turbine, which utilized hydropower from the high head streams. Usage and mechanisms behind hydropower • Run-of-the-river power plants/river power plants Run-of-the-river/river power plants are the most common type worldwide. They use the flow energy of a river, and are normally used to cover the base load. Their capacity is determined mostly by the gradient and the water level. Some run-of-the-river power plants can also dam water at times of low energy demand in order to use it as a reserve when demand is higher. • The so-called diversion hydropower plant is a special type of run-of-the-river plant. The water is dammed in a barrier and redirected onto the turbines by means of a separate feeder channel. In the case of a standard run-of-the-river power plant, there is only a slight difference in the height between the upper and lower water levels, but a diversion hydropower plant exploits the greater height difference created by the diversion. • Storage power plants Storage power plants store the water in a natural or artificial lake and feed it via pipelines into a lower-lying power plant. Such plants can operate independently of natural water inflow, and are particularly suited to balancing fluctuations in regional and national electricity generation and consumption. They are used both to cover the electrical base load and for peak load operation. Usage and mechanisms behind Hydropower • Pumped storage power plants A pumped storage power plant uses two reservoirs to store water, with the greatest possible height difference between the upper and lower reservoirs. During off-peak periods, e.g. at night or when there is a large amount of solar or wind energy in the grid, water is pumped from the lower to the upper reservoir. There, it is once again available for electricity generation at peak load times. Pelton turbines are used to drive the generator. • Types of power plants for exploiting marine energy The kinetic energy of waves, tidal range and tidal flow can also be used to generate electricity. One advantage of using marine energy is the uniform energy supply and the ensuing balancing effect on the renewable energy mix. While tidal range power plants are already technically mature, other technologies such as the so-called wave power plants are still at the development stage. Hydropower Usage - Today https://www.hydropower.org/world-hydropower-statistics Hydropower Usage – Future Potential The potential for additional hydropower remains considerable, especially in Africa, Asia and Latin America. This roadmap foresees, by 2050, a doubling of global capacity up to almost 2 000 GW and of global electricity generation over 7 000 TWh. Pumped storage hydropower capacities would be multiplied by a factor of 3 to 5. Hydropower Usage – Future Potential • Most of the growth in hydroelectricity generation will come from large projects in emerging economies and developing countries. In these countries, large and small hydropower projects can improve access to modern energy services and alleviate poverty, and foster social and economic development, especially for local communities. • In industrialised countries, upgrading or redevelopment of existing plants can deliver additional benefits. Working principles • Principle • Use of gravitational force of falling or flowing water Principle Potential energy - 1 Kinetic energy - 2 Mechanical energy - 3 Electric energy - 4 Turbine – kinetic to mechanical • A water turbine is a rotary machine that converts kinetic energy and potential energy of water into mechanical work. • Reaction turbines • Impulse turbines https://water.usgs.gov/edu/hyhowworks.html Turbine classification • Reaction Turbines • –Derive power from pressure drop across turbine • –Totally immersed in water • –Angular & linear motion converted to shaft power • –Propeller, Francis, and Kaplan turbines • •Impulse Turbines • –Convert kinetic energy of water jet hitting buckets • –No pressure drop across turbines • –Pelton, Turgo, and crossflow turbines Turbine classification Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003 Francis turbine • • • • Most common water turbine in use today Water head from 10 to 350m Few KW up to 800MW Hybrid type • Both reaction and impulse https://en.wikipedia.org/wiki/Francis_turbine Kaplan turbine • • • • • • High-flow, low-head Propeller type with adjustable blades Head 2– 40 m 5 – 200 MW Runner diameeter 2 – 11 m Reaction type turbine https://en.wikipedia.org/wiki/Kaplan_turbine Pelton turbine • Impulse type turbine • High head, low flow • Head 50– 1300 m • Up