Frogmore and partner Royalton have unveiled plans for a Salford skyscraper cluster, but they say this time it will be an exemplar of zero-carbon design.

The partners, both of whom are making their Manchester debut, plan a trio of slim-profile towers as part of a 13-block proposal for the 8.3-acre Pier 7 site they acquired from TH Real Estate.

The plan envisages a 48-storey and a 37-storey tower, along with a smaller 25-storey tower and extends the residential offer from the 800 units in a 2016 planning approval to more than 1,400.

Studio Egret West is leading the planning application. Studio Partington and Carey Jones Chapman Tolcher also worked on the designs.

The plans include two new hotels, one located near the Salford Quays Metrolink Station and a second located at the end of the pier, which is envisaged as a landmark waterfront hotel.

The scheme will be an exemplar for Greater Manchester’s ambitious plans to be a zero-carbon region.

The Cotton Quay site will be interwoven with green space, including ‘rain gardens’ which will be sustained through channelling run-off rainwater from surrounding buildings to create a moist habitat suited to specific plants and species — a pioneering approach to urban green space that hopes to provide an exemplar for other UK developments. Other green areas include the unique floating gardens which will be accessible from St Peter's Basin and will offer a haven for birds, bees and insects.