16 December, 2022

Wave energy is a renewable resource unlike any other. It’s notoriously reliable, predictable, and energy-dense, serving as an important missing piece to the clean energy puzzle. For all its promise, unlocking the power of ocean waves remains a tantalizing quest for energy developers.

For decades, engineers have been trying to turn the immense potential of wave and  tidal energy into electricity. While ocean currents don’t reach the same speeds that wind can, the inherent energy potential by comparison is enormous. Seawater has more than 800 times the density of air, so for the same rotor swept area, water moving at 2.5 meters per second (m/sec)—roughly 5 knots—exerts the same amount of force as would be applied by wind blowing at nearly 100 m/sec (about 195 knots).

With 71 per cent of the earth covered in water, experts say there is a growing interest to exploit the vast potentials of this natural resource.

While the first known wave energy patent was filed by French polymath Pierre-Simon Girard in 1799, it wasn’t until the first decade of the 21st century that pilot-scale deployments demonstrated success for systems capable of providing utility-scale power.

Studies conducted by several commissions in the UK suggest that wave and tidal stream energy has the potential to meet as much as 20% of the nation’s total electricity demand, split roughly three quarters from wave and the rest from tidal. Additionally, the UK is estimated to be home to roughly 50% of Europe’s entire tidal energy resource.

Source: Nigeria Electricity Hub

Even more importantly, a number of promising companies are nearing commercialization, which could create momentum for a wave energy market capable of meeting upwards of 30% of global electricity demand in the coming years on our road to NetZero.

In the case of Nigeria, which intends to become one of the top 20 economies of the world, it would be a mirage, unless it is able to successfully resolve issues surrounding efficient power generation and supply – the driving force for industrial development.

In 2013, Engineer S.I. Ukwuaba, Head, Department of Mechanical Engineering, Petroleum Training Institute, Effurum, Delta State, stated in a paper, titled ‘Tidal Power Potentials in Nigeria: Investigative Study Of Port Harcourt Estuaries,’ Ukwuaba stated that the use of tidal power to generate electricity, in view of “the huge costal landmass of about 853 kilometers of this great nation,” maintaining that a case study of the characteristics of the coastal waves of Port Harcourt, focusing on the feasibilities of siting a Tidal Power Station along the coastline, has already been carried out.

He added that tidal power is a renewable source of electricity which was “environmental-friendly, does not run out of supply and replenishes fast.”

Ukwuaba identified three types of electrical energy that can be sourced from the ocean or high sea as Wave energy, Tidal energy and Ocean Thermal energy.

The wave energy source, according to him, makes use of the kinetic (moving) energy in the moving waves of the ocean, which can be collected into a chamber and used to power a turbine, “when the rising water forces the air out of the chamber and the moving air spins a turbine, which can turn an electricity generator”.

He described the tidal energy as the  one from the trapped down tides as they come to the shore, into reservoirs behind dams.

“When the tides drop, the water behind the dam is let out, just as in regular hydro electric power plant”, he said, citing France as one of the countries already making use of this source of energy to power over 240,000 homes.

The expert also described the Ocean Thermal energy as the one which uses the temperature differences in the ocean – warmer surface and colder inside of the water.

He maintained that Power Plants could be built to use this difference of at least 38 degrees Fahrenheit between the warmer surface water and the colder surface water, to generate electricity, as already used in both Japan and Hawaii.

He disclosed further that, from the data collected from the Institute of Oceanography and Marine Research, Lagos, and with the use of relevant equation “the possible power that could be generated is 6.9 megawatts for the 3 consecutive years of research, in which the best possible location with the highest tidal reading, was at the bight of Bonny, along the Port Harcourt Coastline.

The numerous advantages of tidal power plant as listed by Ukwuaba, included: that, once built, tidal power is free; it produces no greenhouse gases or other wastes; it needs no fuel; it produces electricity reliably; it’s not expensive to maintain, tides are totally predicable and offshore turbines and vertical-axis turbines are not ruinously expensive to build and do not have large environmental impact.

Engr. Ukwuaba, therefore, strongly opined that Tidal Power Stations could be established in Nigeria, stressing that this would “go a long way in meeting our energy needs and advancing the nation to meet up its development plans.”

The effect of the use of fossil fuel in our daily activities has adverse effects on our society. As a result, the need to make a shift to other sources of energy is crucial. The realities of climate change in the world we live in, is no longer news, thus the need to find alternative sources of energy to ensure that the earth remains habitable for mankind and all living things.

The Nigerian environment affords the exploitation of various renewable source of energy, ranging from solar energy, wind, tidal, just to mention a few. Nigeria has the opportunity to harness its energy resources in a clean and environmentally friendly way.

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