On the 13th of June 2025, New Zealand’s Energy Minister Simon Watts and Building and Construction Minister Chris Penk announced that the range of our country’s grid voltage will be expanded. They also announced that the consenting system for installing new solar power systems will be simplified.
Together, this is supposed to make solar panels more beneficial to Kiwis. Let us understand what the changes are, and how they directly affect owners of solar energy systems.
View the video below where I ask Ben Stanton from Taspac what the voltage changes mean:
Expansion of the Grid Voltage Range
The most important announcement from last Friday concerns changes in the tolerance of the nominal voltage of our low-voltage grid. Specifically, the tolerance of the grid’s voltage will be increased from 6% to 10%. But what does this really mean? Let’s start from the very basics.
The electricity that we use in our homes is generated far away in power generation plants such as hydroelectric stations, wind turbines, etc. It is then delivered to us using progressively lower voltage lines, which includes stages such as transmission, sub-transmission, and distribution.
For instance, a hydro power plant generates power that is first transmitted at a high voltage of 220,000 V (or 220 kV). This high voltage is required to deliver power to a faraway point with minimal losses. Remember, voltage of power in a transmission line is similar to pressure of water in a hose - the longer the distance, the higher the voltage required.
Naturally, we cannot use this 220 kV electricity in our home. It will blow away every appliance in the house and possibly the entire building itself! Therefore, this voltage is ‘stepped-down’ at a nearby substation(s) using step-down transformers, and finally delivered to our homes at a voltage of 230 V. This is called the nominal voltage. Think of it as the speed limit on a highway.
But just as you are allowed to drive slightly over or under the speed limit, power in a transmission line is allowed to have slightly higher or lower voltage. If there is too much demand and a lot of customers are drawing a lot of power, the voltage falls below the 230 V mark.
Similarly, if there is low demand and instead solar power systems are exporting more power in the grid than it needs, the voltage may rise above 230 V. But similar to a speed limit, there are exact limits on how much the voltage can fluctuate - which finally brings us to the concept of a ‘voltage range’ and ‘tolerances’.
Until now, New Zealand has allowed a tolerance of ±6%, which means the nominal voltage can safely fluctuate between 216 and 244 V.
Source: MBIE
All the appliances sold in New Zealand are manufactured to work within this range, and most manufacturers build appliances with an even wider range for added safety. With the new change, the voltage range will increase by 10% on either side, which means the voltage can now go up to 253 V and down to 207 V.
The Effect of Voltage Range Expansion on Solar
During the announcement, the Ministers cited the change in voltage tolerances to be a way to ‘drive greater residential solar uptake in New Zealand.’ But why could a higher upper limit help solar panel owners?
When the voltage range is short, there is a limit on how much solar energy can be exported into the grid. When homeowners are generating excess energy and pumping it into the grid, the grid voltage increases. With a smaller tolerance of 6%, network companies have to put a limit on how much solar power you export into the grid. This helps the companies avoid overvoltage and therefore the risk of thermal damage to parts of the grid.
Now, with a greater upper limit, more solar can be exported into the grid, which means homeowners will not lose excess energy or the potential revenue from it. In more technical terms, as put by the Ministry of Business, Innovation, and Employment (MBIE), a wider voltage range will avoid or reduce the curtailment of distributed energy resources (DERs), particularly solar energy systems. However, in our discussion with Taspac Energy’s Ben Stanton, we learnt that you may need to call your installer to reconfigure your inverter for a greater export limit.
The MBIE asked ANSA to conduct modelling to determine how the voltage range change will affect exported solar power, and the results are presented in the graph that follows.
The upward rising graph trends show that the adoption of solar energy and the overall energy generation from solar in the country will significantly increase as a result of the increased voltage tolerance. Specifically, ANSA found that expanding the voltage range will triple the hosting capacity of the grid, which means huge amounts of solar energy can now find room on the grid.
Minister Simon Watts was quoted saying, ‘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.’
