Vehicle to Grid Technology (V2G)

Background

V2G or “vehicle-to-grid” technology that enables bidirectional flow of energy, in which electric vehicles are not only charged (energy from grid) but also work as temporary source of energy that provide the grid with power when required. By implementing vehicle-to-grid technology, a car battery can be either charged or discharged based on energy supply and demand in the gird. Theocratically, it can be a rising grid-demand mitigation technique and support the grid at times of low supply and high demand [1][2][6].

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In consideration for futuristic environmentally friendly and zero carbon plans, further development and domination of renewables are expected, specifically wind and solar. These are weather dependant (non-dispatchable) source of energy. hence, introduces severe fluctuations in energy grid supply which requires dispatchable, probably fossil fuel, source. Therefore, in order to fully or gradually replace the conventional dispatchable energy sources with renewables, different levels of demand mitigation will be required.

Benefit

For The Power Grid

V2G could contribute as demand mitigator rather than a mean and as commonly signified to solve supply-demand mismatch that might be resulted from power generation switch. V2G work of mitigation revolves around the timing of charge and discharge of energy stored in batteries. During the periods of high renewable supply, the EV/battery will charge or available to charge except for periods of high demand in which the EVs will provide power the grid [5].

For consumers

Since vehicle-to-grid solutions are expected to become a financially beneficial feature for energy companies, they have a clear incentive to encourage consumers to take part. After all, the technology, devices, and vehicles compatible with the V2G technology are not enough – consumers need to take part, plug in and enable their car batteries to be used for V2G. We can expect that in the future, consumers are being rewarded if they are willing to enable their car batteries to be used as balancing elements [5].

Compatible vehicles

Currently, Nissan has outpaced other car manufacturers by bringing V2G compatible car models to the market. All Nissan Leafs on the market can be discharged with vehicle-to-grid stations [3]. The ability to support V2G is a real thing for vehicles and many other manufacturers will hopefully join the club of vehicle-to-grid compatibles soon. For instance, Mitsubishi has also announced plans to commercialize V2G with Outlander PHEV. [4]

The Bidirectional charging in V2G unit allows us to not only charge the batteries of electric vehicles but to also take energy from car batteries and push it back to the power grid to help balance momentary spikes in electricity demand. For example, a LEAF’s battery pack holds about 24kWh of electricity, which can power an average household for about two days. According to the Virta company, the power output from EV battery is 6kwh, although the type of battery in solar energy and EV are different. [1] [7] [8]

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To show the available capacity over time based on government policy for EV adoption, we research the battery capacity across all of the EVs nationally as figure  below.

From the EV battery capacity specification, the battery capacity shows the amount of capacity avaliable for storage and transfer the power to the grid compared with normal solar battery capacity which is only 10kwh and 5 kW output.

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 As an extension of project, V2G technology can be adopted to keep the grid carbon content even lower. For instance, because of shift in the charging time to minimum carbon content during the day (as in ‘Ideal Model’ of carbon constraint), CO2 emission decreased due to the shift to minimum carbon content periods. However, V2G can reduce the carbon content by reducing the demand itself rather than shifting it, hence, the V2G will be operated to support the grid to reduce to carbon content.