The UK warns chances of a breakthrough are "receding", as it negotiates with the EU over business rules.
Alok Sharma says he expects the doses to arrive for the start of the UK's vaccination programme.
Hundreds of residents reported hearing explosions in the early hours of Friday caused by the weather phenomenon.
Three employees and a contractor were killed in the blast at a water recycling centre in Avonmouth.
The "ambitious" target would see the UK cutting emissions faster than any major economy so far, the PM says.