The GIB was opened by business secretary Vince Cable at the organisation's headquarters in Edinburgh, Scotland. The aim of the bank is to fund finance low-carbon developments, with offshore wind energy a priority.
The bank will try to encourage private-sector investment. However, the GIB will not be able to borrow money until 2015 at the earliest, despite the efforts of previous energy secretary Chris Huhne.
Some commentators are disappointed that the bank will not be able to borrow money. However, the bulk of the capital for offshore wind is likely to be needed for Round 3 projects after 2015.
Speaking at the launch, Cable said: "Three billion pounds of government money will leverage private-sector capital to fund projects in priority sectors from offshore wind to waste and non-domestic energy efficiency, helping to deliver our commitment to create jobs and growth right across the UK.
"Having the headquarters in Edinburgh is a testimony to our commitment to helping Scotland lead the green revolution."
In addition to offshore wind, other areas for investment include recycling, biofuels, carbon capture and storage, and marine energy.
UK prioritises wind with Green Investment Bank launch
UK: The UK government has officially launched the Green Investment Bank (GIB) with £3 billion (€3.7 billion) in funding.
