Mercury is spending $2 million on developing on a battery directly connected to the national grid that could help avert power cuts.
The Auckland-based energy company will use power from the national grid to store in the 1MW lithium ion battery that will be traded on both the wholesale and reserve markets, a New Zealand first.
Some batteries would be the size of a 40ft (12m) long container, take two hours to power up when energy is cheap and two hours to discharge.
Mercury's Southdown research centre is big enough to locate batteries capable of storing more than 100MW, making them a likely feature of future electricity supply and capable of flattening out daily peak demands for electricity from the grid.
Nine companies have submitted tenders for the project which is scheduled to go live later next year.