EA Networks

Reticulated electricity first arrived in Ashburton in 1908, when private company Craddock & Co established a 220-volt direct current electricity network to supply Ashburton township. The electricity was supplied from a 30 kW generator driven a steam traction engine. A network of 3300-volt and 230/400-volt alternating current lines were later established to supply the township.[2]

In 1921, the Ashburton Electric Power Board (AEPB) was established to operate the distribution network in the Ashburton area, taking over from the private companies and establishing a district-wide network of 6.6 kV and 11 kV distribution lines to replace the DC and 3.3 kV lines. In 1924, the AEPB's network was connected to the national grid and Coleridge Power Station when a 110/11 kV substation was established in central Ashburton. A second connection to the national grid was later established near Methven. After the Second World War, the AEPB established a production facility and reticulation network to supply coal gas to Ashburton township, and was subsequently renamed the Ashburton Electric Power and Gas Board. The coal gas system was disestablished in 1973 when it became uneconomical and the board reverted to its original name.[2]

By the early 1960s, the need for a sub-transmission network became apparent, and in 1967 the AEPB established its first 33 kV subtransmission lines and zone substations, supplied by three 11/33 kV step-up transformers at Ashburton substation. In 1971, the last 6.6 kV lines were converted to 11 kV. As irrigation loads increased and the subtransmission network was extended into the 1980s, two 110/33 kV grid connections were established at Ashburton and Cairnbrae, near Methven, to supply the network.[2] The AEPB also established a 1.8 MW hydroelectric power station at Montalto in 1982.[4]

In the late 1980s and early 1990s, Transpower (then a division of the Electricity Corporation) went about a rationalisation of older transmission lines in the South Island, and as a result dismantled the 110 kV lines between Hororata and Temuka which supplied Ashburton. As a result, a new 220/33 kV grid connection was established in 1992 under the Islington/Bromley to Twizel 220 kV lines at Elgin, 7 km south-east of Ashburton township, to supply the AEPB network in the Ashburton area.[2]

Also in 1992, the Fourth National Government passed the Energy Companies Act, which required electric power boards to be reformed to become commercial power companies. It was decided by the AEPB to become a cooperatively-owned company, and in 1995 became Electricity Ashburton Limited. Electricity Ashburton was subsequently responsible for subtransmission, distribution and retailing in the Ashburton District, as well as the Montalto Power Station.[2]

By 1997, the huge increase in irrigation loads were putting a strain on the 33 and 11 kV lines. To alleviate the issue, Electricity Ashburton decided to convert the 33 kV subtransmission network to 66 kV, and to convert the rural 11 kV distribution network to 22 kV (the urban distribution networks in Ashburton and Methven would remain at 11 kV due to the cost of replacing a large network of underground cables). Electricity Ashburton also took the opportunity to connect the Electricity Corporation's 26 MW Highbank hydro power station to its network instead of to Transpower's national grid, and to relinquish the Cairnbrae grid exit point and connect its entire network through the grid exit point at Elgin.[2]

In 1998, the Fourth National Government reformed the electricity sector, requiring electricity companies to split their lines and supply businesses and to sell off one of them. As a result, Electricity Ashburton decided to concentrate on the distribution business, and sold its retail base and the Montalto power station to Tauranga-based generator-retailer TrustPower in April 1999.

Electricity Ashburton has converted the majority of its sub-transmission network to 66 kV, and has converted a significant portion of its rural distribution network to 22 kV.

EA Networks is a cooperative company in which company shares are owned by consumers connected to the network. There are 30.07 million shares issued in the company: 28.75 million are owned by the Ashburton District Council in a non-rebate and non-voting form. The remaining 1.28 million are owned by consumers, each owning 100 shares in the company, regardless of how many connections to the network they have or how much electricity they use. Around 99 percent of consumers are also shareholders. Dividends from the shares are paid out in proportion to the amount of line charges each consumer pays.[5]

Each shareholder gets one vote in the election of the Shareholders Committee. The Shareholders Committee is made up of seven members: four elected by the shareholders, and three appointed by the Ashburton District Council; and is responsible for representing the shareholders, monitoring and reporting of the company's performance, and appointing the board of directors. The Board of Directors has five members, and is responsible for the corporate governance of the company.[5]

EA Network's service area - the Ashburton District - within the South Island (note the boundaries pictured are of territorial authorities, not distribution companies).

EA Networks' subtransmission and distribution network covers the Ashburton District, a 6,187 km² (2,389 sq mi) area of the South Island, bounded by the Rakaia River in the north, the Rangitata River to the south, and the Pacific Ocean to the east. The area is bound by the Southern Alps in the west, but only three distribution lines extend beyond the foothills of the Southern Alps, all along river gorges. The electricity network consists of 446 km (277 mi) of sub-transmission lines, 2,120 km (1,320 mi) of high voltage distribution lines, and 632 km (393 mi) of low-voltage distribution lines and street light circuits.[2]

There are 17,800 customers connected to the network, the largest of which include a plastics manufacturer (RX Plastics), two meat processing plants (Silver Fern Farms at Fairton and Canterbury Meat Packers at Seafield), a vegetable processing plant (Talley's at Fairton), a skifield (Mount Hutt), and a large water pumping station at Highbank (taking water from the Rakaia River into the Rangitata Diversion irrigation race). There are three major hydroelectric power generators connected to the network - Highbank (26 MW), Montalto (1.8 MW), and Cleardale (1.0 MW). The network is summer-peaking, with peak demand up to 149 MW in summer when irrigation is in use, and up to 62 MW in winter. In the year to 31 March 2012, Electricity Ashburton delivered 576 GWh of to consumers.[2]

EA Networks is supplied electricity from the national grid from Transpower's Ashburton substation, located at Elgin, 7 km south-east of Ashburton (43.94197°S 171.80148°E / -43.94197; 171.80148 (Transpower Ashburton substation)). Electricity is supplied from the National Grid at two voltages - 33 kV and 66 kV. A 33/66 kV transformer at EA Networks' Elgin zone substation, located next to Transpower's substation, provides a connection between the two supplies.[2]

The 33 kV supply from Elgin is used to supply the entire Ashburton township from the Ashburton zone substation (on the site of the former Transpower 110 kV Ashburton substation) and Northtown substation, as well as three major industrial customers at Fairton and Seafield. The 66 kV supply from Elgin is used to supply the remainder of the district, including the town of Rakaia (from Overdale zone substation) and Methven (from Methven 66kV and Methven 33kV zone substations). At the Methven 66 kV zone substation, electricity is stepped down from 66 kV to 33 kV to supply subtransmission lines to Mount Hutt, and along the foothills to Mount Somers and Montalto.[2]

• EA Networks website