Vehicle-to-Grid (V2G): Your Car as a Power Station
Electric vehicles are quietly becoming one of the most powerful energy assets ever built. Soon, the same battery that drives you to work could also help power your home, your school, and your community.
What’s Coming
Vehicle-to-Grid (V2G) technology allows an EV to both charge and discharge electricity through a bi-directional charger. When plugged in, your car effectively becomes a smart battery — storing renewable energy when it’s plentiful and feeding it back when demand is high.
A recent report by Concept Consulting (with Rewiring Aotearoa) estimates that V2G could deliver up to ≈ NZD 2,000 per car per year for the electricity system in New Zealand. MinterEllisonRuddWatts+1
That stands in stark contrast to an internal-combustion engine (ICE) vehicle, which is purely a cost — fuel, servicing, depreciation, emissions. In other words: an EV with V2G has the potential to earn, while an ICE vehicle simply drains value.
As export limits increase (10 kW for single-phase, 15 kW for three-phase) and charger & vehicle standards improve, this capability moves from “interesting” into “practically viable.”
A Glimpse Ahead – The Teacher Example
Picture a teacher with an EV who charges at home overnight on low-cost renewable energy, discharges into the morning peak (earning cash), drives to school, and plugs in again during the day (earning then flips to charging from excess sunshine). While parked, their vehicle becomes part of the school’s local energy hub — helping manage rooftop solar generation, supporting the grid during the morning peak, and staying ready for the trip home. At home it again discharges, into the evening peak (earning again) then recharges overnight continuing the cycle. You don’t have to own the home to participate, a renter brings their V2G vehicle with them.
It’s an ordinary daily routine that could soon play a vital role in how New Zealand balances its energy use.
Managed by SUPA Energy
Supa Energy is already developing community energy hubs — schools, marae, and clubs that generate and share local solar power. In the near future, these hubs could include EVs as mobile batteries, charged and discharged automatically by Supa’s platform according to real-time conditions.
You wouldn’t need to do anything; your car would simply contribute when it can, and recharge when energy is cheap and abundant.
Why This is Important
The chart below from the International Energy Agency shows that most of the world’s battery storage capacity now sits inside EVs — far more than all utility-scale and commercial batteries combined.
fig.1 The capacity of EVs is 20 times that of utility scale batteries.
That means if V2G were enabled at scale, the huge capacity already sitting on local low-voltage networks could do much of the job currently being assigned to large, centralised grid batteries.
Those big systems are financed through electricity prices — so making better use of what we already own would help reduce future costs for all consumers.
Some parts of the energy sector are beginning to understand just how disruptive vehicle-to-grid could be.
fig.2 This illustration (via Rewiring Aotearoa) compares the instantaneous power capacity of New Zealand’s largest generators with the potential output from an electrified vehicle fleet.
It is not an energy claim (GWh), but a capacity one (MW) — exactly what matters for peak reduction, network deferral, and system resilience.
V2G is now being understood — just not by government
To their credit, Rewiring Aotearoa have clearly cottoned on to the scale of disruption vehicle-to-grid could bring.
The graphic above makes the point starkly: even a partial uptake of V2G across New Zealand’s light-vehicle fleet would dwarf the instantaneous capacity of our largest power stations.
This is not about replacing generation. It is about timing, locality, and peak avoidance.
Yet despite this, central government and regulators still treat EVs as a load problem, not a system asset. Policy ignores the much larger prize: millions of privately funded batteries, already paid for by households and businesses, sitting idle 95% of the time.
Until V2G is recognised as infrastructure — not a curiosity — New Zealand will continue to over-invest in poles, wires, and gas peaking plant, while under-utilising the cheapest flexibility resource it has.
Vehicle-to-grid is not speculative. The hardware exists. The economics exist. What is missing is regulatory intent.
The Bigger Picture
- For consumers: an EV that has potential to pay back, rather than simply costing.
- For communities: schools, clubs and marae that double as resilience hubs.
