Organisers have announced a new “long-term partnership” with Edinburgh University, which runs the art school, in the wake of mounting criticism over the impact of the event on the New Town site.
However the impact of the pandemic is said to have been the “driving force” behind the move to relocate the event after 37 years.
Director Nick Barley pledged that the event, which attracted a record attendance of 265,000 in 2019, would be staged “in a more environmentally responsible way” in future while retaining its “village green” atmosphere.
The festival, which has featured more than 900 events in recent years, plans to recreate its celebrated atmosphere in the grounds of the art school campus on Lauriston Place. Events will be held around the campus, including in its sculpture court.
Mr Barley said the festival, which normally spent around £1 million creating its site, would have faced a “huge deficit” had it attempted to return there this August.
It is not expect to announce until June whether audiences will be allowed at events.
He added: "With in-person ticket sales impossible to forecast this August, we simply can't justify incurring the costs of the tents and infrastructure we'd normally put into the gardens.
“Augusts have definitely been getting damper in recent years and I’ve become more and more concerned about our impact on the gardens. That’s been a consideration but hasn’t been the driving force behind this decision.”
Mr Barley said the pandemic, which forced the festival to be staged entirely online last year, had created a “huge tectonic shift” for event organisers.
The majority of this year’s programme is expected to be broadcast online again, with contingency plans to have socially-distanced audiences at some talks if restrictions are eased.
Mr Barley said: "It is highly probable most events will take place online and the need for broadcast studios is more likely than large venues for an audience.
“In the grassy courtyard, we will, if rules allow, recreate the elements of the book festival that our audiences love – bookshops, cafes and open spaces in which to come together safely, offering the ‘oasis of calm’ for which the festival is renowned.
"The college offers excellent studio and theatre facilities for both online broadcasting and potential events with a socially distanced audience.
"We intend that this partnership with the university will be a long-term arrangement, and that we will continue to occupy the university’s spaces when a Covid-free festival can be staged. However digital events will continue to be a key part of future festivals.”
Mr Barley said the partnership opened the possibility of book festival events being staged at other university-owned buildings in future years.
But he added: “The site at Lauriston Place is perfect our needs for the new hybrid festival we want to put on.”
Professor Peter Mathieson, principal of the university, said: “We were delighted to be asked by the book festival to support future events through this mutually-beneficial arrangement. This will help to ensure that people in Edinburgh, and all over the world, can continue to come together to explore the power of ideas through their love of literature.”