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Wave Energy

 

Think of the motion of the waves, the ebb and flow of the tides and the coming and going of the waves.

What is the ocean? An enormous lost strength. How is stupid not to make use of the ocean!”

Victor Hugo - Novantatré, (1874), VII, 5

 

 

Benefits of wave energy

High Energy Potential

The amount of power that comes from wave energy is enormous. “The total wave energy potential is estimated to be 32,000 TWh/yr (115 EJ/yr). This is roughly twice the global electricity supply in 2008 (16,000 TWh/yr or 54 EJ/yr).” (Mørk et al.,2010)

Wave energy contains roughly 1000 times the kinetic energy of wind. Hence, it allows smaller and less conspicuous devices to produce power. Also, water being 850 times as dense as air results in much higher power produced from waves averaged over time.

 

Where Wave Energy Is Needed Most

“Worldwide there are 1.3 billion people living without electricity.” (International Energy Agency., 2014)Two-thirds of the world’s population – 4 billion people – live within 400 kilometers of a seacoast. Just over half the world’s population – around 3.2 billion people – occupy a coastal strip 200 kilometers wide (120 miles), representing only 10 percent of the earth’s land surface. With this population distribution, increasing human numbers and mounting development, the need for sea wave energy for these coastal regions becomes evidently undeniable. (EWP, 2015)

 

Green Jobs

Remote communities and declining industries, such as, the shipbuilding industry are in despair when it comes to jobs and economic sustainability. The wave energy industry has the ability to create hundreds of thousands of ‘green jobs’.

 

Helping To Decarbonize The Global Electric Power Supply

Decarbonizing the electricity grid simply means reducing the carbon emissions produced as a result of using fossil fuels and other man-made contaminants that lead to greenhouse gas emissions and global warming..

 

Growth  

There is high potential for wave energy. By adopting Wave Energy Converters (WEC) it is possible to exploit the abundant wave energy resource for electrical power generation production for an economic locally growth .

 

 

Overview of the wave energy industry

Wave energy is the transport of energy by ocean surface waves, and the capture of that energy to do useful work – for example, electricity generation, water desalination, or the pumping of water (into reservoirs). Machinery able to exploit wave power is generally known as a wave energy converter (WEC).

The first known patent to use energy from ocean waves dates back to 1799 and was filed in Paris by Girard and his son. An early application of wave power was a device constructed around 1910 by Bochaux-Praceique to light and power his house at Royan, near Bordeaux in France. It appears that this was the first oscillating water-column type of wave-energy device. 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.

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, among whom notably were Stephen Salter from the University of Edinburgh, KjellBudal and Johannes Falnes from Norwegian Institute of Technology (now merged into Norwegian University of Science and Technology), Michael E. McCormick from U.S. Naval Academy, David Evans from Bristol University, Michael French from University of Lancaster, Nick Newman and C. C. Mei from MIT.

In the 1980s, as the oil price went down, wave-energy funding was drastically reduced. Nevertheless, a few first-generation prototypes were tested at sea. More recently, following the issue of climate change, there is again a growing interest worldwide for renewable energy, including wave energy.

The market for the production of energy from renewable sources is definitely the economic sector of maximum expansion and not expected to slow down but instead will cover the market given the decreasing availability of non-renewable sources.

The production of energy from wave motion is in fact already a reality with devices still inefficient, but that in some cases closer to the cost of wind energy production.

 

Potential Resources

Given the growing demand for energy from emerging countries and the increasing cost of fossil fuels, unit to the need to limit the emission of pollutants into the environment, the future of production energy can only be given to the use of renewable energy sources.

Renewables are by their nature "discontinuous", therefore it is desirable a mix of sources renewable for the future to create a smart grid.

In addition to traditional energy sources it looms for the future the use of a source that until now it has been excluded: the exploitation of the enormous amount of energy contained in the oceans.

The waves are a form of renewable energy created by wind. The capture of wave energy has been shown to be technically feasible in different forms.

 


 

Annual average wave energy flux in kW per meter of wave front

Wave energy has significant global potential with the USA, North & South America, Western Europe, Korea, Japan, South Africa, Australia and New Zealand among some of the best wave energy sites around the world.

