Business electricity in the Bay of Plenty, NZ: how Powerco, Unison and Horizon Networks price commercial power in Tauranga, Rotorua and the Eastern Bay.
Quick answer
Three lines companies set Bay of Plenty business power costs: Powerco in Tauranga and the western Bay, Unison in Rotorua, and Horizon Networks in the Eastern Bay. All three are price-regulated and charge larger sites on capacity or demand. Growth is driving major grid investment around Tauranga and the Eastern Bay.
Lines network
Powerco · Unison · Horizon Networks
Main business centres
Tauranga · Mount Maunganui · Rotorua · Whakatāne · Te Puke · Kawerau · Ōpōtiki · Katikati
Three lines companies split the region roughly west, centre and east. All three sit under the Commerce Commission's 2025–2030 price-quality path.
| Lines company | Main business centres | Ownership and regulation |
|---|---|---|
| Powerco | Tauranga, Mount Maunganui, Te Puke, Katikati, Waihī Beach | Regulated by the Commerce Commission; its networks run from the Coromandel to the Wairarapa |
| Unison | Rotorua | Owned by the Hawke's Bay Power Consumers' Trust, which holds its shares for Hawke's Bay consumers |
| Horizon Networks | Eastern Bay: Whakatāne, Kawerau, Edgecumbe, Ōpōtiki, Murupara | 100% owned by Trust Horizon (formerly the Eastern Bay Energy Trust) |
Horizon's area runs from Otamarakau in the west to Cape Runaway in the east, and south to Lake Rotomā, Kaingaroa and Ruatāhuna. It covers about 8,400 km² and serves more than 25,500 customers.
Growth. Powerco describes Tauranga as a rapidly developing coastal region, with horticulture, a port and a large regional centre, and expects steady demand growth to continue. Transpower says electricity demand in the western Bay could double by 2050. The Commerce Commission approved Transpower's planned investments for the area in June 2025. Detailed design is under way on line reconductoring and a new transformer at the Kaitemako substation. Transpower and Powerco are also working together on a new grid exit point near Tauriko, and the whole programme is due to finish by the end of 2035.
Network costs are already climbing. Powerco says its prices in the Tauranga area rose 5.6% on average from 1 April 2026: 5.9% for commercial connections, while industrial connections fell 1.0%. Across Powerco's networks, transmission charges rose from $110.8 million to $130.1 million.
How Powerco charges businesses:
Rotorua is on Unison. Unison says Rotorua and Taupō share a strong tourism focus and a high share of holiday homes. Commercial and heavy industry there centres on timber and dairy, some distance from the grid exit point. In Unison's Rotorua and Taupō region, commercial, large commercial and industrial connections make up about 42% of forecast lines revenue for 2026/27.
Unison's commercial pricing has eight brackets by fuse size, with fixed daily charges rising as capacity increases. Larger commercial sites also pay on two measures of demand: their single highest half-hour each month, and their highest half-hour during Unison's on-peak period. The on-peak hours stay the same all year, so you can plan around them.
Horizon Networks prices town and country separately. Urban connections in Kawerau, Edgecumbe, Whakatāne and Ōpōtiki are priced apart from rural ones, because low-density rural lines cost more to serve. Connections larger than 70 kVA are on network maximum demand pricing, metered on their actual demand. Power comes in from three Transpower grid exit points, plus one generator connected inside the network at Aniwhenua.
The Eastern Bay's demand is about to step up. Horizon forecasts maximum demand rising from 93 MW in 2026 to 129 MW in 2027 because of one large customer's decarbonisation, with further industrial step changes possible around Whakatāne and Ōpōtiki. Horizon has a $225 million ten-year investment plan and says peak demand could rise by around 50% over the decade. That plan includes a $14.3 million upgrade of Ōpōtiki's supply from 11 kV to 33 kV to support kiwifruit, aquaculture, port development and housing. In Whakatāne, it plans a transformer upgrade at the Kopeopeo substation in 2028 and a new substation in 2035 to keep the CBD resilient. It has no major capital projects planned for Kawerau over the next ten years.
Firstgas distributes gas in the Bay of Plenty, and its transmission pricing splits the region into separate areas: Tauranga (including Mount Maunganui, Tauriko and Te Puke), Whakatāne (including Edgecumbe), and the Central Plateau, which takes in Rotorua and the Kawerau mills. 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. Our guide to New Zealand's gas supply explains why contracts are getting shorter and dearer. If you're weighing a switch from gas to electric heat, look at the local lines company's capacity charges as well as the energy price.
A site on Powerco's network in Tauranga and one on Horizon's in Whakatāne are charged under very different structures. Send us a bill from each and we'll check how each connection is being priced.
Tauranga, Mount Maunganui, Te Puke, Katikati and Waihī Beach are on Powerco. Rotorua is on Unison. The Eastern Bay, from Otamarakau to Cape Runaway and including Whakatāne, Kawerau, Edgecumbe and Ōpōtiki, is on Horizon Networks.
In most of Powerco's areas, including Tauranga, the peak period is 7am to 11am and 5pm to 9pm on weekdays. Peak prices are set from planned network investment in each pricing region, so they reflect the cost of upgrades the network expects to need.
Unison has eight commercial price brackets based on fuse size, with fixed daily charges rising as capacity increases. Larger commercial connections also pay on their anytime maximum demand and on their maximum demand during the on-peak period each month.
Yes. Horizon prices urban connections in Kawerau, Edgecumbe, Whakatāne and Ōpōtiki separately from rural ones, because rural lines cost more per connection. Connections larger than 70 kVA go onto network maximum demand pricing, metered on their demand.
Horizon Networks is 100% owned by Trust Horizon, formerly the Eastern Bay Energy Trust. Unison is owned by the Hawke's Bay Power Consumers' Trust, which holds its shares for Hawke's Bay consumers. Powerco, Unison and Horizon all sit under the Commerce Commission's price-quality regulation.
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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