Burnley pay Porter tribunal fee
The Football League fixed the fee after the Clarets were unable to agree a deal with Leyton Orient for Porter's services.
Orient will receive further instalments for the 20-year-old which could rise to ?70,000 depending on appearances.
Eddie Howe's side will also have to pay ?100,000 if Porter plays 23 games in helping win promotion to the Premier League during the length of his contract.
Porter joined the club on three-year deal in July after his deal with the League One club expired but they were still entitled to compensation due to the player's age.
They will also receive a sell-on fee if the Clarets make a future profit on the Sidcup-born player.