Environmental Science: Marine energy

Introduction to Environmental Science Prof : Nguyen Xuan Cu Group Do Thi Ngoc Bich Enkhbayar batsukh Pham Thanh Huong Do Thi Ngoc Khanh Nguyen Hanh Mai Tran Thu Trang Trinh Thi Thu Trang Marine energy Content Definitions and overall potential Some kinds of marine energy Potential of Vietnam I Definitions and overall potential • Energy is a quantity that is often understood as the ability a physical system has to work on other physical systems ( in physics ) • Marine energy ( marine power /ocean energy / ocean power) refers to the energy carried by ocean waves, tides, salinity, and ocean temperature differences ( Wikipedia ) • Larger conception : Energy that belongs to the ocean Potential • The oceans have a tremendous amount of energy and are close to most concentrated populations Many researches show that ocean energy has the potential of providing for a substantial amount of new renewable energy around the world • Theoretical potential 50000 40000 Potential TW/h 30000 20000 10000 Osmotic power Tidal /current energy II Some kinds of marine energy 1.Wave energy a General view • Waves are generated by wind passing over the surface of the sea, there is an energy transfer from the wind to the waves • Wave power is the transport of energy by ocean surface waves, and the capture of that energy to useful work (electricity generation , water desalination, or the pumping of water ) • In general, larger waves are more powerful but wave power is also determined by wave speed, wavelength, and water density Wave power devices can be categorized in terms of Location b Some examples • Oil spills Crude oil and refined fuel spills from tanker ship accidents have damaged natural ecosystems • A tarball is a blob of petroleum which has been weathered after floating in the ocean Tarballs are an aquatic pollutant in most environments, although they can occur naturally and as such are not always associated with oil spills Wind farm offshore a General view • Wind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electricity, wind mills for mechanical power, wind pumps for pumping water or drainage , or sails to propel ships in the same location • A wind farm is a group of wind turbines used for production of electric power • A large wind farm may consist of several hundred individual wind turbines, and cover an extended area of hundreds of square miles • Offshore wind power ->Offshore wind farm + solar energy +OTEC => ‘energy island’ Some examples of offshore wind turbine’s base [...]... hydro-electric turbine LIMPET (Land Installed Marine Power Energy Transmitter ) c Advantages vs Disadvantages • The energy is free - no fuel needed, no waste produced • Not expensive to operate and maintain • Can produce a great deal of energy • Waves that are caused by winds can be very predictable • Depends on the waves - sometimes you'll get loads of energy, sometimes almost nothing • Needs a suitable... strongest in winter) 2 Tidal energy a General view • Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of the Earth • Tidal power / tidal energy, is a form of hydropower that converts the energy of tides into electricity or other useful forms of power b Three main kinds of tidal energy • Tidal barrage is... passive cylinder up and down on its springs, creating mechanical energy Then, the machine converts this energy into electricity Systems could be sited on river beds or suspended in the ocean c Challenges • The costs is still high , especially the maintenance costs • Marine growth buildup • Corrosion • Species protection (including fish and marine mammals) from injury) • Avoidance of shipping routes ,... power b Three main kinds of tidal energy • Tidal barrage is a dam-like structure used to capture the energy from Masses of water moving in and out of a flight or river due to Tidal forces • Tidal stream generator  A tidal stream generator/ tidal energy converter (TEC) is a machine designed to extract energy from run of river or tidal estuarine sites  Certain types of these machines function very much...• Salter’s Duck ( Nodding Duck ) • The Pelamis Wave Energy Converter The machine is made up of connected sections which flex and bend as waves pass; it is this motion which is used to generate electricity • Aquamarine Power’s Oyster technology captures energy in nearshore waves and converts it into clean sustainable electricity • Oyster is a wave-powered... vs Disadvantages • Tidal energy is renewable • It is free once the dam is built and the maintenance costs associated with running a tidal station are relatively inexpensive • Tides are easy to predict • Tidal power is not currently economically feasible (costs of building a dam) except kinds using tidal turbines • affect the aquatic ecosystems, transport or fishery 3 Current energy a What is ocean current... Ocean weather may also create problems ( tropical storms or hurricanes ) 5 Salinity energy a General view • Osmosis is the flow of a solvent (water) through a semi-permeable membrane in the direction of the concentrated solution to balance both side's solute concentrations • Osmotic power or salinity gradient power is the energy available from the difference in the salt concentration between seawater and... generator that produces the electrical energy A B b A promising example The Norwegian company Statkraft opens the world’s first facility for osmotic power generation Statkraft says a full-scale commercial osmotic power plant could be ready by 2015 They says osmotic power could produce up to 1,600– 1,700 terawatt hours worldwide – the equivalent of half of the energy generated in the EU today ... protection (including fish and marine mammals) from injury) • Avoidance of shipping routes , recreational uses, such as fishing and diving , slowing the current flow ,changes of estuary mixing 4.Ocean thermal energy a Potential b Ocean Thermal Conversion (OTC) • Method : uses the difference between cooler deep ocean waters warmer shallow or surface run a heat engine + produce useful work ( electricity , freshwater... drives a turbine to produce electricity  The steam condenses within the heat exchanger and provides desalinated water c Advantages vs Disadvantages • OTEC has the potential to offer huge amounts of clean energy • OTEC plants can operate continuously providing a base load supply for an electrical power generation system • OTEC can also supply quantities of cold water as a by-product Used for air conditioning