OWCs

Oscillating Water Columns (OWCs) are a type of wave energy converter that harvests energy from ocean waves by trapping air above a partially submerged water column. As waves enter and leave the chamber, the water column oscillates, forcing air to flow through a turbine connected to a generator. The turbine used is often a Wells turbine, which can operate with bidirectional air flow, allowing electricity generation without a directional turbine.

OWCs are typically built as fixed coastal structures or near-shore installations. They consist of a sealed, submerged chamber with an opening below the mean water line. The incoming waves raise and lower the water inside the chamber, which compresses and releases the air above it. The passing air drives a turbine, usually connected to a generator, and the electricity is sent to shore by a subsea cable. Power take-off can be designed to accommodate different scales.

Advantages include a relatively simple mechanical layout, and potential for robust operation and integration with existing coastal infrastructure. Disadvantages involve high capital costs, challenges with survivability in severe seas, environmental concerns, and limited installed capacity compared with other renewables. Efficiency depends on wave climate and chamber design, and many OWCs are demonstrated at pilot or pre-commercial scales.

In deployment, notable examples include Limpet, a land-installed OWC on Islay, Scotland, among other demonstration projects across Europe, Australia, and North America. OWC research continues to address cost, reliability, and grid integration.