The £2 billion deal with Atos expired last month but has been temporarily extended, with new contracts set to be in place by March 2017.
Postgate said: “We are moving away from one monolithic, long-term contract with a single supplier, to multiple shorter-term contracts with a number of specialist companies. We are saving £90 million over the next two years and we expect to deliver similar savings once we've completed the transition.”
He said this will allow the corporation to be more flexible, get quicker access to new technology as it arrives and get the best possible value for money.
Last week the BBC issued a tender for a seven-year networking and connectivity services contract worth up to £230 million, with options to extend it for a further three years.
Since he joined in July 2014, Postgate said he has implemented “a new structure and approach” for the BBC technology team (called BBC Engineering).
He said the new strategy focuses on providing software, systems and services aligned to the specific needs of individual editorial teams like TV, Radio, News, Sport and Children’s.
“We are also taking a much bigger focus on user experience and design for all the tools and software in our studios,” Postgate added.
He promised internet technologies will play a bigger role in the delivery of BBC services and programmes, reducing the need for multiple production vehicles and opening the door to new forms of content like Ultra-HD or virtual reality.
Postgate also called for better and faster broadband infrastructure.
He said: “What kinds of experiences could we provide in 2020 or 2024 if the nation had universal high speed broadband and a broadcast infrastructure designed to take advantage of it?”
Postgate was appointed in July 2014, replacing interim CTO John Coles. Coles filled the role after John Linwood was forced to leave by the BBC in July 2013 after being blamed for the failure of the £100 million Digital Media Initiative. Linwood subsequently won a claim for unfair dismissal.