Students’ renewable energy designs assist Tonga

19 August 2015
Students’ renewable energy designs assist Tonga

Five University of Canterbury (UC) electrical engineering students have returned from Tonga after assisting the local power company to investigate various renewable energy projects.

Supervisor Dr Andrew Lapthorn from UC’s Department of Electrical and Computer Engineering, said the most novel approach sought to produce biofuel from coconuts, which, although technically possible, was determined by the students as not economically viable for electricity generation.

The five final year students are Aaron Ang from New Plymouth, Andrew Berry from Levin, Mitch Graham from Havelock North, Ben Mulholland from Christchurch and Peter Whyte from Whakatane.

Different options including wind power, tidal energy and solar power were modelled for three different island groups: Ha'apai, Vava'u and Tongatapu. The trip allowed the students to present their research findings and project modelling to representatives from Tonga’s state-owned electricity company, Tonga Power Ltd.

“It’s vastly different from New Zealand in terms of the resources available,” Dr Lapthorn says.

“Up until a few years ago, all the electricity generated in Tonga was from diesel power generators, but this is uneconomical due to the cost of shipping fossil fuels and generator maintenance. Adding more renewable generation can help insulate the community from oil price changes.

“People look at renewable energy and they think things like wind and solar and there's an abundance of that in the Pacific, but there are the challenges such as how to store electricity for use when it is not windy or sunny.

“Our students looked at various storage options, as well as gauging how much energy each different option could produce,” explains Dr Lapthorn.

One location tested for tidal generation gave good levels of energy, but again the economics of producing it meant it wasn’t a feasible option. The most efficient method is solar power, and the UC students were able to help make recommendations about size and location of panels as part of UC’s continuing relationship with Tonga Power.

Diversifying energy sources became an even greater priority for Tonga after Cyclone Ian struck the Ha’apai group of islands in January 2014. It affected more than 80 percent of the infrastructure, including the power system supplied by two 186kilowatt diesel generators.

The students’ research findings will help Tonga further develop an energy road map.

“Tonga relies heavily on external aid from other countries such as New Zealand and China, so the students findings can help inform funding applications to implement chosen power systems,” Dr Lapthorn says.

The week-long trip was mainly funded by UC’s College of Engineering as part of the University’s developing reputation for engaging in projects that are useful for businesses, communities and natural environments.

The University of Canterbury has led a number projects in Tonga over the past few years, including installing solar systems on six school rooftops to help reduce expensive diesel-fuelled power bills.

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