REPORT SUBMITTED ON

-The Future Of Renewable Energy

SUBMITTED BY : POOJA MALIK ROLL NO : 0804034 BRANCH : MECHANICAL (4TH YEAR)

DEPARTMENT OF MECHANICAL ENGINEERING DEENBANHU CHHOTU RAM UNIVERSITY OF SCIENCE AND TECHNOLOGY, MURTHAL

CONTENTS
Introduction to wave energy Wave Energy- Advantages Wave Energy near population centers Ocean Wave Energy technologies 1) Terminator Devices 2) Point Absorbers 3) Attenuators 4) Overtopping Devices Introduction to OPT Utility Scale PowerBuoy How the PowerBuoy works PowerBuoy deployment process Various PowerBuoy projects 1) PB40 PowerBuoy 2) PB150 PowerBuoy Ocean power technologies PB150 device outperforms in sea tests References

Introduction To Ocean Wave Energy

More than 70% of Earth's surface is covered by oceans which contain two types of energy:

mechanical energy from waves and tides and Thermal energy from solar radiations falling on the ocean surface making them the world's largest solar collectors

Waves are caused by the wind blowing over the surface of the ocean. In many areas of the world, the wind blows with enough consistency and force to provide continuous waves. There is tremendous energy in the ocean waves. Wave power devices extract energy directly from the surface motion of ocean waves or from pressure fluctuations below the surface. Wave power varies considerably in different parts of the world, and wave energy can't be harnessed effectively everywhere. Wave-power rich areas of the world include the western coasts of Scotland, northern Canada, southern Africa, Australia, and the northwestern coasts of the United States. The total power of waves breaking on the world's coastlines is estimated at 2 to 3 million megawatts. In favorable locations, wave energy density can average 65 megawatts per mile of coastline.

Wave Energy - The Advantages

Wave energy is the most concentrated form of renewable energy: Widespread throughout the U.S., U.K, Europe & other parts of the world Close to population centers Predictable & dependable, and can be fed into the power grid or stored Load factor of 30-45% versus solar and wind load factors of 10%-35% Environmentally benign & non-polluting: no exhaust gases, no noise, no visibility from shore, safe for sea life Scalable to high capacity power stations (100MW+) 300 sq miles of ocean area off California is estimated to be capable of producing electrical power needs for all of Californias homes.

Wave Energy Near Population Centers

Ocean Wave Energy Technologies

Wave energy technologies convert wave energy which is the sum of potential energy [due to vertical displacement of the water surface] and kinetic energy [due to water in oscillatory motion] into electricity. Thus, these devices operate by means of changes in the height of ocean waves (head or elevation changes). There is a wide variety of wave energy converter designs that can be categorized in several ways.

Potential energy (due to vertical displacement of the water surface)

Kinetic energy (due to water in oscillatory motion)

Wave energy
A variety of technologies have been proposed to capture the energy from waves. Some of the more promising designs are undergoing demonstration testing at commercial scales. Wave technologies have been designed to be installed in nearshore, offshore, and far offshore locations. The OCS Alternative Energy Programmatic EIS is concerned primarily with offshore and far offshore wave technologies. Offshore systems are situated in deep water, typically of more than 40 meters (131 feet). While all wave energy technologies are intended to be installed at or near the water's surface, they differ in their orientation to the waves with which they are interacting and in the manner in which they convert the energy of the waves into other energy forms, usually electricity.

The following wave technologies have been the target of recent development. 1) TERMINATOR DEVICES Terminator devices extend perpendicular to the direction of wave travel and capture or reflect the power of the wave. These devices are typically onshore or nearshore. However, floating versions have been designed for offshore applications. The oscillating water column is a form of terminator in which water enters through a subsurface opening into a chamber with air trapped above it. The wave action causes the captured water column to move up and down like a piston to force the air though an opening connected to a turbine.

2) POINT ABSORBERS A point absorber is a floating structure with components that move relative to each other due to wave action (e.g., a floating buoy inside a fixed cylinder). The relative motion is used to drive electromechanical or hydraulic energy converters. This type of device has many possible configurations. One configuration, called a hose pump point absorber, consists of a surfacefloating buoy anchored to the sea floor. 1) In fig.2 Buoy follows the waves motion up and down. 2) The buoy's motions are transferred via a rope or cable to the generator's moveable part, which in this case consists of a piston. 3) The piston is equipped with very strong neodymium-iron-boron (Nd-Fe-B) magnets and induces currents in the stator's windings. In addition, the piston is connected to a spring system, which gives the generator additional power also when the buoy is mowing down a wave.

