Photovoltaic solar panel systems have been installed on satellites and calculators for many years. Generally solar panels have a low operating cost and the main impediment to its use is the capital cost to supply and install. Nevertheless the solar panel system market is growing rapidly with most systems installed in Germany, Japan and the USA.

In a school environment, solar panel systems seem to be an appropriate solution. Schools generally consume electricity during the day when the sun is shining and solar panels are generating electricity. On weekend and school holidays, excess electricity can be fed back to the grid.

Solar panel systems are also an excellent educational tool helping students appreciate that it takes energy to make energy .

Australia is in the Southern Hemisphere and therefore solar panels should be installed facing North at a certain inclination in order to maximise sunlight capture.

It is critical for solar panels be installed well away from shade. Even partial shading of a few cells will significantly decrease the performance of the whole system.

In a school environment, we recommend installing the solar panels on your roof.

Solar panel systems generate a direct current (DC) commonly at 12 volts. The schools electricity supply is alternating current (AC) at 240 volts. Therefore an inverter is essential to use electricity as well as feed back to the grid.

Batteries can be part of a solar panel system. In a school environment, it is more cost effective to feed electricity back to the grid over school holidays rather than store the energy in batteries.

Solar panel systems are rated in kilowatts (kW) using standard test conditions. There are times when the system is generating less than 2 kW power and there are other times the system is generating more than 2 kW.

In Australia, a 2 kW system may generate between 2900 kWh and 5800 kWh per annum depending on location and solar panel type. The output is equivalent to 2 kW for between 4 and 8 hours per day.

Assuming your school is paying $0.12 per kWh, this equates to a cost saving of $350 to $700 per year.

In regard to greenhouse gas emissions, 2900 kWh of electricity (from brown coal) is equivalent to approximately one tonne carbon dioxide.

There are three main types of solar cells available on the market:

• Mono-crystalline silicon
• Polycrystalline silicon
• Amorphous silicon

If you choose Water & Energy Savers, we will select the most suitable type of system for your requirements and climate.

In order to maximise energy savings we strongly recommend your school implement energy efficiency measures. These are likely to have a better financial payback than solar panels.

Solar panel systems are not necessarily difficult to design and install but you must use designer/installers accredited by the Australian Business Council for Sustainable Energy (BCSE). Water & Energy Savers will only use accredited designers and installers.

All you need to do is occasionally clean the solar panels of dust and bird droppings.

Many communities are currently under water restrictions and therefore finding an alternative water supply for irrigating your school oval and gardens is important. Nevertheless rainwater harvesting is not the best solution. Why? Your school will need a very large roof area and a very large storage capacity to collect enough rain when it is wet in order to irrigate when it is dry. You will also need a large pump system to deliver the water.

We recommend your school first reduce irrigation needs by selecting the right grass and the right irrigation system.

Installing a tank to toilet system is probably the most cost effective solution for a school. Water & Energy Savers have extensive experience in this area.