 

 

Compared to other forms of renewable energy, such as solar photovoltaic (PV), wind or ocean currents, energy from wave motion is continuous but highly variable, even though the levels of wave at a given location can be confidently predicted a few days in advance and the PLF (Power Load Factor) linked to this source may be very high: 80-90%.

       

 

 The waves are also effective "carriers" of solar energy. In deep water waves can travel thousands of miles and to hold on much of the energy. The wave energy is dissipated after it reaches sea bottom that are less than ~ 200 m depth. At a depth of 20 m the wave energy is reduced generally to about one third of the initial energy. It has been estimated that the total annual energy available from waves off the coast of the United States (including Alaska and Hawaii), calculated at a water depth of 60 m, is 2,100 terawatt hours (U.S. Department of the Interior). This estimate was performed at a water depth of 60 m indicate (regardless of the distance from the coast in which this occurred depth) in order to allow comparison of 'energy from wave motion between the different coastal areas, and to eliminate the possible and unpredictable loss of energy of the wave given by its interaction with the seabed of smaller depth. The wave energy is available in the U.S.: in areas of open sea in the Atlantic 2-6 kW / m, 12 to 22 kW / m in regions like Hawaii and 36-72 kW / m in the North West of the United States in coastal areas near Washington and Oregon.

 
European potential

 

Because the wind is generated by an irregular solar heating, the energy of the waves can be considered a form of concentrated solar energy. The levels of solar radiation which are of the order of 100 W/m2 are transferred into waves with (…) of wave front. The transfer of solar energy to the waves is greater in areas with strong winds (especially between 30 ° and 60 ° of latitude), near the equator thanks to the persistent winds, and near the poles due to storms polar, and also, at the increase of distances the quantity of energy stored increase.

EU Member States are increasingly interdependent for energy, as they are in many other areas –i.e. a power failure in one country has immediate effects in others. A radical change is clearly required in the way energy is produced, distributed and consumed. This means transforming Europe into a highly efficient, sustainable energy economy. Europe’s dependence on imported energy has risen from 20% at the signing of the Treaty of Rome in 1957 to its present level of 50%, and the EC forecasts that imports will reach 70% by 2030. If energy trends and policies remain as they are, the EU’s reliance on imports will continue.

Ocean energy generation has the potential to rise to 3.6 GW of installed capacity by 2020 and close to 188 GW by 2050, a significant proportion of this to come from wave energy. It is projected that wave energy could have 529 MW installed by 2020 and nearly 100 GW by 2050. This represents 1.4 TWh/ year by 2020 and over 260 TWh/year by 2050, amounting to 0.05% and 6% of the projected EU-27 electricity demand by 2020 and 2050 respectively.

Seabreath can be the industry leader with the largest market share. Because today is unique patented device does not need a wave climate particularly energy load and is suitable for almost the totality of the types of coasts with a minimum activity of wave motion with minimal cost and high efficiency. 

 

Policy Landscape

The number of policies in place to support investments in renewable energy continued to increase in 2011 and early 2012. Governments continued to revise policy design and implementation in response to advances in technologies, decreasing costs and prices, and changing priorities. Policymakers are increasingly aware of renewable energy’s wide range of benefits—including energy security, reduced import dependency, reduction of GHG emissions, prevention of biodiversity loss, improved health, job creation, rural development, and energy access—leading to closer integration in some countries of renewable energy with policies in other economic sectors.

Analysis Renewable Energy support policies

Analyzing ocean energy targets and renewable energy policies and incentives in various countries the most attractive countries for development and implementation of marine technologies are: in EUROPE: Italy, France, Spain, Portugal, Denmark, UK and Ireland; ASIA: South Korea and all isles; AMERICA: US and Canada.

Adaptability and cost-efficient and high demand of Renewable Energy Resources in developing countries: East African Coast, (South Africa, South America Colombia, Chile, Argentina and Brazil) and  Caribbean Islands (Haiti, Dominican Republic, Cuba and Jamaica).

 

Targets for Renewable Energy

Targets for renewable energy in 2011 existed in at least 118 countries, more than half of which are developing ones.

