It's estimated that if 30% of New Zealand cars were electric, their vehicle to grid output would be the equivalent to all of our power stations running at full power combined. After many discussions and lots of research, Rewiring Aotearoa has recognised that it is not the regulations or the system holding what’s known as vehicle-to-everything (V2X) back here. Bidirectional chargers can be installed in New Zealand and Rewiring Aotearoa has confirmation from at least one EDB that no additional approvals are needed to export, though some vehicle-to-grid (V2G) will need this, like if it’s not part of a system that already exports or doesn’t have the right spec inverter etc.

The main blockage appears to be from car manufacturers that have yet to unlock the capability here, even if it has been unlocked elsewhere. We understand some manufacturers can unlock it for specific cars if a request is made and we’re expecting some announcements in the next quarter from other big manufacturers. 

According to energy expert Jonathan Holmes, vehicles with CCS charging (which is the most common form in modern EVs) use the ISO15118-2 standard for charging and can be ‘made’ to do V2G with a software bypass firmware upgrade on the V2G charger. This may have an impact on warranties. Newer vehicles compliant with ISO15118-20 will do V2G natively along with many other benefits (if the manufacturer unlocks it). 

Specific chargers are required to make use of the car’s large battery and the ones that have been available up until now have been very expensive. But bidirectional chargers from Sigenergy that can charge at up to 25kW have been approved in New Zealand and the company released a video saying it has enabled V2X on its app (Beauden Barrett has one of the chargers in his house), while StarCharge, one of the world’s largest charger manufacturers, officially launched its Halo V2G bidirectional charger in Australia recently and it is thought these will soon be available in New Zealand. 

Nissan and Mitsubishi have unlocked the capability on their cars and the huge number of cheap Nissan Leafs helping out around the home could be a particularly good thing for low-income households, but very early Gen 1 Nissan Leafs can’t do V2X. Plug-in hybrids have relatively small batteries and it is challenging to get CHAdeMO V2G chargers in New Zealand. 

While V2X is not here in a big way yet, it’s getting closer, there are no real technical or regulatory barriers in the way, and it’s yet another reason to upgrade your fossil fuel car to an EV when the time comes because there's an opportunity to create a new revenue stream and that will lead to faster payback.

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Technology like vehicle to home (V2H) or vehicle to grid (V2G) turns EVs from what many believe is a problem (‘the grid won’t be able to handle all this extra charging load’, which is BS, by the way) into a resource (‘batteries in cars could help smooth the peaks on the grid and power their home or their neighbours’ home and provide weeks of resilience in a natural disaster'). It's estimated that if 30% of New Zealand cars were electric, their vehicle to grid output would be the equivalent to all of our power stations running at full power combined.

Electric vehicles already make economic sense because they are so much cheaper to run, but they also offer new opportunities. For example, someone installing a Tesla home battery today might pay about $15,000 for a 13.5 kWh battery, or about $1,100 per kWh of storage. In comparison, you can get a BYD Atto 3 with a 50kWh battery for about $50,000. In other words, it's a cheaper battery - that comes with a free car! The same is true of a $5,000 second hand Nissan Leaf. While this is the case technically, to date there have not been practically available V2G chargers other than a few test cases.

V2G chargers are relatively new to market, but more options are becoming available and prices continue to decrease. It’s also important to note that a battery by itself often still makes economic sense and provides home resilience when a vehicle is not parked, but the point to be made is that we are about to get a lot of energy storage that can help with the grid and can reduce the need for gas and coal fired electricity production - and it’s going to come free with our cars. A petrol tank doesn’t do that.

Some EVs can already run appliances (what’s known as Vehicle to Load). For example, you can already charge your laptop or run a fridge with some models, but these big batteries could be doing much more than that. A recent paper in Nature suggested “V2G can provide short-term storage when EVs sit idle, which is the case for over 90% of the time for privately owned cars. The technical feasibility of V2G has been demonstrated in over 100 pilot projects since 2002.”’

