Tesla doesn’t agree with Singapore’s choice to charge its residents for the amount of carbon dioxide needed to power the Model S, an electric vehicle that produces zero tailpipe emissions.

Singapore’s Land Transport Authority tested the high-end EV and concluded that it consumes 444 Wh/km, nowhere near the 181 Wh/km that Tesla claims the car consumes.

One Singapore citizen, Joe Ngyuen, said he was forced to pay an extra $15,000 tax for his Tesla Model S because of the LTA’s ruling.

According to the Verge, a spokesperson from Tesla said in a response to the LTA ruling that “an electric car like the Model S has almost three times lower CO2 per km than an equivalent gas-powered car. Moreover, as Singapore increases the percentage of grid power from solar and wind, the CO2 from electricity drops with each passing year.”

Tesla said that by consuming 181 Wh/km, the Model S releases 90g of CO2 per kilometer. The company added that the Mercedes S-Class emits 200g of CO2 per kilometer.

The California-based company said it has been communicating with the LTA to confirm that the Model S’ consumption is being properly tested and to ensure that the authority fully understands the issues in question. Tesla believes that the two sides will soon come to an agreement on the circumstances.