In New Zealand, energy company Meridian has begun public consultations on water-only permits for the planned US$567M hydro tunnel scheme for the north bank of the Waitaki River that could include a 34km long headrace tunnel.
The water consents are a necessary prerequisite to proceed with technical assessments of options, land use and construction consents. The company proposes an intake just above Waitaki dam and either an underground power station near the intake or a surface power station 34km downstream.
The concept is currently based upon prefeasibility studies and previous investigations. Although detailed geotechnical work is yet to be undertaken, a tunnel in the range of 10m to 12m in diameter is proposed through Greywacke. Early plans call for two or three TBMs to bore the tunnel in a construction period loosely allocated as four to six years.
The tunnel scheme could generate up to 285MW per annum, six times the capacity of the existing Waitaki dam power station. Meridian said it needs 12% more water than allocated under the Waitaki Regional Plan to make the scheme viable, provision does exist for such non-complying applications. Press reports said local lobby groups have spoken out against the scheme.
