Tate has announced that the first phase of its new Tate Modern development in London is to open its doors to the public next summer - part of the London 2012 Festival.

The former power station's Oil Tanks - circular spaces spanning 30m (98ft) across and 7m (23ft) high - will provide dedicated space for showing "art in the live form". In addition to the industrial chambers, neighbouring galleries will provide new spaces for the attraction to display its collection of artworks. The tanks will also offer new learning areas.

Tate trustees revealed that the completion of the first phase had been made possible through a number of donations that had helped raise 70 per cent of the £215m development cost. Phase two of the development, which will provide more floors of galleries and increase Tate Modern's exhibition space by 70 per cent, is not due for completion until at least 2016.

Lord Browne, chair of the Tate trustees, said: "Once completed, the new Tate Modern will represent the most important new building for a national arts organisation in the UK since the creation of the British Library in 1998." Tate director Nicholas Serota added: "The new building will allow us to show more of our collection, while the Oil Tanks promise to be some of the most exciting spaces for new art in the world."