by The ocean contains a vast amount of untapped energy in the form of ocean waves. As waves travel across the surface of the sea, they carry enormous amounts of kinetic energy. Wave converters are devices that use this ubiquitous energy source to generate electricity from ocean swells and waves. By capturing the renewable power of waves, these innovative technologies offer a clean and sustainable alternative to fossil fuels.
Types of Wave Energy Converters
There are several main types of wave converters currently under development to turn ocean wave motion into electricity.
Oscillating Water Column Devices
One common design is the oscillating water column (OWC) device. An Wave Energy Converter consists of a partially submerged, hollow structure with an opening below the waterline. As waves enter the chamber, they cause air inside to be compressed. The air is ducted to a turbine, similar to a wind turbine, which spins a generator to produce power. Some OWC devices have a two-way flow, with air being sucked back into the chamber during the outflow part of the wave cycle.
Overtopping Devices
Overtopping devices, such as the Wave Dragon, are positioned parallel to incoming ocean waves. As waves pass by the device, they are funneled up a raised ramp. The collected water is then channeled inland to a hydroelectric turbine to generate power before being discharged back to sea. These systems operate similar to a small dam, capturing wave energy through water elevation differences.
Point Absorber Devices
Point absorber wave converters are small and floated off the coast, absorbing power from multiple directions. They work by utilizing the relative motion between a floating buoy and a fixed structure below, connected by a shaft to drive an electricity-generating turbine. Changes in water depth and pressure created by passing waves cause the floating portion to move up and down, powering the generator. These flexible devices can operate in deeper waters farther from shore than other designs.
Advantages and Challenges of Wave Energy Converters
Wave Energy Converter holds significant potential as a durable renewable resource with many advantages over other green electricity sources. However, the technology also faces important technological and economic obstacles that must be overcome to make it commercially viable on a large scale. Here are some key pros and cons:
Advantages:
– High energy density – Wave energy density near coastlines averages around 30 kW/m, providing a consistent, baseload supply of power.
– Predictability – Wave patterns can be reliably forecast days in advance using weather and ocean models, allowing for improved grid integration.
– Modularity – Wave farms can be scaled up incrementally as demand grows by adding more individual wave energy devices.
– Minimal land use – Devices are anchored or floating offshore, avoiding conflicts over land use.
Challenges:
– High capital costs – Initial investments in wave farms are costly due to the specialized offshore equipment and engineering required.
– Surveillance needs – Remote monitoring and maintenance of ocean equipment increases operational expenses.
– Exposure to harsh marine environment – Devices must withstand storms, corrosion from saltwater, and interactions with marine life.
– Intermittency – Power output fluctuates with wave conditions and individual device performance, requiring on-grid energy storage or system overcapacity.
– Installation difficulties – Offshore construction and array installation presents logistical difficulties of working in ocean waters.
While wave energy converters currently have higher levelized costs than many other renewable technologies, research and development are steadily bringing costs down as the field advances. After decades of work at smaller pilot scales, large-scale wave farms with multiple megawatts of capacity are now being deployed worldwide.
The world’s largest wave energy array, consisting of four Pelamis P2 machines totaling 2.5 MW, was installed off the coast of Portugal. Meanwhile, the Mutriku OWC plant in Spain’s Basque country has been reliably generating power using wave energy since 2011. As technology matures and costs decline further, wave power is expected to become an important contributor to the global renewable energy mix in the coming decades. With vast untapped wave resources worldwide, the future looks bright for continuing progress in wave energy conversion.
*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it.
