What are Wave Energy Converters?
Wave energy converters (WECs) are devices that harness the energy generated from ocean surface waves and convert it into more usable forms of electricity. There are several different types of WEC designs currently being researched and tested, but they all operate on similar principles. As waves pass through WEC devices installed offshore, the mechanical motion created by the waves is captured and transformed into electric current through various mechanisms like pressurized fluid pumps, oscillating water columns, or rotating component systems. This renewable electricity can then be transmitted via undersea cables to nearby coastal areas and integrated into local power grids.
Oscillating Water Column Devices
One of the most developed Wave Energy Converter technologies is the oscillating water column (OWC) device. In an OWC system, waves enter a partially submerged chamber through a concrete or metal structure. As the waves rise and fall, they force air to be alternately compressed and expanded inside the chamber. This periodic air movement is channeled through turbine blades inside the chamber, which spin an electrical generator to produce power. Early prototype OWC devices were able to achieve conversion efficiencies of over 80%, demonstrating the viability of this wave energy harvesting approach. Portugal’s Pelamis Wave Power developed one of the first multi-megawatt OWC power plants and deployed successful ocean trials.
Overtopping Devices
Another common WEC design currently seeing deployment is the overtopping device. These systems have large reservoirs above sea level that wave energy can “overtop” into as waves surge upwards on the shoreward side. The reservoir collects this dammed wave water, which is then released back to the sea through low-head hydropower turbines. This releases the kinetic energy of the falling water through the turbines to rotate generator motors and produce electricity. One of the advantages of overtopping WECs is their ability to effectively collect and store energy from waves even during low wave conditions. They also have a small footprint offshore compared to other wave energy systems. The largest overtopping WEC device to date was developed by Danish company Wave Dragon and tested off the coast of Portugal.
Point Absorber Arrays
Point absorber WEC technology utilizes small buoy-like devices anchored to the seafloor that capture wave energy independently as waves pass beneath and around them. As waves cause the floating portion of a point absorber to rise and fall relative to its submerged section, mechanical linkages convert this relative motion through hydraulic pumps or magnetic linear generators to produce electricity. Arrays of these lightweight point absorbers can effectively harness energy from multiple wave crests and troughs at once. Companies like Mocean Energy, Ocean Power Technologies, and Seabased have developed innovative point absorber array systems and undergone sea trials to optimize wave energy capture potential through density, spacing, and structural design of the arrays.
Power Take Off Systems
No matter the specific WEC design, all wave energy conversion technologies require an effective power take-off (PTO) system to transform the captured wave motions into rotary or linear motions suitable for driving electric generators. These PTO components, such as hydraulic cylinders, turbine motors, and magnetic linear generator coils, are a critical interface between the wave-induced mechanical energy and power generation units. Innovations in low-losses PTO technologies like hydraulic control systems, direct drive linear generators, and magnetic power take-off solutions are actively being researched to maximize conversion efficiencies and reliability for offshore wave energy applications. Advancements in power electronics and control strategies for grid-interfacing the variable output from WEC arrays is also an active area of technology development.
Lifecycle Performance and Environmental Impacts
Fully assessing the viability and competitiveness of wave energy converters requires evaluating their projected performance, costs, and environmental footprint over their entire operational lifespans. Factors like device reliability in harsh offshore conditions, maintenance requirements, component replacement intervals, energy payback period, and decommissioning impacts all influence the potential for wave energy to compete economically with traditional power sources on both small and large scales. Several recent Lifecycle Assessments (LCAs) of different WEC designs have estimated their embodied and operational emissions to be considerably lower than fossil fuel power generation. And their carbon payback times through displacement of more polluting energy sources could be as little as a year for some large-scale WEC projects according to some projections. Continued improvements in structural materials, device uptime records, and supply chain optimization will be key to verifying wave energy’s environmental advantages and reducing costs to competitive levels.
Global Progress in Wave Energy Development
While still an emerging technology, significant progress has been made internationally in developing and validating commercial-scale wave energy systems. The Portuguese shoreline has been a hotbed of WEC testing and demonstration projects due to its ideal wave climates and supportive national research initiatives. Notably, the Pelamis seagoing snake-like wave device reached multimegawatt deployment and grid connections in both Portugal and Scotland. Australia has also fostered multiple commercial-scale wave farm projects like the CETO 6 wave energy array developed by Carnegie Wave Energy. And in the United States, developers like CalWave Power Technologies and Columbia Power Technologies have undergone utility-scale wave testing on the shores of Oregon and California. Major global research centers focused on advancing WEC technology include the US Department of Energy’s Pacific Northwest National Laboratory and international initiatives like the IEA Ocean Energy Systems implementing collaborative R&D between nations. While still facing cost and reliability challenges to compete at scale, wave energy’s potential as a sustainable source seems closer to full realization through continuing worldwide progress.
Challenges and the Roadmap Ahead
Despite promising advances, wave converters must still overcome technical and economic hurdles to achieve widespread commercial deployment. Key challenges include optimizing power capture over variable ocean conditions, improving device reliability and survivability against storms and corrosion, reducing manufacturing and maintenance costs, and gaining confident predictability in long-term energy output. Standardized performance measurement and certification protocols must also advance to give utilities and investors assurance in WEC technology and operations.
governments worldwide continue supporting research addressing theseissues through grants, tax incentives, and offshore test site operation that are aimed at driving down WEC costs to competitive ‘grid parity’ levels. With continued progress, it’s projected wave energy could potentially supply up to 10% of global power needs by 2050 according to some forecasts. If technology and project development overcome present barriers, wave energy conversion looks poised in coming decades to emerge as a formidable new marine renewable resource powering sustainable growth worldwide.
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1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it.