A University of Canterbury postgraduate electrical and computer engineering student is designing a hybrid renewable energy power system for the Ha'apai Island group in Tonga.

In January last year, cyclone Ian struck the Ha'apai group and destroyed up to 70% of homes and buildings, affecting more than 80% of the infrastructure including the previous power system supplied by two 186 kilowatt diesel generators.

University of Canterbury student Hantt Cao is carrying out computer modelling research to completely rebuild the entire power system after this disaster.

Cao will focus on creating a renewable energy source as opposed to one that runs on fossil fuels. In the Ha'apai island group, solar and wind energy are feasible options.

Dr Andrew Lapthorn, supervising lecturer, says Cao is developing models to determine what a power system made up of renewable energy sources such as wind and solar would look like and how it would perform.

“A lot of renewable energy sources are intermittent and their performance hard to predict due to the weather. A new renewable power system will need to be quite smart in order to maintain a quality power supply to the island,” says Lapthorn.

Cao is looking at the technical design as well as the economic side to determine the best combination of generating resources and how that would compare with the diesel system that was used before the cyclone, Lapthorn says.

Tonga Power, Tonga's state owned electricity company, will determine whether they proceed with a renewable energy option for Ha'apai.

As part of Tonga's energy roadmap the government is committed to converting a portion of Tonga's electricity generation to renewable energy sources, Lapthorn says.

“They already have some solar generation on Tongatapu and Vava'u. However as Tonga is quite a poor nation and they have limited resources for such projects and rely heavily on external aid from other countries such as New Zealand and China. Cao's thesis could be used as a basis for some funding application to implement the power system,” says Lapthorn

“He has a strong passion for renewable energy having seen first-hand the effects of fossil fuel energy production on the air quality in China and this was a major contributing factor for him to choose New Zealand to pursue his studies,” he says.

The University of Canterbury has led a number projects in Tonga over the past few years including installing solar systems onto five school rooftops. The university's College of Engineering expects to send research students to Tonga this year to continue helping Tonga Power.