The Huntly Power Station is the largest

thermal power station A thermal power station, also known as a thermal power plant, is a type of power station in which the heat energy generated from various fuel sources (e.g., coal, natural gas, nuclear fuel, etc.) is converted to electrical energy. The heat ...

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

and is located in the town of

Huntly Huntly ( or ''Hunndaidh'') is a town in Aberdeenshire, Scotland, formerly known as Milton of Strathbogie or simply Strathbogie. It had a population of 4,460 in 2004 and is the site of Huntly Castle. Its neighbouring settlements include Keith ...

in the

Waikato The Waikato () is a region of the upper North Island of New Zealand. It covers the Waikato District, Waipā District, Matamata-Piako District, South Waikato District and Hamilton City, as well as Hauraki, Coromandel Peninsula, the nort ...

. It is operated by Genesis Energy Limited, a publicly listed company (currently 51% owned by the NZ Government). The station has five operational generating units – three 250 MW coal-and-gas-fired steam turbine units, a 50 MW gas peaking plant, and a 403 MW combined cycle gas turbine plant. The station also plays an important role in voltage support for the Northland, Auckland and Waikato regions.

Operation

Generation

Each of the four original generating units, which are capable of burning either coal or gas, installed in stages between 1973 and 1985, is capable of generating 250 MW (

Megawatt The watt (symbol: W) is the unit of Power (physics), power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantification (science), quantify the rate of Work ...

s) of

electricity Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwel ...

, giving a historical generating capacity of 1000 MW. Its chimneys are 150 metres high and each chimney has two flues that are 7 metres in diameter. The plant uses a reheat steam cycle, with C A Parsons turbines and Combustion Engineering boilers. In 2004 the power station was upgraded with the addition of a 50 MW gas turbine plant, and in 2007 the

combined cycle A combined cycle power plant is an assembly of heat engines that work in tandem from the same source of heat, converting it into mechanical energy. On land, when used to make electricity the most common type is called a combined cycle gas turb ...

gas turbine A gas turbine or gas turbine engine is a type of Internal combustion engine#Continuous combustion, continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas gene ...

(CCGT) plant was commissioned. This plant increased the total generating capacity of Huntly by 403 MW (250 MW gas turbine + 153 MW steam turbine). The new turbine represented an investment of NZ$520 million and it increased the total installed capacity to 1453 MW. In 2007, Huntly operated at a load factor of 85% and was providing a large amount of the baseload energy needs of the northern

North Island The North Island ( , 'the fish of Māui', historically New Ulster) is one of the two main islands of New Zealand, islands of New Zealand, separated from the larger but less populous South Island by Cook Strait. With an area of , it is the List ...

. In 2007, the plant was mainly gas-fired, but a dry winter in 2008 prompted more coal thermal generation. In December 2012, Genesis Energy placed one of the four Huntly Power Station 250 MW units into long-term storage. The second coal-fired 250 MW unit was permanently retired in June 2015 after being placed in storage (with a 90 day return to service) in 2013. In February 2021, a third 250 MW unit was brought back online to assist with drought and gas shortages and made available until September 2021. Most of the coal it is burning is imported from Indonesia, with much of it coming to Huntly by truck from Ports of Auckland, while some comes by rail from the Port of Tauranga.

Fuel and coolant

The four 250 MW units were constructed as dual fuel, able to operate on natural gas from Taranaki or coal from the nearby Rotowaro coal mine. A 10 km conveyor belt was constructed to carry coal from the mine to the power station. Previous to the substitution of coal, Huntly used gas from the fields to power the generation of the main units as well, but these were switched in the 1990s because of dwindling resources. Natural gas to power units 5 and 6 comes from several gas fields in

Taranaki Taranaki is a regions of New Zealand, region in the west of New Zealand's North Island. It is named after its main geographical feature, the stratovolcano Mount Taranaki, Taranaki Maunga, formerly known as Mount Egmont. The main centre is the ...

. The gas is transmitted along the 307 km, 750 mm diameter Maui gas pipeline from Oaonui production station near Opunake, which was commissioned in 1979 to supply the station. The station uses water from the

Waikato River The Waikato River is the longest river in New Zealand, running for through the North Island. It rises on the eastern slopes of Mount Ruapehu, joining the Tongariro River system and flowing through Lake Taupō, New Zealand's largest lake. It th ...

for cooling. However, in order to protect aquatic life, conditions are imposed by the resource consent (issued under the

Resource Management Act The Resource Management Act (RMA) passed in 1991 in New Zealand is a significant, and at times, controversial Act of Parliament. The RMA promotes the sustainable management of natural and physical resources such as land, air and water. New Zea ...