to 400 MW https://en.wikipedia.org/wiki/Pelton_wheel Turgo turbine • Medium head applications(50 – 250 m) • Impulse water turbine • Lower efficiency, lower cost https://en.wikipedia.org/wiki/Turgo_turbine Crossflow turbine • Heads less than 200 m • Flat efficiency curve • Lower peak efficiency Water wheel • For free-flowing or falling water • No longer in common use • Up to 60% efficiency Hydropower calculations • P = power in kilowatts (kW) • g = gravitational acceleration (9.81 m/s2) • ŋ = turbo-generator efficiency (0<n<1) • Q = quantity of water flowing (m3/sec) • H = effective head (m) Marine energy • Tidal power • Wave power • Marine current power • Osmotic power • Ocean thermal energy Hydopower Advantages • It is fueled by water, so it's a clean fuel source, meaning it won't pollute the air like power plants that burn fossil fuels, such as coal or natural gas. • It is a domestic source of energy, allowing each state to produce their own energy without being reliant on international fuel sources. • The energy generated through hydropower relies on the water cycle, which is driven by the sun, making it a renewable power source, making it a more reliable and affordable source than fossil fuels that are rapidly being depleted. Hydro Advantages • Impoudment hydropower creates reservoirs that offer a variety of recreational opportunities, notably fishing, swimming, and boating. Most water power installations are required to provide some public access to the reservoir to allow the public to take advantage of these opportunities. • Some hydropower facilities can quickly go from zero power to maximum output. Because hydropower plants can generate power to the grid immediately, they provide essential back-up power during major electricity outages or disruptions. • In addition to a sustainable fuel source, hydropower efforts produce a number of benefits, such as flood control, irrigation, and water supply. Effects of Dams on Biodiversity • • • • About 60% of the world’s river flow is regulated. There are more than 40,000 large dams with heights >150 m. Reservoirs cover a total area in excess of 500,000 km2. Large hydroelectric dams are among the most controversial of alltypes of development projects. • Focus - criticism of the World Bank and other internationalfinancing agencies. • Critics point out - destruction of biodiversity What dams do? • Anthropogenic alterations that disrupts dynamic processes and so impact on ecological integrity of natural system. • Dams disrupt the river continuum and cause upstream and downstream shifts in biotic and abiotic parameters. Impact order • 1st order impacts: Immediate abioticeffects • 2nd order impacts: Changes in channel and flood plain biology • 3rd order impacts: Long term biotic changes and “new equilibrium” Biodiversity • Fresh waters are home to a relatively high proportion of species, with more per unit area than other environments (10% more than land and 150% more than the oceans). • only about 45,000 species of freshwater animals, plants and microorganisms have been scientifically described • at least an additional million more species remain to be named. Biological Impacts • Blocking migratory • species. • Changing turbidity. • Filtering out of woody debris which provides habitat and sustains a food chain. • Trapping silt in reservoirs and reducing downstream productivity. Changing conditions of underwater terrain – running water becomes still – deep water zones, – temperature and oxygen conditions changes Hydropower Disadvantages • Unstable for riverine species. • Possibly fostering exotic species. • Reservoirs may be colonised by species which are vectors of human and animal diseases. • Dam management diminishes or stops normal river flooding and affecting biodiversity. • Changing the normal seasonal estuarine discharge which can reduce the supply of nutrients, impacting the food chains that sustain fisheries in inland and estuarine deltas. • Modifying water quality and flow patterns downstream. Migration • Anadromous fishes (salmon and hilsa) catadromous fishes (eels) • Many stocks of Salmonidae and Clupeidae have been lost as aconsequence. • Eg. Columbia River, USA, more than 200 stocks of anadromous, Pacific salmonids became extinct. • Sturgeon populations in the Caspian Sea rely on hatcheries mainly in Iran, since Russian dams block natural spawning migrations. • Hydroelectric dams in the Amazon basin have halted the long distance upstream migration of several species of catfishes and interrupted the downstream migration of their larvae