Energy of sea currents, tides and waves

The waters of the seas and oceans are an endless source of energy. This is due to the fact that they are in constant motion due to currents, tides and waves. Since these phenomena are self-repeating natural processes, we can talk about renewable energy sources. If used wisely, they can contribute to ensuring many recipients of uninterrupted energy supplies, obtained without harm to the environment. In this article, we will present how the energy of sea currents, tides and waves can be used to produce electricity.

Energy of sea currents

Sea currents are vast and nearly constant movements of water in seas and oceans, driven by factors such as wind, temperature differences, water salinity, and the Earth’s rotation. Similar to wind energy, the energy from these currents can be harnessed by converting it into kinetic energy using turbines, which can then be converted into electricity.

Despite the immense power carried by sea currents worldwide, their utilization remains minimal. This is primarily due to technical challenges in capturing this energy and, more importantly, the insufficient understanding of sea currents’ impact on ecosystems. The extent to which we can harness sea current energy without disrupting the natural balance remains unclear. However, ongoing scientific research holds promise for enabling larger-scale utilization of sea current energy in the future.

Tidal energy

Tides, characterized by the rise and fall of sea levels due to gravitational forces from the Sun and Moon along with Earth’s rotation, offer a potential energy source in the realm of approximately 200 GW. Despite this, extracting energy from tides is deemed safer than other sources.

Various methods are employed to harness tidal energy, including tidal stream generators and high tide dams. Innovative approaches under consideration include dynamic tidal energy, which utilizes long dams to create significant water level differences along the shoreline. Another method, tidal lagoon, involves storing energy from high tide levels for later use.

Although tidal energy is not widely utilized due to cost constraints and the limited availability of suitable locations with substantial sea level differences or flow speeds, advancements in turbine design technology suggest that tidal waves could emerge as economically viable and environmentally friendly energy sources.

The Rance Tidal Power Plant in northwestern France, operational since 1966, marked the inception of tidal energy utilization. With a peak power output of 250 MW and an average of 57 MW, it remained the largest facility of its kind until 2011 when the Tidal Power Plant on Lake Sihwa in South Korea, boasting a maximum power output of 254 MW, took its place.

Wave energy

Sea waves result from the interaction of wind with the water surface and their characteristics are influenced by various factors including wind speed, duration, distance over which they are generated, and the seabed’s depth and topography. The energy transmitted by waves is determined by factors such as wave speed, wavelength, and water density. Objects floating on waves undergo oscillating movements, offering opportunities to harness wave energy in diverse ways. Common methods include pneumatic, float, and overflow power plants.

A collection of devices designed to generate electricity from sea wave energy is termed a wave farm. Given the novelty of this technology, wave farms are predominantly in the project phase currently. Countries with extensive coastlines, such as Great Britain, the United States, Russia, and Italy, are actively engaged in developing wave farms. The aim is to ensure future energy security for their populations in an economically and environmentally sustainable manner.