Solar hot water systems on roofs are a common sight in Alice Springs – about half the homes in Alice Springs homes have already made the switch to solar hot water systems.

Alice Springs has, on average, more sunny days per year than most towns in Australia. Considering water heating accounts for about 27% of the average household energy use, it makes a lot of sense to go solar.

Although it is more expensive to purchase and install a solar hot water system than an electric or gas hot water system, they are more cost effective in the long term.

System components and running costs

Solar hot water systems have three main components which are:

• the solar collectors - heat from the sun is absorbed through solar collectors;

• Hot water storage tank – the heated water is stored in the tank ready for use; and

• a booster – used to maintain water temperature during long periods of cloudy or wet weather or when hot water demand is high. Under the Alice Solar City program, installation of a ‘one-shot’ boosters is mandatory (see below for further information).

Solar systems deliver significant savings in water heating costs, depending on how often the booster is used, compared to other hot water systems. In Alice Springs, the running costs for correctly sized and operated solar hot water system for an average family ranges from $50 - $100. This compares to $3-500 for an electric storage system or $500-1000 for a gas storage system using LPG.

A recent improvement to solar hot water technology is over temperature protection, otherwise known as OTP. Solar hot water systems have a built-in mechanism in to ensure that water in the tank does not over-heat on days of excessive solar radiation. This mechanism involves discharging hot water from the tank when the temperatures approach boiling – a common occurance on a hot summers day in Alice Springs. Whilst this mechanism protects the tank, it also wastes energy and water.

The OTP system prevents over-heating of the water in the tank with the addition of an extra valve and a small over-flow cylinder which is attached to the tank. Once the temperature of the system gets too high the valve will close thereby forcing the heat transfer liquid that runs through the system into the over-flow vessel and preventing the water in the tank from continueing to heat up.

All systems installed under the Alice Solar City project must have the OTP system fitted.

Correct use of boosters

Correct use of the booster is critical to ensure low running costs and longer life for the solar hot water system. Most systems in Alice Springs use an electric booster, which is generally controlled using a circuit breaker located in the house’s switchboard. When the water is colder than desired, the household manually turns on the booster, which heats the tank electrically.

This system relies on householders remembering to turn the booster switch off. Unfortunately, it is common for electric boosters to be left switched on – which means the system uses electricity rather than the sun to heat the water.

To address this issue, one-shot boosters are now being used (all systems installed under the Alice Solar City project must utilise a one-shot booster). One-shot boosters are devices that indicate when the booster needs to be used; once the booster is turned on it will heat the water in the tank and then automatically switch off.

Funding assistance

There are significant financial reasons to go solar. Not only will you saving money on your water heating costs, you can also access be generous financial incentives to assist with the cost of installation.

Eligible Alice Springs residents can access a 35% incentive, up to $2000 off the cost of installing a solar hot water system with electric boost or up to $2100 off the cost of installing a solar hot water system with gas boost.   These rebate amounts apply to 300litre / 2 panel system capable of supplying the average home - other rebate amounts apply to other system sizes and types. This funding is applicable to participants in the Alice Solar City residential program – see here for how to join.

As part of their support for the Alice Solar City incentive, Solahart also provided $150 cash back for all householders that install a Solahart hot water system through Alice Solar City. This payment will automatically be sent to householders after Alice Solar City receives confirmation of the installation of the system (from the Register Supplier who installs the system). Please allow up to 8 weeks for processing.

In addition to the above, householders may also be eligible to receive a rebate through the Renewable Energy Certificates (RECs) scheme, which is part of the Australian Government’s Mandatory Renewable Energy Target. The RECs scheme effectively creates a value for the renewable energy that is generated by installing a solar hot water system. Each eligible solar hot water system generates a set number of RECs, which can be ‘sold’ to organisations who have an obligation to under the Mandatory Renewable Energy Target. The value of this rebate varies according to the market price for RECs, however the value as of July 2010 is approximately $1,200 for a typical 2 panel 300 litre solar hot water system (ie the 302JOTP).  Householders should check the current REC value applicable for the particular system that they are intending to install, as it can vary considerably.

To take advantage of this RECs rebate, after you have had a solar hot water system installed, simply complete a short application form, attach relevant documentation and send to the organisation that purchases RECs. Payment is usually made to the householder within a few weeks. In Alice Springs, most householders sell their RECs to Power and Water Corporation – see here for more information. Please note Alice Solar City has no direct involvement in the RECs scheme.

So, with around $3000 worth of incentives, and significantly lower running costs for the life of the system, there’s never been a better time to go solar!

Alice Solar City aims to provide incentives for 1000 rooftop solar hot water systems to be installed in Alice Springs homes.   Funding is expected to be available for the life of the program, but may be utilised earlier depending on demand.

For more information about solar hot water systems download the solar hot water fact sheet