A massive solar PV system atop a school in Melbourne showcases the possibilities of a fully integrated clean energy solution.

Not many people would feel too happy about going back to high school but if you get to walk around on the roof instead of sitting in class it’s a different story. The installation crew at EnviroGroup were ask to do just that during the installation of a new 299kW solar PV system at Doncaster Secondary College in north-east Melbourne.

With security and space issues a major concern, it was decided to place the majority of the Fronius string inverters on the multiple roofs available.

The Fronius Eco 27 units, with an IP66 rating, were chosen due to their reliability and performance in harsh environments. A total of ten of the inverters were installed along with a Fronius Smart Meter for consumption monitoring.

The Eco inverters are ideal for commercial-scale PV projects, says Fronius technical product coordinator Balaji Ganesan.

“Large-scale projects often require less flexibility from an inverter but higher than normal efficiency in order to maximise yields,” Ganesan says. “We are continuously shifting the limits of minimising costs whilst maximising yield by focusing on the power density of our inverters.”

Power density refers to the ratio of output power of the inverter to its size (kW/kg). The key factors setting the Fronius Eco apart from its competitors are the higher output power, lighter design and lower cost.

“One of the greatest advantages of using a string inverter is its modularity,” Ganesan says. “When one decides to have a PV system in a school or college, where the buildings are prone to have multiple rooftops, the modularity of the string inverters become design and installation friendly.”

Keep it simple

Melbourne-based EnviroGroup is one of the newest additions to the Fronius Service Partner program. EnviroGroup marketing coordinator Noel Anthony says the company has been consistently using Fronius inverters on its projects since 2015. “[Customers] all love different things about it – some like the monitoring, for others it’s the simplicity.”

The EnviroGroup team is especially proud of the Doncaster Secondary College project, which has generated over 382,470kWh within its first year of operation, offsetting more than 100 tonnes of C02. The site consumes 76% of the energy generated on its roof and has little to no export during school hours. Overall, the school is offsetting about 30% of its energy demands via solar.

“It was the most fun [of our installations] as nine of the 10 inverters were placed on the roof,” says Anthony. “The last inverter was installed on a wall so students can learn about solar power as part of their lessons.”

There are multiple benefits for education institutions in installing solar PV, including financial and educational.

“Work is starting to pick up in educational institutions,” Anthony says. “Schools want to showcase leadership in sustainability and solar PV is a rare opportunity for them which also has positive financial return.

“Schools like Doncaster Secondary College already have sustainability programs in areas such as waste reduction, recycling … and solar PV is something students can get involved in directly.”

Live performance data is received via Fronius Solar.web, which shows savings the system is delivering and has an error alert function in case of system fault to reduce the downtime and maximize energy yield.

An unusual aspect to the project was the installation of weather collecting data points on the site. “That’s pretty special,” Anthony says. “It’s essentially giving us weather data from the site itself, which can be used as a reference point for performance and generation guarantees.”

Worth the energy

Due to costs of solar PV coming down, the payback period for schools like Doncaster Secondary College can be between five and nine years, he says. “We’ve done enough commercial jobs now that we can basically design for the project and have no over-runs … we’re always on time. This is important for schools as they only have the end of year holidays to install these types of projects and also keeping in mind that during summer there is a narrow window of time that we can have people working on a rooftop.”

However, each job always has its challenges and Doncaster Secondary College was no exception. “It’s a large surface,” Anthony says. “So one of the challenges was to keep the costs down and also to work around pre-existing appliances on the roofs like HVAC units. We have an in-house engineering and project management team so adjustments could be made on the fly.”

Given that the school grounds were accessible to people after hours, security was a consideration and was partly why the majority of inverters were placed on rooftops.

EnviroGroup is doing a significant amount of work in commercial solar installation, just having completed a large project for the University of Melbourne at its Southbank campus.

“We are on the cusp of a commercial solar boom … it’s just bigger and better from here on in,” Anthony says. “We’re working now with products that are extremely reliable and very proficient in offering help and support.”

EnviroGroup supports the transition to a 100% renewable energy future with a strong belief that renewable energy not only addresses Victoria’s reliance on coal but also empowers people through distributed generation.

“The current system of energy generation is one of the largest contributors to climate change. A renewable energy future will help combat climate change and also provide long-term stability in power prices for Australians.”