The graph below shows the moment when the School Council at the Good Shepherd Lutheran Primary School knew it was onto a good thing with its solar PV and energy efficient LED fit out.
It shows energy consumption and on-site generation across a day in late February at the school’s site in Melbourne’s outer eastern suburbs.
The magic mark occurred first at about 11am during the middle of the school day, when power consumption from the grid across the school dropped to next to nothing – or a tiny 4.77 kilowatt hours.
This is the same amount of power needed to run a small bank of standard laptop computers.
Soon after, at 5pm, the school achieved the same result, albeit at a time when most students and teachers had packed up for the day.
“Our total energy use is down by about 40 percent,” the school’s Business Manager, Hilton Haeusler said.
“But there are periods during school time when we’re close to powering our entire school from the solar PV on the roof of our gym and classrooms.
“Most weekends and school holidays we’re not drawing anything from the grid at all and we’re sending a large amount of energy back into the grid.
“We get a small feed in tariff for that. It’s nice for our school community to know that we’re helping to make the grid a bit greener.”
The Good Shepherd Lutheran Primary School opened its doors back in 1979 and now employs more than 70 teachers and staff who provide an education for 530 students each year at its Croydon Hills campus.
The school’s energy use is driven by the usual suspects. Lights, computers and other tech equipment, air conditioners and heating.
Approximately two years ago, after noticing another steep rise in energy costs, the School Council agreed to a plan to cut its grid dependence.
Energy services specialists Verdia devised a plan to fund, design and construct the energy upgrade without eating into the School’s bank balance.
Verdia managed the program, from the development and design, to procurement and finance, construction and ongoing performance monitoring. Westpac financed the program, with the project expected to pay for itself in just over five years and then deliver a decade or two of significant energy bill discounts.
The first leg of the energy efficiency program involved the replacement 481 old style fluorescent tubes and metal halides as well as down lights and external flood lights. New super-efficient LEDs were installed in their place, cutting energy use, slashing maintenance costs and providing a better performing and more uniform level of lighting.
“Lighting was costing us about $8,000 year in the gym alone,” Mr Haeusler said.
“And at least once a week, I would see someone from our maintenance team with a box of fluorescent lights up a ladder replacing worn out or broken tubes.”
Verdia CEO Paul Peters said LEDs performed better than most other lights because they didn’t waste energy in the form of non-light producing heat.
“A typical LED luminaire should last at least five times as long as old lighting technology, and this translates to a big reduction in maintenance time and costs,” Mr Peters said.
“And they use about 50 percent less energy, which takes more cost out of your energy bill.
“We replaced the School lights about twelve months ago and it has cut energy use by almost 22,000 kilowatt hours. That’s a big reduction.”
Next in line was a 300 panel 96 kilowatt solar PV installation for the school’s gym and Senior Primary School classrooms.
A bigger system could have been installed at the school, but there was a greater cost benefit by remaining under the 100 kW Small Scale Technology threshold administered by the Federal Government.
“It was better for the school to stick with that smaller installation, but even at that level there are times in the middle of the school day when they’re almost at zero consumption,” Mr Peters said.
“All up the school has reduced its energy use by about 40 percent and are saving about $35,000 a year in energy costs.”
The school is looking at battery storage as a natural next step, along with more solar PV on a new section of school buildings.
“We’re also starting to look at how to incorporate the energy performance reporting into classroom lessons for our students,” Mr Haeusler said.
“We couldn’t be happier with where we ended up. The less money going to the energy companies means more money we can spend on our students.”
Good Shepherd is one of five Lutheran schools that have embarked on Verdia’s energy efficiency programs. More than 3,000 LED lights and 1,568 solar panels with a generating capacity of 504 kilowatts have been installed at the schools, reducing energy costs by an estimated $171,399 a year.
The latest school to come on line was Holy Trinity Lutheran College at Horsham.