Some Original Bores Are Still Supplying Steam

Taupo Times, Volume XIV, Issue 64, 17 August 1965, Page 1

Some Original Bores Are Still Supplying Steam

Five of the steam bores put down 13 years ago are still being used to supply Wairakei geothermal poiver station. Although the quantity of steam from these original bores has dropped slig'htly, they are still efficient. The project engineer, Mr A. C. L. Fooks, made this comment when a new bore to feed the station was opened up yesterday morning.

The bore is about 2000 ft. deep and will be used in the steam supply to the generating station, along with twb others previously opened up. Mr Fooks said that the new bores would be connected up by next winter. They will replaee bores wThich have been running down. The one opened yesterday appeared to be quite a reasonable one, he added. The new bores have yet to be equipped with separators, to separate the steam from water, and will later be connected up to the steam mains leading to the power station. Where the pressure of some of the original bores has dropped beyond that which is capable of feeding the high pressure lines to the power house, they have been shut down. There are at present 58 bores being used to supply the turbines. The steam is fed through five high pressure and four low pressure lines and produces a steady output of power of about 165,000 kw. As a comparison, the Aratiatia hydro power station produces about 80,000 kw. Inthe process, 2,700,0001bs. of steam an hour are used to drive the 13 turbines. When it has passed through the last turbine, it is eondensed,

and flows into the Waikato River at the rate of 270,000 gallons an hour. This is equal to about a 15 cusec flow of water, compared with the flow of the Waikato River at about 4500 cusecs. The water separated from the steam at the bores is equal ot about 50 cusecs. Since 1956, surveys for steam have been made outside Wairakei, and up to 150 men have been employed at times, directly and indirectly, on investigation drilling. The number fluctuated, Mr Fooks said. There was, however, one drill rig being operated by 15 men continuously and others were employed 011 ancillary works.

The aim was to determine a pattern of prospective fields around the Wairakei area, Mr Fooks said. Seven bores had been put down at Waiotapu, three at Oraki Korako and one at Te Kopia. There were more than 20 at Te Mihi, which is an extension of the present Wairakei bore field to the west. Surface indications were that these fields would be worth-while for geothermal power generation. Preparations have also been made for investigating fields at Broadlands and Rotokawa. A thermal area at Ngawha, near Kaikohe, was also being investigated, Mr Fooks said.