The growing interest in the development of renewable energy technology is a result of growing concern over the threat posed by global climate change. The ocean offers a substantial amount of potential energy resources, and investment in ocean energy is projected to increase as renewable energy technology advances.
Research in the fields of ocean thermal energy conversion, wave, tidal, and offshore wind energy has produced promising technologies that have even seen commercial application in certain situations. These resources have the potential to lessen the harm posed by climate change, but the ocean ecosystem has to be safeguarded while these technologies are being developed. Ocean-based renewable energy sources may be used without endangering the marine ecosystem if projects are sited, scaled, and executed according to environmental regulations.
Given its size and strength, the ocean could likely store an ample amount of energy in the form of heat, currents, waves, and tides to supply all of the world’s energy needs. However, the obstacles to developing ocean energy technology have been formidable, and ocean energy still only makes up a very small fraction of global energy production. Now, however, there is a greater interest in renewable energy due to growing concern about global climate change and other environmental effects of the world’s reliance on fossil fuels.
More focus is anticipated to be placed on the enormous energy reserves in the water as the world’s commitment to renewable energy grows in the future. One of the most crucial and divisive discussions now a days is the usage of energy resources. The greatest strategy to reduce energy usage could be to make investments in energy efficiency and practice more conservation. However, it is unclear whether demand-side control will be enough to achieve carbon emission reduction targets. Today, there are up to 2 billion people without power in the globe and if population growth in emerging nations keeps accelerating, there will almost probably be an increase in demand for power. At the same time, even with improvements in efficiency, growing standards of living and dependence on technology in industrialized nations may lead energy consumption to rise more quickly than population.
The majority of research into renewable energy has gone toward the development of solar, wind, biomass, and geothermal sources. While each of these sources has great promise, a comprehensive approach to renewable energy will result in the greatest and most reliable energy strategy.
We predict that in light of this, governments, businesses, engineers, and scientists will increasingly focus on the enormous amounts of energy that the oceans hold. Ocean energy production always involves certain difficulties, but thanks in part to the offshore oil sector, most of the equipment and expertise required to produce energy from the ocean already exists.
According to research, the technological barriers to conquering ocean energy should not be too great. For a small number of locations, some uses of a wave, offshore wind, and maybe tidal energy may already be economically viable and continued work in this domain results in a decline in costs of ocean energy to competitive levels.
There are various forms of Renewable energy resources from the ocean including:
Ocean thermal energy conversion (OTEC): By harnessing the heat stored in warm surface water to create steam that drives a turbine and bringing cold, deep water to the surface to recondense the steam, OTEC harnesses the ocean’s inherent thermal gradient to generate power. The overall amount of electricity that might be produced by OTEC is thought to be around 10 TW (10 trillion W or 10 billion kW), which is roughly equivalent to the present level of world energy consumption but given that the cost of producing electricity from OTEC now ranges between 8 and 24 cents/kW h, which is much more expensive than the cost of fossil fuels, it is doubtful that this resource will be completely utilized unless it is subsidized.
Wave energy: One of the most promising renewable energy sources has long been wave energy. The energy source is not only abundant but also more reliable than other renewable energy sources, With the availability of wave power at a specific site reaching up to 90% whereas that of solar and wind is often just 20–30%. The strongest winds are found in temperate latitudes between 40 and 60 degrees north and south, on the eastern margins of oceans, where the potential for wave energy is highest. According to the World Energy Council, wave energy has the potential to produce up to 2 TW of power globally.
Although wave energy production is still not economically viable compared to fossil fuels, the situation is becoming better as more sophisticated technology is developed. Costs have decreased significantly over the past few years, and businesses are now aiming for prices of less than 10 cents/kW-h or perhaps 5 cents/kW-h for the newest designs. With this pricing, wave plants might effectively compete with conventional power plants.
Tidal Energy: When compared to solar, wind, and wave energy, tidal power has the distinct benefit of being quite predictable. Tidal energy development is appealing due to the regularity of the tides and enormous energy potential. The initial tidal barrages resemble dams constructed across estuary mouths to capture the energy of the tidal flow. When compared to a hydroelectric dam, a tidal barrage normally only absorbs the energy of the water flowing out of the estuary from high to low tide, enabling water to flow in both ways where, technology for tidal barrages is quite advanced and has enormous promise in particular locations. Western Europe as a whole could produce up to 105.4 TW h/yr with tidal power plants, whereas the United Kingdom could produce up to 50.2 TW h/yr. Around 500–1000 TW h/yr of potential energy are thought to be available globally, however, owing to financial limitations, only a small portion of this energy is expected to be used.
Offshore Wind: Recently, wind energy has drawn a lot of attention as one of the most promising and practical sustainable energy solutions. One of the cleanest forms of energy now accessible, wind power can, depending on location, be economically competitive with fossil fuels. While the majority of wind energy is concentrated in land-based locations, interest in offshore wind energy is rising. Over the oceans, there are often very powerful winds, they reach faster speeds and are less turbulent than winds over land, and no geographical features obstruct the wind’s access. Since the architecture of offshore wind power is quite similar to that of onshore windmills, a lot of the technology is already quite advanced. In contrast to wind farms on land, offshore wind carries the power to fields, high-voltage cable has to be installed from windmills to the beach. The main technological challenge in developing offshore wind sources is building foundations stable enough to endure in the harsh ocean environment and withstand storms, as well as economically transporting these foundations and anchoring them offshore. This challenge is in addition to getting energy to shore.
In general, if we talk about Pakistan then there exists a huge opportunity to utilize Pakistan’s offshore and coastal areas’ waves and tides to generate renewable energy. The 170 km of the Indus Delta is home to the intricate stream network that makes up the Sindh coast. These streams have high-velocity tides that flow in and out at 0.2–0.5 m/s. The Indus Deltaic stream system has been the subject of early feasibility studies for energy extraction by NIO Pakistan. The 17 major streams have the ability to generate 1100 MW of electricity, according to estimates. Due to tidal fluctuations, seawater ingresses inland at some locations up to 80 km, which is advantageous for coastal Sindh’s ability to absorb energy from tidal currents. The oceans encompass 71% of the surface of our planet. Massive solar energy from the sun is captured by the seas. The potential energy that is absorbed in the form of incoming radiation from the sun that produces thermal energy is stored in the seas. A working fluid can exploit a 10 °C temperature differential between the surface and bottom waters. Ocean thermal energy conversion (OTEC) is a process that turns the temperature differential that the seas absorb into electricity. Tidal and wave energy from the ocean provides advantages over energy generated using various fossil fuels, and using sustainable ocean energy sources has a number of advantages as well so, it’s high time to materialize the opportunity of generating energy from our ocean power bank.
The author is MD IRP/Faculty Department of H&SS, Bahria University Karachi