Currently, over 90% of new power generation relies on renewable sources. However, solar and wind energy can produce electricity only intermittently, leading to fluctuations in supply. A pilot project in Delaware has demonstrated that electric vehicle (EV) owners can earn considerable income—amounting to thousands of dollars annually—by utilizing their idle vehicles as a sophisticated storage system. This system stores excess electricity generated during peak production and discharges it during high-demand periods.

Recent findings indicate that the average electric vehicle is parked for 95% of the day. This highlights the potential for power utilities to tap into the energy stored in these vehicles during peak hours and recharge them when demand is lower. Willett Kempton from the University of Delaware estimated that EV owners could profit by selling their stored energy back to the grid.

“Electric vehicles can act as a cheaper energy storage solution compared to traditional battery installations, provided they’re plugged in most of the time,” says Kempton. This innovation could bolster power system reliability and enhance the integration of renewable energy sources.

The Delaware project showcased adaptations on four Ford electric vehicles contributed by Delmarva Power. Throughout 2025, V2G (vehicle-to-grid) charging was monitored, revealing that each EV could generate up to $3,359 annually if energy sold aligns with market rates.

Despite initial optimism about V2G technology when it was first studied in 1997, nearly three decades later, it remains mostly experimental in select regions across the U.S., Europe, Japan, and China.

The complexity of reversing energy flow from grid to vehicles has posed significant challenges, necessitating adjustments from automakers, utility companies, and regulatory bodies alike.

The core issue lies in the power grid predominantly relying on AC (alternating current), while most household appliances—including EVs—convert AC to DC (direct current) when charging. For vehicles to supply power back to the grid, this energy must be converted back to AC.

Implementing this safely requires V2G components compliant with stringent safety regulations. Currently, the simplest V2G setup involves installing a wall-mounted charger that converts DC to AC, making it suitable for solar installations. Various manufacturers, including Volkswagen and Nissan, now provide wall chargers compatible in select areas.

However, these wall chargers can reach high costs. To combat this, companies like Tesla, BYD, and Renault are innovating EVs equipped with built-in converters for DC to AC inside the vehicles. Additionally, experts like Kempton are working on new safety standards for AC chargers. With broader adoption, the cost of implementing V2G technologies could be substantially less, adding just a few hundred dollars to the price of a vehicle.

Presently, a rivalry exists between manufacturers adopting DC V2G, such as Volkswagen and those focused on AC V2G, like Tesla. This scenario is likened to the VHS versus Betamax format war of the 1980s, as explained by Alex Schoch, an executive at Octopus Energy. “While Betamax had superior quality, VHS emerged as more affordable, ultimately dominating the market,” he adds.

“There’s potential for both standards to coexist for a time, but long-term scalability demands a dominant standard,” Schoch states. “We unequivocally back AC.”

For consumers considering investing in V2G, a feed-in tariff structure is vital, allowing them to profit from supplying energy back to the grid. In 2024, Octopus launched the UK’s inaugural V2G tariff, though access remains limited for many EV owners. The partnership with BYD allows customers to lease V2G-enabled chargers and electric vehicles.

“Today’s EVs and the next generation rolling out are increasingly V2G-compatible,” Schoch notes, indicating a future with immense distributed energy capacity across the nation.

The advent of V2G technology could help achieve real-time balance in grid supply and demand. However, the rising number of V2G-equipped EVs may strain existing power systems, potentially necessitating grid upgrades.

Recent research indicates that a holistic approach to grid upgrades would be more economical than incremental improvements as V2G technology expands. The study’s lead researcher, Xu Liangcai from the National University of Singapore, emphasizes the need for proactivity in preparing power systems for the emerging V2G landscape.

“Initially, I thought V2G would be a panacea,” remarked co-author Ziyou Song, also from the National University of Singapore. “However, it’s clear that significant upgrades to power systems are essential to accommodate increased demand for charging.”