), specifying the quantity of water that can be removed by the station along with the maximum temperature of the water when returned to the river (25 °C). These conditions mean that on very hot summer days the station cannot operate at maximum capacity, and has sometimes effectively been shut down. A new

cooling tower A cooling tower is a device that rejects waste heat to the atmosphere through the cooling of a coolant stream, usually a water stream, to a lower temperature. Cooling towers may either use the evaporation of water to remove heat and cool the ...

has been built as part of expansion works at the site, which allows one 250 MW unit to run at full load even during such times.

Transmission and distribution

The majority of the energy generated at Huntly Power Station is transmitted through the national grid to

Auckland Auckland ( ; ) is a large metropolitan city in the North Island of New Zealand. It has an urban population of about It is located in the greater Auckland Region, the area governed by Auckland Council, which includes outlying rural areas and ...

, New Zealand's largest city, which lies to the north of the station. Huntly is connected to the rest of the national grid via a large substation switchyard and six 220 kV transmission circuits carried on three high capacity

transmission lines In electrical engineering, a transmission line is a specialized cable or other structure designed to conduct electromagnetic waves in a contained manner. The term applies when the conductors are long enough that the wave nature of the transmis ...

. These transmission lines are: * a double circuit line (HLY-TMN-A) to Stratford in

, via Te Kowhai and

Taumarunui Taumarunui is a small town in the King Country of the central North Island of New Zealand. It is on an alluvial plain set within rugged terrain on the upper reaches of the Whanganui River, 65 km south of Te Kūiti and 55 km west of T� ...

* a double circuit line (HLY-OTA-A) to

Ōtāhuhu Ōtāhuhu is a suburb of Auckland, New Zealand – to the southeast of the CBD, on a narrow isthmus between an arm of the Manukau Harbour to the west and the Tāmaki River estuary to the east. The Auckland isthmus is the narrowest connect ...

substation in Auckland, via Drury and Takanini * a double circuit line (HLY-DEV A) to the Ohinewai switching station, where it connects with the Otahuhu to Whakamaru C line The Huntly switchyard also includes a grid exit point for supply to the local 33 kV

distribution Distribution may refer to: Mathematics *Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations *Probability distribution, the probability of a particular value or value range of a varia ...

network in the Huntly area, where the 35 MW / 35 MWh Rotohiko battery started in 2024.

Future

The plant contributes over half of New Zealand's emissions of greenhouse gases from electricity generation, has repeatedly drawn the ire of

environmentalists Environmentalism is a broad philosophy, ideology, and social movement about supporting life, habitats, and surroundings. While environmentalism focuses more on the environmental and nature-related aspects of green ideology and politics, ecologi ...

and has been the focus of associated protests. A 2006 government report outlining future

climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...

mitigation and energy policies was seen by the operator as a sign that the plant might have to be closed by 2015 under these plans, with around 10 years of design life still remaining. It was also noted that, apart from being difficult to replace as a source of power (due to New Zealand's annually growing generation demand, especially around

), such a decision would also be uneconomical for the foreseeable future, even if coal prices were to rise. In May 2012, resource consent was granted by the Waikato Regional Council to continue running the gas and coal units for a period of 25 years. In April 2016, Genesis Energy announced that the Huntly Power Station would continue operation of its two remaining coal / gas burning units until December 2022. The two gas turbine generators would continue to operate into the future. Company chief executive Marc England has stated "By 2025, Genesis will only use coal in its thermal units in abnormal market conditions, and it is our intent to remove coal completely by 2030". Genesis plans a trial of bio-fuel over summer 2022/23, and builds a 100 MW / 200 MWh grid battery for winter 2026.

In popular culture

In the online game ElectroCity, run by Genesis Energy,

coal-fired power station A coal-fired power station or coal power plant is a thermal power station which burns coal to generate electricity. Worldwide there are about 2,500 coal-fired power stations, on average capable of generating a gigawatt each. They generate ...

s take the form of Huntly. The Huntly Power Station features in the video for the

Purple Pilgrims Purple Pilgrims is a New Zealand dream pop duo composed of sisters Clementine and Valentine Nixon. Background Sisters Clementine and Valentine Nixon are great-granddaughters of folk musician Davie Stewart. They were raised itinerantly between ...

song "Two Worlds Apart"''.'' The power station is featured as an external setting for the 2002 television film Atomic Twister, fictionally named as Hellman-Klein Nuclear Power Plant in

Tennessee Tennessee (, ), officially the State of Tennessee, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Kentucky to the north, Virginia to the northeast, North Carolina t ...

. It appears, fully modelled, in ''Microsoft Flight Simulator'', where it was added on February 23, 2023 as part of a free update. The Huntly Power Station is featured in '' A Minecraft Movie'' as the potato chip factory.

References

External links

Huntly Power Station
(from the Genesis Energy Limited website) {{Electricity generation in Waikato Coal-fired power stations in New Zealand Natural gas-fired power stations in New Zealand Buildings and structures in Waikato Huntly, New Zealand 1980s architecture in New Zealand Brutalist architecture in New Zealand