Turbidity • Reservoirs trap suspended particles, reducing turbidity downstream. • Many species are adapted to natural turbidity. • Eg. turbid water catfishes have small eyes, refined senses of smell and touch in their sensitive barbels. • Downstram biota changes • Clear water increases visual predator attack (birds). • Indigenous species affected adversely. • Other animal species may move in – filter feeders and aquatic vegetation may flourish. – sediment burrowing species reduces due to lack of sediment • increased turbidity, above natural levels, can interfere with primary production (Arthington & Welcomme 1995). Sedimentation • Reservoirs tend to serve as sediment traps since river velocities and carrying capacity for particles decrease in reservoirs (McCartney et al. 1999) • Sedimentation can degrade habitat both in the reservoir and below the dam, as well as reduce storage capacity. • Many of the mollus can extinctions in the Mobile Bay (USA) due to siltation • Suspended silt may reduce the feeding efficiency of filter-feeding bivalves and other species. • About 50 km3 of sediment, nearly 1% of global reservoir capacity, was estimated in 1997 to be trapped behind dams. Seasional Variability of Flow and Flood Plains • The pattern of flow of a river undergoes a regular series of changes with the seasons. The patterns can differ profoundly from region to region • e.g. in an Indian river the peak flow may be during the monsoon,in an Arctic river during snow-melt or ice breakup. • The expansion and contraction of the river controls living space and access to particular habitats. • Species in a drainage basin adapt to the seasonal patterns . • It is from river flow events that species take cues to migrate,spawn, etc. • Some species are adapted to strongly seasonal flow regimes with flooding. • Changes in flow patterns through intensive flow regulation after impoundments and possible changes in algae, bacteria and fungi, which form potential mollusc food sources. Inland Deltas • Naga Hammadi barrage area of the lower Nile, Egypt • Perch- Zingel streber and Zingel zingel (IUCN -vulnerable) • Salmonids- Hucho hucho, (endangered, and salmon -Salmo trutta. • The European beaver, Castor fiber, has left the territories influenced by the dam. • The mean annual fish catch has dropped by 87% Estuarine and Marine Impacts • Many of the effects in estuaries are similar to upstream, e.g. loss of habitat and changes in seasonal flow, turbidity and productivity. • Total shifting of ecosystem Is Hydropower really sustainable? • Siltation reduces a dam’s water storage so water stored in the wet season cannot be stored for use in the dry season • The life of dams can be extended by sediment bypassing, special weirs, and forestation project to reduce silt production. At some point, it becomes uneconomic to operate in most cases. Is Hydropower really sustainable? • Water flow can decrease in areas due to environmental problems such as global warming • The North Cascades glaciers have lost a third of their volume since 1950, resulting in stream flows that have decreased by as much as 34% • No burning of fossil fuels • Even though water sources can eventually be reduced, other water resources will always be available due to the water cycle Conclusion • Dams alter river ecosystems and subsequently require development of new relationships between human kind and natural resources associated with these ecosystems. • Dams built to receive benefits will accrue humans with energy, water supply, transportation, flood control, fishing, recreation, aesthetics, and so on. • https://www.youtube.com/watch?v=nvzx1QCXCes References • • • • • • • • • • • • • https://en.wikipedia.org/wiki/Francis_turbine https://en.wikipedia.org/wiki/Kaplan_turbine https://en.wikipedia.org/wiki/Turgo_turbine https://www.renewablesfirst.co.uk/wp-content/cache/page_enhanced/www.renewablesfirst.co.uk//hydropower/hydropower-learning-centre/crossflowturbines//_index.html_gzip https://en.wikipedia.org/wiki/Pelton_wheel https://en.wikipedia.org/wiki/Cross-flow_turbine https://water.usgs.gov/edu/hyhowworks.html https://en.wikipedia.org/wiki/Hydroelectricity http://www.iea.org/publications/freepublications/publication/technology-roadmap-hydropower.html https://www.hydropower.org/world-hydropower-statistics http://www.renewables-made-in-germany.com/en/renewables-made-in-germany/technologies/hydropower/hydropower/technologies-and-applications.html http://energyinformative.org/the-history-of-hydroelectric-power/ Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003