Power self-sufficiency possible

When the cold southerly blows strong across Dunedin, Swami Hansa, in shorts, T-shirt and sandals, celebrates his investment in wind power.

• Family takes pride in growing their own [2]

It is a fact, he says, that every time the windspeed doubles, the power output from his wind turbine quadruples.

A good stiff breeze makes the needles of his volt meters jump; his batteries get a top-up and his hot water gets a boost.

Whatever electricity is left over after that surges through his antique oil heaters. And if the wind does not blow, then solar panels keep his house alive with electricity.

"Sometimes I've got so much power I don't know what to do with it," Hansa laughs.

Hansa is something of an alternative energy guru perched high on a hill overlooking Harbour Cone on the Otago Peninsula.

His conversion to an "off-the-grid" lifestyle began 20 years ago when he bought the rural property and was quoted $39,000 to be connected to the power line at the bottom of the valley.

He admits that capturing his own wind and solar energy has not come cheap, although he is a little vague on the question of the actual cost of his energy "experiments".

He has two banks of solar panels, two wind turbines, a roof-mounted solar hot water system and a complex array of controllers, converters, fuse boxes, gauges, batteries and cables.

Modern solar panels are expensive, he says, although a lot more efficient than those he installed 15 years ago.

Wind turbines are also expensive to buy and tend to "fly to bits" after a time.

The wind turbine he inherited soon succumbed to the violent gusts his hilltop home is exposed to - up to 170kph - and its replacement, on top of a 12m steel pipe tower, also caused endless trouble.

"There are so many pressures on the turbine and so many things can go wrong unless it's well constructed."

But, finally, Hansa believes he has found the answer. He flew to the Falkland Islands specially to investigate a Scottish-made turbine in use by about 80 property owners there.

The Proven Energy turbine cost him almost $20,000 but has features he believes make it ideal for the climate extremes of Dunedin.

Its most notable feature is that, unlike most turbines, it faces away from the wind rather than into it.

This, Hansa believes, along with its flexible blade system and slow rotation speed - up to 300rpm - reduces stress.

Hansa, who trained as a broadcasting technician and still practises as a freelance television cameraman, has an opinion on most of the wind turbine designs available.

While admiring the innovators, he warns consumers to be wary of new and unproven entrants into the windpower market.

POWER OPTIONS

Generating power from the wind or sun and selling it into the national grid is still not economically viable for most people, according to a Dunedin business specialising in installing such systems.

Ian Buchan, of Power Options, provided the ODT with some facts and figures to ponder.

-A photovoltaic system capable of generating one kilowatt of electricity would require 10 100watt solar panels costing a total of $10,000.

-To connect the panels to the grid would require an approved, highly specialised "grid interactive inverter" and the cost, including installation, would be $5-$6000.

-"But here's the real rough part." In Dunedin one kilowatt of photovoltaics will provide a daily average of about four kilowatt hours.

-Four kilowatt hours is less than a quarter of what a normal house uses. "An energy-efficient house would take 20 kilowatt hours a day" but some houses are taking up to 50 kilowatt hours a day.

-He says it could take up to 20 years to pay back a grid system at today's prices.

-A wind turbine, in the right place, can produce all the power a house will need but the cost of a complete, installed system that will feed into the grid is between $20,000 and $27,000.

-An average wind speed of between 4 and 5 metres per second is required to make a wind turbine economically viable. Many of Dunedin's hill areas would qualify.

-"Solar water heating's far more cost-effective than hooking up grid interactive power . . . you can get your money back in five to seven years."

-"You only have to spend $6000 or $7000 on solar hot water and you get $1000 back from the government for doing it." That will save 70% of your hot water bill.

-Hot water can be "at least a third and in some places, a half" of the power account of a home.

 

Photos by Jane Dawber; prints available from otagoimages.co.nz [3].