Marine Renewable Energy Resources: Background

This chapter concerns ocean processes that are viable sources of renewable energy in various forms, such as offshore wind, waves, tides, ocean currents, marine biomass, and energy from ocean thermal differences among different layers (Appiott et al., 2014). Most of these energy forms are maintained by the incoming heat from the sun, so they represent indirect solar energy. Tidal energy is an exception, driven by the varying gravitational forces that the moon and sun exert on both the earth and its oceans (Butikov 2002). Marine renewable energy offers the potential to meet the increasing global energy demand, while reducing long-term carbon emissions. Although some marine renewable energy resources are still in a conceptual stage, other sources have been operational with varying degrees of technical and commercial success. The following section briefly discusses various forms of marine renewable energy sources that are currently in operation or in a demonstration phase.

Offshore Wind Power: Background

Offshore wind power relates to the installation of wind turbines in large water bodies. On average, winds blow faster and more uniformly at sea than on land, and a faster and steadier wind means less wear on the turbine components and more electricity generated per turbine (Musial et al., 2006). The potential energy produced from wind is proportional to roughly the cube of the wind speed. As a result, a marginal increase in wind speed results in a significantly larger amount of energy generation. For instance, a turbine at a site with an average wind speed of 25 km/h would provide roughly 50 per cent more electricity than the same turbine at a site with average wind speeds of 22 km/h.

Offshore wind power is also the most developed form of marine renewable energy in terms of technology development, policy frameworks, and installed capacity. Turbine design and other project elements for offshore wind have benefited significantly from research on and experience with land-based wind energy projects and offshore oil and gas development (Steen and Hansen, 2014). It is already a viable source of renewable energy in many regions and is attracting global attention because of its large-scale resource potential, also often close to major electrical load centers in coastal areas. In light of these factors, offshore wind energy appears to have the greatest immediate potential for energy production, grid integration, and climate change mitigation.