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Finding Cheap Solutions On Wave Energy Estimation

Finding Cheap Solutions On Wave Energy Estimation

Looking at finding ways to make wave energy economically more feasible was the aim of the guest lecture which was given by Professor Jonathan Blackledge on Wave Energy Estimation at the DUT on Monday this week

Prof Blackleadge is the Deputy Vice-Chancellor: Research at the University of KwaZulu-Natal (UKZN). His guest lecture was delivered at the DUT Research and Postgraduate Support Directorate which is based on the Steve Biko Campus.

Prof Blackledge’s lecture focused on the digital economy, wave power, wave energy convertors, the relationship between power density and the levy index as well as experimental results in terms of designing and implementing renewable energy systems. He said generating electricity from open sea surface waves has great energy potential.

“Sea surface waves can provide a continuous source of energy if suitable technologies can be found that yield relatively cheap wave energy conversion ‘products’ that are simple to manufacture on mass.

In order to help achieve this, it is necessary to understand the dynamics of wave motion. Most work in this area has focused on two distinct approaches which are computational fluid dynamics and statistical modelling,” he said. He also added that one also had to look at the placement of wave energy convertors near shore or offshore in terms of location.

“The power available in the waves is much greater offshore. Near the coastline, the average energy density of a wave decreases due to the interaction with the seabed,” he said.

Prof Blackledge also stressed that other factors in the placement of wave energy convertors included looking at the engineering challenges, construction costs, environmental impacts and the scale of electricity production. There are currently various wave energy convertor types such as oscillating water columns, point absorbers, surging devices and wave amplitude oscillators.

“My choice for a new wave model is on a powerbuoy which requires low maintenance. These buoys provide historical data on the wind velocity, wave height and wave period as well as other data on an hourly interval.

Using this data, we can consider the relationship between a stochastic model for the time variations in wave height that in turn is based on a non-Gaussian model for the wind force characterised by the levy index.

The buoy can also used to capture and convert wave energy into a mechanical force which is enhanced by sensors which continuously monitor the performance of the various subsystems and surrounding ocean environment. In the event of a large oncoming wave, the system automatically disconnects. So in a nutshell, we want to develop a stochastic model for the wind velocity that is statistically significant, and in order to do this, we have to look at some real data on wave heights and freak waves,” he said.

Prof Blackledge and his PhD students have designed the inertia buoy resonance generator and he believes that the potential for this design is great. He is hoping to work with DUT and form a partnership with regards to this product, but at the moment, the funding that is needed for this project is roughly $20 000. He added that if DUT comes on board, he believes the model prototype has the potential to make lots of money as well.

Professor Blackledge holds a PhD in Theoretical Physics from London University and a PhD in Mathematics from the University of Jyvaskyla, Finland. He has published over 250 scientific and engineering research papers, including 14 books, has filed 15 patents and 18 technologies to license, five of which have been used to establish new start-up companies. A past supervisor to over 300 MSc/MPhil and 56 PhD research graduates, he holds fellowships with leading institutes and societies in the UK, including the Institute of Physics, Institute of Mathematics and its Applications, British Computer Society and the Royal Statistical Society.

-Waheeda Peters

Pictured: Prof Jonathan Blackledge talks about ways to make wave energy economically feasible.

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