- For New Zealand: a flatter, more stable electricity system that reduces overall costs and carbon.
V2G extends the same principles discussed in the Distribution Pricing post: flattening peaks, filling troughs, rewarding flexibility, and keeping more value within communities. As the technology matures, our collective battery — millions of EVs — could become the backbone of a smarter, fairer energy system for Aotearoa. However, unfortunately we have hit a speed hump:
NZ vs AU – Who’s Positioning for V2G?
fig.3 In New Zealand, BEV sales jumped through 2023 under the Clean Car Discount, then dropped sharply after rebates were removed on 1 January 2024 and Road User Charges (RUC) were introduced for EVs from April.
Recent reporting links this policy shift to a significant fall in EV uptake compared with 2023 levels. RNZ+1
In Australia, federal and state policies have mostly pulled the other way:
- fringe benefits tax (FBT) exemption for many EVs,
- various state rebates, rego discounts and other incentives. EV Council+2Australian Taxation Office+2
Result: Australia is steadily growing EV share, while New Zealand has tapped the brakes.
From a V2G perspective, this is significant. Every EV is a potential:
- home battery,
- community battery, and
- system-wide flexibility asset.
If we slow EV adoption, we slow the build-out of this “free” (paid for by owners, not government) distributed storage and lean harder on large utility-scale batteries that are paid for through everyone’s power bills.
Vehicle-to-grid (V2G) represents the largest scalable source of distributed storage available to the electricity system. International work shows that its deployment is constrained not by technical feasibility, but by the absence of clear standards, coordinated regulatory frameworks, and consistent market signals. To unlock this opportunity, New Zealand should provide clear direction to OEMs to supply bidirectional-capable vehicles, align with international standards, streamline connection processes, and ensure pricing frameworks reflect the value of flexible capacity. In a coordinated system, V2G enables EVs to operate as distributed storage, supporting peak demand management, renewable integration, and system resilience.
We still hold the Bledisloe Cup, but right now Australia is ahead on using EVs to make their electricity system more efficient. New Zealand has a choice: treat EVs as just another vehicle to tax, or recognise them as core national infrastructure that can help flatten peaks, integrate renewables, and reduce long-run costs for all consumers.
About Battery Wear
People often ask whether Vehicle-to-Grid will “wear out” their car battery.
In reality, the energy drawn during V2G is tiny compared with what the battery delivers while driving.
When an EV is on the road, it’s pushing nearly two tonnes of car through wind and hills — using roughly ten times more power than when it’s gently cycling electricity to or from the grid while parked.
Early evidence suggests that light, shallow cycling can actually help keep modern lithium batteries balanced and healthy.
It’s still early days, and we’ll learn more as real-world V2G emerges, but it’s unlikely that sensible use for grid support will noticeably shorten battery life — and may even improve it.
References:
Concept Consulting & Rewiring Aotearoa, Powerful Potential: New Zealand’s Vehicle-to-Grid Opportunity (2025) – indicative ≈$2,000/EV/year. https://www.concept.co.nz/uploads/1/2/8/3/128396759/v2g_in_nz_v2.0.pdf
Supa Energy https://www.supa.energy/
EV Market Stats NZ https://evdb.nz/ev-stats
EV Market Stats Australia https://evdbau.com/market-stats
Rewiring Australia https://rewiringaustralia.org/report/factsheet-for-electric-vehicles
The Shameless Plug Episode 3: Dan Adams https://www.youtube.com/watch?v=mjwa0XvgrC0
Rewiring Aotearoa Vehicle To Grid Trial | QEA
Potential of V2G in NZ https://www.minterellison.co.nz/insights/two-way-traffic-the-potential-of-bidirectional-ev
Australia Struggling to Implement V2G + The Energy Article
Accelerating Bidirectional Charging in Australia: Vehicle-Grid Network https://figshare.uts.edu.au/articles/report/Accelerating_Bidirectional_Charging_in_Australia_Insights_from_the_Vehicle-Grid_Network_s_Inaugural_Roundtable/31920768/3