New Zealand utility Contact Energy invites comments on four options to develop hydropower on the Clutha River ranging from 86 MW to 350 MW.
Contact invited comments on a special Internet site linked to the utility website, www.contactenergy.co.nz.
�Normally, developers select a preferred project upon which they consult with the community,� the Contact website said. �We don’t yet have a preferred option — we want to hear people’s views more generally and on each of the options that we are currently reviewing.�
The utility said it wants people to tell Contact what they think about the possibility for new hydro development and what ideas they might have for possible hydro schemes. It proposes to announce a preferred option in 2010, leading to further discussion of a more clearly defined proposal.
The four hydro schemes under consideration were inherited by Contact Energy from its predecessor, Electricity Corp. of New Zealand.
Options include 350-MW Tuapeka Mouth, 185-MW Beaumont, 160-MW Queensberry, and 86-MW Luggate.
350-MW Tuapeka Mouth
The Tuapeka Mouth project is the largest and the most invasive of the four options.
Located on the Clutha River, 2 kilometers above the mouth of the Tuapeka River, Tuapeka Mouth would feature a 50-meter-tall, 520-meter-long roller-compacted concrete dam creating a 3,400-hectare reservoir. It would inundate Beaumont township and much of Rongahere Gorge, requiring relocation of the township and its residents.
Four steel penstocks of 7.8 meters in diameter would supply four turbine-generators, likely to be Francis units. It would generate an estimated 1,950 gigawatt-hours per year.
The Beaumont project would include a 30-meter-tall concrete gravity dam and powerhouse, 4 kilometers upstream from Beaumont on the Clutha. It would create a 620-hectare reservoir extending 23 kilometers upstream and inundating an area above the dam similar to that of the Tuapeka Mouth project.
Four steel penstocks of 7.8 meters in diameter would supply four turbine-generators, either Kaplan or Francis units. It would generate an estimated 1,070 GWh per year.
The Queensberry project would include a relatively low, 14-meter-tall concrete gravity dam just upstream from Poison Creek on the Clutha. Queensberry’s 220-hectare reservoir largely would be confined to the existing river channel.
It would feature a powerhouse at the dam, plus a canal, either 12.5 kilometers long or 9.5 kilometers long, to a second powerhouse at Kidd Creek.
The dam powerhouse would have either Kaplan or bulb-type turbines, while the canal powerhouse would utilize two Francis units. The project would generate an estimated 850 GWh per year.
The smallest project, Luggate would feature a 25-meter-tall concrete gravity dam, 2 kilometers downstream from Luggate Bridge. Its 230-hectare reservoir largely would be confined to the existing river channel.
Three steel penstocks would feed three turbines, either Kaplan or Francis type. The project would generate an estimated 500 GWh per year.