ANSA also notes that this would be particularly beneficial to homes with energy storage systems, as users can now store excess energy in batteries and export it to the grid during periods of peak demand. This will be a win-win situation for both the system owners and energy companies.
As an added benefit, increasing the voltage tolerance will also prevent future costs of managing the voltage fluctuations dynamically, i.e., companies will have to spend fewer resources on constantly matching demand and supply. In its results, ANSA also states that raising the voltage range would avoid network expenditure to upgrade conductors to relieve voltage constraints.
As Mr. Watts put it, ‘Expanding the voltage range could help avoid hundreds of millions of dollars in infrastructure upgrade costs to accommodate rooftop solar and EV charging being passed on to Kiwi households.’
Possible Drawbacks of the Voltage Range Expansion
Although the changes in voltage tolerances may seem like a big deal, especially with the notable impact it can have, the change itself is quite simple and comes with little to no drawbacks. Here’s a brief discussion of a few potential drawbacks:
Cost
The first question with any major network-related change is about the cost associated. The good news in this case is that there is a very minimal cost associated with increasing the voltage tolerance. Physically, the network companies will have to make minor changes to the settings of their transformers. Policy-wise, the authorities will have to modify documents related to power transmission as well as appliance manufacturing. Both of the above things are inexpensive in nature.
It is important to note that the alternative options to allow a greater solar uptake are far more complicated and expensive, such as reconfiguring the network topography, installing new equipment, or more closely monitoring supply and demand. Here’s a snapshot from MBIE’s document discussing the changes to the voltage range:
Source: MBIE
Risk to Appliances
Another, slightly more discussed drawback of the change is the risk to existing appliances. When the voltage tolerances change from ±6% to ±10%, there is a possibility that it will affect household appliances that do not have the ability to handle a voltage of 10% over 230 V. However, as mentioned previously, most brands today manufacture appliances with a voltage range that is wider than the market’s network range.
Moreover, most appliances sold in NZ are the same as those in Australia, which means most appliances have a wider range anyway. With the range expansion, the government will require manufacturers to have an appliance voltage range that matches or exceeds the new range of the network.
The official announcement document includes a footnote that says, ‘New Zealand appliance standards have aligned with international ±10% voltage requirements since the 1980s, meaning compliant appliances should already operate safely within the new voltage range.’ All in all, unless you have a seriously old appliance, it is unlikely that the changed network voltage range will have any effect on your appliances.
Changes to the Consenting Process
Alongside the voltage range changes, the government also announced ‘common sense’ changes to the building consent process. For new builds with solar in the plans, building consent turnaround will be halved, from 20 days to 10 - saving homeowners around $400 in time and compliance costs.
The government also confirmed that consent is no longer needed to install solar on existing homes.
Summing It Up
When it comes to the allowable voltage range, New Zealand has been an outlier for quite a while. Numerous countries, including the UK and some European nations already have a voltage tolerance of ±10%, with most of Australia also having a tolerance of +10% and -6%. From this perspective, it seems that this change was obvious.
But rather than just achieving standardization with the rest of the world, the main goal of this shift is boosting solar power. This is also clear from Mr. Watts’ closing comment, which goes like this – ‘ Combined, these common-sense and cost-effective changes will boost the resilience of New Zealand’s electricity supply, make it easier and cheaper for Kiwis to build sustainable homes, and spur New Zealand’s residential solar market into the future.’
Overall, we think this is a welcome change that’s a win-win for all parties, including solar power system owners and network companies. While there are a few possible drawbacks to the change, the benefits far outweigh the costs.
Ultimately, what remains to see is how quickly the energy companies raise the export limits for solar, and how much it impacts the return on investment for solar panel owners. But as we discussed previously, it is not a question of whether this change is good for us, because based on international standards, expert opinions, and ‘common sense’, we know for sure that this is an excellent decision.
Therefore, if you have been pondering about switching to solar for a while, there has never been a better time! Also, remember to get multiple quotes from reliable installers before making a decision.
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