A future where households or businesses can send power stored in their EV batteries back to the electricity grid is taking shape. In February 2025, the Australian Renewable Energy Agency (ARENA) and RACE for 2030 released a National Roadmap for Bidirectional EV Charging. The Roadmap envisages bidirectional EV charging (Bidi) for residential use in Australia by 2030. There has been much talk in New Zealand of the contribution smart EV chargers can make to our energy system by shifting load at times of peak demand. But is Bidi also on our horizon and, if so, what do we need to be doing to progress it?

What is bidirectional EV charging?

Bidi allows users to not only charge their vehicle but also to allow electricity to flow from their EV battery to an external electricity system. Bidi can take many forms (collectively known as Vehicle to Everything – V2X). For example, Bidi would enable users to act as generators, with the ability to provide power to:

• appliances (Vehicle to Load – V2L)
• homes or buildings (Vehicle to Homes and Buildings – V2H/B)
• the electricity grid (Vehicle to Grid - V2G).

The Roadmap focuses on V2H/B and V2G.

Why is Bidi useful? 

As our energy system becomes more renewable, we face the challenge of intermittency. Bidi can provide an additional source of fast and flexible battery energy storage. The Roadmap estimates that the usable storage capacity in Australia’s EV fleet will be over three times the total National Electricity Market (NEM) storage capacity by 2050 [1]. Flow on benefits may include lower energy bills, local industry opportunity, and emissions reduction. 

Bidi can also be a quick and accessible source of energy in a natural disaster or climate emergency. EVs can act as a mobile power generator and back-up power source if grid outages occur. V2L technology was used by some households during Cyclone Gabrielle [2]. 

How does V2G work?

To use Bidi to support the grid (V2G), a consumer would need:

1. an EV with V2G capability;
2. a compatible bidirectional charger; and 
3. smart software to manage the energy being injected into the grid.

Interoperability between the three elements is essential and that’s where things get complicated.

What’s happening in Australia?

EV automakers and EV supply equipment manufacturers around the world are in the process of developing Bidi products and many EVs already in Australia are Bidi capable. Just last month, Essential Energy (one of Australia’s largest EDBs) and scientific agency CSIRO announced new, market-ready V2G technology [3]. There is enthusiasm for Bidi in Australia, but it will compete with larger markets for Bidi technology and will need to address barriers to market entry. 

Incentivising automakers to release this capability in the Australian market over the next 24 months is an immediate issue. Among the 18 actions identified in the Roadmap, the five most urgent areas for action are:

1. National policy commitment
2. Time-limited installation rebates to address early adopter disadvantage
3. National Electricity Rule changes to enable dynamic tariffs and national consistency for networks 
4. Clear direction on interoperability standards
5. Clarity on national smart grid architecture requirements

V2G in New Zealand

Energy Minister Simon Watts has said that V2G is one option being considered for New Zealand’s energy security and affordability. In addition to regulatory work underway, he has encouraged the sector to work together to enable it [4]. To facilitate V2G in New Zealand, regulatory and legislative changes are needed to ensure grid safety, interoperability, and fair market access, including updating standards, streamlining connection processes, and establishing smart tariff structures. The economics of Bidi must also stack up. While Bidi-capable chargers are increasingly available globally, at this stage they are significantly more expensive than other EV chargers. Consumers will also need to be incentivised to participate in Bidi, for example via rebates on electricity charging for consumers who feed electricity back to the grid (V2G) or free electricity time if a consumer uses Bidi.

Some positive steps are being made:

• New Zealand has adopted updated Standard AS/NZS 4777.1:2024, which is designed to accommodate new technologies like V2G systems. 
• Trials are underway for flexibility trading platforms to help establish a local flexibility market (e.g., where service providers who might aggregate distributed energy resources can sell that flexible energy resource to an EDB).
• Load management for hot water heating trials will help inform how to approach V2G load management.
• Counties Energy is conducting trials using a V2G system to understand the technology and its applications in the New Zealand environment [5]. 
• New Zealand company Evnex is working towards bringing a V2G capable charger to market [6]. 
• The Electricity Authority (EA) has recently consulted on new ways to empower electricity consumers including measures to reward consumers for supplying electricity (e.g., energy stored in batteries) at peak times. While the consultation papers are directed towards solar and battery packages, any resulting settings may also encourage uptake of V2G in New Zealand.
• The EA's current consultation on the opportunities and challenges of a decentralised electricity system will enable consideration of V2G.
• Transpower’s refreshed Te Kanapu future scenarios will explore the potential role of V2G.
• The Government has set aside $68.5m to provide concessionary loans to private operators to co-invest in public EV charging infrastructure [7]. This is intended to accelerate the roll-out of EV chargers which should, in turn, increase EV uptake in New Zealand.

We will need that greater EV uptake and significant consumer education and engagement to make V2G mainstream. One common concern raised about Bidi is battery degradation. This could impact the warranties that EV makers are prepared to provide to end users. Any battery degradation cost will also need to be factored in when considering how best to incentivise consumers to participate in a local flexibility market. 

Mainstream use of Bidi has huge potential for individuals and businesses with EV fleets to contribute to New Zealand’s energy efficiency and stability. However, it is unlikely that this will happen quickly. There will need to be collaboration between government agencies, electricity distributors, retailers, charging infrastructure providers, and EV manufacturers to ensure a smooth transition to V2G technology. 

Australia will be a good test.

Next steps

In New Zealand, we want to be fast followers. We want to see policymakers prioritising regulatory changes, industry leaders looking to invest in V2G technology, and retailers and EDBs helping to educate consumers and keep them informed about the benefits and opportunities of Bidi. Please get in touch with one of our energy experts if you would like to know more. 

This article was co-authored by Lydia Sharpe, a Senior Solicitor in our Construction and Infrastructure team.

Footnotes
1. National Roadmap for Bidirectional EV Charging, p.8
2. Can you use an EV battery to power your home? | Genesis NZ
3. Vehicle-to-grid technology hits the market - Energy Magazine
4. EV 'batteries on wheels' for electricity grid support mooted by government | interest.co.nz
5. EV batteries get second life with new charging initiative - Case Study - Counties Energy
6. Evnex Blog | How does V2G work? An explainer on vehicle-to-grid charging
7. Accelerating the roll-out of public EV chargers | Beehive.govt.nz