Arno Gasteiger

Reaping the wind

Like huge mechanical locusts, turbines at the Tararua Wind Farm harvest the breezes that funnel through the hills near Palmerston North. Is this the look of the future for our landscape? With diminishing gas reserves, fluctuating hydro lake levels and mounting pressure to reduce carbon dioxide emissions, interest in alternative energy source is growing. A “sunset clause” in New Zealand’s electricity-supply legislation and the high cost of getting power to remote homes make DIY generation worth a serious look.

Written by       Photographed by Arno Gasteiger

Every morning when Les and Beverley Black­well wake up, their thoughts drift to a small grassy knob behind their home on Great Barrier Island. There, on top of the hill, their thoughts drift wind turbine is most probably “churning away like a sewing machine.”

“It’s withstood some tremendous storms, and the first thing we do when we get up is to check that it is still there,” says Les.

The turbine has been part of the Blackwells’ power sys­tem for six years and, to­gether with three solar panels mounted on the roof of their garage, generates more electric­ity than they can use. It has also become a land­mark along the stretch of sealed road between Tryphena and Claris that overlooks Med­lands Beach and the dunelands that shelter the Blackwells’ home and orchard.

Both Les and Beverley descend from pioneering families who carved their names into the landscape of the rug­ged Hauraki Gulf island. Like the rest of the thousand or so perma­nent residents on the Barrier they have never known the convenience of mains power and are used to kerosene lamps, candles and the drone of a die­sel generator. It wasn’t until Les re­tired that they decided to join the growing number of people switching to renewable-energy sources.

“We loved the idea of 24-hour power,” says Beverley. “Diesel was getting very costly, so we decided to find out about other options.”

They started with one 120 W so­lar panel and a small battery bank, but gradually their alternative set-up grew to three panels, the “windmill” and 12 deep-cycle batteries. They sold the 6 kW diesel generator that had been their main power source and now rely on a vintage 1935 Lister engine as an emergency back-up for the rare periods of overcast, windless weather. The Lister, six trusty horsepowers inside the immaculately polished framework of a museum piece, chugging away for eight hours on a gallon of diesel, is Les’s pride and joy. But as much as he loves cranking it up, the Blackwells rarely need it these days and start it “per­haps once a month, even less at times, and mostly just to keep it in running order.”

Great Barrier Island is the largest community in the country without reticulated power, and perhaps half of the island's residents and organisations—including the police—are reducing their dependence on generators by tapping the power of sun and wind.
Great Barrier Island is the largest community in the country without reticulated power, and perhaps half of the island’s residents and organisations—including the police—are reducing their dependence on generators by tapping the power of sun and wind.

Beverley says the system “was hard to live with for starters when you had to keep an eye on everything so you didn’t use too much, but now we’ve got the hang of it and are really thrilled with it. The special thing about the windmill is that it is still working at night, so you go to bed when your batteries are perhaps a bit low and you wake up the next morn­ing and everything’s fully charged up.”

Great Barrier Island is New Zea­land’s largest community without a power plant or connection to the national grid. There are no power poles or power lines. Instead, the island’s homes are festooned with wind turbines, solar panels, solar water heaters (or simple coils of black plastic pipe) and all sorts of inventive contraptions whose power-generating function is not immedi­ately obvious. A grey box in the middle of a paddock just out of Claris, with countless aerials and solar pan­els hanging off it, serves as the local telephone exchange.

The Barrier’s diesel generators are gradually being relegated to a sup­porting role, bursting into action mostly to back up renewable-en­ergy sources. The switch hasn’t been without challenges, but to many islanders that is part of the appeal.

In 1989, Barrier resi­dents rejected a proposal by an Auckland com­pany to build three small diesel-fired power plants at Tryphena, Claris and Okiwi. In its application, the company promised the island would finally catch up “a century after the first regular electric­ity supply was provided in New Zealand.” The proposal offered elec­tricity to every home that joined the scheme, but at a cost five times that of grid power on the mainland. The islanders turned down the proposal, and today use only as much power as they can generate themselves, forfeiting luxuries such as street lighting and night landings at the small airstrip.

But relying on renewable-energy sources doesn’t mean a feral existence at the whim of the weather, says Murray Willis, who has installed a number of alternative power systems on the island. “Living on the Barrier is simply a matter of designing your house with renewable-energy sources as an integral part.”

The home he shares with his wife, Jan, is testimony to that principle. Nestled in native bush on Harpoon Hill, overlooking Whangaparapara Harbour, it is an octagonal open-plan dwelling designed to bathe in the sun from dawn to dusk a far cry from the stereotypical alternative lifestyler’s shack with next to no crea­ture comforts. Fridges, freezers, a washing machine, food processors, a bread-maker, a cappuccino maker, several computers, an electronics workshop with power tools and even a dehumidifier all run happily on electricity generated by solar panels, a wind turbine and a small water tur­bine turned by a creek that runs through the neighbour’s property.

