Business electricity in Northland, NZ: how Top Energy and Northpower price commercial lines, what changed in April 2026, trust discounts and grid risk.
Quick answer
Two lines companies shape Northland business power costs: Top Energy in the Mid and Far North, and Northpower in Whangārei and Kaipara. Both charge by connection size and time of use, both raised prices on 1 April 2026, and both pay discounts back to customers. More than half of the region's electricity is imported.
Lines network
Top Energy · Northpower
Main business centres
Whangārei · Kerikeri · Kaitāia · Kaikohe · Dargaville · Paihia · Ruakākā · Mangawhai
Northland has two lines companies, with the boundary at Hukerenui, about 25 km north of Whangārei. Your address decides which one you're on.
| Lines company | Where it runs | Ownership and regulation |
|---|---|---|
| Top Energy | Mid and Far North, from Hukerenui to Te Paki near Cape Reinga: Kerikeri, Kaikohe, Kaitāia, the Bay of Islands | Owned by its customers through the Top Energy Consumer Trust; prices regulated by the Commerce Commission |
| Northpower | Whangārei and Kaipara districts: Whangārei, Ruakākā, Dargaville, Mangawhai | Consumer-trust owned; exempt from price-quality regulation |
Top Energy serves about 34,500 consumers. Northpower supplies more than 63,000 homes and businesses.
Distance, mostly. Top Energy describes its area as sparsely populated with no dominant urban centre, served by long feeders. Small connections make up 99% of its customers, and average use is about 9,500 kWh a year, one of the lowest in the country. A long rural network's cost is shared across relatively few kilowatt-hours.
How you're charged depends on the size of your connection:
One point to check: Top Energy says retailers often don't pass its time-of-use signals through. On a flat-rate retail plan, moving load out of the peak won't cut what you pay for lines.
Northpower's total lines charge, covering distribution and transmission, rose by an average of 7.7%. Top Energy's headline prices rose 6.3% before its discount, including a 17% increase in the transmission costs it passes on. Top Energy is also collecting more through fixed daily charges, about 49% of revenue, up from 43%, and lowering off-peak rates. Why business bills are rising in 2026 covers the national drivers.
Yes, from both networks, through their trust ownership:
This is the weak spot. On 20 June 2024 a transmission tower near Glorit carrying both 220 kV circuits into Northland fell during maintenance, and about 88,000 customers lost power. The Electricity Authority's review found that limited supply came back within hours through 110 kV lines and local generation, which met 45% of peak demand. Enough transmission capacity to meet all of the region's load wasn't restored until 2:47pm on Sunday 23 June, and many large businesses were asked to restrict their use until then. The Authority estimated the cost at more than $37.5 million.
Top Energy's northern network relies on a single transmission circuit to Kaitāia, backed by more than 15 MW of diesel generation outside the town for planned outages. At the southern end, Northpower is building a $20 million, 34 km subtransmission line from Maungaturoto to Mangawhai for the town's growth, targeted for mid-2027.
Slowly. Northland uses about 1,200 GWh a year and imports more than half of it, the NZ Herald reported in September 2026. Transpower says the area north of Whangārei imports around 224 MW at peak from Auckland. The Ngāwhā geothermal plant produces about 450 GWh a year, and three large-scale solar farms, 67.7 MW in total, now connect to Top Energy's network at Kaitāia.
That is also where the network is constrained. Top Energy says the Kaikohe–Kaitāia 110 kV line can export at most 53 MVA, so it will no longer approve new large-scale export generation there unless upgrades are financially supported. Transpower added a protection scheme on the Maungatapere–Kaikohe corridor in December 2025, allowing about 40 MW more export, and says bigger upgrades need confirmed generation projects so Northland communities don't pay in advance.
Firstgas runs gas distribution in Northland, supplied through transmission delivery points that include Whangārei, Marsden and the Kauri and Maungaturoto dairy factories. From 1 October 2026 its distribution charges for business gas customers rise by an estimated 11.4% to 11.5%, against about 5% for homes. Gas Industry Co's 2026 study says falling domestic gas supply could force commercial and industrial users onto higher-priced alternatives or out of business.
Sites on both sides of the Hukerenui boundary mean two tariff structures and two discount schemes. Send us a bill from each site and we'll check what your retail plan passes through.
Top Energy covers the Mid and Far North, from Hukerenui (about 25 km north of Whangārei) to Te Paki near Cape Reinga, including Kerikeri, Kaikohe and Kaitāia. Northpower covers the Whangārei and Kaipara districts, including Dargaville and Mangawhai. You can't choose between them: your address decides.
Usually, yes. Northpower pays a discount to every active ICP on its network, business connections included, as a credit on your power bill in May or June. Top Energy builds a posted discount into its prices. That discount is based on consumption and is next due in May 2027.
Northpower says fuel, labour, equipment and materials cost more, and it is replacing old equipment and passing on higher transmission and regulatory costs. Top Energy's headline rise of 6.3% includes a 17% jump in the transmission costs it passes through.
Mostly, yes. Three of Northpower's four large commercial and industrial categories include a daily capacity charge per kVA and an excess demand charge; the fourth is priced on peak, shoulder and off-peak kWh. Top Energy charges connections of 110 kVA or more a daily capacity charge per kVA as well as time-of-use rates.
Very, as 2024 showed. The June 2024 Glorit collapse brought down a tower carrying both 220 kV circuits into Northland. Local generation met 45% of peak demand until repairs, and many large businesses were asked to cut their use until enough transmission capacity to meet all load was restored at 2:47pm on 23 June.
Primary sources first. Every figure on this page comes from one of these, each with the date we last accessed it.
Last updated by the Manage My Bills Energy Team.
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