Targets for renewable energy include indicators like following: renewable energy shares in primary or final energy supply, in heat supply; installed electric capacities of specific technologies, and others. 

Figure 2 represents 27 EU countries renewable sources shares in final energy, for 2005, 2010, and objects for 2020. 13 of them has set 20% or even more ambitious targets. 

Some of the countries (world) adopted particular targets for electric capacities of Ocean energy technologies.

 

  

Country

Capacity target

South Korea

6,159 GWh by 2030

UK

2 GW by 2020

France

800 MW by 2020

Ireland

500 MW by 2020

Denmark

500 MW by 2020

Portugal

300 MW by 2020

Spain

100 MW by 2020

Philippines

70.5 MW by 2030

 Renewable energy targets – Ocean energy

 

 

EU Renewable shares of final energy, 2005, 2010, and targets for 2020

 

 

Current and future targets for ocean energy in European countries (EU-OEA, 2010)

  

With the adoption of the most recent Renewable Energy Directive (2009/28/EC), the EU has committed to reducing its greenhouse gas emissions by 20% by 2020. A reliable mix of electrical power generation will have to be established to meet these objectives. Wave energy is a renewable source of energy and as such it does not emit carbon dioxide or other particles.

As a result, wave energy is suitable for replacing energy generation from fossil fuels. It has been estimated that 300 kg of CO2 could be avoided for each MWh generated by ocean energy. Therefore, for 20 GW (49 TWh/year) of installed wave energy, the CO2 emissions avoided could be as much as 14.5 Mt/year.

 

Power generation 

At least 109 countries had some type of renewable support policy to promote renewable power generation. More than half of these countries are emerging economies. All these policies can be divided into three categories: Regulatory policies, Fiscal incentives, and Public financing. The most common policies/incentives are the following:

  • Feed-in-tariffs (FIT): is a policy mechanism designed to accelerate investment in RE technologies. It achieves this by offering long-term (15-25 years) contracts to renewable energy producers based on the cost of generation of each technology. There are many variations in FIT design. Levels of support provided under FITs vary widely and are affected by technology cost, resource availability, and installation size and type:
 

FIT payments in selected countries, 2011-2012

  

  • standard (RPS): a mechanism that places an obligation on electricity supply companies to produce a specified fraction of their electricity from renewable energy sources.

  • Capital subsidy, grant and rebate 

  • Investment and production tax credits

  • Reductions in sales taxes, energy taxes, CO2 taxes, VAT and other taxes 

  • Energy production payment 

  • Public investment, loans and grants 

  • Public competitive bidding

  

 

Number of incentives

2-3

4-5

6-8

Australia

Belgium

Canada

Cyprus

Estonia

Denmark

Ireland

Finland

France

Japan

Germany

Italy

Malta

Greece

Netherlands

Norway

Israel

Portugal

 

Malaysia

United Kingdom

 

South Korea

United States

 

Spain

 

 

Sweden

 

 

United Arab Emirates

 

 Renewable Energy support policies
 

 


 

Feed-in-tariffs (FIT)

Electric utility quota obligation/ renewable portfolio standard (RPS)

Capital subsidy, grant and rebate

Investment and production tax credits

Reductions in taxes

Energy production payment

Public investment, loans and grants

Public competitive bidding

Australia

 

 

 

 

 

 

 

 

Belgium

 

 

 

 

 

 

 

 

Canada

 

 

 

 

 

 

 

 

Cyprus

 

 

 

 

 

 

 

 

Denmark

 

 

 

 

 

 

 

 

Estonia

 

 

 

 

 

 

 

 

Finland

 

 

 

 

 

 

 

 

France

 

 

 

 

 

 

 

 

Germany

 

 

 

 

 

 

 

 

Greece

 

 

 

 

 

 

 

 

Ireland

 

 

 

 

 

 

 

 

Israel

 

 

 

 

 

 

 

 

Italy

 

 

 

 

 

 

 

 

Japan

 

 

 

 

 

 

 

 

Malaysia

 

 

 

 

 

 

 

 

Malta

 

