Backyard wind power feeding grid

By CHRIS DANIELS energy writer

Jim jokes that the only real source of decent wind power back in his home town of Nashville comes from the country music industry.

But when he's here in New Zealand, living in his modest but classy holiday home at Whangateau near Warkworth, Jim doesn't need the wailing slide guitars from the Grand Ole Opry.

He has just installed an entirely New Zealand designed and constructed two-kilowatt wind turbine, one that keeps his TV running and computer from crashing when the power lines go down.

Not only does his system save on frustration and hassle, but Jim can earn money from his wind turbine, when it pumps electricity back into the national grid.

The brainchild of Auckland man Duncan McMillan and his company Gusto Energy, Jim's wind turbine is different from what you might expect to find at a semi-isolated, rural site, mainly because his house is also connected to the local power grid.

One of his problems is that the house on the hill has beautiful views, but is literally at the end of the line, which means an unreliable supply, especially in bad weather.

Duncan, a mechanical engineer who has worked on wind tunnel testing of yacht designs, has put together a system to allow crucial power to be generated by the wind turbine and stored in batteries, ready to use if the line goes down.

The computer, TV, fridge and necessary lights all switch seamlessly over to the batteries when the power goes down, allowing the house up on the hill to keep the lights on while the others are reaching for the candles. One of the biggest features of Jim's system is that when the wind is blowing and little power is being used in the house (for instance when he is back in Tennessee), the wind turbine generates electricity that is put back into the grid - meaning Jim's meter runs backwards.

His wind turbine, which is installed on a 13-metre pole, can generate up to 6000 kilowatt hours of electricity a year. An average family would use around 10,000 kilowatt hours in a year.

It could generate even more than that, but Jim did not want to cut down kahikatea and totara trees that block wind coming from one direction.

"I'm not an ugly American, I like to keep things the way they were," he says. Jim, a Nashville doctor who spends at least six months of the year here, says he bought the system, which costs around $40,000, to add value to the property, save money and make a contribution to the environment.

"I like new technology - I like to give back to New Zealand," he said.

There was also the financial advantage of money earned on his power account when the meter ran backwards - when the wind is blowing, but very little electricity is being used in the house.

"It's making me money when I'm in Tennessee," he says.

Essentially, Jim's system system allows energy from the wind turbine to charge batteries. Energy from the batteries is used to power dedicated loads in the house, and if there is any surplus energy available from the wind turbine it is sent back to the grid via the incoming network supply feed from the meter box.

But not everyone can get a system just like this. One of the big issues taxing the minds of the power retailers is what price should someone like Jim be paid when he exports power back into the grid.

When it comes to accounting for all the electricity used, they are also moving towards installing two meters - one for electricity coming into a house, the other for power being sent out into the grid.

There have also been objections to small generators like this getting the same price for "exporting" power as he does for "importing" it.

The Government and energy planners hope to see more systems like Jim's installed. It has recently announced that it will be bringing in new rules that it hopes will ease some of the difficulties faced by those wanting to install small-scale electricity generation.

Several projects had been cancelled because of the difficulty of getting interconnection agreements with local lines companies.

Most of these companies have no standard terms and conditions for connecting to their network, meaning each plan needs a special connection contract.

The proposed new rules will allow generation up to 10 kilowatts to be connected to local lines without an extra charge. This is enough to supply an average sized house. (Jim's is small - just 2kW.)

A 10kW system could come from solar panels, a small wind turbine, so-called "micro-hydro" plants or even diesel generators.

Many energy experts, including those working for the Government, feel there needs to be a move away from the big centralised grid connected to big power stations to a more flexible and robust system where small local networks with their own generation are connected by the national grid.

These regulations may standardise the way lines companies are required to treat small-scale generation like Jim's.

Proponents of these small-scale generators are also hoping that the Government's new Electricity Commission, that will take control of the power industry in March, will impose rules requiring power companies to allow customers to "plug in" to the network , both importing and exporting electricity.

Perhaps surprisingly, the big power companies do not mind this too much - just so long as they can keep an accurate track of who uses what power and when.

That is why they want two meters on such houses: one keeping track of electricity going in, the other watching power coming out.

Duncan McMillan hopes that many more people will start looking at installing wind turbines and systems like Jim's.

In the meantime Jim's computer keeps running and his fridge stays cold - all thanks to a happy marriage between the local power grid and his New Zealand-built wind turbine spinning away on the pole at the back of the lawn.

Gustoenergy

Gusto wind turbine

3.2 metres diameter.

13 metres high.

Can generate up to 6000kWh a year. A typical household uses between 5000 and 15,000 kWh a year.

Is connected to a bank of eight batteries.

Total cost of installing turbine and system was around $40,000.

Many small wind turbine systems are designed for use in remote areas, where the national power grid does not go, but the Gusto turbine can be used as an emergency back-up system where power supply is unreliable, or simply to reduce power bills.

Developed and built in New Zealand, the Gusto turbine is designed for our windy conditions.