Lake Coleridge Power Station

Engineering Site (eg Portland cement works, Maori fortifications)


The New Zealand government's first major involvement in electric power supply was at Lake Coleridge on the Rakaia River. It provided Christchurch’s total power needs in the early 20th century.

Constructed began in 1911 following the 1910 Aid to Waterpower Act which gave the government authority to borrow money for hydro-electric development. The station, with its three 1500 kilowatt (kW) generators (six were planned), was opened on 15 November 1914 by Prime Minister William Massey. Regular supply was given to Christchurch in March 1915.

The construction of the powerhouse was a remarkable feat for that time, in that it had to be built on loose shingle of the Rakaia River and this led to many troubles which the New Zealand engineers had to master. However, this experience benefited subsequent stations, such as Waitaki and Highbank, and contributed to world knowledge on how to construct big hydro plants on loose shingle.

Also of significance was the construction of two 66 kilovolt, 100 kilometre (km), transmission lines to Christchurch, which were the highest voltage and longest length in New Zealand at the time. This work was started in 1913, and was completed in November 1914.

The progressive development of the scheme owing to post-World War One demand led to further generators, a second intake, surge chamber, tunnel and pipelines and the final commissioning in 1930 with total output increased to 34,500 kW.

To meet the potential of the scheme, it was necessary to obtain further water which came first from the Harper River, later from a diversion of water from the Acheron Stream and finally from the Wilberforce River.

Through the sale promotion of Lake Coleridge power, most of the boroughs and counties near Christchurch were induced to become electricity supply authorities. The making of numerous contracts with relatively small-scale consumers or groups became unwieldy and led to the Government passing the Electric Power Boards Act 1918, which was later consolidated as the 1925 Act, setting the ground work for the orderly distribution of electric power in New Zealand.

The New Zealand's Electricity system IPENZ Engineering Heritage Record has an overview of the history of electricity supply in New Zealand from the early 20th century.

Designers: Public Works Department, Electrical Branch
Constructors: Powerhouse building – Taylor Bros & Moorhead, Christchurch Intake, tunnel, surge chamber, etc – Public Works Department, Electrical Branch
Penstocks – Dunedin Engineering & Steel Company
Turbines, generators and allied transformers, switchgear – Public Works Department, Electrical Branch
Manufacturers of power plant: Turbines – Escher Wyss & Cie, Zurich
Generators – Bruce Peebles & Co Ltd., Edinburgh

There are several marble plaques located in the entrance to the building which document important centenaries and people in the history of electricity (see images below). One, dating from 1919, marks the centenary of Hans Christian Oersted's (Danish physicist and chemist) discovery of the magnetic effect of an electrical current. The other plaque commemorates English physicist Michael Faraday's 1831 development of the method for creating electric current through moving magnets. The Faraday Society in the United Kingdom advises that, as far as they are aware, the Faraday Centenary Memorial tablet is the only one in the world in a power station (Bruce Comfort, pers com 2009).

Heritage recognition
IPENZ “Engineering to 1990” project

This item of New Zealand’s engineering heritage was recognised as part of the IPENZ “Engineering to 1990” project which the Institution organised to help celebrate the country’s sesquicentenary in 1990. A plaque was unveiled to mark the significance of this power station as part of the development of the nation.

Rosemary Britten, Lake Coleridge: The power, the people, the land, Christchurch, 2000


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Lake Coleridge, 100 kilometres from Christchurch, Upper Rakaia River.


Access Info
Public access is restricted. External views of the facilities can be seen from Hummocks Road.

Nature of Engineering
Electrical Power Generation and Distribution, Building and Construction


Creator unknown: Photograph of a scene at Lake Coleridge, Canterbury, including the hyroelectric power station, [192?]. ID: PAColl-9380. Permission of the Alexander Turnbull Library, Wellington, New Zealand, must be obtained before any re-use of this image

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Generator Room, hydroelectric Station, Lake Coleridge, taken in April 1932 by an unidentified photographer. ID: 1/2-112295-F. Permission of the Alexander Turnbull Library, Wellington, New Zealand, must be obtained before any re-use of this image

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Oersted Centenary Plaque, May 2006. Image courtesy of B. Comfort

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Faraday Centenary Plaque and Lake Coleridge Power Station's 75th anniversary plaque, May 2006. Image courtesy of B. Comfort

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Lat: -43.364069 Long: 171.526912