Unlocking the full potential of EVs with vehicle-to-grid technology

Decarbonization of the mobility sector is a critical step in tackling climate change, but it also presents significant challenges, particularly for power grids. As EV adoption accelerates, so does the strain on the electrical grid, raising concerns about grid stability.

But what if EVs could be part of the solution?

EVs can already help stabilise the grid by adjusting their charging power. But their full potential lies in the vehicle-to-grid (V2G) technology, which allows them to operate bidirectionally – not only drawing energy from the grid but also feeding it back.

Turning EVs into profitable energy assets  

With battery capacities ranging from 50-100 kWh for passenger cars to 500-700 kWh for heavy-duty vehicles like trucks and buses, EVs can store vast amounts of energy. For instance, consider 20 heavy-duty vehicles parked at the same depot, each with a 500-kWh battery. The total energy stored in these batteries amounts to 10 MWh, which corresponds to the daily electricity usage of approximately 1,000 Danish households.

If even a small portion of the energy stored in parked EVs were accessible for additional uses, it could unlock huge potential for the electricity system.

To maintain a stable and reliable grid, the production and consumption of electricity must continuously match. Traditionally, this balance has been achieved mainly by fossil-fuel-based power plants. However, as we transition to a more renewable-based power system, alternative solutions are necessary. With V2G technology, EVs can support the operation of the electrical grid: when electricity production exceeds consumption, such as during periods of high wind, EVs can charge, acting as a load. Conversely, when consumption surpasses production, EVs can discharge energy back into the grid, functioning as generators.

On a more local level, V2G can serve as a critical backup energy source. In Japan, where earthquakes are frequent, bidirectional charging was already used in 2011 as a resilience measure to ensure power availability during outages.

Regardless of the specific utilization of V2G technology, V2G needs to bring value to the EV owners – such as monetizing the service when energy is sent back to the grid.

Imagine a fleet depot where hundreds of EVs sit parked overnight. V2G technology would enable fleet operators to sell power back to the grid during peak demand and recharge at lower off-peak rates. This could create an additional revenue stream, ultimately reducing the total cost of ownership (TCO).

Compelling, right? So, are we all set to plug in and cash out? Unfortunately, not yet.

Regulatory and technical roadblocks

The technology exists. Private households can already buy batteries to store their production from solar systems and utilise the energy during evening hours or even sell electricity back to the grid. So, what distinguishes this from an EV battery?  

A major difference is that EV batteries are mobile. Although an EV battery typically has five times the capacity of a stationary home battery they connect to different parts of the grid. This creates a substantial challenge: ensuring a seamless and standardised interaction between EVs, charging infrastructure, and grid operators.  

Currently, various stakeholders - including automakers, energy providers, and regulatory bodies - are not fully aligned, leading to inconsistencies in technical standards and deployment strategies. One of the biggest challenges of V2G is the complexity of standardising the infrastructure that includes EVs, hardware, and software capable of bidirectional charging.  

Automakers, manufacturers of chargers, and stakeholders in the eMobility sector recognise the significance of the technology and are adopting it. The German research center FfE has estimated that, from the perspective of the energy system, ideally 30% of electric vehicles should be bidirectional by 2030. However, the current market is constrained on both the vehicle and charger fronts, making investments in robust and scalable infrastructure, such as advanced inverters, crucial to offer users a wide range of options.  

Additionally, regulatory frameworks are not yet fully adapted to accommodate V2G technology. In many regions, electricity markets and grid infrastructure are designed around traditional energy production, making it difficult for EV owners to sell electricity back to the grid in a streamlined and profitable manner.

To make V2G more attractive, new pricing models must be implemented - ones that fairly compensate EV owners for providing grid services and make it financially appealing to integrate their vehicles into energy markets.

Scaling up V2G through collaboration

Despite these technical and regulatory barriers, V2G is becoming a reality. It is already being tested with various EU pilot projects, marking an important step forward, but broader deployment requires greater regulatory and infrastructural alignment. At Spirii, we are actively maturing V2G technology through EU research and development projects. Notable examples are the FLOW project, which explores user-focused and interoperable solutions to enhance V2G opportunities and the AHEAD project, where we explore the cybersecurity challenges associated with the implementation of V2G.  

Ultimately, V2G technology will only reach its full potential when we achieve the right combination of advanced charging infrastructure, standardized protocols, and financial incentives for consumers.

For this to happen, governments and industries must collaborate to create policies that encourage this transition and allow the technology to scale. If successful, V2G could unlock a future where EVs empower both their owners and the energy grid.

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