"Drivers park their cars up to 95% of the day"
The mass adoption of electric vehicles (EVs) presents opportunities for significant battery deployment to support the electric grid, in particular to increase penetration rates of renewable energy sources (RES) by balancing their intermittent nature  .
The main forms of EV-power system interface include V1G, V2G, V2H (to-home), and V2B (to-building). The current EV charging infrastructure implements the V1G interface, a unidirectional controlled charging system (AKA "unidirectional V2G").
Vehicle-to-grid (V2G) is a system that orchestrates the bidirectional power flow btw EVs and the grid (from the grid to EVs to charge batteries, and from EVs to the grid to support the latter). EVs that are compatible with the grid and allow for bidir power (and data) flow are known as gridable electric vehicles (GEV) .
The potential of GEV paradigm in helping the grid to fulfill grid power needs through ancillary services is extensive. It can provide functions such as frequency regulation, voltage regulation, peak shaving, load leveling, congestion mitigation, and renewable energy storage. But V2G adoption, which requires specialized hardware (e.g., bi-directional inverters), currently faces challenges such as high investments and high upfront costs, as well as regulatory issues.
V2G can only be implemented if the points of interaction between the two elements, the VE and the grid, recognize each other. ISO/IEC 15118 standardizes the V2G communication interface . As part of the Combined Charging System (CCS), 15118 standard covers wired (AC & DC), wireless charging applications and enables the integration of EVs into the smart grid.
Global V2G key players include NUVVE (San Diego based company that claims to hold V2G patents), Enel Energia, Moixa, E. ON, The Mobility House, among others. Global top five players hold a share about 85%. Europe is the largest market, with a share about 45%, followed by Asia-Pacific and North America, having a total share of around 50% .