While batteries are individually small, they add up. As an example, just 120,000 homes (or five percent of New Zealand households) with a medium-sized battery could potentially reduce the peak load as much as our largest hydro power station, Manapouri. While these batteries would not hold as much energy as Manapouri, they could output the same amount of power for an hour or two when the system really needs it. 

Every home with a battery basically removes themselves from peak, and it could potentially remove their neighbours from peak, too. 

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If you want to completely go off grid you will need a very large solar and battery system to cover all your energy needs and you can face particular challenges such as town planning regulations. There are a lot of benefits for most New Zealanders remaining connected to a grid system, so we are not advocating that homes go off grid, but having solar and a battery ensures you have more resilience, control and independence whilst grid connected.

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Yes. 95% of a lithium battery has the potential to be recycled. Our explainer Closing the Loop shows that the renewable energy transition is a big opportunity to create a more circular economy. By 2050, more than half of the demand for materials like cobalt, graphite, and lithium could be met by recycled secondary supply. Others expect this to occur even earlier.

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Yes. New Zealand has strict standards that apply to batteries including the location and installation. If these are followed, the risk of fires is extremely low. 

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Most lithium-ion batteries are warrantied for around ten years, but some now have warranties for 15 years. How long they last depends on the conditions, where it is stored and how it is used. 

Smart energy management systems that monitor and control the charging and discharging of your solar battery can enhance efficiency and prolong battery life. 

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A 5 kWh battery is between $6,000 to $7,500, while a 15kWh battery is between $14,000 to $18,000. 

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It depends what your motivations are. It’s a firm ‘yes’ if you are keen to reduce your household emissions, improve your energy resilience and create an all electric home. If you are primarily concerned by the return on investment, unlike solar (which is an economic slam dunk for most homes today), batteries aren’t a clear call just yet, but those economics are improving every day and battery prices continue to drop by more than expected. 

It may well make financial sense if you are on a time of use rate for your electricity (where the cost varies throughout the day) or can join a plan where you can export energy at peak times and be rewarded for it, like those offered by Octopus Energy and Flick.

Rewiring Aotearoa is advocating strongly for batteries to become more "bankable" by levelling the playing field and paying customers that export energy at peak times, something we call Symmetrical Export Tariffs. This would show the true value of a battery and help to speed up the payback period and adoption.

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