TREP 03 Lot 1- 350kW solar PV facility and 400kW/900kwh BESS at ‘Eua, 300kW solar PV facility and 900 kW/450 kWh BESS at Vava’u

The component is leading by Tonga Power Limited. A component to install solar PV facility and Battery Energy Storage System in 'Eua and Vava'u. It is still in its design stage. The design has recently completed for review by the Project Management Unit (PMU) and Construction Supporting Consultants from Australia (Entura).

The land deeds for Vava'u and 'Eua have now been secured by TREP and Tonga Power Limited (TPL) for the implementations.

The community consultations have conducted for 'Eua and Vava'u. There were no major concerns toward the Project but lower tariff and job opportunities for local people. The consultation team instructed that the tariff is done by the Government of Tonga. The main objective for the implementation is to reduce the dependency on imported fuels to lessen the impacts of climate change and to produce sustainable and clean energy in Tonga. There is a potential reduction for tariff but it is not the role of the TREP project.

Vava'u Community Consultation


'Eua Community Consultation


'Eua Island Vava'u Island
The proposed sub-project consists of a solar PV array and grid stabilising BESS integrated into the existing power system.
The proposed additional solar PV is expected to increase renewable energy to about 37% (from approx. 13%). Solar PV power output will then, at frequent times, force the diesel generators below minimum load and into reverse load. To prevent this situation a BESS is included to stabilise the power flows and provide a voltage and frequency source when the diesel generators are off. The new solar PV array will be installed approximately 600m to the East of  the existing solar PV array, and the BESS would be installed at the existing power station and connected to the LV BUS. A new switchboard is also required to increase the LV BUS rating sufficient to cater for all connected generators
The proposed addition of 300 kW PV is expected to take this to about 16% renewable energy. At this level of renewable penetration, solar power input may force the diesel generators below minimum load. Thus, a battery energy storage system (BESS) is included to stabilize the power flows. This BESS will also
provide a voltage and frequency source to allow the diesel generators to be turned off when more renewable generation is installed in the future. The new solar PV array will be installed on land directly to the east of the power station, along with the BESS. These will be connected directly to the existing LV bus at the power station.




TREP-03 Lot 1: 'Eua & Vava'u Solar & BESS​​​​​​​

Bidding was undertaken using International Competitive Bidding method with the Contract awarded to Infratec. the contract was signed 3rd April 2020 with a current estimated completion date of July 2021


The winning bidder for Lot 1 was Infratec NETCon JV at the bid price of USD $4,577,461 equivalent (including arithmetic corrections).​​​​​​​