Home / Uses / Off-grid power on Great Barrier Island

Storing power on an island with no grid

Great Barrier Island, Aotea, has no connection to the national grid. Homes, businesses and community buildings generate and store their own power. This page looks at where hydrogen storage could fit.

Everyone is already off-grid

On Aotea, a lodge, a store, a school or a community hall all run their own systems, typically a battery bank, local generation and a diesel generator for long calm or dull spells. Fuel arrives by barge, so every litre carries freight cost and spill risk. Hydrogen offers a different kind of storage, holding energy for weeks rather than the days a battery bank manages.

What it would keep running

Lodge or store refrigeration
Water pumps from tanks
Lighting and hot water
Internet and phone link
Workshop tools

Wind and water as the source

The system's charging sources are wind or micro-hydro off the grid. Many island properties have exposed ridges or streams. A turbine or micro-hydro can feed the electrolyser when there is surplus, and the hydrogen keeps at 30 bar or less until it is needed. Its by-product is water, which returns to the loop.

For businesses that open seasonally, such as accommodation and cafes, that means a quiet winter can bank energy for a busy summer, rather than running a generator through peak season while visitors are trying to enjoy the island's dark skies and quiet bays.

How it works →

The H2OME loop: an electrolyser splits water into hydrogen, the hydrogen is stored in a tank for weeks, a fuel cell turns it into electricity for your home, and the water returns to the loop.

Honest about efficiency

Round trip efficiency is 30% or less, so far more energy goes in than comes out. On an island where local generation is already sized carefully, that is a real cost, and the wind or water resource has to cover it. The pilot would measure the resource first. It is in development, and island sites would be pilot candidates, not customers yet.

Questions

Does it replace a battery bank?

It includes its own 30 to 40 kWh LiFePO4 battery for day to day use and instant switch-over. Hydrogen adds weeks of storage on top, which is what a battery bank alone cannot do at a sensible size.

Can it get to the island?

Freight logistics for island installs would be worked out with each pilot site. It is designed as a compact, fixed system, but barge scheduling and handling would be part of planning.

Will it cut diesel use?

Potentially, if the property has enough wind or micro-hydro to cover the round trip losses. Where the resource is thin, a diesel fallback may still make sense, and the pilot would be honest about that.

Elsewhere

Every use →

Join the pilot list

Pilot installs go to people on this list first. Rural homes, farms and remote sites especially. No spam, no payment.