A South African has developed and patented a new technology for wave-power generation. Doug Da Costa, a mechanical engineering draughts-person, has come up with a near-shore wave power generator that collects wave energy and converts into electricity.
The device consists of two pontoons lying parallel to each other; about 3.5 meters in diameter, in between the pontoons are the pivoted floating torque tubes with shafts operating actuator arms. These operate hydraulic cylinders pumping oil into a hydraulic system, which operates hydraulic motors driving electric generators.
The device is moored in water depths of 20 to 30 meters and is connected to the shore by an electrical cable, which makes the efficiency of wave power collected the crucial factor in determining cost effectiveness.
Da Costa’s patent technology is different than others as they collect energy from a single point, which according to Da Costa is less efficient, where as his technology collects energy throughout the wave. The unique characteristic of Da Costa’s device is that all the equipment including the hydraulic systems and electrical generators/switchgear, are housed inside the sealed pontoons, protecting them from harsh sea conditions.
A 1:50 scale model has been tested at the Council for Scientific and Industrial Research’s (CSIR) marine engineering research center at Stellenbosch University, proving that his design works. A full-scale prototype, once up and running, is expected produce between 1 MW and 1.5 MW of power, depending on its location Da Costa said. The locations need to be granted by the government.
According to Da Costa the CSIR test was too small to achieve meaningful results. "We were able to take some measurements of linear deflections of the torque tubes against each wave size, but the scale was too small to conduct meaningful tests.
”We are very grateful to the CSIR for using its research funding to conduct the tests and are delighted that it has now installed a bigger wave generator facility tank that will enable us to test a 1:10 scale model. We have applied to the Industrial Development Corp. and the Innovation Fund for further development funding,” Da Costa said. He expects to receive a decision on funding from both by the end of April.
"If we can test the 1:10 scale and it is successful, we will be able to bring on board a commercial partner to inject funds into the project."
Da Costa predicts that if only 10% of South Africa’s 2,800 km coastline was used to generate wave power, it could generate approximately 8,400 MW, the equivalent of three coal power stations without the pollution. Eskom’s current nominal capacity is 4,200 MW.
He estimates that it will take about five years to put all of the required infrastructure in place, but says individual modules could be rolled out much sooner.