State lawmakers mandated the fee in 2009 after a vigorous lobbying campaign by Georgia Power. Consumer groups opposed the fee.
The utility says the early collection will allow it to shave hundreds of millions of dollars from the cost of financing the $14 billion project.
The state's municipal power companies and most of its electric membership cooperatives are sharing in the Vogtle costs, although most are not charging customers yet.
Georgia Power customers will see further increases in 2012 and 2013 under a compromise deal approved two weeks ago by the state Public Service Commission.
The further increases will add about $4 more to the typical residential monthly bill.
By 2013, that typical bill will be $216 more per year than it is today.