3) ATTENUATORS Attenuators are long multisegment floating structures oriented parallel to the direction of the waves. The differing heights of waves along the length of the device causes flexing where the segments connect, and this flexing is connected to hydraulic pumps or other converters. These are also known as heavy- surge devices. The best working example of an attenuator is the PELAMIS device.

4) OVERTOPPING DEVICES Overtopping devices have reservoirs that are filled by incoming waves to levels above the average surrounding ocean. The water is then released, and gravity causes it to fall back toward the ocean surface. The energy of the falling water is used to turn hydro turbines. Specially built seagoing vessels can also capture the energy of offshore waves. These floating platforms create electricity by funneling waves through internal turbines and then back into the sea.

Introduction to OPT
Ocean Power Technologies, Inc. is a pioneer in wave energy technology that harnesses ocean wave resources to generate reliable, clean and environmentallybeneficial electricity. OPT has a strong track record in the advancement of wave energy, and participates in an estimated $150 billion annual power generation equipment market. OPT's proprietary PowerBuoy system is based on modular, ocean-going buoys that capture and convert predictable wave energy into clean electricity. The Company is widely recognized as a leading developer of on-grid and autonomous wave energy generation systems, benefiting from 15 years of inocean experience. OPT is headquartered in Pennington, New Jersey with an office in Warwick, UK. OPT undertake three different projects: 1) UTILITY SCALE POWERBUOY Converts ocean waves into power for the grid. 2) AUTONOMOUS POWERBUOY Converts ocean waves into power for at sea-applications. 3) MARINE ENERGY INFRASTRUCTURE Products and expertise to ensure successful networking and transmitting offshore of marine energy to onshore grids.

UTILITY SCALE POWERBUOY

Ocean Power Technologies' PowerBuoy is designed to convert ocean wave energy into useable electrical power for utility-scale grid-connected applications. The PowerBuoy can be deployed in arrays scalable to hundreds of megawatts. The rising and falling of the waves offshore causes the buoy to move freely up and down. The resultant mechanical stroking is converted via a sophisticated power take-off to drive an electrical generator. The generated power is transmitted ashore via an underwater power cable. Potential uses include: Generating electricity in commercial-scale utility power plants providing up to hundreds of megawatts of endless, clean, renewable energy from the oceans waves. Providing power to grid applications and large energy users for: a) Cities and large towns with isolated grids or in remote locations . b) Department of Defense bases worldwide. c) Powering oil and gas platforms. Making clean, fresh drinking water from ocean water. Producing hydrogen from seawater by electrolysis. Providing power and cooling for floating computing centers. Processing natural resources in remote areas and off-grid applications. Powering CO2 sequestration applications in depleted marine oil fields.

How the PowerBuoy Works

PowerBuoy resembles a giant vertical dumbbell anchored to the sea floor. The top portion of the 115-footlong device floats on the oceans surface The rise and fall of waves moves the buoy up and down (mechanical stroking) which drives an electric generator. As it bobs among the waves the motion pushes pistons to create mechanical energy to drive an electrical generator. This AC power is then conditioned and transmitted ashore as high-voltage power via underwater cable. PowerBuoy sensors continuously monitor the various subsystems and ocean environment and feed that information to an on-board computer. This enables real time control of the PowerBuoy to ensure efficient conversion of random, broadband wave energy to electricity. OPTs wave power generation system includes sophisticated techniques for automatically disconnecting the system in large waves, and automatically restoring operation when wave conditions normalize.

FIG 6 : PowerBuoy and Undersea Substation

In terms of its viability, the PowerBuoy offers the following feasibilities:

Impervious to any kind of harsh weather conditions prevailing in the high seas A maximum capacitance of the equipment is 150kW, with a varying energy output between 30 to 50% depending on the equipments oceanic positioning State-of-the-art communication systems, optic fiber cables and the extremely superior Supervisory Control and Data Acquisition Systems (SCADA) Power generation carried out in waves that range between 4.9 to 22.9 feet

