(Drone images of solar panels on a roof at Monash University's Clayton campus. Image credit: Exciton Science)

Buildings in Melbourne could generate almost three quarters of their own energy needs if solar technology is fully integrated into roofs, walls and windows, new research has found.

In their latest study, Monash University researchers together with collaborators from the University of Lisbon modelled the viability and impact of window-integrated photovoltaics alongside other solar technologies over a 37.4 square kilometre area of central Melbourne at a city scale as well as an individual and neighbourhood scale.

(above image: (Drone images of solar panels on a roof at Monash University’s Clayton campus. Image credit: Exciton Science)

At a city scale, the analysis found that photovoltaics or solar technology could provide up to 74 percent of the energy consumption which is required by the city’s buildings.

Of this, rooftop solar contributed 88 percent of the solar supply whilst wall and window integrated solar constituted 8 percent and 4 percent respectively.

However, wind and wall-integrated solar technology was shown to suffer less reduction in efficiency during winter relative to rooftop and to deliver greater consistency in benefits and value on a year-round basis.

When analysed at a neighbourhood scale, meanwhile, the potential contribution of window-integrated solar rose to 18 percent – a phenomenon which reflects high building heights and window to wall ratios.

Published in the journal Solar Energy, the research was led by members of the ARC Centre of Excellence in Exciton Science based at Monash University along with collaborators at the University of Lisbon.

It is the first study worldwide to model the viability and impact of window-integrated photovoltaics, alongside other solar technologies, at a city scale.

During the study, the team compared building energy consumption throughout the city with the electricity product which could potentially be achieved through fully and widely building integrated solar.

The energy consumption is based on 2018 data from the Melbourne CBD which was obtained through power companies.

The potential contribution of solar radiation and PC was derived through detailed modelling.

This took into account factors such as the impact of shadows casted by shading systems and balconies, as well as the performance characteristics of the various solar technologies.

It featured the 37.4 square kilometre area of Central Melbourn – of which 31.5 square kilometres was built floor area in 2019 comprising of residential and commercial buildings.

The results showed that the photovoltaics potential of this area is driven mainly by the possibility of adding further rooftop solar.

While blocks with high rooftop and wall solar potential are found across the city, meanwhile the greatest potential for window-integrated solar gains is in the city’s high-density urban centres such as the central business district.

A prototype semi-transparent solar cell in development as an alternative to window glass. Image credit: Exciton Science.

Professor Jacek Jasieniak, lead author of the study said photovoltaics can play a significant role in reducing carbon emissions in Melbourne’ inner-urban built environment.

Jasieniak says this would complete a full-circle movement which would see the city’s buildings returning to lower power generation in the CBD.

“By using photovoltaic technology commercially available today and incorporating the expected advances in wall and window-integrated solar technology over the next ten years, we could potentially see our CBD on its way to Net Zero in the coming decades,” Jasieniak said.

“We began importing coal-fired power from the Latrobe Valley in the 1920s to stop the practice of burning smog-inducing coal briquettes onsite to power our CBD buildings, and it’s now feasible that over one hundred years later, we could see a full circle moment of Melbourne’s buildings returning to local power generation within the CBD, but using clean, climate-safe technologies that help us meet Australia’s Net Zero 2050 target.”

Co-author Dr Jenny Zhou says that whilst much attention is being devoted to new buildings more could be done in terms of policies to encourage retrofitting of existing building stock to meet climate change challenges.

She says the research provides a framework that can help decision-makers move forward with implementing photovoltaic technologies that will reduce city reliance on fossil fuels.