The UK's new deadline for 2018 ETS compliance is 22:59 GMT on 29 March, the government said today. The deadline was previously set for 26 March.
The UK government will change the deadline again if the country's EU exit date is amended further, it said. In this scenario, the ETS compliance deadline would be set at the EU exit date, or at 30 April, if the UK's EU exit date is changed to 1 May or later. A 30 April deadline would match the date for other member states to surrender EU ETS allowances.
The remaining 27 EU member states agreed yesterday to delay the timetable for the UK's departure from the EU.
The EU 27 pushed back the UK's scheduled EU exit date to 12 April, from 29 March. Remaining member states also agreed to extend the UK's scheduled departure to 22 May, if the UK parliament votes next week to approve prime minister Theresa May's withdrawal agreement, and confirms that the country will exit the bloc with a deal in place.
The UK's participation in the EU ETS will be extended until the end of next year if the UK parliament votes to approve the draft withdrawal package.
But based on the latest Brexit timeline, the country will crash out of the European carbon market on 12 April if it exits the EU without a deal.
Compliance deadlines for UK parties were brought forward in 2017 to ensure that the deadline fell before the country's departure from the EU, which had been scheduled for 29 March.
The UK initially brought forward its ETS compliance deadline to 15 March 2019, but changed this to 26 March earlier this month.