“uneven” playing field for its decision to shelve plans to build a NZ$100 million biodiesel plant. (US$1=NZ$1.3).   Dickon Posnett, managing director of Argent Energy’s NZ subsidiary, said New Zealand’s proposed legislation in the Biofuels Bill makes the playing field too uneven. “Ethanol gets a government-backed subsidy, through relief from excise duty, that amounts to…