Harnessing Renewable Energy: Ocean, Solar, and Wind Power

Posted on Apr 2, 2025 in Geology

What is Ocean Energy?

Ocean energy is a term used to describe all forms of renewable energy derived from the sea.

There are two broad types of ocean energy: mechanical energy from the tides and waves, and thermal energy from the sun’s heat.

Ocean energy is classified as:

  • Wave energy: Generated by converting the energy of ocean waves (swells) into other forms of energy (currently only electricity). There are many different technologies that are being developed and trialled to convert the energy in waves into electricity.
  • Tidal energy: Generated from tidal movements. Tides contain both potential energy, related to the vertical fluctuations in sea level, and kinetic energy, related to the horizontal motion of the water. It can be harnessed using technologies using energy from the rise and fall of the tides or by technologies using energy from tidal or marine currents.
  • Ocean thermal energy: Generated by converting the temperature difference between surface water and water at depth into useful energy. Ocean thermal energy conversion (OTEC) plants may have a range of applications, including electricity generation. They may be land-based, floating or grazing.

What is Solar Energy?

Solar energy is energy which is created from sunlight, or heat from the sun.

Solar power is captured when energy from the sun is converted into electricity or used to heat air, water, or other fluids.

There are currently two main types of solar energy technologies:

  • Solar thermal: These systems convert sunlight into thermal energy (heat). Most solar thermal systems use solar energy for space heating or to heat water (such as in a solar hot water system). However this heat energy can be used to drive a refrigeration cycle to provide for solar based cooling. The heat can also be used to make steam, which can then be used to generate electricity using steam turbines. It is considered more efficient to build solar thermal electricity generators at large scale, typically in the tens to hundreds of megawatts.
  • Solar photovoltaic (PV): The conversion of sunlight directly into electricity using photovoltaic cells. PV systems can be installed on rooftops, integrated into building designs and vehicles, or scaled up to megawatt scale power plants. Research and development and deployment in on-grid and off-grid applications is progressing rapidly, and a range of other solar energy technology innovations are currently being explored, for example photosynthetic based solar energy technologies and solar enhanced fuels.

What is Wind Energy?

Wind energy is generated by converting wind currents into other forms of energy using wind turbines.

Winds are generated by complex mechanisms involving the rotation of the Earth, the heat capacity of the sun, the cooling effect of the oceans and polar ice caps, temperature gradients between land and sea, and the physical effects of mountains and other obstacles.

Wind turbines convert the force of the wind into a torque (rotational force), which is then used to propel an electric generator to create electricity. Wind energy power stations (known as wind farms) commonly aggregate the output of multiple wind turbines through a central connection point to the electricity grid. Across the world there are both on-shore (on land) and off-shore (out to sea) wind energy projects.