“It’s absolutely wonderful,” says Great Barrier resident Beverley Blackwell of her and husband Les’s renewable-energy system, which consists of a wind turbine, photovoltaic panels, batteries and an inverter. “I love having 24-hour-a-day power. Before, I had to do things like washing in the evening, when the generator was going. And the house is so quiet now.” She says women on the Hauraki Gulf island have become very knowledgeable about alternative power. “We often get together and talk about it. It makes a difference from talking about what we’re going to wear!”

A copper kettle on the gas hob is one of few clues that this is a place where the inhabitants have put some thought into energy efficiency. “It heats water faster than an electrical jug,” says Willis. “We don’t have an electric toaster either, and no electric heating. We rely on passive solar heating, gas and a wood stove to heat the place and our water.”

For any household, hot water, heating and cooking are the biggest electricity guzzlers, and for grid-con­nected homes they make up most of the power bill. To Willis, using gas-produced electricity to heat water seems “almost criminal.”

“To use natural gas to heat water to run turbines to produce electricity and to then use that electricity to heat water again in the home wastes most of the energy in the gas. It’s much more efficient to use the gas directly in califonts, but in our generation ‘califonts’ is a bad word because most people remember them as things that hung over the bath and exploded in flashes of light and flame!”

Willis says the hardest places on the island to power purely through renewable sources are the handful of shops and cafes that rely on large freezers. They still need to run diesel generators. But the medical centre, police station, a chemist’s shop and most Department of Conservation buildings all hum along on power from the wind and the sun.

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It isn’t just people on re­mote islands who are looking to renewable-energy sources for independence from a centralised power supply. Remote rural communities throughout New Zea­land are considering their options in the face of often astronomical costs for new grid connections and a “sun­ set clause” in the electricity legisla­tion. A short paragraph at the end of a long list spelling out the obligations of lines companies states: “This sec­tion shall expire with the close of the 31st day of March 2013.” From that date, lines companies will no longer be obliged to mend or maintain lines to areas deemed uneconomic, with landowners probably having to pick up the tab for maintenance or up­grades. For those affected, the trade off between buying in power and generating it themselves may well come out in favour of the do-it-your­self option.

The wind-whipped tops above Totara Valley, in the foothills of the Tararua Range, have become an experimental station and a second home for Phil Murray, a PhD student at Massey University. At present, this rugged sheep and beef country is sup­plied by a rural electricity line.

Murray is working with the three families that farm the area to assess the natural power-generation options their land offers.

For Murray, the fun part of the project is roaming the hills on a quad bike, wrapped in all-weather gear, his face into an often eye-watering wind, to check an array of wind-monitoring instruments he’s set up on 10-metre poles on exposed ridges and in natu­ral wind funnels. The sites have been selected for both their wind-power potential and, to minimise energy-transmission costs, their proximity to the farms.

Each of Murray’s anemometers and wind vanes captures a continuous flow of information about wind speed and direction as the breezes sweep over the tops. Another instrument records the sun’s radiation and, together with a fellow Massey student, Murray has also checked the valley’s meandering streams for hydro generating potential. Collectively, the measure­ments map the area’s natural energy-supply options.

Solar-powered electric fence energisers are a great innovation for remote areas, or close to the sea, where conventional fence wire is quickly weakened by rust.
Solar-powered electric fence energisers are a great innovation for remote areas, or close to the sea, where conventional fence wire is quickly weakened by rust.

Murray is also fol­lowing the ups and downs of the community’s power demand. Twenty-five power meters installed in farm­houses and shearing sheds chart the daily and seasonal changes in electricity use associated with farm life. As well as the predict­able cycles of winter highs and sum­mer lows, power peaks show up for the shearing season, and changed electricity-use patterns even pinpoint the birth of a baby in one of the homes.

Murray says such electricity con­sumption data are essential when it comes to assessing the generation ca­pacity a community needs and con­sidering whether the adoption of re­newable-energy sources makes eco­nomic sense. Already, in common with farmers elsewhere in New Zea­land, the Totara Valley families some­times pay more for the rental of the power line than for the electricity they use.

Farmers are well equipped to meet the power challenge, says Murray: “They already have the nous, the practical ability and a largely autono­mous lifestyle, and feel a strong con­nection to the land, so do-it-yourself power generation has a natural philo­sophical fit.”

After much number crunching, it became clear to Murray that nature could provide enough, even too much, power for the Totara Valley community. “One of the anemom­eter masts toppled in a particularly strong gust. The last recorded maxi­mum wind speed on this mast which is now horizontal was 54 me­tres per second. That’s 196 kilometres an hour!”

