We sat down with Stace Tzamtzidis, Director of Sales at solar engineering and technology company Planet Ark Power (a partner of Planet Ark), to ask what the most frequently asked questions are from schools considering rooftop solar.  

Q1: How much do rooftop solar systems cost?

A: There are several factors that influence the price of rooftop solar installations, including the brand and quality of the solar panels and inverter and the type of building the installation will be fit to (e.g. Is the building multi-storied? Is the roof tiled or made from steel?). 

A solar system under 100kW will vary in price from $0.80 to $1.30 per watt installed, totalling between $80,000 and $130,000 for the entire system (after government rebates are applied). Typically, a solar system has a payback of two to four years and reputable solar companies are able to provide accurate solar generation and annual savings estimates up front. 

Q2: How big do solar systems need to be to power a whole school?

A: The size of the solar system will depend on two main factors: your budget and how much roof space your building has. For 1kW of solar PV (rooftop solar), 6-7m2 of roof space is required. Schools typically install systems between 30kW to 100kW to be able to take advantage of the instant rebates that apply (see question ten for more on rebates). 

To put that into perspective, Planet Ark Power installed a 99kW solar system at Cranborne Park Primary School in Victoria, which generates approximately 144,000 kWh per annum. This has reduced the school’s electricity bill by roughly 48% or $19,000 a year. 

Q3: How much money can a school save by installing rooftop solar?

A: For every 1kW of solar PV, the solar generation is typically 3.3kWh per day. If you are paying $0.25 per kWh for your electricity from your retailer, then the savings for a 100kW solar PV system will be approximately $22,584 per year. This figure assumes your school is still using 75% of the energy the solar system generates during weekends and holidays for things like refrigeration and computer servers.

Q4: How does selling excess solar energy work?

A: The solar energy generated from your solar system that isn’t used can be exported into the electricity grid to be used by your neighbours. It is up to retailers how much they will pay to purchase this energy from you, so the rate you receive will vary. It could be as low as zero (this happens when demand is very low when excessive amounts of solar energy are being exported into the grid) or as high as $0.12 per kWh. 

This works very well for schools as they tend to have surplus energy to sell during holiday periods and the weekends. Visit your retailer’s website to find out what rate they offer or visit Energy Made Easy to compare energy plans from different retailers. 

Q5: Is it possible to calculate how much carbon a school with solar will prevent from entering the atmosphere? 

A: Yes, for every kWh of solar your installation generates we can calculate the carbon savings. How much carbon your solar system prevents from entering the atmosphere will vary depending on where your school is located (the sunnier the location, the higher the carbon savings). Planet Ark Power installed 200kW of rooftop solar at Bayside College in Victoria, offsetting 133 tons of carbon dioxide emissions each year. Over the lifespan of the panels, that’s the equivalent of planting 444 trees!

Q6: Is solar as reliable as conventional forms of energy? 

A: Solar is a very reliable source of energy and is used every day to power all kinds of businesses, schools, homes and even farms. A number of factors can impact how much energy a system is able to generate, including shading, cloud cover and dirt build up on panels. However, when a reputable solar company is contracted these factors will be taken into consideration during the early planning stages. As solar works in conjunction with the electricity grid, solar production varying during the day is not noticeable. 

Q7: How long do rooftop solar systems last? Do they have to be maintained?

A: Solar panels have a design life of 25 years while good quality inverters can last ten or more years. Rooftop solar needs very little maintenance during its lifetime. Smart monitoring solutions allow owners and operators to monitor solar performance from a smart device from anywhere in the world. 

Q8: Do systems have to be purchased outright or can they be leased? 

A: Solar PV systems can be purchased outright (Capex), under an operating lease (where you pay principal and interest), or even under a Power Purchase Agreement (where the solar system is owned and operated by a third party that sells the energy to the host at a cheaper rate than an energy retailer). 

Q9: What happens to the solar panels at their end of life?

A: Solar panels, frames and inverters can be recycled. There are a number of recycling facilities in Australia that extract the metal, glass and copper from these devices. While solar panel recycling is still in its infancy in Australia, the Federal Government recently listed it as a high priority in the Product Stewardship Investment Fund, which means Australia will hopefully soon have a national recycling scheme for solar panels funded by the product manufacturers.

Q10: Is financial support from the government available to schools?

A: For solar systems under 100kW there is the small-scale technology certificate rebate, and the large-scale generation certificate rebate is available for systems larger than 100kW. Planet Ark Power primarily installs large-scale systems, and our staff can identify any other rebates that may apply in your region. We recommend you discuss the purchase of the solar system with your financial advisor to best structure the purchase agreement to suit your needs and budget.