Lake Onslow is a man-made

lake A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...

east of

Roxburgh Roxburgh () is a civil parish and formerly a royal burgh, in the historic county of Roxburghshire in the Scottish Borders, Scotland. It was an important trading burgh in High Medieval to early modern Scotland. In the Middle Ages it had at lea ...

and south of

Alexandra Alexandra () is a female given name of Greek origin. It is the first attested form of its variants, including Alexander (, ). Etymology, Etymologically, the name is a compound of the Greek verb (; meaning 'to defend') and (; genitive, GEN , ; ...

in the

Otago Otago (, ; ) is a regions of New Zealand, region of New Zealand located in the southern half of the South Island and administered by the Otago Regional Council. It has an area of approximately , making it the country's second largest local go ...

region of New Zealand. It lies above sea level. It was formed in 1890 by the damming of the

Teviot River The Teviot River is a river in New Zealand, a tributary of the Clutha River. See also *List of rivers of New Zealand This is a list of all waterways named as rivers in New Zealand. A * Aan River * Acheron River (Canterbury) * Acheron Riv ...

and Dismal Swamp, with a new dam built in 1982 that raised the lake level by . It has been considered as the site for a

pumped-storage hydroelectricity Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing (electrical power), load balancing. A PSH system stores energy i ...

project.

History

Lake Onslow first formed in 1890 when a dam was built that flooded the Dismal Swamp; the Teviot River flowed through the swamp. The water from this lake was used for mining, irrigation and hydroelectricity. In 1982, a new and higher dam was built that raised the lake level by ; the old dam is now drowned. The water usage rights jointly sit with Pioneer Energy (formerly the Otago Central Electric Power Board) and the Teviot Irrigation Company. In 2019, the

Interim Climate Change Committee The Interim Climate Change Committee (or ICCC) is a ministerial advisory committee created by the New Zealand Government in mid–April 2018 to explore how New Zealand transitions to a net zero emissions economy by 2050. The Interim Committee wa ...

proposed that the lake be used for a pumped hydro-storage system to provide backup electricity generation in dry years. The project had first been considered by hydrologist Earl Bardsley of the

University of Waikato The University of Waikato (), established in 1964, is a Public university, public research university located in Hamilton, New Zealand, Hamilton, New Zealand. An additional campus is located in Tauranga. The university performs research in nume ...

since 2002 and proposed in 2005. In July 2020, Minister of Energy

Megan Woods Megan Cherie Woods (born 4 November 1973) is a New Zealand Labour Party politician who served as a Cabinet Minister in the Sixth Labour Government and has served as Member of Parliament for Wigram since 2011. Early life Woods was born and gr ...

announced that the New Zealand government would fund a detailed feasibility study of the plan. If progressed, the scheme would be the biggest infrastructure project in New Zealand since the 1980s, employ an estimated 3500 to 4500 people, and take four to five years to build and a further two years to fill. One option could be 5 TWh of storage and a 1.2 GW power station, equivalent to half a year of full production. If the project goes ahead it will completely drown and submerge a small scroll plain with its swirling and migrating meanders (formerly known as Dismal Swamp). The scroll plain is a miniature example of the nearby Taieri Scroll Plains and has formed because of the low and decreasing gradient of the stream valley due to slow progressive tectonic back-tilting of the catchment. In March 2023, the government estimated the cost of the storage project at $15.7 billion. In December 2023, the Energy Minister in the new National-led government,

Simeon Brown Simeon Peter Brown (born 8 April 1991) is a New Zealand politician and Member of Parliament in the House of Representatives for the National Party. Early life and career Brown was born in Rotorua in 1991. His family moved to Clendon Park, Au ...

, announced the axing of the pumped hydro scheme, saying, "This hugely wasteful project was pouring money down the drain at a time when we need to be reining in spending and focussing on rebuilding the economy and improving the lives of New Zealanders".

Climate

Notes

References

External links

Onslow Pumped Storage – Earl Bardsley
() {{DEFAULTSORT:Onslow, Lake Lakes of Otago Proposed renewable energy power stations in New Zealand Proposed pumped-storage hydroelectric power stations