17-04-2012, 01:10 PM
MARINE TIDAL CURRENT ELECTRIC POWER GENERATIONTECHNOLOGY
MARINE TIDAL CURRENT ELECTRIC POWER GENERATION TECHNOLOGY.ppt (Size: 427 KB / Downloads: 104)
1. INTRODUCTION
It’s a well know Fact that
“Marine” means Relating to sea or Oceans.
“Tides” are periodic rise and fall of water level of sea, which is caused due to action of sun and moon on water on earth.
Oceans and Seas constitute almost 70% of the earth’s surface area, have long been appreciated as a vast renewable energy source. The energy is stored in oceans partly as thermal energy, partly as kinetic energy (waves and currents)
The potential of electric power generation from marine tidal currents is enormous. Tidal currents are being recognized as a resource to be exploited for the sustainable generation of electrical power.
The kinetic energy present in marine and tidal currents can be converted to electricity using conventional turbine technology.
2. ABSTRACT
Marine tidal power fundamental concepts
Main projects around the world &
Also regarding electrical generator topologies associated to tidal turbines.
3. TIDAL KINETIC ENERGY BACKGROUND
The global marine current energy resource is mostly driven by the tides. The tides cause water to flow inwards (flood tide) and seawards (ebb tide).
Tidal current flow is very predictable, to within 98% accuracy for decades. Tidal charts are accurate to within minutes, for years ahead. Tidal current is independent of prevailing weather conditions such as wind, fog, rain, and clouds that can impact other renewable generation forecasts.Thus, reliable amounts of tidal power can be forecast with confidence.
The total kinetic power in a marine current turbine has a similar dependence as a wind turbine and is governed by the following equation
Where A is the cross sectional area of the turbine, v is the fluid density and p is the fluid density.
5. ADVANTAGES & LIMITATIONS OF TIDAL POWER.
ADVANTAGES:
It is Inexhaustible,
Independent of rain,
free from pollution,
Large area of land is not required,
The high load factors resulting from the fluid properties and the predictable resource characteristics make marine currents particularly attractive for power generation and advantageous when compared to other renewable energies.
LIMITATIONS:
Cost
Construction
Variability
Damage to Machinery
Also hamper other natural uses of estuaries such as fishing or navigation.
6. DIFFERENCE BETWEEN TIDAL ENERGY AND OTHER SOURCES OF ENERGIES.
Weather Conditions.
Predictable.
Cost.
Silent Operation.
7. TURBINE TECHNOLOGIES AND CONCEPTS
The harnessing of the energy in a tidal flow requires conversion of kinetic energy in a moving fluid, (in this case water), into the motion of a mechanical system (turbines), which can then drive a generator.
Most turbines can be characterized as belonging to two fundamental types
Horizontal Axis Turbines.
Vertical Axis Turbines.
HORIZONTAL AXIS TURBINES:
These are close in concept to traditional windmills operating under the sea, the axis of rotation is horizontal and aero turbine plane is vertical facing tides.
VERTICAL AXIS TURBINES: ART AND STATUS (PROJECT).
VERTICAL AXIS TURBINES:
These are close in concept to traditional windmills operating under the sea, the axis of rotation is vertical and blades may also be vertical.
The Blue Energy Project (Canada):
8. ELECTRIC GENERATORS TOPOLOGIES
Some of wind electric generator topologies could be used for tidal turbine.
For illustration, the strongest tidal current located at the southwestern tip of the Korean Peninsula, pilot tidal current power plant of 1MW uses Gorlov Helical Turbine and two generator topologies: a doubly-fed induction generator (500KW) and a synchronous generator (500KW).
There are two topology Categories: the direct and the indirect driven technology.In tidal turbine application, maintenance is a key feature and sometimes it is considered as a barrier to marine turbine development. It is then recommended to avoid gearbox, Systems that need regular lubrication and induce additional losses. In this context, direct driven generators are an alternative solution.
An advantage of this topology is that the generator can be located under or upper the tidal turbine. That means that the size of the generator is not constraint by the turbine.
9. Harnessing the Tides: Marine Power Update 2009
In April 2007, Verdant Power project was installed in the East River between Queens and Roosevelt Island in New York City; it was the first major tidal-power project in the United States.
Later, SeaGen, (Marine Current Turbines and generators) was installed by in Strangford Lough in Northern Ireland in April 2008. The turbine began to generate at full power of just over 1.2 MW in December 2008 and was reported to have fed 150kW into the grid. It is currently the only commercial scale device to have been installed anywhere in the world.
Roosevelt Island Tidal Energy project, says the firm aims to have "at least 35 MW" in the water by the end of 2011.
UK to develop large scale ocean energy projects - Aquamarine To Develop 1 GW of Ocean Energy, and also the same company Aquamarine Power has signed a Development Agreement with Airtricity, the renewable energy development division of Scottish and Southern Energy (SSE), aimed at developing sites capable of hosting 1,000 megawatts (MW) of various types of marine energy by 2020.
10. CONCULSION
This paper has review the state of art of marine tidal turbines.
This paper will also review marine tidal power fundamental concepts and main projects around the world.
It will also report issues regarding electrical generator topologies associated to tidal turbines.
Moreover, an attempt has been made to highlight current and future issues so as to index some emerging technologies.