Business power in Southland: what sets your price

Which lines company is your Southland business on?

On the mainland there are two, and PowerNet manages both from Invercargill.

*Average connections in the year to 31 March 2025 (Commerce Commission).

If you're not sure which you're on, look at your ICP number: one containing "TP" or "HE" is on The Power Company's network.

The two networks could hardly be more different:

• Electricity Invercargill is compact. Its Invercargill network is almost entirely underground, which it says makes it one of the most reliable in New Zealand; Bluff's is mostly overhead because of the rocky ground. On Commerce Commission figures, it has about 27 connections per kilometre of line.
• The Power Company runs nearly 9,000 km of lines and 37 zone substations at about 4.2 connections per km, the lowest density of New Zealand's 29 networks on Commerce Commission figures. Its network peaks in winter.

What drives commercial lines charges in Southland?

Both networks build their lines charges from daily charges set by your connection's capacity plus time-of-use energy charges, but their cost pressures differ.

The Power Company

Its revenue requirement for 2026/27 is $98.4 million, up 13.1%. A large part of that increase comes from one major customer electrifying, which needs new distribution and transmission infrastructure. Its costs, including Transpower's, are largely fixed, so most of the increase went into capacity charges. Half-hour-metered individual customers are moving from a 50/50 fixed/variable split to 60/40.

How your connection is priced depends on its size:

• 150 kVA and above: connection-specific prices for 264 customers. Sites closer to zone substations and grid exit points use less of the network and can pay less.
• Smaller connections: urban or rural rates. Towns such as Gore, Winton, Te Anau, Riverton and Edendale are priced as urban.

Key industries on the network include sheep, beef and dairy farming, meat processing, coal mining, forestry, timber processing and tourism. For processors, see our notes on food production energy.

Electricity Invercargill

Its revenue requirement is $25.96 million, up 9.7%. That includes a 17.3% rise in transmission charges and a 10% rise in distribution charges. It sets connection-specific prices for 161 larger customers.

Both networks use the same time-of-use bands for smaller connections:

How does The Power Company discount work?

As a consumer-owned company, The Power Company returns $11.71 million (including GST) for 2026/27. The discount is credited through retailers and appears on September or October bills. To qualify, you must have been connected at midnight on 31 August 2026 with a supply of 8 kVA or more.

For general (non-residential) connections, the discount is a percentage of fixed charges plus 1.35 cents per kWh. Larger customers are assessed individually.

Where does Southland's power come from, and where does it go?

The Power Company's network draws from four Transpower grid exit points: Invercargill, North Makarewa, Gore and Edendale. Up to 112 MW of local wind and hydro generation also feeds into it.

The region's biggest electricity user is the Tiwai Point aluminium smelter near Bluff, which uses about 13% of New Zealand's electricity. It has power supply agreed until 2044, with provisions to cut its use when national supply is short. The Manapōuri power station was built to supply it, and the smelter says it contributes about 6.5% of Southland's GDP.

Industry is electrifying too. EECA's 2022 Southland study covered 40 large process-heat sites that together used 1,518 GWh of energy a year, mostly from coal. Gas in the South Island means LPG (why gas costs are rising). EECA also cautioned that local electricity infrastructure was not yet ready for larger electrification projects without affecting security of supply.

How exposed are Southland businesses to outages?

Two recent events show the exposure:

• October 2025: a day after a windstorm, 17,800 of The Power Company's 38,200 customers were still without power. PowerNet said the backbone of its Southland and south Otago networks was "broken".
• August 2026: a Transpower grid fault, on a day of storms and lightning, cut supply to most of Southland for around two hours, affecting about 25,000 customers.

For cold stores, processors and anyone with critical load, backup supply belongs in the energy plan.

Stewart Island is separate. Its council-owned network runs on diesel, and the council says island consumers pay 89 cents per kWh; a solar farm with battery storage has been under construction since May 2026.

What should a Southland business check?

• Your network. A "TP" or "HE" in your ICP means you're on The Power Company's network.
• If you're 150 kVA or more: your connection-specific price and how far you sit from a zone substation.
• When you use power across the peak, shoulder and night bands.
• The discount credit on your September or October bill.

Manage My Bills reviews commercial connections nationwide from our Manukau office. If you run a Southland processor, cold store or other large site, send us your bills and your ICP number.