BPN June's cover featured an artist’s impression of plans to refurbish Legion House in Sydney into one of the most sustainable buildings in the world.

The building is part of the 161 Castlereagh Street project, where an office tower is being developed for tenants ANZ and Freehills.

Grocon unveiled its design ambitions for the heritage listed Legion House in May.

It will be the builder’s corporate headquarters, and the first Australian CBD office building to disconnect from the mains electricity grid.

The developer is working with sustainability consultants Umow Lai and architects FJMT on the project, as well as heritage architects Weir and Phillips.

Plans include using ‘green’ construction materials and methods, including sustainable bamboo and timber elements.

Water saving initiatives would include air-cooled chillers and vacuum toilets, ensuring the building is also water- balanced.

On-site renewable power will be generated through biomass gasification technology, with surplus energy supplied to the neighbouring office tower.

Work will include an extension incorporating two new office floors. The internal lift and stair will be relocated to the exterior of the building, creating a new ‘visually interesting’ laneway entry.

Grocon CEO Daniel Grollo says they were keen to take the next step, “Following on from Pixel in Melbourne, which is currently the greenest building in Australia as rated by the Green Building Council …”

Project manager Dan McLennan says they were keen to populate the building with products pioneered in the Pixel project.

“Interestingly from a design standpoint, the plans will allow the building to retain heritage items including internal chimneys, as well as avoid building in any obtrusive columns.”

He adds: “We also believe the project will demonstrate how biomass gasification has the potential to be used as a power source in much bigger projects, especially within campus developments, but really, it’s scalable to any size.”

The unit will potentially utilise waste office paper, combing it in a plant room with sawdust into cork-sized bricks, it will be heated but not burnt, with the power generated then expected to pay back and exceed the energy used across the entire building lifecycle’s footprint within 30 years.

The project investment partner GPT’s CEO Michael Cameron says Legion House will set a new benchmark for the creation of sustainable city precincts.