The Gentailers
The five companies that dominate NZ electricity — generating power and selling it to you.
The Big Four
New Zealand's electricity market is dominated by four "gentailers" — companies that both generate and retail electricity. This vertical integration gives them natural hedging against price volatility: when wholesale prices spike, their generation arm profits even as their retail arm pays more.
Retail Market Share
Note: Mercury's market share jumped in 2022 when it acquired TrustPower's retail business. The remaining ~15% is split among ~35 smaller retailers.
| Company | EBITDAF (FY2023) | Change | Government Stake |
|---|---|---|---|
| Mercury | $841M | +45% | 51% |
| Meridian | $783M | +10% | 51% |
| Contact | $573M | +5% | 0% (fully private) |
| Genesis | $524M | +19% | 51% |
Market Position Comparison
Different metrics reveal different competitive positions — capacity doesn't equal generation, and generation doesn't equal retail share.
| Company | Installed Capacity | Generation Share | Retail Share | Strategic Position |
|---|---|---|---|---|
| Meridian | ~2,800 MW (32%) | ~30-35% | ~19% | Generation long — net seller to market |
| Mercury | ~1,850 MW (21%) | ~18-22% | ~26% | Retail long — net buyer from market |
| Contact | ~1,800 MW (21%) | ~20-24% | ~18% | Roughly balanced; geothermal baseload |
| Genesis | ~1,700 MW (20%) | ~18-22% | ~22% | Thermal flexibility; Kupe gas stake |
| Others | ~500 MW (6%) | ~5% | ~15% | Mostly retail-only; some industrial gen |
Generation share varies by year depending on hydrology. Meridian's South Island hydro means its share increases in wet years. Capacity figures are nameplate MW; actual available capacity varies.
Generator + retailer = gentailer. It's an industry term for vertically integrated companies that produce electricity and sell it directly to consumers. This structure emerged from the 1998-99 breakup of the state-owned ECNZ.
New Zealand's largest retail electricity provider since acquiring TrustPower's retail business in 2022. Mercury operates 17 generation sites — all renewable — spanning the nine Waikato River hydro stations, five geothermal plants in the Taupō Volcanic Zone, and four wind farms. The company is North Island-focused, with all generation assets there.
Ngā Tamariki expansion (+46 MW, 2025-26), Puketoi wind farm (228 MW consented), potential North Waikato wind farm (~300 MW). Also building grid-scale battery at Whakamaru.
New Zealand's largest electricity generator by capacity. Meridian inherited the crown jewels from the ECNZ breakup: Manapōuri (NZ's largest hydro station) and the Waitaki scheme. The company controls ~50% of NZ's total hydro storage. Also owns the Powershop retail brand and recently acquired Flick Electric.
Meridian plans to build 7 new renewable projects by 2030. Pipeline includes wind farms in Wairarapa and Manawatū, solar northwest of Christchurch, and a 100 MW battery (now operational at Ruakākā).
New Zealand's largest electricity and gas retailer by customer count. Genesis plays a unique role: it owns Huntly Power Station, the country's largest thermal plant and critical dry-year backup. This makes Genesis essential to system security but also NZ's biggest electricity-sector emitter. Also owns a 46% stake in the Kupe gas field.
In 2025, the other three gentailers agreed to pay Genesis to keep Huntly's Rankine coal/gas units available through 2035 as "strategic energy reserve." Without it, Unit 2 was set for retirement in early 2026. Genesis is also building a 100 MW / 200 MWh battery at Huntly.
The only fully private gentailer (no government ownership). Contact is NZ's geothermal leader — Wairakei (1958) was the world's second commercial geothermal plant. The company just opened Tauhara (2024), featuring the world's largest single-shaft geothermal turbine. Also owns the Clyde and Roxburgh hydro dams on the Clutha River and gas peaking plants at Stratford.
Contact is NZ's geothermal growth engine. Tauhara ($924M, opened Nov 2024) added 174 MW. Te Huka expansion (+51 MW) is next. The company is also building Kōwhai Park, a 168 MW solar farm in Christchurch.
Competition Concerns
The gentailer structure has been controversial since the 1998-99 reforms. Critics argue it concentrates market power; defenders say it provides stability. Here's the debate:
- Independent retailers must buy wholesale electricity from the very gentailers they compete against at retail
- Combined $2.7B profits during a cost-of-living crisis "doesn't pass the optics test" (Consumer NZ)
- Customer satisfaction surveys consistently show gentailers rank lower than smaller independents
- Limited liquidity in hedge markets makes it hard for independents to manage risk
- 25+ years since reforms, yet gentailers still control ~85% of retail market
- Vertical integration emerged in most competitive electricity markets globally (Australia, Singapore)
- Natural hedging reduces financial risk, enabling long-term generation investment
- NZ wholesale electricity prices remain competitive by OECD standards
- Gentailers invest billions in new renewable generation (Tauhara, Turitea, Harapaki)
- The Huntly strategic reserve deal shows gentailers can cooperate on system security
Regulatory response: The Electricity Authority is working on "level playing field" measures to improve access to hedging products for independent retailers. The Commerce Commission monitors market power. But structural separation (breaking up the gentailers) is not currently on the agenda.
What you can do: Consumers can switch retailers via Powerswitch.org.nz. Switching rates run 9-14% annually — modest but meaningful pressure on incumbents.
💡 The Big Picture
The four gentailers are the backbone of NZ's electricity system — they generate most of the power, supply most of the customers, and invest billions in new capacity. Their profits fund the renewable transition. But their dominance limits competition and keeps independent retailers on the margins. Whether this structure serves New Zealand well is one of energy policy's most contested questions.