Smart bi-directional chargers are able to distribute energy to the home or the grid when required (or stop charging if there is too much pressure on the network). Customers can also set limits via apps, so they can benefit from supplying energy to the market from their car but always maintain a minimum amount of charge so it is always ready to go. 

Australia is a fair way down this path and there is currently a national roadmap being created for V2G that will hopefully be implemented in New Zealand given the Government has said it would match standards across the ditch. With 1.5 million EVs expected to be on Australian roads by 2030, it is estimated that just 10% of them with V2G capability could meet around one third of the National Energy Market's total storage needs.

‍A trial in Baltimore using Ford F-150 Lightning utes, which come with a ‘back-up mode’ that can power homes that have extra kit installed, paid owners to take pressure off the grid. 

“EV owners simply plug in their trucks, and they automatically discharge to cover home energy usage between 5:00 and 9:00 p.m. on summer weeknights, when the electricity system is stretched thin cooling homes. Then the trucks automatically recharge overnight, when demand is lower and supply is more available.”

While many large vehicles like public buses are in use at peak times, some are well-suited to V2G. In the US, a scheme using electric school buses to support the grid (and get paid for it) has shown promise. 

Farmers often require a lot of machinery and, again, they are largely designed for one main purpose. But, as Forest Lodge Orchard has shown, if those machines are electric they will be cheaper to run - and if they can be plugged in at peak times and dump the energy stored in their big batteries automatically when the price gets high enough, it will make those machines more valuable. 

It is clear that any energy strategy being developed needs to think of cars and other vehicles not just as consumers of energy as they have been in the past, but as providers of energy storage in the future.

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Absolutely. Rooftop solar is the cheapest delivered electricity available to New Zealand households and finding ways to use it during the day is what is likely to save the most money on your electricity bills because you can avoid higher grid prices. 

On average, a solar install will cost 13c per unit of electricity, including upfront costs and interest on a loan. The average for a unit from the grid is around 35c, so there's a big gap.

Using solar to heat your water is the best thing you can do as that accounts for around 30% of an average home’s electricity use, and more if there are lots of people in the house. 

Those with a resistive electric cylinder and solar can basically use it as a ‘thermal battery’ and time it to heat during the day (some set their cylinders to overheat) and, if needed, on cheap night rates. This ends up being similar to the lifetime costs of a hot water heat pump. 

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Solar can also run other appliances in the house during the day so, if you can, it pays to set timers for things like dishwashers, washing machines and, if your house isn't too draughty, heaters. Any excess can be exported to reduce your electricity bill further, so nothing is wasted (shop around for the best deal on exports as they vary).

If you have an EV and it is at home for a least a few hours a week during the day, you already have a battery, so it makes a lot of economic sense to direct the solar into your car. Electricity from home is the cheapest fuel, and solar is the cheapest electricity.

Batteries are not yet an economic slam dunk in New Zealand and are primarily for resilience, but they are fun to tinker with, prices continue to fall, and Electricity Authority changes to rules that offer fairer prices for exporting at peak will improve the numbers. 

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Good batteries are important when you’re moving big hunks of metal, but when they’re depleted and not fit for driving, they can still work well for stationery energy storage and this is a crucial part of the transition to renewables.

Redwood Materials, the massive battery recycling company started by ex-Tesla Chief Technology Officer JB Straubel, recently claimed a record after it put 792 individual EV battery packs together and produced 63 megawatt hours for a small data centre that was set up alongside. 

In New Zealand, 'second life batteries' have been used at fast charging stations to limit stress on the grid.

If they can’t be used to store energy, the materials in these batteries are highly recyclable. For EV lithium-ion batteries, it is already the case that recycling can achieve >90% extraction of lithium, cobalt, nickel, and manganese [11]. Best-in-class recovery rates are as high as >99.6% for cobalt and nickel, and >95% for lithium [12]. Unlike fossil fuels, which are burned and need to be replenished, these materials are more like strategic assets. 

This is why we said in our Closing the Loop explainer that we need to approach the energy transition with a circular mindset, not a linear one. We also need strong regulation and incentives to improve recycling rates of metals and minerals, including strengthening product stewardship rules. 

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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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