 

 

 

 

 

 

 

Netherlands

 

 

 

 

 

 

 

 

Norway

 

 

 

 

 

 

 

 

Portugal

 

 

 

 

 

 

 

 

South Korea

 

 

 

 

 

 

 

 

Spain

 

 

 

 

 

 

 

 

Sweden

 

 

 

 

 

 

 

 

United Arab Emirates

 

 

 

 

 

 

 

 

United Kingdom

 

 

 

 

 

 

 

 

United States

 

 

 

 

 

 

 

 

 

 

 Analysis Renewable Energy support policies


Analyzing ocean energy targets and renewable energy policies and incentives in various countries the most attractive countries for development and implementation of marine technologies are: in EUROPE: Italy, France, Spain, Portugal, Denmark, UK and Ireland; ASIA: South Korea and all isles; AMERICA: US and Canada.

Adaptability and cost-efficient and high demand of Renewable Energy Resources in developing countries: East African Coast, (South AfricaSouth America Colombia, Chile, Argentina and Brazil) and  Caribbean Islands (Haiti, Dominican Republic, Cuba and Jamaica).

 

The technologies already used

Currently, only few plants use the energy of the sea in commercial installations, are much more numerous experimental facilities and prototypes, which are showing in many cases full economic feasibility and leave great hope for the future of these technologies.

Recently begin to emerge environmental impact problems given by both wind and photovoltaic plants. Notwithstanding that small plants spread of these sources do not subtract land and have little impact or almost zero, the problem arises for large industrial plants, as well as landscape problems begin to arise also problems of disposal of old systems, especially solar. These two areas are in decline.

Take in consideration the possibility of producing energy from cold fusion even if they are from a few decades that follow each other announcements and denials and is yet to be verified the possibility of having production levels that are economically convenient. The other sources of energy from the oceans according with the U.S Department of Energy are:

  • Ocean currents. global resource potential estimated at below 1,000 TWh/yr.

  • Salinity gradient with global potential resources estimated around 2,000 TWh/yr.

  • Thermal conversion with global potential resources estimated at around 10,000 TWh/yr.

  • Tidal with global potential resources estimated at around 250 TWh/yr

 

These systems above have limits given by: small number of sites available for installations, greater environmental impact both landscape and wildlife, and lower efficiency.

The industrial production of energy from wave, with estimated global potential energy up to 80,000 TWh/y exploitable, does not present too many problems landscaped and does not require the use of toxic or polluting substances. A variety of technologies are being studied for capturing energy from waves. The various technologies are given by: terminators, attenuators, absorbers, and overtopping devices.

 

Terminators

Devices such as "Terminator" are usually installed on the ground or near-shore, floating versions have been designed for off-shore applications. The oscillating water column (OWC) is a form of termination in which the water enters, from an opening located below the surface, into a chamber in which air is contained. Wave action causes a movement of the level as a piston and pushes the air towards a turbine. A prototype full-scale 500-kW was designed and built by Energetech (2006) is being tested in the sea at Port Kembla in Australia, another project is under development in Rhode Island.

A project, which under construction has moved much closer to Seabreath, is the IVEC PTY LTD Australian, but has less efficiency because it does not provide by external valves of compensation.

Floating offshore project that uses the OWC is also the "Mighty Whale", under development at the Marine Science and Technology Center in Japan since 1987.

 

Attenuators

Attenuators are long multi-segment floating structures. The different heights of level along the length of the device causes a bending in the connecting segments which are connected to hydraulic pumps or other converters. Among the attenuators with more advanced development is worth mentioning the McCabe and Pelamis by Ocean Power Delivery, Ltd. (2006). The pump wave McCabe has three pontoons linearly hinged together. The pontoon in the middle is connected to a submerged damper plate which causes a resistance than caissons placed on the bow and stern. Hydraulic pumps are applied between the center and frames and are activated by the movement of the same. The hydraulic fluid under pressure can be used to activate a generator or to pressurize the water for desalination. A prototype full-size of 40 m has been tested off the coast of Ireland in 1996, and the device is already in the process of commercialization.

