MPower has been awarded a contract to build a large-scale energy storage system in Rarotonga, capital of the Cook Islands. The contract is for the design and installation of a 5.6MWh Battery Energy Storage System (BESS) at the 1MW Te Mana Ra Solar PV facility connected to the nation’s electricity grid.

The BESS is intended to provide increased flexibility for the island’s electricity utility to manage the increasing renewable generation feeding into the grid.

The NZ$4.3 million lithium-ion storage solution is a key element of the Government of the Cook Islands’ Renewable Energy Sector Project. The BESS project is expected to be completed by the first half of 2018.

Nathan Wise, CEO of Tag Pacific Limited, MPower’s ASX-listed parent company, told EcoGeneration about the project.

What issues is the BESS expected to solve?

MPower’s BESS has proprietary grid stabilisation capability which regulates the variations in power output on the one hand and demand by users on the other. Consequently, MPower’s BESS will be a valuable component in the Cook Island’s increasing drive towards 100% renewable energy.

Unlike many other companies who are aspiring to participate in the energy storage sector, MPower already has years of deep practical experience in Australia, with sites in Western Australia, the Northern Territory and Queensland.

What share of generation is solar on Rarotonga?

The Cook Islands has made significant advances in the implementation of solar power generation, so much so that at certain times of the day supply may exceed demand. This is where MPower’s BESS will help to match the demand and supply cycle.

Is there any other renewable generation on the island?

In addition to its implementation of solar power generation, we understand that the Cook Islands also has some bio fuel generation capability.

Is there much residential solar on the island?

The Cook Islands has made steady progress in implementing residential solar over the last few years. Because of the relatively high proliferation of residential installations, the time when the power is currently being generated does not always match when it is required. The further deployment of residential solar has effectively now been paused pending the introduction of MPower’s BESS.

MPower’s BESS will be the mechanism by which the Cook Islands excess generation of solar power will be “time-shifted” to periods when demand for solar power would otherwise be greater than the supply.

Will it be shipped to site complete or assembled there?

MPower’s BESS is modular and is designed, manufactured and fully tested at MPower’s facility in Ingleburn, NSW.

How much diesel do you think the BESS will offset?

In broad terms diesel fuel consumption is approximately 250 litres per MWh. MPower’s BESS has a peak storage capacity of 5.6MWh with an average of one cycle per day, therefore at peak capacity and assuming that maximum solar energy is stored, the offset could be up to 511,000 litres of diesel a year. Consideration must also be given to the 10-year design life.

Are you working on any Australian projects?

MPower’s ability to deliver large scale renewable energy projects in remote locations was most recently demonstrated with the completion of a 5MW solar plant in Samoa. As an experienced and serious contender in the renewable energy sector, MPower is investing heavily and is currently working on a significant number of Australian projects, details of which cannot be disclosed at this time.