On a fine day, Murray can see the turbines of the Tararua Wind Farm turning on a ridgeline in the distance. Collectively, they produce enough electricity to power 16,000 homes. Murray envisages a smaller version of the turbines one day replacing his an­emometer masts, a series of micro-hydro systems turning in one of the streams, and rooftop solar panels har­nessing the sun’s power. And he sees surplus electricity flowing back into the national grid, easing the peak loads and perhaps delaying the need for major line upgrades.

On Glen Meredith’s farm, near Riversdale, in Wairarapa, cattle are conveniently contained by a solar system that delivers a 6500-volt jolt. After a hefty shock, animals will treat even a couple of flimsy wires with respect. Since the shocks last only a millisecond, the beasts face no risk of electrocution.

This vision of distributed genera­tion, with renewable-energy sources providing electricity close to where it is actually needed, is the way of the future, says Murray’s supervisor, Ralph Sims, an associate professor and the director of Massey Universi­ty’s Centre for Energy Research: “I doubt we’ll ever see monoliths like the South Island’s hydroelectric power stations built again. The fu­ture lies in mixes of small-scale power-production units making enough electricity to serve their com­munities, with any excess being fed back to customers in the cities.”

Sims says the growing demand for a more sustainable and reliable en­ergy supply is just one of the ele­ments stimulating interest in alterna­tive energy. The mounting pressure to reduce greenhouse gas emissions from burning coal and gas is also add­ing momentum, as is the prospect of diminishing gas supplies and the ex­pectation of price increases. To­gether, these issues are helping to change the image of renewables from something associated with tree-hug­ging hippies to a high-tech industry coming of age.

The factors driving the change are no longer purely economic, as they were during the oil shocks of the 1970s, says Sims: “They now include environmental and societal benefits such as the reduction of greenhouse gas emissions, increased security of electricity supply and increased con­sumer awareness of the value of waste minimisation and sustainable use of natural and mineral resources. Sev­eral multinational energy companies have begun to reposition some of their business interests in preparation for a world less dependent on fossil fuels, and are investing in renewable energy as a profitable solution.”

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Compared with other developed countries, New Zealand already has one of the highest levels of renewable energy supply. Twenty nine percent of our total energy supply including electricity, heat and transport fuels comes from renewable sources. If one looks only at the statistics for electricity generation,the figures look even better, with 73 percent coming from renewable sources. Hydro has the biggest share, at 64 percent, followed by geothermal energy at 6 per cent and other renewables such as solar, wind and biomass at a combined 3 per cent.

However, the renewable share has dropped significantly since the 1970s, and New Zealand is going against in­ternational trends by increasing its reliance on fossil fuels to feed the country’s fast-growing appetite for energy. Sims: “Renewables used to be at around 80 per cent. The ratio in New Zealand is still good, but our biggest problem is the rapid growth in electricity demand that has oc­curred over the past 10 to 20 years. Our hydro supplies have been con­strained, so the demand has been met mainly by gas-powered power sta­tions, which has directly contributed to the problem of climate change.”

In the past 100 years, New Zea­land’s use of energy has doubled every 22 years. The energy sector now con­tributes the largest portion of New Zealand’s human-made carbon dioxide emissions-91 per cent, or 28 million tonnes. Within the total energy mix, electricity generation and transport are the worst culprits, and these are the areas where the focus on renewable energy is strongest.

Up close, the heads of the Tararua Wind Farm's Danish-built 660 kW turbines are dauntingly large, but each generates sufficient power for 330 homes. The district's bountiful breezes make Tararua the world's most efficient wind farm, with power generated nine days out of ten and production at 47 per cent of the theoretical maximum (if the wind blew at optimal speed all the time).
Up close, the heads of the Tararua Wind Farm’s Danish-built 660 kW turbines are dauntingly large, but each generates sufficient power for 330 homes. The district’s bountiful breezes make Tararua the world’s most efficient wind farm, with power generated nine days out of ten and production at 47 per cent of the theoretical maximum (if the wind blew at optimal speed all the time).

Aside from avoiding the problems intrinsic in the use of fossil fuels, Sims says using more natural energy re­sources would diversify the electric­ity market and provide a buffer against events such as last winter’s hy­dro crisis. During July 2001, ex­tremely low hydro-lake inflows com­bined with an 18 per cent increase in electricity demand during a cold snap, sparking fears of blackouts and power rationing. Average wholesale electricity prices rocketed from five cents per kilowatt-hour to about 30 cents. Most households escaped big price hikes, but many commercial us­ers who didn’t have the protection of a hedge contract were hit with hefty increases in their power bills.

In the end there were no power cuts, thanks to a collective effort to save electricity and the fact that gas-powered plants in the North Island came on stream, making up for the shortfall of the southern hydro lakes.

Sims would have preferred to see that back-up generation come from renewable sources. He is perfectly se­rious when he says New Zealand could be totally independent of fossil fuels. “I’ve been saying this for 10 years: we could be the first country in the world not only to have 100 per cent renewable electricity but 100 per cent renewable energy, because we’ve got the resources—high mean annual wind speeds, large and increasing vol­umes of forest residues, strong ocean currents, relatively good solar radia­tion levels, numerous streams and riv­ers with potential for small hydro schemes, available land with fertile soils and a good year-round climate for growing energy crops.”

