Reduction in Clutha power?

Press, 24 September 1981, Page 26

Reduction in Clutha power?

By

Bryan James,

"Otago Daily Times, through NZPA

Recent studies of official Ministry of Energy and forecasts showing a likely 16 per cent reduction in the Upper Clutha Power Scheme’s energy potential have also shown that the potential from the lower Clutha has been more than halved by the planners. The 1981 Energy Plan said a low dam scheme, which minimised the loss of productive agricultural land, could provide an additional 1000 gigawatt hours of energy a year from the Clutha below Roxburgh. Yet just a year ago, the power planners said this section of the river could produce 2300 gigawatts of electricity.

The 1981 plan does not specify how many dams, or where they should be, but recently in Dunedin, the District Commissioner of Works. Mr R. D. Grant, said it was likely one would be at Tuapeka Mouth, where the Tuapeka River joins the Clutha, with possibly one other at Beaumont, further upstream. The plan suggests that the lower Clutha scheme could not begin producing power before 1995. although the 1980 plan said the investigations were at a stage then at which approvals to proceed would be feasible within two or three years. The 1981 plan said the scheme could be constructed at costs comparable or cheaper than the series of low dams planned for the Lower Waitaki River.

It said increased emphasis is being placed on the need to save agricultural land from inundation, and this may result in a reduction of the Lower Clutha Scheme's forecast potential and an increase in the cost of the electricity produced. "The potential development may be reduced to 1100 gigawatts or less," the plan said. This is about equivalent to the energy generated from the Ohau A power station on the Upper Waitaki. In documents contributing to the 1980 plan, the lower Clutha was said to have a potential output of more than 2000 gigawatts at the same order of unit cost as the Upper Clutha.

One of the documents speculated on the prospects of moving to the lower Clutha after building the Clyde Dam. and using the equipment and works teams on a similar concrete dam at an unspecified site. This option was never officially exercised, and the Clyde Dam

will be built by private contract.

From a figure of 2300 gigawatts a year ago, the energy output' of the low’er Clutha went to “over 2000 gigawatts" in one of its constituent reports; to "1100 gigawatts or less" in a constituent report of this year's energy plan, to an additional 1000 gigawatts in this year's plan.

In December last year, after the “Otago Daily Times" had disclosed that Ministry of Works and Development survey' teams were making physical surveys of potential dam sites, the Minister of Energy (Mr Birch) said that lower Clutha hydro proposals would exclude high dams that would flood large areas of high value land. The intention to investigate the river's hydro potential from below Roxburgh was made public in May last year.

"I have directed the Electricity Division, with the Power Division of the Ministry of Works and Development,. to: follow a set of guidelines,” Mr Birch said. “These are that high value agricultural land is to be recognised; that efforts be made to define, proposals that minimise the amount of such land that would be flooded, while generating as much electricity as possible, that site investigations be restricted to those sites at which objectives would be achieved; and that no further work should be done on proposals which are already known to involve considerable impact on farmland." Both energy plans stress the urgent need to develop the country's hydro electricity resources to meet forecast demands and retain a "reserve" for dry years. The 1981 plan emphasises that by 1985 hydro electricity, which is the cheapest form to develop. will provide 76 per cent of this demand. The forecast reductions in previously planned or expected energy potential from the whole Clutha River system could mean more emphasis by the power planners on developing hydro resources elsewhere, such as the' Waitaki system. The lower Waitaki dams, for example. did not figure in last year's Energy Plan, yet they are now incorporated in this year's 10-year forecast cycle, with the first dam shown to be producing power in five years. New information concerning the Upper Clutha power development vindicates information put forward by the Otago Catchment Board to

the Planning Tribunal last year, according to Dr A. F. Mark, a member of the Catchment Board.

At a board meeting. Dr Mark said that staff members were seriously challenged at the planning hearing, and the board's objection to granting water rights for the Clyde Dam was overturned.

Dr Mark recommended that the board should take the matter up with the national authority and find out what the position is now, and that the decision to grant water rights for the high dam was made invalid information.

The board's recommendations were overturned on the basis that the value of the power was greater than the value of the land resources that would be flooded. The tribunal also heard objections from a number of residents.in the high dam area, and f came to a split decision, with a 3-2 vote to uphold the tribunal's decision. Dr Mark said that in the public interest, the figures for the cost of power from the high dam must now be questioned and re-evaluated.