NZ Grid Live
Every grid-connected power station in New Zealand on a single map, sized by capacity and coloured by fuel. The Cook Strait HVDC link animated with its real flow direction and magnitude — watch it reverse as the South Island wind rises and Auckland goes to sleep. Aggregate load, fuel mix and wholesale prices update live from public Transpower and em6 feeds.
What you’re looking at
Every dot is a real grid-connected power station, sized by its capacity and coloured by fuel — hydro, wind, geothermal, solar, gas, coal, co-gen and batteries. Hover any one for its name, fuel and capacity.
The bright line crossing Cook Strait is the HVDC inter-island link — the most consequential single piece of infrastructure on the country’s grid. Its dashes flow in the direction power is currently moving and quicken as the magnitude rises. The number above the map is the live MW reading; the arrow flips when the link reverses, which it does several times a day.
The stats panel breaks the country into its two halves. North Island demand and generation, South Island demand and generation. The North Island has more people and less hydro; the South Island has fewer people and more hydro and wind. The HVDC link squares the difference, and the panel shows which way and how hard. Below that, the renewable share, the colour-coded fuel mix bar, and the wholesale spot prices at the North and South Island reference nodes — the bigger the N–S spread, the harder the HVDC is working.
Use the controls below the map to scrub back through the last 24 hours, or hit a higher speed to play the day as a timelapse — 60× compresses a full grid day into 24 minutes; 900× into 96 seconds. The per-island demand updates every 5 minutes, the HVDC reading every half-hour, the fuel mix once an hour.
How New Zealand’s grid works
New Zealand has one of the world’s most renewable national electricity systems, with around 85 percent of generation coming from renewable sources in a typical year. The fleet runs on a foundation of hydro in the South Island and the central North Island, geothermal in the Taupō Volcanic Zone (where ground steam is essentially free baseload), and a growing fleet of wind farms in the windier coastal and Manawatū regions. Solar farms have started arriving at scale only recently — Genesis’s Lauriston solar farm in Mid Canterbury and Lodestone Energy’s six-site Northland and Bay of Plenty rollout are the first commercial-scale projects. Gas peakers (Stratford, McKee, Junction Road), the Whirinaki diesel peakers, and the Huntly Rankine units (which can burn coal or gas) round things out by filling the gaps when renewables can’t.
The country is split into the North and South Island grids, joined only by the Cook Strait HVDC link. Power on each island flows through Transpower’s 220-kilovolt national grid backbone, which connects generation to local distribution networks at 14 operational zones from Northland to Southland. The largest single load is the Tiwai Point aluminium smelter near Bluff, which alone draws around 570 megawatts continuously from Manapouri’s 850 MW Doubtful Sound power station — almost the entire output of the country’s biggest hydro station, dedicated to making aluminium ingots for export.
The Cook Strait HVDC link, explained
The HVDC inter-island link is the single most important piece of New Zealand’s electricity infrastructure. Built in 1965 and progressively upgraded, the link uses high-voltage direct-current technology to send up to 1,200 megawatts of power either north or south through a 40-kilometre submarine cable across Cook Strait, with overhead lines extending from Benmore in North Otago to Haywards near Wellington. The two converter stations turn AC power from one island’s grid into DC for the cable, then back to AC at the other end.
The HVDC reverses direction multiple times per day in normal operation. South Island wind farms blowing strong overnight push power north to a sleeping Auckland; the morning peak in Auckland and Wellington pulls power south-to-north as North Island gas peakers fire up; daytime sun and South Island hydro flexibility shifts the flow again; the evening peak pulls north once more. Watching the link reverse is one of the clearest signals you can see of how a renewables-heavy national grid actually balances itself in real time.
Fuel mix, baseload and peaking
The visible character of New Zealand’s grid changes constantly. Geothermal sits at a near-flat 1,200 megawatts day and night because the heat source doesn’t switch off — it’s the country’s true baseload. Hydro ramps up and down with demand and is the system’s main flexibility resource, but it’s also water-limited: in a dry year (most recently 2024) the South Island lake levels constrain how hard hydro can be pushed. Wind is highly variable, contributing anywhere from a few megawatts on a still anticyclonic night to nearly its full 1,400 MW capacity during a roaring westerly. Solar is still small but growing fast. Gas and the Huntly coal units exist primarily to fill the gaps — the system pays for them to be available even when they’re not running, because in the worst hour of a dry, still, cold winter day the country needs them to be there.
Wholesale prices and the North–South spread
The wholesale electricity market sets a price every half-hour at hundreds of nodes around the network, but six reference nodes — Otahuhu (Auckland), Whakamaru (central North Island), Haywards (Wellington), Kikiwa (Nelson), Islington (Christchurch) and Benmore (North Otago) — are widely watched as a proxy for what the market is doing. When the South Island has surplus cheap hydro and wind, Benmore’s price drops to a fraction of Haywards’s; the bigger that North–South spread, the more the HVDC is being used to flow power north. When the spread closes, either both islands are well-supplied or the HVDC has hit a constraint and can’t move any more power. The spread is one of the simplest barometers of how stressed the grid is on any given day.