Making a profit from the Riverton sun

Les Gibbs beside the solar panels outside his Riverton home.
Les Gibbs beside the solar panels outside his Riverton home.

Alex Fensome takes a look at energy efficient buildings in Southland. Why did their owners make the choice to become energy-efficient? What's stopping others doing the same? Here, Les Gibbs discusses his solar-powered Riverton home.

Riverton man Les Gibbs could not be happier he decided to invest in solar power.

As a farmer in the Hauroko Valley, Mr Gibbs used it to run his electric fences, but for his retirement home he was ready to try a much bigger project.

He was determined to reduce his reliance on electricity companies as much as possible - so much so he was willing to try selling electricity back to them.

He's a pioneer of household solar panels in Southland, with three banks of them on his Riverton house.

The first solar panels he installed five years ago came from the United States and produced 180W of power.

"I got them half the price of normal," he said.

This week, he began installing a new bank of panels made in China. They are the same size and produce 300W.

"Technology has moved on a bit," Mr Gibbs said. "They are [also] much better value for money."

His contract with Meridian Energy credits him every watt he puts into the grid, driving down his power bill still further.

In the 12 months to September 25, the house used 4294 kilowatt hours of electricity, or 11.76kWh a day.

The average house would use around 20kWh a day, he said.

The solar panels produced 3194kWh, 1580kWh of which was exported into the grid when the house demand was low.

Since the panels were first installed, he had produced 9425kWh.

He has a battery bank which stores the electricity from the panels for use in the house, with the excess fed into the grid.

However, he may soon get rid of the battery bank and just feed all the power into the grid, effectively using it as his battery bank, he said.

The only problem with that is it leaves the house vulnerable to a power cut.

Then there is the water system.

"Solar power and solar water are totally different things," he said.

A solar collector on the roof - not the same thing as a solar panel - feeds heat down to the storage tank.

Even on an overcast day, the pipe is slightly warm to the touch.

Mr Gibbs said on a sunny day, even in winter, it can get up to 85 degrees celcius - too hot to keep your hand on for long.

A wood pellet stove completes the picture, stoking up the underfloor heating.

In addition to the panels and heater, Mr Gibbs has installed several other efficient technologies.

In his garage and workshop area, there are LED strip lights which are switched on by a sensor when someone walks into the room.

The LEDs - a string of small lights laid on the ceiling beams - produce more illumination than an incandescent bulb for a fraction of the electricity.

A five metre strip uses 120 watts. "It's a tenth of the electricity of a bulb," he said.

The LEDs come on a tape which can be unwound to any length required. It would be ideal for any house or commercial premises.

Had the technology been available at the time he would have installed them in the living areas too. Instead, he uses low-energy bulbs, he said.

Big north-facing windows add light and heat to the home.

Mr Gibbs also insulated the house with concrete cladding and sheep's wool, one of the most efficient natural insulators.

So what is stopping everyone using this technology? It is really quite simple. It still costs a lot to set up and can be complicated to run.

But that is going to change.

Already, the price of solar panels is at an all-time low and it is only going to get cheaper and more efficient, Mr Gibbs said.

Many of the control systems and much of the technology behind his house could also be made easier for everyday people to understand, he said.

The Energy Conference was a good opportunity to spread awareness of the possibilities of solar technology, he said.

"Solar panels work extremely well down here. The air is much cleaner than the northern hemisphere - in Germany, small scale generation like this produces more electricity than New Zealand uses in total - and we've got more sun resource."

The Southland Times