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 twicethe 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)
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..
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.
Given the growing demand for energy from emerging countries and the increasing cost of fossil fuels, unit to the need to limit emissions of CO2 and 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.
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.
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.
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.
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).
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:
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.
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 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. ). 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.
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.
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.
Types of ocean energy sources and technologies