NEW ZEALANDERS are increasingly turning to solar power - although experts warn the advantages of the systems come with costs and their popularity may be doing more harm than good for the environment.

There were 9533 solar connections in New Zealand at the end of March, up on 5760 at the same time last year and 2712 the previous year, according to the Electricity Authority.

Environment Centre Hawke's Bay manager Sarah Grant said solar systems had several advantages. Their fuel source was free and would always be there, they required little maintenance and they were becoming more efficient.

The up-front capital cost of a solar system was high, but conventional power prices were increasing every year, so each year solar became a bit more realistic and worth the investment, she said.


Palmerston North City Council eco design advisor Nelson Lebo said a new home in an area away from powerlines could be a good candidate for solar power. However, there were better ways for others to be sustainable.

Mr Lebo said research showed the carbon footprint of solar was around 10 times greater than geothermal or wind power. The manufacture of panels and frames in China used coal, he said.

"The bottom line is there's heaps of better things people can invest in to save money and that are better for the environment."

They could superinsulate ceilings, properly install curtains, use LED light bulbs and insulate hot water pipes, said Mr Lebo.

According to the Energy Efficiency and Conservation Authority, the main barrier to the uptake of solar energy was the cost.

Solar generation made up only 0.1 per cent of New Zealand's total renewable energy.

Price reductions in solar equipment had made it more popular with homeowners.

A recent report by the Concept Consulting Group Ltd on the effect of solar panels on greenhouse gas emissions said solar photovoltaic (PV) uptake was expected to displace generation from existing fossil-fuelled stations and therefore reduce emissions, in the short-term.

However, it would have a limited effect in the medium term as uptake would substitute for new low emission power stations such as wind and geothermal.

This differed with most other countries because most of New Zealand's electricity was generated from renewable sources and large-scale renewables represented the cheapest option for future electricity supply in New Zealand.

In the long term, PV was expected to modestly increase the need for fossil-fuelled generation because solar generated more power in summer than winter, the opposite of New Zealand's power demand needs.

Of this year's solar connections, 9022 were residential, 262 commercial and 249 industrial, according to the Electricity Authority.

Regardless of the cons, there would always be cases where the panels were seen as a win-win.

Thomas Hoskins of Hoskins Energy Systems in Wairarapa said the company had experienced a rise in solar installations over the past 10 years.

Customers Rose Hughes and husband Al built on a rural Greytown block five years ago. Mrs Hughes said the cost to add a transformer to the network as well a cable to the house would have been high. There was also a risk of maintenance costs given the rural nature of the site.

"We live within our power generating means and we have a greater understanding of the relationship between power generation and what we use."