He says the one thing that is miss­ing is the will to use these resources, although even this may be starting to take shape, at least politically. A slim document released in September 2001, outlining New Zealand’s first National Energy Efficiency and Con­servation Strategy, laid down some ground rules for a sustainable-energy future played out between two main goal posts: a 20 per cent improve­ment in energy efficiency over the next decade, and an increase in en­ergy supplied by renewable sources of between 19 and 42 per cent.

The latter is still the subject of debate, a more precise target being expected by July 2002.

The exact siting of the turbines was based on anemometer profiles of wind speed and direction, which showed, among other things, that wind speed increased with altitude in the evening. Research student Phil Murray is continuing the collection of data in the district.

Equally political are ongoing dis­cussions about the price of carbon. The government has so far shied away from introducing a carbon tax but it wants to ratify the Kyoto Pro­tocol on Climate Change by Septem­ber 2002, which would commit New Zealand to reducing greenhouse gas emissions to 1990 levels by the end of this decade. The trading of emission rights for greenhouse gases between signatories to the protocol will even­tually lead to a price tag on carbon emissions.

While these discussions continue, alternative energy is already becom­ing an economic reality for some. Mark and Coby Carter, who cut off the mains supply to their farmhouse near Beading this summer to rely on solar power and their home built Ralph Sims, a professor at Massey University and a long­ standing advocate of renewable energy here installing a solar hot water system on his house says New Zealand could become the first country in the world to have 100 per cent renewable energy. High wind speeds, in­creasing volumes of forest residues, strong wave action, good solar radiation levels, abundant potential for small hydro schemes, fertile soils and a good climate for growing energy crops all make it a feasible proposition. wind turbine, typify a new, 21st-cen­tury approach to energy. “Something I’ve always dreamed of doing is hav­ing my own hydro scheme,” says Mark Carter. “I played around as a kid with water wheels and drains, but we don’t have water of any conse­quence around here, so the wind is the next best thing.”

The result of four years’ “tinker­ing,” Carter’s automated wind tur­bine tilts out of the wind if the breeze becomes too strong or the batteries are full—courtesy of a car window-winding mechanism and a micro­ processor for which Carter wrote the software. At a friend’s home, Carter used a recycled windscreen-wiper motor to move solar panels so they followed the sun’s path across the sky. He now divides his energies between the farm and Ralph Sims’ research group, where his next challenge is to develop an Internet capability for controlling stand-alone alternative power systems.

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Among trampers and locals, the Tararua Ranges are notorious for strong and persistent winds, so it is perhaps not surprising to find the southern hemisphere’s largest wind farm along a ridge of its northern foothills, just south of the Manawatu Gorge. As the prevailing westerlies sweep across the lower North Island they are funnelled through the gap between the Tararuas and Ruahines, providing wind flows strong enough to turn the turbines’ 23.5 m blades at maximum capacity more often than at any other wind farm in the world.

The 48 turbines are spread across the ridge of a private 700 ha farm. Cattle and sheep graze beneath the 40 m steel-lattice towers and a few windblown macrocarpa trees, unper­turbed by the rhythmical sweep and whirring hum of the blades.

A small control house doubles as a visitor centre. Inside, the walls are papered with posters of wind farms overseas and a portrait of Sir Edmund Hillary endorsing the use of “hilltop breezes to generate power.” Next to a workshop full of spare parts, a small room houses the wind farm’s central nervous system: a computer which tracks the electricity output of each turbine, monitors the strength of the wind and sends hourly email updates to the cellphone of the farm’s service manager, Stephen Lauridsen.

“My job is to keep them running as much as possible,” he says as he climbs down from one of the tur­bines after a regular maintenance check. “But they do most of that themselves.”

Ralph Sims, a professor at Massey University and a longstanding advocate of renewable energy-here installing a solar hot-water system on his housesays New Zealand could become the first country in the world to have 100 per cent renewable energy. High wind speeds, increasing volumes of forest residues, strong wave action, good solar radiation levels, abundant potential for small hydro schemes, fertile soils and a good climate for growing energy crops all make it a feasible proposition.
Ralph Sims, a professor at Massey University and a longstanding advocate of renewable energy-here installing a solar hot-water system on his housesays New Zealand could become the first country in the world to have 100 per cent renewable energy. High wind speeds, increasing volumes of forest residues, strong wave action, good solar radiation levels, abundant potential for small hydro schemes, fertile soils and a good climate for growing energy crops all make it a feasible proposition.

Each turbine turns into the wind and automatically adjusts its blades to meet the force with the biggest area. As long as wind speeds stay above the required minimum of 14 km/h, which they do on more than nine days out of ten, the turbines keep turning. Sometimes, when gusts become too strong for the rotors to cope, the blades feather out of the wind and the turbines shut down to prevent damage. If something goes wrong, the computer calls Lauridsen.