PowerBuoy Deployment Process

Various PowerBuoy Projects

OPT has been actively developing PowerBuoy wave energy conversion technology since 1994. Using extensive wave tank and computer modeling, scientificallygrounded scaling techniques, and long-term sea testing, OPT has successfully developed PowerBuoys from 150W to 40kW and, most recently, to 150kW, conducting more than 58 months of ocean testing on eight PowerBuoy systems in the Atlantic and Pacific Oceans. OPTs PB40 PowerBuoy Under the U.S. Navys Small Business Innovation Research (SBIR) Program, OPTs first PB40 dual-absorber PowerBuoy, was deployed off the coast of New Jersey for two 1-year periods and survived the wind and wave forces of several gales and hurricane remnants during those periods prior to removal for maintenance. The long duration prototype ocean test in New Jersey demonstrated the survivability of the dual-absorber PowerBuoy in an array of ocean wave conditions. OPT received a follow-on contract from the Office of Naval Research (ONR) to conduct ocean test activities directed toward furthering the research in ocean wave energy by installing a grid-connected wave power system at the U.S. Marine Corps Base (MCBH) at Kaneohe Bay in Oahu, Hawaii. The purpose of the project was to evaluate the technical feasibility of converting wave energy into usable electric power for Navy applications. OPT and the Navy have been funding the development and demonstration of a wave power system in Hawaii under this commercialization program. The infrastructure at the MCBH site consists of subsea and land power and fiber optic cables for the grid connection, a shore station that contains the grid connection equipment and communications and control system, and the seabed construction for the anchor/mooring system to support two buoys. Preparation for the project and the design of the PowerBuoy deployment in Hawaii enabled OPT to achieve a number of key credibility milestones for OPT and the industry. Environmentally, the independent Environmental Assessment (EA)

performed for the project resulted in a Finding of No Significant Impact (FONSI), the best rating achievable. Also, OPTs PowerBuoy interface with the electrical utility power grid was certified as compliant with national (UL) and international standards, thereby permitting OPT to do the first utility grid connection of the technology. As part of the program, the Navy provided ongoing support and expertise to OPT on anchoring, mooring systems, marine survivability, and related subsea design areas. In addition to the milestones above, the program has made significant accomplishments: A utility-grid cable was deployed and on-shore infrastructure installed. Years of in-ocean experience has been gained allowing us to hone and perfect OPTs control systems. OPTs hydrodynamic models have been validated and refined and are now proven to be within 10% to 20% of real-world performance measurements. OPTs Active Impedance Matching System (AIMS) algorithm has demonstrated a significant improvement in measured efficiency. A direct drive advanced Power Take-Off (PTO) with significant improvements in efficiency and reliability has been developed. OPTs PB40 PowerBuoy was connected to the utility grid. The long-term PB40 deployments in Hawaii, along with those in New Jersey and other worldwide locations, have given OPT the knowledge to make the step to large scale power production systems, which recently culminated in the deployment of its first PB150, 150kW PowerBuoy, a major milestone in OPTs technology development plans.

OPTs PB150 PowerBuoy OPTs newest addition to its utility-scale product line is the PB150 PowerBuoy. The first utility-scale 150 kilowatt PowerBuoy, fabricated in Scotland, was deployed in 2011 off the Eastern coast of Scotland for ocean trials. A second PB150 PowerBuoy is being fabricated in Portland, Oregon, and is planned for

deployment at Reedsport, Oregon. The deployment of the first utility-scale PB150 PowerBuoy in Scotland in the North Sea marked an important milestone in the Companys commercial development. The PB150 PowerBuoy offers many features for wave energy projects. It generates power with wave heights between 1.5 and 7 meters (4.9 to 22.9 feet). OPTs mooring approach and PowerBuoy structure permit deployment of the PowerBuoy system across a wide combination of storm wave, tidal, and current conditions, making it suitable for a broad range of wave climates. The PB150 is typically configured in arrays of two to three rows, minimizing the footprint of the project. The PB150 PowerBuoy offers a sustained maximum peak-rated output of 150 kilowatts. Typical capacity factors for the PB150 range between 30% to 45%, depending on location. The PowerBuoy provides grid-quality electricity and is independently certified to meet all required grid interconnection standards. The PowerBuoy has fiber optic communications and Supervisory Control and Data Acquisition (SCADA) systems. In January 2011 OPT achieved the worlds first Lloyds Register certification for the PB150 utility-scale wave power device. This provides independent, third-party assurance on the design of the PB150 PowerBuoy for its intended use, as analyzed against international standards, and its survivability in severe wave conditions. OPT has also developed an Undersea Substation Pod (USP) for which a patent has been issued to OPT, which can aggregate the electrical output from up to ten PowerBuoys into a single transmission cable to shore. This approach minimizes costs of submarine transmission cable to the shore-based interconnection. The USP provides control and SCADA capability for all connected PowerBuoys.