A similar concept is used by the Pelamis (designed by Ocean Power Delivery Ltd. [2006]). The Pelamis has four cylindrical floating caissons are 30 m long and 3.5 m in diameter connected by three hinged joints. The decline of the hinge joints, caused by the movement of the waves, active hydraulic pumps located in the joints. A full-scale prototype in four segments of 750 kW has been tested sea for 1,000 hours in 2004. For this test was followed by a first order in 2005 and a commercial WEC by a consortium led by Portuguese electricity Enersis SA. Currently the project Pelamis is stopped due to problems of structural failure.

 

Absorbers

A device of this kind is the PowerBuoyTM developed by Ocean Power Technologies. The construction includes a floating structure with a relatively immobile component, and a second component in motion caused by the waves (a buoy floating within a fixed cylinder). The relative motion is used to drive energy converters electromechanical or hydraulic. A demonstrator prototype PowerBuoy of 40 kW was installed in 2005 for a sea trial opened in Atlantic City, New Jersey. In the Pacific Ocean have been made other tests in 2004 and 2005 off the coast of Oahu Hawaii basis.

The WEC AquaBuOYTM under development by the Group AquaEnergy, Ltd. (2005) is an absorber which exploits the vertical movement of the buoy as a piston contained in a long tube under the buoy. The movement of the piston puts pressure sea water. The AquaBuOY was tested on a scale prototypes, and a demonstration plant offshore of 1 MW has been realized in Makah Bay, Washington. The Makah Bay demonstration consists of four units rated at 250 kW located 5.9 km (3.2 nautical miles) offshore in water about 46 m deep. Other absorbers tested are the Archimedes Wave Swing (2006), which consists of a cylinder full of air which moves up and down to move the wave. This movement with respect to a second cylinder fixed to the seabed is used to drive an electric generator linear. A device with a capacity of 2 MW has been tested at sea in Portugal.

 

Overflow devices

The devices have overflow tanks which are filled by 'shock waves to levels above the surrounding media. The released water tank is used to drive turbines or other conversion devices.

The overflow devices have been designed and tested both for onshore and offshore floating. The devices include the offshore DragonTM Wave (Wave Dragon 2005), which provides that wave reflectors focus waves towards the center of the structure and therefore increase the effective height of the wave.

The device overflow WavePlaneTM (WavePlane Production 2006) has a smaller tank. The waves are channeled directly into a room that conveys the water to a turbine or a conversion device.

 

Other minor tens of devices are currently under study and experimentation. However Seabreath is the best concept known for the production of energy from wave motion.

 

OCEAN ENERGY SOURCES

DESCRIPTION

TECHNOLOGY TYPES

Ocean wave

Energy sourced from movements of water near the surface of the earth in an oscillatory or circular process

Attenuator, Collector, Overtopping,

Oscillating Water Columns,

Oscillating Wave Surge Converter

(OWSC), Point Absorber,

Submerged Pressure Differential,

Terminator, Rotor.

Tidal current

Energy sourced by natural currents created by the movement of the tides.

Horizontal/Vertical-axis turbine,

Oscillating Hydrofoil, Venturi.

Salinity Gradient

The application of salinity gradients to store solar energy or to exploit the entropy of mixing fresh and salt water.

Semi-permeable Osmotic

Membrane.

Ocean Thermal Energy Conversion

OTEC draws energy from the thermal gradients that exist between the warm surface water and the cold deep water of the ocean.

Thermo-dynamic Ranking Cycle

 Types of ocean energy sources and technologies

 

 

Technologies Innovation

Unlike large wind turbines, there is a wide variety of wave energy technologies, resulting from the different ways in which energy can be absorbed from the waves, and also depending on the water depth and on the location (shoreline, near-shore, offshore). Recent reviews identified about one hundred projects at various stages of development.

 

The number does not seem to be decreasing: new concepts and technologies replace or outnumber those that are being abandoned. Several methods have been proposed to classify wave energy systems, according to location, to working principle and to size (“point absorbers” versus “large” systems). See Top Ocean technologies in Figure 11, according with the level of development.

