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V2G Bidirectional Charging Earnings

Calculate annual net earnings from exporting energy back to the grid via bidirectional charging.

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What this tool does

This calculator estimates annual net earnings from vehicle-to-grid (V2G) bidirectional charging by applying a simple revenue-minus-cost formula. It multiplies daily exported kWh by the export rate and days per year to compute gross income, then subtracts battery degradation cost (kWh cycled × wear cost per kWh) to produce net earnings. The model assumes a constant export rate and linear battery wear; real-world returns vary with tariff structure, charge-discharge efficiency, and battery chemistry.

Inputs
(kWh)
(£/kWh)
(days)
(£/kWh)
Result
Result

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Formula
Annual net V2G earnings (£)
kWh exported per day
Export rate (£/kWh)
Days per year
Battery wear cost (£/kWh)

How the V2G bidirectional charging earnings calculator works

The calculator computes annual net income from exporting stored electric-vehicle battery energy to the grid. It takes four inputs: daily kWh exported, the export rate paid by the energy supplier, the number of days per year the vehicle participates, and the estimated cost of battery wear per kWh cycled. The tool multiplies daily export volume by the rate and participation days to find gross revenue, then deducts cumulative battery degradation cost to show net annual earnings.

The formula

Gross export income = kWh exported per day × export rate (£/kWh) × days per year
Battery wear cost = kWh exported per day × days per year × degradation cost per kWh
Net V2G earnings = Gross export income − Battery wear cost

The calculator also displays total kWh exported annually (daily kWh × days per year).

Where this method is most accurate

The formula assumes a flat export rate throughout the year and linear battery degradation proportional to energy cycled. Accuracy is highest when the export tariff is time-invariant, charge-discharge round-trip efficiency remains constant, and the battery's state-of-health cost estimate reflects the vehicle's specific chemistry and warranty structure. Real V2G schemes may use time-of-use pricing, demand-response bonuses, or frequency-regulation payments not captured here. Battery wear cost per kWh varies widely by manufacturer, cycle depth, and ambient temperature.

What this tool does not do

It does not model time-of-use tariffs, peak/off-peak pricing, or ancillary-service payments. The calculator omits round-trip charging losses (typically 10–15%), inverter efficiency, or tax treatment of V2G income. It does not certify any specific vehicle or charger for grid-export capability, nor does it account for contract terms, connection fees, or grid-operator eligibility rules. The battery wear estimate is user-supplied; the tool does not calculate degradation from first principles or verify warranty impacts.

Disclaimer

This tool is for educational and estimation purposes only. It does not constitute financial, tax, or vehicle-modification advice. Actual V2G earnings depend on tariff structure, grid-operator agreements, equipment certification, and battery warranty terms that vary by manufacturer and jurisdiction. Users remain responsible for verifying vehicle compatibility, supplier contract details, and any regulatory or safety requirements before participating in vehicle-to-grid programmes.

Questions

What is V2G bidirectional charging?
Vehicle-to-grid (V2G) bidirectional charging allows an electric vehicle to export stored battery energy back to the electricity grid. A compatible charger and vehicle can discharge power during peak-demand periods, earning revenue from the energy supplier or grid operator. The technology requires bidirectional on-board chargers and a V2G-enabled supply tariff.
How is battery wear cost per kWh estimated?
Battery wear cost per kWh represents the amortised expense of capacity degradation caused by charge-discharge cycles. It is typically derived by dividing projected battery replacement cost by total warranted cycle throughput. Manufacturers and researchers publish different estimates depending on chemistry (NMC, LFP) and cycle depth; users supply their own figure based on vehicle warranty data or third-party studies.
Does the calculator include charging losses?
No. The formula uses the kWh exported figure directly and does not deduct round-trip efficiency losses. Real bidirectional systems lose 10–15% of energy to inverter conversion and battery internal resistance. To model net-of-losses income, reduce the daily kWh exported input by the estimated efficiency factor before entering it.
Can I use this calculator for time-of-use tariffs?
The tool assumes a single flat export rate. For tariffs with peak and off-peak prices, calculate a weighted-average rate (peak hours × peak rate + off-peak hours × off-peak rate, divided by total export hours) and enter that figure, or run separate scenarios for each pricing period and sum the results manually.
What participation-days figure is realistic?
Participation days depend on daily driving patterns and minimum state-of-charge requirements. Many V2G users export only on weekdays when the vehicle is parked at home overnight, yielding roughly 250 days per year. Vehicles that travel long distances or require full charge each morning may participate fewer days. The default of 300 days is illustrative; actual availability varies by household routine.

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Sources & Methodology

The calculator applies the formula: Net V2G earnings = (kWh exported per day × export rate × days per year) − (kWh exported per day × days per year × degradation cost per kWh). This subtracts estimated battery wear cost from gross export revenue to yield annual net income. The method assumes constant export rate and linear degradation; it does not model round-trip efficiency losses or time-variant pricing.

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