PB Dimen PB150 PowerBuoy Dimensions shown in feet

P Dime

The first utility-scale 150 kW PowerBuoy, fabricated in Scotland, was deployed on 15 April 2011 and ocean trials are currently being conducted at a site approximately 33 nautical miles from Invergordon, off Scotlands northeast coast. The power produced to date in this commissioning phase has been as planned and is consistent with the test protocols and OPTs predictive models for the wave environment experienced, further validating the predictive hydrodynamic and power take off models this time at larger physical scales. A broad range of operations and functional tests are being performed, examining the response of the PowerBuoy's structure and mooring system to the waves and the power produced by the on-board generator. A wave data buoy located near the site provides detailed information regarding incoming waves. Data collected during the trials is being transmitted from the PowerBuoy in real-time for analysis by OPT's engineers in both the UK and the US. The power produced to date in this commissioning phase has been as planned, and is consistent with the test protocols and OPT's predictive models for the wave environment experienced. On-board equipment duplicates grid-connection conditions to ensure the buoy's electrical systems are subject to full operational testing for utility applications. This power generation data further validates the Company's experience with its grid-connected Hawaii PowerBuoy system. It demonstrates the PowerBuoy's ability to produce the level of power expected to be generated in varying conditions, and to predict power accurately for different-sized PowerBuoys, at a range of sites. A second PB150 PowerBuoy is being fabricated in Portland, Oregon and is also planned for final assembly last summer, for deployment in 2011. This buoy is the first in a planned array deployment where 10 PB150 PowerBuoys will be installed for the 1.5 MW Reedsport Project supplying power to the Pacific Northwest electric grid. OPT has received two grants from the U.S. Department of Energy for the Reedsport Project. The most recent is for the PB150 Deployment and Ocean Test of the first unit. OPT will deploy a full scale PB150 PowerBuoy (PB150B2) system in the Oregon Territorial Sea and collect detailed operating characteristics

during 2 years of operations. These data will be used to validate the performance at that site. As OPT pursues its commercialization strategy, the Lockheed Martin - Missions Systems and Sensors business unit has teamed with OPT in efforts to minimize the fabrication and assembly of OPTs 150kW PowerBuoy. Lockheed Martin is the largest United States defense contractor with a plethora of engineering and manufacturing resources as well as very structured and rigorous process development and improvement capabilities. Lockheed Martin will supplement OPTs capabilities with resources that are experienced in transitioning development models into production with a focus on process improvement.

Ocean Power Technologies PB150 Device Outperforms in Sea Tests

The new generation utility-scale PowerBuoy device, the PB150, has delivered better-than-expected initial results from tests being conducted off the northeast coast of Scotland. Rated at 150 kilowatts, this device was designed and developed by OPT to work in arrays of multiple PowerBuoys to generate renewable energy at commercial-scale wave power stations worldwide. It was deployed on April 15, 2011 for ocean trials at a site approximately 33 nautical miles from Invergordon, Scotland. The trials are expected to continue for an additional one to two months. Wave conditions encountered have included storm waves, and electrical power generated by the PB150 has included peaks of over 400 kilowatts. Average electrical power of 45 kilowatts was generated at wave heights as low as 2 meters. These levels of power exceeded OPTs expectations of performance for this first PB150 deployment, and verifies that the system could produce up to 150 kilowatts on average, in higher wave conditions. On-board equipment replicates grid-connection conditions to ensure the PowerBuoys electrical systems are subjected to full operational testing for utility applications. The power take-off systems performance has exceeded expectations with respect to its energy conversion efficiency in the irregular ocean wave conditions encountered. The device is transmitting data in real-time for analysis by OPTs engineers in both the United Kingdom and the United States. A wave data buoy located near the site provides detailed information regarding incoming waves. Using that information, OPTs engineers calculate the power levels that should be achieved by the PB150, and analyze these against actual power generation. The result of this process confirms the Companys ability to predict accurately the PowerBuoys performance in varying wave conditions.

References
http://www.forbes.com/sites/toddwoody/2012/02/08/the-next-wave-inrenewable-energy-from-the-ocean/ www.oceanpowertechnologies.com/ http://www.ocean-news.com www.darvill.clara.net/altenerg/wave.htm http://ocsenergy.anl.gov/index.cfm http://www.marineinsight.com/sports-luxury/equipment/pb150-an-efficientenergy-generating-powerbuoy/ http://www.oregonwave.org/ocean-power-technologies-deployment-ofpb150-powerbuoy-off-scotland/