Photovoltaic solar panels where ever possible should form part of any green renovation.
What size installation?
- Residential roof mounted photovoltaic systems typically start at 1.5kW and range up to 5kW
- Ideally you would install a system which had an average annual production the same as your power consumption.
- The ATA have created Sunulator, a spreadsheet tool allowing you to model the financial effect of different size solar systems. The tool includes the ability to import historical usage data from your energy provider and makes allowance for various electricity providers pricing tariffs.
- Before deciding to install larger arrays, consider how much the equivalent spend would allow you to reduce your consumption by? For example installation of solar hot water, energy efficient lighting, draft sealing, thermal curtains, solar air heaters.
Checklist / Questions to ask
- Sufficient area of roof facing within 30 degrees of North.
- Free from significant amounts of shading. Use a smart phone sun path app to check for shading compromise.
- By default rooftop arrays are often configured in a single or small number of strings. Partial or complete shading on just one panel in a string hence resulting in performance drops for all panels in the string. This can be avoided through the use of a) Micro inverters (inverter per panel) or b) Power Optimisers. Ask your solar installer for details.
- On average – Australia receives twice the amount of solar irradiance of countries such as Germany (world leader in installed PV). A rooftop system in Australia with a significant shade compromise will often still generate more power than the same panels mounted in other countries without shade compromise. With the falling cost of PV and increasing electricity costs – even partially shaded roofs in Australia may be worth installing panels on.
Where to buy?
Reasons why solar panels might not work for you?
Unfortunately some renovations just can’t incorporate solar panels. Common reasons are:
- You live in an apartment and don’t have rights over your roof area.
- You don’t have any north east, north or north west facing roof area.
- Your roof area is permanently in shade.
In these cases you can purchase 100% green power electricity.
Upgrading existing installations
Some states in Australia have changed their stance from forcing users to forfeit feed in tarrifs to allowing upgrades without penalty. If you have an existing system on a FiT that is no longer available it’s worth seeking advice on your current upgrade options.
Capacity of batteries is rapidly increasing and costs rapidly reducing to the extent that they should be considered as part of a Solar PV installation.
Batteries allows you to store excess power generated through the day to cover your evening use and avoid peak power tariffs.
For more information read our review of grid connected plus solar products.