  

Some links of ocean top technologies:

Fixed: Isolated: Pico, In breakwater: SakataTapchan

Floating: Mightywhale,Oceanenergy,Sperboy,OceanlinxAquabuoyIPS Buoy,FO3,Wavebob,PowerBuoyPelamis ,PS frogSearevWaveroller,oysterAWSWavedragon

Oscillating water column:  IEA Technology

 

 

Environmental impact

The conversion of energy from wave motion to usable forms of electricity or other sources of energy is generally thought to be of low environmental impact. However, as with any emerging technology, the nature and extent of environmental concerns remains uncertain. The impact that occurs is still to be verified for specific sites where the installations are made.

However it is not far-fetched to think that such structures as well as having a low environmental impact, it is also useful for restocking of game in the area.

There have already been studies of the impact on coastal physiography, the oceanographic conditions, marine and biological resources, and the land use compatibility of land and marine resources, cultural resources, infrastructure, recreation, public safety, visual impact, and none of these resources were found to be significantly influenced by plant type as WEC.

  

 

Environmental factors require monitoring:

 

The visual impact and the noise

For the type of device are specific in relation to the height of the freeboard and the generation of noise above and below the water surface.

The OWC devices typically have the highest free edge and are the most visible. For navigation on the high seas is required hazard warnings such as lights, sound signals, radar reflectors.

In the OWC devices, the air is sucked and ejected and likely sources of noise above the water. This does should not happen in Seabreath or should be attenuated for the fact that it is always the same air used in the air duct, only in particular conditions there is an exchange with the outside via the compensation valves.

The underwater noise you should have from devices with turbines, pumps, and other moving parts immersed in water, case that not applied to the Seabreath.

The type of frequency of the entire system is important in assessing the impact of noise.

 

Impact near-shore

The reduction of the wave given by the converters of energy from wave motion might be a factor to take into account, however, the impact on the characteristics of the waves are to be observed at 1-2 km away from the WEC device in the direction of wave's move. There should not be a significant impact on the coast in terms of reducing the wave if the devices are placed at more than this distance from the shore.

Little information is available on the impact given to biological communities to reduce the height of the waves. The marine habitat may be affected both positively and negatively.

The surfaces of the WEC devices could provide substrates for various biological systems and may be a positive complement to the natural habitat.

A potential conflict with other users of marine space, as commercial shipping, fishing and boating, can occur when there is a careful selection of the sites of installation.

The impact may be potentially be positive for sport fishing and commercial.

 

Toxic releases

May be linked to accidental leaks or spills of liquids used in systems working with hydraulic fluids.

Possible impacts can be minimized through the choice of non-toxic liquid and with careful monitoring, with appropriate intervention plans for a plan to contain the leakage. The use of biocides to control the growth of marine organisms can also be a source of toxic emissions.

However Seabreath does not provide for the use of liquids and, except for certain sensitive parts, any bio proliferations do not compromise the functioning.

 

Installation and decommissioning

For the Installation the only possible interference to the bottom of the ocean is given by the presence of energy cables to the transport of the energy to the coast that may have negative impacts on marine habitats.

For the decommissioning, the potential impacts of decommissioning are mainly related to the disturbance in the marine habitat that has adapted to the presence of the structure.

The installation procedure should be designed to minimize impacts on the lives of benthic communities and areas rich in biological diversity.

The growth of benthic organisms, such as corals and sponges, we supposed that the support provided by the device from the system components can be beneficial to the ecosystem.

Even the visual pollution and noise is of low intensity.

     

 

in-depth pdf

 

  State of art analysis - Waveplam.pdf

  Wave energy overview.pdf

  Best practice - Waveplam.pdf

  Development and Evaluation Protocol.pdf

  Ocean wave energy - Analyzing hi-tech opportunities.pdf

  Ocean Energy Technologies.pdf

  Ocean Wave Energy Conversion JVining.pdf

  Renewable Energy Potential of Small Island States.pdf

  Review and analysis of ocean energy system.pdf

  Potential wave energy Australia.pdf

Prospettive di sviluppo dell'energia dal mare in Italia - ENEA 

 Finanziamenti Italia.pdf

 

 

Wave energy links

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