A solar energy storage system installed by a low-income student cooperative has reduced power bills for its tenants by around 55 per cent during its first year of operation.

Former resident Dr Bjorn Sturmberg was the project manager of the Solar + Storage project when it was switched on at the Stucco student cooperative in Sydney's Newtown in late 2016.

His project team worked for 18 months to get the system running and originally aimed to reduce the tenants' bills by 20 per cent.

"It's a huge success as I would say, and it's delighting," Dr Sturmberg said of the first year's results.

PHOTO: From left, current Stucco tenants Edie Griffin and Cooper Adams with Solar + Storage project manager Bjorn Sturmberg.
(ABC Radio Sydney: Luke Wong)

 

"So now seeing what it has done in terms of tenants' electricity bills, let alone the environmental impacts, is excellent."

Stucco, which is run by full-time students of the University of Sydney, owns the solar system and batteries and sells the power generated to its tenants.

The installation cost $130,000 which was aided by a $80,000 grant from the City of Sydney.

In 2017 the system produced 41.5 megawatt hours (Mwh) of renewable energy — more than the 36.4 Mwh used by the tenants, with the excess solar power sold back to the grid.

Dr Sturmberg said the system was making a return on investment of about 8 per cent and calculated it would pay itself off after 13 years.

"Which is unfortunately a little bit longer than what the batteries are warrantied for," he said.

"But we always knew that would be the case, and that's one of the reasons the City of Sydney gave us a grant to get this off the ground because it's really a cutting-edge demonstration project."

After graduating university, Dr Sturmberg was awarded a fellowship from the Myer Foundation to start SunTenants, a social enterprise focused on bringing solar energy to rental properties.

"It's become an unexpected pivot in my career from theoretical physics to running a social enterprise, that's for sure."

Easing financial stress

On average, each tenant now pays around $240 for their annual power usage compared to an estimated $540 when solely purchasing from a grid retailer.

Nursing student Cooper Adams is the president of the cooperative, where there are 40 tenants living in eight accommodation units.

She has lived there for more than two years and said she was amazed by the cost savings.

"Studying full time and working as a student, it just means less financial stress, more time spent studying so I can do better at university."

 

 

Edie Griffin is studying neurology and is one of two solar officers in charge of billing her fellow tenants for their electricity use. She said they used power conservatively at the heritage building where there are nine refrigerators and eight electric ovens.

PHOTO: The portions of electricity used from the solar panels, battery storage and the power grid during the project's first year. (Supplied: Stucco)

"Even though we are two-thirds average off the grid, we do still try to keep our usage down."

She said tenants were able to keep energy costs down despite the extended warm weather being experienced in the city.

"We worked out for one particular unit, over a three-month period during summer, with an oven and a fridge, they were averaging paying $13 a week for that unit of five people," she said.

"So that's quite a low figure for what is being run on the electricity, and that's also including their own fans."

PHOTO: Thirty-six batteries store power for use during peak hours when prices are three to four times higher. (Supplied: Stucco)