Nissan is supplying New York City with fuel-efficient cabs, including six electric cars for testing, but acknowledged uncertainties Tuesday about an ongoing "debate" over charging standards for electric vehicles.

The battle in fast-charging stations, the equivalent of gasoline stands for electric vehicles, is threatening to turn into a futuristic replay of other major platform wars like VHS of Panasonic Corp. vs. Sony Corp.’s Beta in video.

Nissan Executive Vice President Andy Palmer said the debate was still going on, and it was unknown whether nations will adopt the CHAdeMo used by Nissan, or the competing one called Combo backed by General Motors Co. and European automakers. The standards use different plugs and aren’t compatible.

Palmer said Nissan as a leader in electric vehicles must persuade others that its standard is the best.

"The disadvantage is that we are setting the standard," he said.