energy type public traded as nzx mcy asx myt industry electric power generation predecessor ecnz mighty river power founded 1 april 1999 1999 04 01 headquarters auckland new zealand key people fraser whineray ceo products electric power services electricity retailing revenue nz 1 564m 1 operating income nz 493m 1 net income nz 160m 1 total assets nz 6 085m 1 total equity nz 3 315m 1 owner new zealand government 51.15 % number of employees 800 subsidiaries metrix metering website www.mercury.co.nz mercury energy is a new zealand electricity generation and electricity retailing company . in 2015 mercury had a 17 % share of the new zealand retail electricity market . 2 all of the company s electricity generation is renewable . it owns and operates nine hydroelectric generating stations on the waikato river and five geothermal plants in the taupo area . 3 in 2013 the company then mighty river power generated 15 % of the country s electricity and had a market share of 19 % . 4 according to its own website the company supplies 22 % of new zealand peak energy demand with about 80 % of this coming from hydro power . 5 contents 1 history 1.1 mercury energy 1.2 mighty river power 1.2.1 partial privatisation 1.2.2 name change 2 power stations 2.1 generation developments 2.2 international developments 3 subsidiaries 4 see also 5 references 6 external links history edit mercury energy edit logo of the former mercury energy mercury energy limited was formed in 1994 by the auckland energy consumer trust to own and run the electricity supply business previously operated by the community owned local authority auckland electric power board . in 1998 law changes obliged aepb to sell the electricity retailing and generation part of the business . in 1998 but after the 1998 auckland power crisis mercury energy s electricity retailing division was sold to mighty river power which was then a wholly state owned soe . mighty river power s retailing division continued the former trading name mercury energy . the electricity distribution business mercury energy limited changed its name to vector limited and continued the distribution and transmission operation . mighty river power edit logo of the former mighty river power mighty river power was established on 1 april 1999 when the 1998 reform of the electricity sector took effect . the electricity corporation of new zealand ecnz was broken up into three state owned generating companies mighty river power genesis energy and meridian energy . mighty river power took over the ownership and operation of the eight hydroelectric power stations on the waikato river new zealand s longest and also inherited the assets of two largely decommissioned oil fired power stations at marsden point near whangarei . in addition the 1998 reforms forced the separation between lines transmission and distribution and supply generation and retailing . on 1 april 1999 mercury energy then the major lines and supply company for auckland new zealand s largest city was split between lines and supply . mighty river power inherited mercury energy s retail base and its share in the southdown power station in conjunction with the natural gas corporation . mercury energy then became the name of mighty river s retail business and the sub transmission and distribution business of mercury energy was renamed vector . in 2000 mighty river purchased into the rotokawa geothermal power station to operate and maintain the station and own the geothermal turbines in a joint venture with the tauhara north no. 2 trust . also that year mighty river power commissioned the mokai geothermal power station in a joint venture with the tuaropaki trust . one aspect that sets mighty river power apart from other geothermal generators is that it works in partnership with m ori landowners the t ngata whenua to benefit both mighty river power and the t ngata whenua . citation needed in september 2002 mighty river gained 100 percent ownership of the southdown power station . in 2004 mighty river announce plans to refurbish the marsden b plant to fire it on coal to increase supply security north of auckland . marsden b had been mothballed since it was completed in 1978 due to rising oil prices following the 1973 oil crisis and there being cheaper alternatives available . greenpeace staged a nine day occupation of the site in 2005 and after the northland regional council granted consent appealed to both the environment court and high court eventually overturning the consent . mighty river appealed the high court decision to the court of appeal but in march 2007 dropped the proposal . in 2008 mighty river increased its generating capacity by opening the 100 mw kawerau geothermal power station increasing supply security to the eastern bay of plenty a large timber processing area . in 2010 it opened the 140 mw nga awa purua geothermal station near taupo complete with the largest single shaft geothermal turbine in the world . the commissioning of nga awa purua increased mighty river s geothermal capacity to 385 mw becoming the nation s largest geothermal electricity generator with 52.7 percent of all installed geothermal capacity . partial privatisation edit in december 2011 the national government announced plans to reduce its shareholding in mighty river power as well as in the three other state owned energy companies from 100 percent to 51 percent and to sell off the remaining 49 percent as part of its controversial mixed ownership model plan . mighty river power was to be the first company to be partially sold in september 2012 pursuant to legislative changes and market conditions . 6 7 however threatened legal action and unfavourable market conditions saw the government delay any sale until march 2013 at the earliest . 