“Most of the time the wind speeds are well within the turbines’ opera­tional range,” he says. “It is only about one per cent of the time that the wind exceeds 90 km/h and the turbines shut down.”

Lauridsen has kept a performance record since day one, when the first turbine started to feed electricity into the Central Power network in a light breeze in November 1998. Most turbines have since worked more than 90 out of every 100 days, and during almost half of that time they have run at full capacity. “This is one of the best sites in the world,” says Lauridsen. “The wind farm runs at 47 per cent of the maximum output that it could possibly generate if it were windy all the time. In Europe, reaching 30 per cent of the maximum capacity is considered good.”

The wind at the Tararua site is so strong and reliable that turbine manufacturers use recorded stress data from the farm when designing new components. But apart from be­ing the most efficient, the Tararua Wind Farm like its smaller cousin, Hau Nui, in the Wairarapa has the honour of operating successfully without any government grants or subsidies. That’s in direct contrast to wind-power projects overseas, says Deion Campbell, northern genera­tion group manager for Trustpower, which owns the Tararua Wind Farm. “Several overseas governments, in­cluding Australia, have legislated to encourage the development of renewable-energy sources such as wind power,” he says. “This is not yet the case in New Zealand.”


The 48 turbines at Tararua have the capacity to produce 32 MW of electricity, but the site has the poten­tial to accommodate 103 turbines, which would more than double gen­eration. Although the necessary re­source consents have been obtained, Campbell says expansion of the wind farm has yet to become commercially viable and it remains unclear when it might go ahead.

An advertising campaign last year targeted 16,000 customers, encour­aging them to switch to Trustpower and pay $2 extra per month on their power bill to help finance the wind farm. Only 200 people were willing to part with the extra money, a fact Campbell says is “indicative of the belief New Zealanders have that we are already clean and green.”

Early this year, a consortium of overseas corporate interests was keen to enter into a carbon credit trading agreement, but Campbell says the deal couldn’t go ahead because politi­cal negotiations over how such ar­rangements would work are still tak­ing place. “Until the government ratifies the Kyoto Protocol and then puts in place any CO2-reduction or renewable energy incentives, it is un­likely that further wind-power projects will be commercially viable in New Zealand.”

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When wind’s time comes, chances are Christchurch-based engineer and inventor Geoff Henderson will be pitching his New Zealand-made turbines against the currently used Danish Vestas models. Henderson raised $2.6 mil­lion in 2001 through a public share offer in Windflow Technology, a company set up to build two-bladed turbines locally, based on his patented technology.

Henderson’s main goal is to bring a slice of the fast-growing wind-power industry to New Zealand: “In the 1990s, installed wind power in­creased from 2000 to 12,500 MW that’s more than a six-fold increase. In 1999, wind power was a $10 bil­lion industry, and the yearly growth rate was 25-30 per cent, faster than for any other form of generation.”

With enough money for the first turbine in the bank, Henderson has spent the past several months scout­ing for talent to build it. The blades are being made by an Auckland boat-builder, the tower and hub castings are likely to come from Dunedin, and a Christchurch engineering work­shop will eventually assemble the ma­chine with an imported gearbox, gen­erator and hydraulic system.

Henderson’s enthusiasm for wind power goes back to his student days at the University of Canterbury, where he spent the final year of his engineering degree building a wind turbine. After a three-year stint as an energy consultant in Auckland, he left to work on wind farms in California and for a turbine developer in Eng­land. It was in England that he devel­oped his two-bladed rotor design and a torque-limiting gearbox system for which he now holds a patent in New Zealand, Australia and the United States. Inspired by New Zealand’s market-based approach to econom­ics, the Resource Management Act and the global debate about climate change, he decided to return at the end of 1990, “all fired up and keen to contribute something.”

“With proven experience overseas and patented technology I had in­vented, I expected to be embraced with open arms and thought people would be wanting to get the wind-power industry up and running,” he says. “Given that New Zealand has one of the best wind resources in the world the fundamentals seemed right, but it’s taken more than 10 years to get to this point.”

Henderson says he hadn’t counted on the effect of the long-term take­or-pay contracts the 1974 govern­ment had signed with the consortium that was developing the Maui gas field. “There was nothing in New Zealand that would use the gas fast enough to make the Maui field worth developing. The energy demand was growing rapidly, so the government signed a contract to take the gas, giv­ing developers guaranteed revenue. That set a locomotive in motion which has dictated New Zealand’s en­ergy policy ever since.”

Under the watchful eye of his dog, lucky, Owen Maher operates a control valve on his self-made farm hydro dam at Ohingaiti, near Mangaweka.
Under the watchful eye of his dog, lucky, Owen Maher operates a control valve on his self-made farm hydro dam at Ohingaiti, near Mangaweka.

