Manawa energy currently operate 26 power schemes from the Bay of Plenty in the north, to Otago in the south.

Trustpower’s retail business sells electricity, gas, fixed and wireless broadband, and mobile phone services, totalling approximately 416,000 connections.

[4] In 1913, the Tauranga Borough Council applied to the Department of Lands to have the Omanawa Falls vested in their body corporate for the purposes of water power generation.

In October 1914, the Public Works Department gave its approval for water to be taken from the Omanawa River to generate electricity and circulate it throughout the borough and surrounding area.

Mandeno designed a hot water cylinder for the house, that was built from galvanized iron insulated with 150 mm of pumice.

Within four years the council had expanded its reticulation to supply rural areas as far as Gate Pa, Otumoetai, Papamoa and Oropi.

In 1921 Lloyd Mandeno undertook some investigations and proposed that the borough consider building a new power station using the head generated by fall on the Wairoa River.

The falls and the power station were to named after a couple who operated a cookhouse during construction and whose son had been killed in World War I.

As a result, the electricity department was forced to arrange with the SHD to take supply from its Aongatete and Te Puke.

Approval to proceed was granted by the New Zealand government in 1963 continual upon the station's output being equally shared with the Tauranga Electric Power Board.

[11][5] While involved with the power board he invented, developed and introduced into service the single wire earth return reticulation system.

[5] In response to the introduction of the Energy Companies Act in 1992, the Tauranga and Rotorua Electric Power Boards proposed to merge, but it was rejected both by the public and the government.

This allowed the specialist infrastructure and utility investor Infratil Ltd to acquire 11 million shares and become its largest shareholder.

The merger which occurred on 31 October 1997 guaranteed that the City Council's shareholding in Trustpower would provide an annual revenue of NZ$3.3 million over the next five years.

As by now Trustpower had built up a substantial generation portfolio it elected to be a generator/retailer and so sold its lines and its contracting business, PowerLink Limited.

Following a competitive sales process, TrustPower sold its lines business to United Networks Limited (formerly Power New Zealand) for $485 million.

This led to it purchasing the following hydro power stations and schemes: Arnold, Branch and Waihopai, Kumara, Mangorei, Motukawa, Paerau, Patearoa, Patea (for $72m) Wahapo, Waipori (for $70m) as well as the Tararua Wind Farm (for $49m).

In 2006 Infratil purchased Allient Energy's shareholding for NZ$6.20 a share, which gave it 51% and thus majority control of Trustpower.

[citation needed] In May 2022, Trustpower sold its mass market retail business, retail customer base and the Trustpower brand to Mercury NZ Ltd.[17] The company retained its hydro-electricity assets to become NZ's largest independent electricity generator, representing around 5% of the New Zealand generation capacity and changed their name to Manawa Energy, [18] Manawa means ‘heart’ and it speaks to the heart of the company's operations in the Bay of Plenty.

In 1998 Trustpower decommissioned the Omanawa Falls Power Station and gifted it to the Tauranga City Council.