8 the government began taking registrations of interest from the public in mighty river power shares on 5 march 2013 . 9 10 more than 35 000 people tried to register in the first six hours 11 causing the registration website to crash for much of the day . 12 13 by midnight more than 90 000 people had registered . 14 15 in anticipation of the sale in april 2013 state owned enterprises minister tony ryall said director fees would be increasing from 49 000 a year to 85 000 and the chair s fees from 98 000 to 150 000 despite still being majority owned by taxpayers . the financial markets authority approved the sale of mighty river power on 12 april with the initial public offering ipo opening on 15 april . 16 however the ipo was temporarily suspended on 22 april while a supplementary disclosure was issued after the labour and green parties in opposition announced plans to reform the electricity market if elected to government at the 2014 election . at the close of the ipo on 5 may there were 113 000 shareholders and on 8 may the opening share price was set at 2.50 raising 1.7 billion . 17 the government was slightly disappointed blaming the labour green policy for putting off many more potential shareholders and with the finance minister indicating before the policy was announced that the price would be in the 2.70 to 2.80 range . 18 the government retained 51.78 percent of the shareholding with another 1.02 percent owned by other crown interests mainly the new zealand superannuation fund . 19 by september shares had slumped to 2.16 well below the float price 20 and in october the company announced it would be buying back up to 50 million in shares . 21 by november 2015 the share price had exceeded the listing price at 2.88 . the gas fired southdown power station a 170 mw combined cycle power station in south auckland was closed in december 2015 . name change edit the company announced that it will change its name from mighty river power limited to mercury nz limited on 29 july 2016 . 22 power stations edit mercury operates 13 power stations all in auckland waikato and the bay of plenty . in total the company has 1638 mw of generating capacity composed of 1078 mw hydroelectric 385 mw geothermal and 175 mw natural gas . name type location capacity mw annual generation average gwh 23 commissioned notes arapuni hydroelectric waikato river 196.7 805 1946 aratiatia hydroelectric waikato river 78 330 1964 atiamuri hydroelectric waikato river 84 289 1962 karapiro hydroelectric waikato river 96 490 1948 kawerau geothermal kawerau bay of plenty 100 800 2008 maraetai hydroelectric waikato river 360 885 1954 1971 mokai geothermal north west of taupo 112 900 2000 joint venture with tuaropaki trust nga awa purua geothermal north of taupo 140 1100 2010 joint venture with tauhara north no. 2 trust world s largest geothermal turbine 147 mw rated ngatamariki geothermal north of taupo 82 2013 ohakuri hydroelectric waikato river 112 400 1962 rotokawa geothermal north of taupo 33 210 1997 joint venture with tauhara north no. 2 trust waipapa hydroelectric waikato river 51 242 1961 whakamaru hydroelectric waikato river 100 494 1956 generation developments edit name type location planned capacity mw status puketoi wind puketoi ranges consent application lodged august 2011 . 24 granted june 2012 25 te ia a tutea geothermal north east of rotorua initial exploration 26 turitea wind south east of palmerston north 180 consents approved international developments edit name type location planned capacity mw status hudson ranch geothermal california usa 50 opened may 2012 26 tolhuaca geothermal southern chile exploration 26 puchuldiza geothermal northern chile 27 weilheim geothermal germany exploration 26 subsidiaries edit in addition to its generation assets mercury also incorporates or has major shareholdings in bosco connect an electricity retailer to inner city apartments metrix a metering and meter reading business tiny mighty power 28 an electricity retailer glo bug a pre pay electricity retailer see also edit electricity sector in new zealand list of power stations in new zealand references edit a b c d e annual report 2016 pdf . mercury energy . 23 august 2016 . market share snapshot . electricity authority new zealand . retrieved 10 march 2016 . generation . mercury energy . energy in new zealand . mbie . july 2014 . mighty river power about us generation . mighty river power . retrieved 1 december 2007 . romanos amelia ; bennett adam 15 december 2011 . mighty river power first soe to go . the new zealand herald . retrieved 12 january 2012 . mighty river power first state owned asset to be sold english . 3 news . 15 december 2011 . retrieved 12 january 2012 . watkins tracy 3 september 2012 . sale of mighty river power delayed . fairfax media via stuff.co.nz . retrieved 15 october 2012 . gower patrick 5 march 2013 . mighty river sale opens . 3 news nz . market may take a hit as mighty river sale attracts huge interest . nz herald . 4 march 2013 . brokers contact mighty river investors . 3 news nz . 6 march 2013 . mighty share website crashes . 3 news nz . 5 march 2013 . mighty river share website crashes . nz herald . 5 march 2013 . mighty river share registration high . stuff.co.nz . 6 march 2013 . demand for mighty river hits 90 000 . 3 news nz . 6 march 2013 . mighty river sale gets fma approval . 3 news nz . 12 april 2013 . hutchison jonathan 10 may 2013 . shares rise after i.p.o. of new zealand power utility . ny times . bennett adam 9 may 2013 . mighty river 2.50 price hit by power policy . the new zealand herald . retrieved 9 may 2013 . parker tasmyn 17 may 2013 . stock takes mighty nervous . the new zealand herald . retrieved 17 may 2013 . mightyriverpower pair snap up shares . 3 news nz . 30 september 2013 . mighty river power to buy back shares .