Solar panels on a roof. Photo: Fabian Rieger / 123RF
Households with solar panels on their roofs will be able to send more power back to the grid - and get faster building consents - under changes announced by the government.
Energy Minister Simon Watts and Building and Construction Minister Chris Penk said planned changes would expand the permitted voltage range for electricity networks, to enable solar power systems to return more power to the grid.
The government would also clarify that a building consent was not needed to install rooftop solar panels on existing buildings.
Councils would be required to process building consents for new homes with solar panels within 10 working days, down from the standard 20.
Watts said New Zealand's residential uptake of rooftop solar was lower than many other countries'. He said changing that would mean people could save money on power bills and contribute more to a secure electricity system.
"Rooftop solar will play a crucial role in supporting energy security and reducing emissions. But our networks need to be able to better support the growing flow of electricity from consumers, while also dealing with growing demand for more electric vehicle charging.
"That's why we are expanding the voltage range from +/- 6 percent to +/- 10 percent to manage the changing flow of electricity from rooftop solar and EV charging. This will future-proof our electricity system and help electrify the economy.
"Modelling suggests this change could boost solar investment and overall generation by a whopping 507 GWh through increased solar connections. This is great for the security of our energy supply."
Mike Casey, Rewiring Aotearoa chief executive, said the changes were "incredible news". He said the electricity system was restricted to ensure that voltage remained within a certain range.
"You can think about voltage like water pressure. What it means is there's all sorts of issues where people are being restricted in the amount they can export back to the grid for fear we go over that voltage level and the pressure on the wires gets too much.
"It's updating the regulations to better align with solar and battery systems being installed in homes and farms now."
Building and Construction Minister Chris Penk. Photo: RNZ / Samuel Rillstone
He said that would mean more generation, "which is exactly what New Zealand needs… for households in Australia, the average size for solar systems is about 10kWh. In New Zealand it's 5 or 6kWh because solar installations are being built to the size people are allowed to export.
"This allows for higher levels of solar panels to be on homes. It makes larger systems more economical. When you finance solar panels on your mortgage it probably costs you 13c per kWh - there are many retailers out there buying power off you at more than 13 per kWh. So every piece of power that you don't use in your home that goes back to the grid is actually still in the economic best interest of the household."
He said the more solar that was generated on the rooftops of New Zealand, the more it backed up the hydro system and meant it could be used more as a battery.
"It's a massive win for energy security."
'Low base'
Powerswitch general manager Paul Fuge said solar had become a bit more competitive in recent times and there had been quite a rapid uptake from households. About 4 percent now have solar power, "but from a low base".
He said there was "huge potential" for solar in New Zealand, because the country had a high number of sunshine hours.
Penk said the building consent system could help accelerate the shift to renewable energy.
"With the energy system preparing for a surge in residential solar, the consenting process needs to play its part to support the transition.
"We are proposing changes to the Building Act that will make it clear that a building consent is not needed to install rooftop solar panels on existing buildings.
"Right now, decision-making is inconsistent between councils - creating unnecessary barriers for homeowners who want to take responsibility for their environmental impact and make sustainable choices.
"As a further incentive, we are also proposing that Kiwis who choose to include solar panels in the design of new homes will have their entire building consent fast-tracked and processed in 10 working days instead of the standard 20 working days, saving Kiwis around $400 a day in time and consenting costs."
Casey said the changes were a no-brainer.
"It's such a fiscally responsible thing to do now, to put solar panels on buildings."
Does solar power pay off for households?
Casey said a system could pay itself off in five to six years. "The more electric the home is the better the payback of the solar system. If you're using gas for water and cooking and a wood fire for heating, the payback on a solar system is much longer."
He said people with an EV or using electricity for all their household needs could get payback much more quickly.
Fuge said it also gave people an opportunity to hedge their power bills.
"Basically by putting in solar power you've hedged your solar electricity price for the next 25 years. If power prices are going to keep going up then the solar just gets better."
It would cost about $12,000 to $20,000 for a typical household system, he said.
Sign up for Ngā Pitopito Kōrero, a daily newsletter curated by our editors and delivered straight to your inbox every weekday.
