Plans akin to 'shooting last tiger'

BY PENNY WARDLE

Putting a hydro scheme on the Wairau River has been compared to shooting the last tiger, at an Environment Court hearing in Blenheim.

Save the Wairau lawyer Mike Hardy-Jones argued on Monday that New Zealand's future power generation lay with geothermal energy and the country should skip the step of using up all available rivers. "Why shoot the last tiger, so to speak," he said. "Then we will have both the power and the values of pristine rivers."

At 370 gigawatt hours (GWh) , the Wairau scheme represented only about four months of New Zealand's yearly increase in power consumption, he said.

TrustPower expert witness Brent Layton argued that extra generation offered by the hydro-electric power scheme proposed for the Wairau River would be critical to Marlborough and New Zealand.

The court is considering whether the electricity generation and retail company should be granted necessary consent, after earlier approval by a Marlborough District Council appointed panel was appealed.

In the short term, there was no need to panic about energy supply in New Zealand not matching demand, said Dr Layton, a senior fellow of the New Zealand Institute of Economic Research. But that could change if too many proposed power schemes were denied resource consent.

Each year the Nelson Marlborough region used 1145GWh of electricity and generated 260GWh, said Dr Layton. The Wairau scheme would produce 370GWh a year, adding about 0.8 per cent to national generation capacity. Dr Layton listed benefits including cost competitive electricity from a renewable resource and improved security of supply, especially when hydro lakes were low.

Because electricity prices in New Zealand reflected transmission losses, power bills in Marlborough tended to be higher than in areas with significant generation nearby, said Dr Layton. If the Wairau scheme was built, savings were a benefit, whether passed on to consumers or captured by TrustPower.

Asked by Fish & Game lawyer Maree Baker what percentage of its electricity Marlborough would have to import if the scheme went ahead, Dr Layton said he'd calculated 45 per cent plus.

"Do we have the ability to sustain the region if it gets islanded (cut off)," she asked.

With the new Wairau scheme running and all Marlborough and Nelson generation working full tilt, the district got close to meeting average demand but there would be a large shortfall at peak periods, he said. However, what was relevant to consumers was not capacity but electricity that was available when they needed it, he said.

"If we ran every New Zealand power station at 100 per cent for 24 hours, 365 days a year, they would generate 82,000GWh; twice their actual output," said Dr Layton.

Hydro schemes' output was less than 50 per cent of full capacity compared with around 40 per cent for windfarms, while gas was in the 90s.

Wairau would generate about 370GWh; sufficient for 50,000 homes, he said.

While relatively small, the scheme could be nationally useful because limited storage in canals and headponds meant generation could be "ramped up" for short periods.

Comparative flow figures suggested that the scheme would be especially complementary with the Waitaki system, which provided about 65 per cent of national hydro storage capacity.

Government's ratification of the Kyoto Protocol created an extra incentive to harness renewable energy, said Dr Layton.

The Wairau plant's generation of an additional 370GWh a year would avoid 140,000 tonnes of CO2 a year compared with gas and 333,000 tonnes compared with coal.

- The Marlborough Express