But now, with New Zealand’s gas reserves diminishing, the climate change debate gaining urgency and a commitment to an increase in renew­able-energy sources, Henderson says the winds of change are blowing in his favour. He says he’s on track to have his first wind turbine up and running by September this year, most probably near Gebbies Pass, on Banks Peninsula, if the resource con­sent application goes through.

Christchurch City Council has pledged to take the electricity the 500 kW turbine will produce for a guaranteed price. That revenue alone won’t be enough to finance the next stage of the project, but Henderson plans another share float next year to raise $4 million to build up to 10 wind turbines for a pilot wind farm in the South Island.

Whether or not the money will flow remains to be seen, but the wind certainly will. Steve Reid, a scientist at the National Institute for Water and Atmospheric Research (NIWA), has spent many a day leaning into a stiff breeze as part of his research project to map New Zealand’s wind patterns, and he says there’s enough of it to make wind power a good op­tion for the country.

New Zealand straddles the Roar­ing Forties, and both islands lie across the prevailing westerly winds. While sea breezes are generally stronger and less turbulent than land breezes, Reid says there are several terrestrial sites that are worth exploring.

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Where there is wind there are often also waves, and with more than 10,000 km of coastline, much of it ex­posed to power­ful surf, wave power could be another future source of elec­tricity for local communities. Andrew Laing, an oceanographic scientist at NIWA, says interest in wave power has in­creased recently, both within New Zealand and internation­ally.

NIWA has recently com­pleted a numeri­cal simulation of 20 years of wave conditions in the south-west Pacific, and the resulting data help pinpoint the most prom­ising sites for ocean-powered electricity gen­eration on New Zealand’s coastline.

“The most powerful areas in New Zealand are around the south-west coast,” says Laing, “but that is also the most isolated and remote region, and difficult to exploit.”

The 15 kW hydro plant often produces more power than he can use, so excess is dissipated through old heating elements mounted in the wall of the generator shed. The spot is favoured by possums for "sunbathing," says Maher.
The 15 kW hydro plant often produces more power than he can use, so excess is dissipated through old heating elements mounted in the wall of the generator shed. The spot is favoured by possums for “sunbathing,” says Maher.

Laing says it’s still early days for wave power in New Zealand, but there are operational systems under trial in northern Europe. “There are a number of different ways of using waves. Some devices can be moored offshore and some constructed up against the coast. Some use the head from small reservoirs which are filled by waves sloshing up a cliff face; others rely on the force of the waves to move air up and down a fixed column and drive a turbine; others use either jointed rafts or moored pistons that pump fluid through pipes to drive small turbines.

“There are three things that influ­ence the selection of a good site: you need powerful waves, so you’d be looking for the stormiest area, but you also want consistency, and that’s where the West Coast is good. You also want long swells, as the amount of energy you can get out of waves depends not only on their height but also on their period.”

Laing says previous estimates of the power in ocean waves around New Zealand exceeded 100 kW per metre of wave front in some areas. NIWAs recent work suggests the fig­ures near the coast are somewhat lower but still encouraging. So far, wave power hasn’t proved economic, but “it’s not far down the track, par­ticularly for remote or island com­munities. For example, there may be potential for Pacific Island countries where the south-east trades create good and steady swells.”


While there are no immediate plans for wave-power generation in New Zealand, there is overseas inter­est in our coastline. A subsidiary of the New Jersey company Ocean Power Technologies, which is set to harness wave power off the coast of Melbourne, is keeping an eye on pos­sibilities this side of the Tasman Sea.

The company’s New Zealand rep­resentative, John Huckerby, says the Australian project is a pre-commer­cial trial of a system of buoys, fixed to the seabed, that generate electricity by moving up and down under water with the swell. The movement drives a generator on the ocean floor, which sends the electricity to a shore-based substation via an underwater cable.

Huckerby says the 4 m-diameter buoys can be used to make up larger or smaller power plants as required, not unlike wind farms. However, be­cause waves have a greater energy density than wind, it is possible to generate the same power as a wind farm from a smaller area. Huckerby sees potential for New Zealand to take advantage of its marine setting: “The waves are world-class in terms of their energy content, and there are a number of promising sites along the south- and west-facing coasts.”

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From using the sea as an energy source, it’s only a small step to using sun­light, another resource which is abundant in this country. The amount of solar radiation hitting the New Zealand land surface in just half an hour exceeds the country’s total energy demand for a year, but at present most of it is turned into heat or used up in evaporation. However, Tony Bittar, chairman of the Photo­voltaic Association, says any place in New Zealand gets enough sunshine to make solar panels a worthwhile investment, albeit only in the long term.

“The initial cost is still quite high, and finance is the big­gest hurdle in the way of spreading photovoltaic panels throughout New Zea­land. But solar panels are one of the few products that come with a 20-year guar­antee, and within their life span they save you more than if you’d put the money in a bank.”

