The Petty Harbour Hydro Electric Generating Station is a hydroelectric generating station in Petty Harbour–Maddox Cove, Newfoundland and Labrador. It was constructed in 1898 and it was the first hydroelectric generating station in Newfoundland. It was built by the St. John's Street Railway Company, a company established by Robert Reid. Operation commenced on 19 April 1900. In 1920 Reid renamed the company the St. John's Light and Power Company. On 7 February 1921, an avalanche destroyed 23 m of the wooden penstock that carried water from the dam to the generating station, cutting off all electrical power to St. John's for almost five days. Then, in 1924, the plant changed ownership to the Royal Securities Corporation of Montreal, where they began extensive reconstruction of the plant and watershed area. On 1 May 1978, the plant was entered in the Canadian Engineering Heritage Record as a model reflecting progressive adaptation to emerging technology, and remains today as one of the few plants of its type still in active service.

General Information

Location: Petty Harbour-Maddox Cove, Newfoundland and Labrador Owner: Newfoundland Power Capacity: 5.3 MW Average Yearly Output: 18 gigawatt-hours Head: 57.9 metres Average Streamflow: 5.6 cms On-Line: 1900 Original Design: G.H. Massey, A.C. Rice Original Construction: Reid Newfoundland Company

Equipment

Turbines

Unit 1: (installed in 1902) Inward-flow Girard type (impulse turbine) 1.4 MW Manufactured by Stillwell, Bierce & Smith Vaille Co. Replaced in 1912 with Horizontal Francis turbine 1.57 MW Manufactured by Voith Unit 2: (installed in 1900) Victor type (early Francis turbine) 1.4 MW Manufactured by Stillwell, Bierce & Smith Vaille Co. Replaced in 1908 with Horizontal Francis 1.57 MW Manufactured by Voith Unit 3: (installed in 1926) Horizontal Francis 2.05 MW Manufactured by Armstrong Whitworth

Generators

Unit 2 (installed in 1900): 3-phase, 60 Hertz, 550 volts Manufactured by Westinghouse Replaced in 1926 with 3-phase, 60 Hertz, 2,300 volts Manufactured by General Electric Unit 1 (installed in 1902): 3-phase, 60 Hertz, 550 volts Manufactured by Westinghouse Rewound in 1926 to 2,300 volts Unit 3 (installed in 1926): 3-phase, 60 Hertz, 2,300 volts Manufactured by General Electric

Construction

Powerhouse

48.8 metres long by 7.3 metres wide by 4.9 metres high Masonry construction

Penstock

Original: 1,057 metres long, 2.4-meter by 2.4-meter cross-section wooden flume 112.2 metres long, 2.4-meter by 2.4-meter cross-section rock tunnel 115.2 metres long, 2-meter-diameter steel penstock Replacements: 1926: 975-metre-long, 2.3-meter-diameter wood stave penstock 1953: Steel penstock (surge tank riser) replaced with 2.3-metre-diameter steel pipe 1999: Lower 740.7 metres of penstock replaced with 2.3-metre-diameter steel pipe 2021: Remainder of penstock replaced with 2.3-metre-diameter steel pipe Intake Structure: Concrete with steel gate and lift (integral to forebay dam)

Dams & Reservoirs

Forebay

In 1900, rockfill with timber facing. Replaced in 1926 with concrete gravity. Steel anchors added in 1992. 9.1-meter maximum height.

Bay Bulls Big Pond

Zoned earthfill (rebuilt 1998–1999) Concrete outlet conduit

Cochrane Pond

Earthfill with concrete overflow spillway and timber crib outlet.

Tailrace

Unlined canal excavated in rock 137 metres long