Vol.13 No.4 - December 2005

 

Knock-on effects: instruments measure temperature and snowfall at Rose Ridge in the Southern Alps and low water at Lake Tekapo, May 2003. Winter snowfall helps recharge the lake following spring melt. (Photos: Bob Newland and Ian Halstead)
Graph of New Zealand mean temperature shows that the temperature has generally been increasing since about 1900.

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Wellington by night. (Photo: Alan Blacklock)
Energy drives the New Zealand economy and supports our standard of living. Our economic growth has, in part, been fuelled by our access to energy, both for production and transport. Since the 1980s we have benefited from having competitively priced energy based on the ready availability of hydro power and Maui gas, and access to imported transport fuels. Increasingly, there is more pressure on these supplies. While there is still a significant hydro resource available, little additional capacity is on the horizon.

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As one of New Zealand's largest hydropower plants, the Clyde Dam, in Central Otago, represents the big end of the scale. (Photo: Alan Blacklock)
For more on small hydro schemes see 'Energy in rural Māori communities'.
Dennis Jamieson charts hydro’s central role in powering New Zealand, and looks to the future of the resource.
Hydropower is a vital component of New Zealand’s energy supply.

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Water-level recorder and telemetry system at Ahuriri River near Omarama. (Photo: Bob Curry)
Water-level recorder at Lake Moawhango. (Photo: Bob Curry)
Bob Curry describes the present-day role of the National Hydrometric Network and the future with EcoConnect.
Managers of New Zealand’s infrastructure, industries, and resources are keenly interested in daily information on how much energy is required and how much is available. For instance, they want to know if there will be enough electricity for the next season ahead.

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Retrofitting a house at Waipoua and installing a photovoltaic system in Waihi. (Photos: Guy Penny and Neil Woodfield)
Installing the hydro generator at Waipoua.

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Picture this!
Photo: Kelson Tu’akoi
Photo: Braden Tu’akoi
Equal first prize winners in the Science Photography section at the NIWA Waikato Science and Technology Fair, brothers Kelson (left) and Braden Tu’akoi.
There’s more to science fairs than building a better mousetrap or testing the acidity of soft drinks. At the NIWA Waikato Science and Technology Fair, brothers Kelson and Braden Tu'akoi took equal first prize in the Science Photography section.

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Wright volcano
Wright volcano
An undersea volcano on the Kermadec Ridge, about halfway to Tonga and about 190 km southeast of Macauley Island, has been named after NIWA marine geologist Ian Wright.
Technically speaking, Wright is a 'volcanic centre', with two separate volcanic cones, covering about 290 km2 (about the size of Ngauruhoe volcano). Both cones rise over 1500 m, and appear to have collapsed repeatedly.
Wright volcano was discovered last year during a New Zealand-American expedition on RV Tangaroa.

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Waves off Raglan on the North Island's west coast. (Photo: Murray Smith)
Map of mean wave height. (Click for detail)
Modelled hot spots for tidal energy in Cook Strait. (Click for detail)
As harvesting the oceans' energy becomes a viable proposition, Craig Stevens, Murray Smith, and Richard Gorman describe some of the research that underpins the reality.
New Zealand sits in one of the most dynamic regions in the world’s oceans. The 'roaring forties' and 'furious fifties' can whip up waves as high as three-storey buildings.

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Lying down on the job, Jim gets up close and personal with Antarctic conditions.
Jim Renwick is one of NIWA’s climate scientists, based in Wellington. When we spoke to Jim last month, he had just returned from Antarctica. Swapping survival suit for dinner jacket, he received a prize at the Royal Society’s formal awards dinner – the Meteorological Society’s Kidson Medal for the outstanding scientific paper on a weather/climate topic.

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Increases in the numbers of river-flow (blue) and climate stations with solar radiation data (red) recording sites since 1965.
Heating degree days (HDD) and cooling degree days (CDD) for Auckland.
Maps of average annual wind speed and solar radiation based on climate-station data.
Andrew Tait, Ben Liley, John Sansom, and Roddy Henderson discuss how, with good quality data, we can improve our knowledge of our country’s substantial renewable energy resources.
New Zealand is fortunate in having large renewable energy resources for its population, supply

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Power transmission companies can now prioritise pylons for inspection, thanks to a NIWA risk-assessment tool. (Photo: Alan Blacklock)
Breach of the stopbanks during the Bay of Plenty floods in July 2004 threatened the substation near Edgecumbe, responsible for all power from there eastwards. Risk assessment can help identify vulnerable key infrastructure before it’s too late. (Photos: Environment Bay of Plenty)
NIWA research helps energy producers assess risk and devise risk-management practices.

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A 360-degree, all-sky image taken at NIWA in Lauder. (Photo: Mike Kotkamp)
Fig. 1: Average percentage of clear skies over New Zealand recorded by satellite.
Fig. 2: Annual total energy in gigajoules (GJ) per m2 under clear skies when collectors are mounted in different positions.
Solar tracking instrument. (Photo: Mike Kotkamp)
Ben Liley, Andrew Tait, and Greg Bodeker discuss what we know of New Zealand’s solar energy resource.
Solar radiation is the basis of most of our renewable energy.

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One of NIWA’s aims with this magazine is to contribute to science education in New Zealand. To this end we distribute Water & Atmosphere without charge to New Zealand high schools. Most of the magazine’s articles are assigned ‘Curriculum Connections’ to indicate which of the NZ NCEA Achievement Standards they can complement as a classroom resource.

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Conventional anaerobic pond used for treatment of dairy farm wastewater. (Photo: Rupert Craggs)
Aerobic pond designed for growing algal biomass and scrubbing CO2. (Photo: Fouad Al Momen)
Rupert Craggs heads a team that uses enhanced ponds to recover energy and produce biofuel.
Can the pond systems used for wastewater treatment by New Zealand’s rural communities, farms, and industries be turned into small power stations providing electricity for local use?

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An example of results from a numerical model shows a line across the Manawatu hills near Te Apiti wind farm. (Click for detail)
Portable wind-monitoring station in Northland. (Photo: Graeme Mackay)
The NIWA SODAR on Tararua wind farm in 2000 and a sample wind profile. A foam plastic sound baffle is placed around the instrument to improve its performance. (Photo: Errol Lewthwaite)
Pete Mason and Dennis Jamieson check out the upgraded SODAR in 2005. (Photo: Bob Newland)
New Zealand is blessed with an abundant wind resource.