Bittar says photo­voltaic technology has already made quiet in­roads into the energy scene. New Zealand’s coastline is dotted with solar-powered lighthouses, the emer­gency telephones on Auckland’s southern motorway run on the power of the sun, and kilometres of electric fences round farmland and nature reserves up and down the country are fed by solar pan­els. And in Antarctica, at latitudes of more than 70° S, the 24-hour summer sunlight powers instruments, meteorological sta­tions and machinery.

Bittar says solar ra­diation levels anywhere in New Zea­land are far higher than those in the many places in Europe or Japan where solar panels or water heaters are offered as a standard option in any new home. “In Germany they have about 1000 kW per square me­tre per year; in New Zealand it’s one­and-a-half times that much any­where, and in some places a lot higher.”

In Germany, the main incentive to go solar may be a feed in tariff that allows people to sell their sun gener­ated electricity to the grid at a much better price than the one they pay for using grid power.

In New Zealand, there are only a handful of people feeding self gener­ated electricity into the national grid even though it’s three years since Simon and Kristina Cope be­came the first to do so.

Mark Carter, from Feilding, typifies the do-it-yourself Kiwi tinkerer, delighting in concocting something from the materials at hand. Among the devices he has come up with is one which uses a car window-winder to move a turbine out of harm's way when the wind rises to destructive levels.
Mark Carter, from Feilding, typifies the do-it-yourself Kiwi tinkerer, delighting in concocting something from the materials at hand. Among the devices he has come up with is one which uses a car window-winder to move a turbine out of harm’s way when the wind rises to destructive levels.

The Copes’ home in the Auckland suburb of Mt Roskill is easy to find. Almost every inch of the roof is cov­ered either with solar panels or by the solar water heater. When the sun shines, the Copes’ power meter spins backwards, feeding surplus energy from the rooftop down the power line. When the sun sets, the Copes revert to mains power, using the na­tional grid as a huge storage battery.

“Eight years ago that wasn’t possi­ble in New Zealand,” says Simon, an electronics engineer, electrician and director of a renewable-energy busi­ness, Sunpower. “Back then, we had no option but to disconnect from the grid, and the power from the solar panels went into a battery bank, which could store two weeks’ worth of our elec­tricity needs. Net meter­ing has made a huge dif­ference, because the bat­teries last only about 10 years and cost $10,000, so that’s $1000 a year, which is about how much people pay for grid power.

“The need for batter­ies can negate any incen­tive to generate your own electricity, and it’s been a big hin­drance for suburban systems. In a ru­ral situation, where somebody’s been quoted thousands of dollars to get power to their property, having to set that sort of money aside still makes it worthwhile, but for somebody who’s connected to the grid it doesn’t.”

Cope says the price of solar panels has come down since he got involved in 1994, but to supply an average household is still a significant invest­ment unless one can stay connected to the grid. “It is still more of a state­ment of commitment to the environ­ment than to your bank balance.”

One of the challenges facing the photovoltaic industry, says Cope, is the global expansion of the electron­ics industry and the subsequent short­age of silicon for solar-energy use. The challenge is to make PV panels more efficient while using less material, and Cope says the latest thin-film technology goes some way towards doing this.

It was a similar material shortage that inspired the design of one of the few New Zealand-made solar water heaters. During the 1970s copper be­came expensive, so Arthur Williamson, then a professor in chemical engineering at the Univer­sity of Canterbury, sought another material for making heat pipes.

In those days Williamson’s inter­est in pipes was mainly academic, but today pipes are his core business and the main technology behind the Thermocell solar water heaters, manufactured at his Christchurch based company.

At the entrance to Thermocell, visitors are treated to a simple per­formance of the basic principle the company product employs. Two cop­per pipes, sealed at both ends, stick up out of a heating element. One contains air, the other has been evacuated of air and contains a small amount of water. As both are heated, the evaporating water heats the top of the evacuated pipe almost instantly, while the top of the other pipe re­mains cool.

“We are using the same idea, but in a flat version, like a big steel enve­lope which has been evacuated except for a small amount of volatile fluid,” says Williamson. The metal envelope becomes the solar collector on the roof, concentrating the sun’s energy to heat water pumped through a thin pipe under its hot top end.

The conversion of the sun’s en­ergy into heat is the oldest, most ad­vanced and most economical of the uses of solar energy. As well as heat pipes, there are now several other technologies on the market, includ­ing simple rooftop collec­tors that warm the water in many home swimming pools and designs that in­corporate specially coated heat conducting surfaces.

A domestic solar water heater usually produces up to three quarters of the energy required to pro­vide year round hot water, and has to be backed up by conventional methods such as gas or electricity. But if half the country’s existing electric water heaters were replaced, and electricity used purely as a back-up when the sun didn’t shine, there would be no need for an additional fossil-fuel power plant.

