This paper examines the impact of charging tariffs on the economic viability and market effects of Vehicle-to-Grid (V2G) technology, particularly in the context of Germany and other European Union countries. The authors use the agent-based electricity market model PowerACE to simulate four scenarios, analyzing how different tariff structures influence V2G revenues and market dynamics. Key findings include: 1. **Economic Viability**: The current V2G tax scheme in Germany and other European countries levies substantial taxes, fees, and surcharges on electricity purchases, requiring a significant price spread for profitable trading. The study highlights that current legislation falls short of EV owners' financial expectations for V2G participation. 2. **Tax Regime Impact**: A more favorable tax regime could boost V2G trading, leading to profits in line with owner expectations and reducing the need for stationary battery storage investments. This would also lower wholesale market prices. 3. **Market Dynamics**: The role of EVs shifts from price-takers to price-makers, posing long-term profitability risks. The study recommends implementing favorable tax regimes to mitigate these challenges and facilitate effective V2G integration. 4. **User Willingness to Pay**: The research compares users' willingness to pay for a V2G charging tariff with the actual charging costs under different tariff designs. Results show that most households would be willing to participate in V2G under a discounted charging tariff with reduced taxes and fees. 5. **Regulatory Challenges**: The current double taxation of EVs for both charging and discharging electricity, along with the lack of refunds for taxes paid during discharging, creates systemic flaws. Reducing or removing these taxes could create a more viable business case for EV adopters. 6. **Limitations**: The study acknowledges limitations such as assumptions about EV behavior, the simplification of multiple aggregators, and the accuracy of price forecasts. These limitations may introduce uncertainties in the projections of V2G economic benefits. Overall, the paper underscores the importance of favorable tax regimes in encouraging V2G market adoption while maintaining its economic viability.This paper examines the impact of charging tariffs on the economic viability and market effects of Vehicle-to-Grid (V2G) technology, particularly in the context of Germany and other European Union countries. The authors use the agent-based electricity market model PowerACE to simulate four scenarios, analyzing how different tariff structures influence V2G revenues and market dynamics. Key findings include: 1. **Economic Viability**: The current V2G tax scheme in Germany and other European countries levies substantial taxes, fees, and surcharges on electricity purchases, requiring a significant price spread for profitable trading. The study highlights that current legislation falls short of EV owners' financial expectations for V2G participation. 2. **Tax Regime Impact**: A more favorable tax regime could boost V2G trading, leading to profits in line with owner expectations and reducing the need for stationary battery storage investments. This would also lower wholesale market prices. 3. **Market Dynamics**: The role of EVs shifts from price-takers to price-makers, posing long-term profitability risks. The study recommends implementing favorable tax regimes to mitigate these challenges and facilitate effective V2G integration. 4. **User Willingness to Pay**: The research compares users' willingness to pay for a V2G charging tariff with the actual charging costs under different tariff designs. Results show that most households would be willing to participate in V2G under a discounted charging tariff with reduced taxes and fees. 5. **Regulatory Challenges**: The current double taxation of EVs for both charging and discharging electricity, along with the lack of refunds for taxes paid during discharging, creates systemic flaws. Reducing or removing these taxes could create a more viable business case for EV adopters. 6. **Limitations**: The study acknowledges limitations such as assumptions about EV behavior, the simplification of multiple aggregators, and the accuracy of price forecasts. These limitations may introduce uncertainties in the projections of V2G economic benefits. Overall, the paper underscores the importance of favorable tax regimes in encouraging V2G market adoption while maintaining its economic viability.