Students travel to Tonga with renewable energy ideas

Vava'u, Tonga, was one of the island groups modelled for potential sustainable energy generation. Photo / Getty Images

Electrical engineering students from the University of Canterbury have just come back from Tonga, where they provided assistance to local power company Tonga Power Ltd, looking at several renewable energy projects.

All five students who traveled there are in the final year of their degrees at UC. Aaron Ang, Andrew Berry, Mitch Graham, Ben Mulholland and Peter Whyte were supervised on the trip by Dr Andrew Lapthorn of UC's Department of Electrical and Computer Engineering.

Dr Lapthorn said among the ideas floated was the production of biofuel from coconuts. Whilst it would have been technically possible, the students used their skills and knowledge to determine the approach would not be economically viable for electricity generation.

Other options - including wind, tidal energy and solar - were each modelled for the island groups of Ha'apai, Vava'u and Tongatapu, and the students presented their findings to representatives from Tonga Power.

"It's vastly different from New Zealand in terms of the resources available," says Dr Lapthorn.

"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."

He says green energy can come from a greater variety of sources than often thought.

"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."\

The UC students found the most efficient method of powering Tonga was indeed solar. They were able to make recommendations as to the size and location of panels, in a continuing collaborative relation with Tonga Power.

The need for diversification of Tonga's energy generation came following Cyclone Ian, which rattled the island group of Ha'apai in January 2014 and interfered with 80 percent of the islands' infrastructure, including its power system made up of two small and costly diesel generators.

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

The College of Engineering at the University of Canterbury provided most of the funding for the group's trip, fostering its connection with projects that help businesses, communities and the environment. A previous excursion to Tonga involved the installation of solar systems on six schools to reduce their spending on diesel power.

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