Wave energy: Operation and Prospects

Wave Energy: Operation and Prospect

Name ID

Hasan, Md. Mahedi 12-21498-2

Presented By:

Course Instructor: Mr. Rethwan Faiz

•Provide alternatives to fossil-fueled power plants for the generation of electricity•ocean contains energy in the form of •Wave and • Tidal Current. •Wave energy is the transport of energy by ocean surface

waves, and the capture of that energy to do useful work

INTRODUCTION

•200 years back when the first known patent to use energy from ocean waves by Girard and his son.• In around 1910 an application of wave power device was

constructed by Bochaux-Praceique to light and power his house.• . From 1855 to 1973 there were already 340 patents filed in the

UK alone.•Modern scientific pursuit of wave energy was pioneered by

Yoshio Masuda's experiments in the 1940s

History

History (contd.)•Masuda tested various concepts of wave-energy devices

at sea, with several hundred units used to power navigation lights.• Among these was the concept of extracting power from

the angular motion at the joints of an articulated raft, which was proposed in the 1950s by Masuda.•A renewed interest in wave energy was motivated by the

oil crisis in 1973. A number of university researchers re-examined the potential to generate energy from ocean waves.

• Stephen Salter's 1974 invention became known as Salter's duck or nodding duck, although it was officially referred to as the Edinburgh Duck. In small scale controlled tests, the Duck's curved cam-like body can stop 90% of wave motion and can convert 90% of that to electricity giving 81% efficiency.

• The world's first marine energy test facility was established in 2003 to kick start the development of a wave and tidal energy industry in the UK.

History (contd.)

•According to the Installation Site•onshore WECs•onshore-nearshore WECs•nearshore-offshore WECs

WEC Classification

•According to the principle of operation•Overtopping devices•Point absorber buoy•Oscillating Water Columns (OWCs)•Surface attenuator

WEC Classification(contd.)

•According to the energy capture system•generate electricity by means of turbines coupled to a generator •wave energy to move a mechanism then transform this motion into electricity without an intermediate fluid

WEC Classification(contd.)

Overtopping devices• An Overtopping device captures sea water of

incident waves in a reservoir above the sea level, then releases the water back to sea through turbines.

• This device uses a pair of large curved reflectors to gather waves into the central receiving part, where they flow up a ramp and over the top into a raised reservoir, from which the water is allowed to return to the sea via a number of low-head turbines.

• The potential energy obtained in the overtopping water is then converted to electrical energy by leading the water from the reservoir back to the sea via a low head turbine connected to a generator.

Existing Technologies & Operations

Oscillating Water Columns• The collecting chamber• has a wide bottom that is open to and submerged in the

ocean. The collecting chamber extends well above water and becomes narrower towards the top.

• Because of its constant submersion in the ocean, it is important that the collecting chamber is resistant to damage from salt water and frequent wave activity.

• This compression and decompression pushes the air through a PTO system (connected to the top of the chamber), converting the airflow to energy.

• Power-Take-Off • is the second main component of an OWC device. It

converts the pneumatic power into a desired energy source • It must be able to convert airflow going both out of and

into the collecting chamber into energy. • Turbines that accomplish this are called bidirectional

turbines.

Existing Technologies & Operations(contd.)

Hanna Turbine• Hanna Turbine was invented by environmental activist

John Hanna in 2009.• The Hanna Turbine was developed to improve upon the

pioneering Wells Turbine.• It has no moving parts that come in direct contact with the

ocean.• The turbine has two rotors with back-to-back

asymmetrical airfoils. Both rotors are mirror images with low angles of attack.

• The airfoils have higher lift coefficients and less drag than the Wells Turbine. This makes the Hanna design less prone to stalling and offers more torque with a larger operating window.


Point absorber buoy• Power Buoy is a point absorber or buoy, currently

in-use or in-planning at 9 locations around the world, but primarily within Australia and the United States.

• It generates power using a hydroelectric turbine.

• Power Buoys are manufactured by Ocean Power Technologies (OPT) in Pennington, New Jersey.


Point absorber buoy(contd.)The rising and falling of the waves offshore causes the buoy to move freely up and down. The resultant mechanical stroking drives an electrical generator. The generated wave power is transmitted ashore via an underwater power cable.

OPT power stations have been designed for extreme wave conditions. Sensors on the Power Buoy continuously monitor the performance of the various subsystems and surrounding ocean environment. Data is transmitted to shore in real time.


•Surface attenuator• These devices act similarly to point absorber buoys, with

multiple floating segments connected to one another and are oriented perpendicular to incoming waves.


RoadBlocks

•most wave energy systems are fairly small, and aren’t suitable for powering large buildings or structures.•similar to solar or wind power, the amount of energy that can be harnessed is contingent upon the size of the waves at any given time.

Conclusion

As technologies develop, scientists and experts are looking at ways to harness more power from waves and the ocean.

Thanks Very much

Engineering

Wave energy: Operation and Prospects