Page 4 – Hydro and the environment
Environmental and social concerns began to make an impact on hydroelectric projects from the 1960s. The first sustained opposition to planned work occurred in relation to Lake Manapōuri.
Manapōuri and aluminium
New Zealand’s cheap and plentiful hydro resources were attractive to the electricity-hungry aluminium-smelting industry. The government signed a contract with Comalco in 1960, giving the company the right to use Manapōuri power for 99 years for a smelter at Bluff. Work on a power station began three years later.
The government proposed to raise the water level of Lake Manapōuri to ensure security of supply to the aluminium smelter. The resulting controversy became a benchmark against which public involvement in environmental issues in New Zealand would be measured.
The proposal attracted considerable opposition from the latter half of the 1960s. In the early 1970s the Save Manapōuri campaign mobilised New Zealanders who wanted to protect its pristine wild environment. Manapōuri became an election issue, and when Labour became the government in 1972 they decreed that the lake would not be raised.
A powerhouse was built deep underground, with a long tailrace tunnel, in inaccessible and rugged country. It was completed in 1971. In the late 1990s a second tailrace tunnel was bored to increase the station’s power output.
Death on site
The Manapōuri Project was not just difficult politically. In 1967 alone, with 1,000 men on site, there were 223 serious accidents, and 18 men died during construction of the power station. Tunnelling was particularly hazardous – deaths occurred due to rock falls, accidents with the trains, and during drilling.
Damming the Clutha River
Following Roxburgh, the Clutha River was studied for added hydro potential. Up to five dams were considered, from Tuapeka below Roxburgh, to Clyde and other sites upstream of the existing station. An earth dam constructed in the late 1950s raised Lake Hāwea substantially to improve storage.
Control of the level of Lake Wānaka for storage was then considered. By the 1970s, when proposals became firmer, the public’s increased environmental awareness, and a growing tourism industry, made the process of getting projects approved far more difficult. Control of Lake Wānaka became politically impossible.
Water flow is critical to hydroelectrical generation. Droughts in 1972 and 1973 resulted in electricity rationing. Shop window lighting, neon advertising and flood lighting were all banned, and domestic users were urged to ‘save power, shower with a friend’.1
Attention began to focus on a dam at Clyde, with its height a matter of great debate. The National government decided on a high dam in 1976, and construction began in 1979. As a result of feared planning-permission delays to the project, the government passed empowering legislation in 1982 to get the dam built. The Clyde dam was finished in 1990, and commissioned in 1992 – after extensive stabilisation work in the gorge that was to become Lake Dunstan.
End of an era
After 1990 there were no more large government-commissioned hydro stations. Electricity Corporation New Zealand, set up by the government in 1987, focused on improved efficiencies in generation through upgrading turbines and generating equipment, and the automation and remote control of stations. Since the commissioning of the Clyde station in 1992 there has been no substantial increase in hydro capacity in New Zealand.
Potential hydroelectric development, 1990
A report in 1990 identified large potential hydro resources of up to 12,380 megawatts which could be exploited – 80% were in the South Island, in Canterbury, the West Coast, Otago and Southland. The report suggested it would be worthwhile to study the plentiful water resources on the West Coast (hardly developed for hydro power at all), and how they might be channelled eastwards to supplement river flows.
More than 2,000 megawatts, much of it in the South Island, was identified as having few apparent problems for development. From the perspective of the 1990 report it appeared that New Zealand would be well-served in the future, but two decades later not one of the potential schemes had been developed.