This page describes the available wave energy available in Tongatapu and 'Eua.

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Wave Energy in Tonga

The regional analysis of the cost of wave energy (See here) concluded that Tongatapu and ‘Eua could be suitable to support wave energy converters. Wave energy is larger on the South Coasts of Tongatapu (See image below) and previous study have identified the South Coast of Tongatapu as suitable to host a Oscilating water column device. This page expands the regional wave energy analysis to the whole of Tongatapu and ‘Eua to identify suitable offshore wave energy conversion hotspots.

Finding suitable wave energy sites

Bathymetry consideration

Tongatapu has a bathymetry would allow the installation any type of wave energy converters. Wave energy converters can be divided in these three categories: Offshore, Nearshore and onshore devices.

Benchmark device

Wave energy converters come with different cost and efficiency. The cost of operation and maintenance and on the environment can also vary greatly and it can be very hard to decide whether Tongatapu would benefit more from one type of device at a location or another device elsewhere. It is impossible to compare the cost and efficiency of all the wave energy converters because they are not all at the same stage of development. For example, some devices only have a theoretical efficiency while other more advance wave energy converters have a measured (i.e. verified) efficiency. In order to help with decision on what device would be more suitable for Tongatapu, we calculate the cost of energy generation of one wave energy converter, the Pelamis.

From the many wave energy devices developed globally, the Pelamis wave energy converter is one of only two to have reached commercial readiness. Although Pelamis Wave Power Ltd, the firm behind the device, went into administration at the time of writing this report, the milestones reached and the research behind the Pelamis device are unprecedented and unmatched by any other device. Because of the large amount of literature on the Pelamis, it is still a benchmark and, although it is unlikely that more Pelamis devices will ever be built (at least under the same name), the device’s physical characteristics and cost evaluation can be used to probe the economic feasibility of wave energy.

Pelamis costs

Cost Type Cost range
Operation and Maintenance US$ 1.72 - 8.48 million
Total US$ 6.32 - 14.10 million

Wave Power and energy cost for pre-selected sites

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Site name Mean available wave power (kW/m) Annual Pelamis power output (MWh) OM cost range (USD/MWh) Total cost range (USD/MWh)
Kalau Is. 32.7 1007 68 - 337 251 - 560
Tonga WB1 26.8 744 930 - 4583 339 - 758
Duff Reef 26.4 630 109 - 538 401 - 895
Euaiki Reef 24.4 730 94 - 465 346 - 772
Tonga WB2 23.1 593 116 - 572 426 - 951
Houma Toloa 21.9 566 122 - 600 447 - 997
Hufangalupe 17.9 341 202 - 995 741 - 1655
Montapu Beach 17.8 393 175 - 863 643 - 1436
Mui_Hopohopoponga Point 16.2 401 172 - 846 630 - 1407
Finehika Beach 13.4 301 229 - 1127 840 - 1876

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