Arthur Williamson’s son, Nick, who is also involved in the company, is chairman of the Solar Industries Association, which wants to see a ten­fold growth in the industry in two years. “Somewhere between 800 and 1000 solar water-heating systems are sold throughout New Zealand each year,” he says. “We want to take that to 10,000 systems a year by the end of 2004. It’s an ambitious target, but an achievable one. You’ve got 20,000 to 25,000 new houses being built a year, and in addition to that about 50,000 to 60,000 hot water cylinders need replacing each year. That’s the time to think about putting in a solar wa­ter heater.”

Those who lobby for a bigger share for renewable-energy sources see the sector as being at a pivotal stage, where a number of factors political, economic, technological are coming together to give it the push it needs for significant growth. But there are still many barriers, not least the fact that a similar push is happening in most developed countries, creating lucrative opportunities elsewhere.

Kiwi inventor and businessman Paul Williams is one of the latest to pull out of this part of the world. His invention, a particular type of biomass combustor, may soon be helping the system.

In American pig industry to clean up its act if it manages the jump from small-scale operation to commercial waste-treatment the 1970s, when Williams was living in Hastings, he was looking for a cheap way of drying foodstuffs

Rather than inventing something from scratch, he looked for an old and proven technology that he could adapt. He came up with gasification, a process used in the 1920s to pro­duce coal gas to power cities, and again during the World War II to power cars with gasified wood chips.

For Owen Maher and others, there is great satisfaction in the independence gained by producing one's own electricity, but capital costs of alternative energy systems are discouragingly high. Hydro plants and cheap Maui gas have kept the price of electricity low in New Zealand. However, new generating plants will be more costly, increasing the attractiveness of power produced by wind, wave and sun.
For Owen Maher and others, there is great satisfaction in the independence gained by producing one’s own electricity, but capital costs of alternative energy systems are discouragingly high. Hydro plants and cheap Maui gas have kept the price of electricity low in New Zealand. However, new generating plants will be more costly, increasing the attractiveness of power produced by wind, wave and sun.

When Williams first looked at the process, it was the heat production that interested him most, but today the fact that organic waste can be used as fuel is the focus. After spending more than 20 years refining g units along the way Williams sold and patenting his technology and sell­inhis idea in March 2000 to a Perth-based company for $A6 mil­lion, a directorship and a substantial share parcel

The company changed its name to Renewable Energy Corporation and began its expansion into markets with a big waste problem. A few months later, a plant was sold to a poultry factory in Virginia, and plans were drawn up for a multimillion-dollar project with the world’s largest pork processor, Smithfield Foods, in North Carolina. While Williams himself had moved to the US by then, the company retained its headquarters in Melbourne and a manufacturing plant in New Zealand, and planned to keep it that way.

But in February 2002, the com­pany directors, chaired by Williams, decided to close down the Australa­sian operation and concentrate activi­ties in the United States. The compa­ny’s former marketing manager, Steve Wilson, says: “What Paul had made in the 1970s was a small plant suit­able, say, for a tea grower in Kenya using residue from plantations to dry the tea leaves. Then the company in­vested $10 million to transform it into a sophisticated waste-to-energy sys­tem. The market for that is so huge in the US because they are dealing with massive waste volumes and paying serious dumping fees, energy is more expensive, and you can sell the ash from the process as fertiliser.”

To stem the loss of further home­grown talent and technology, advo­cates of alternative-energy sources are looking for some form of government support, not through subsidies, but via other incentives such as manda­tory targets, changes to building codes, technology-specific financial support and tradable renewable-en­ergy certificates. Alistair Wilson, chairman of the New Zealand Wind Energy Association, fears that with­out such incentives New Zealand will miss the boat. “You’d be amazed at the sheer volume of activity of New Zealand’s renewable-sector players in Australia, which has a clear target to increase renewables,” he says.

Australian initiatives to build wind farms and set up local turbine production leave Wilson with a sinking feeling, particularly as proposals for four gas-fired power plants for this country are going through various stages of the consent process. Three of them are extensions of existing plants (at Otahuhu, Huntly and Taranaki), with each expected to produce 360-400 MW in energy. In addition, a new plant is proposed at Whirinaki, near Napier, with a ca­pacity of about 100 MW. Wilson says planning an energy future based on dwindling gas reserves doesn’t make sense, and that if the plants go ahead there will be little room for renewables to get a foothold. “They would add 1300 MW to an 8000 MW system, so we’d be looking at thermal generation having an even higher per­centage of the new energy mix. Mean­ while the rest of the world is looking to increase the share of renewables.”

On Great Barrier Island, though, the Blackwells have no doubt that re­newable energy is an investment in the future, and they wouldn’t be with­out their trusty turbine. Their ears have become attuned to the whir of its blades, so much so that they can almost tell how much power is flow­ing into their batteries. And they know there will always be enough of it—for free.