Publication
Grid Connected Solar Systems

The solar electricity industry is one of the fastest growing industries in the world. In Australia, sales of solar modules have increased at more than 20 percent per annum during the last few years.

Solar (photovoltaic) modules convert energy from the sunlight into electrical energy. The physical process for this involves a temporary shift in the energy level of electrons within the crystalline substrate of the individual cell. Only a small percentage, 10- 15%, of the sunlight is converted into usable electricity the rest is either reflected or turned into heat.

There are three different types of photovoltaic solar modules available, monocrystalline, polycrystalline and amorphus. A solar panel or module generally consists of a number of solar cells wired together to provide the required voltage and current ratings.
The life of a well manufactured solar module will be in excess of 25 years. It is not uncommon to find 30 year old modules still perfectly operating.
Modules virtually require no maintenance, but dust or grime will reduce the output and for optimum efficiency they should be cleaned

Since the mid 90’s it has been possible to connect domestic solar modules by means of inverters direct to the electricity grid. The DC electricity from the module is fed into a grid interactive inverter which converts the DC electricity into AC electricity. This AC electricity is than used by any loads operating in the house and if there is surplus electricity being generated by the modules the inverter will feed electricity back into the grid. Conversely when the modules are not generating enough electricity to power the house, the grid will supply power to the house.
Systems are usually sized so that the solar modules generate roughly the same amount of electricity consumed over a period of a year. A growing number of electricity retailers are supportive of grid interactive solar systems and will credit self generated and exported electricity to the householder.
However care should be taken not to oversize the solar system as power generated in excess of all requirements is generally not purchased unless a buy back contract is in place. The power buy back rate may be lower than the actual cost of purchased electricity and the high capital cost for the additional solar power can not be justified.

People who choose grid interactive systems generally do so for environmental reasons. Coal fired power stations are amongst the largest contributors of pollution and significantly increase the green house effect. Every bit of electricity produced by renewable energy sources will help to reduce the impact. Many people regard solar or other renewable energy technologies as essential to the survival of our planet.

With the current cost of solar modules it takes years for the resulting energy benefit to repay the purchase price of grid interactive systems . Prices are improved with availability of a $4.00 per watt rebate from the government for a system with capacity up to 1000 watt. This results in a rebate of $4000 for a 1000 watt system and a net cost to the customer of around $10,000.

A 1000 watt system will generate on average 4-6 kWh of electricity per day resulting in a saving of around $0.90 at current electricity cost. From this a payback on investment of 30 years can be calculated. However with the predicted increases in the costs of electricity in the future a return on your investment can realistically be anticipated in less than 10 years.

You may wish to consider the investment potential of a solar installation. A $10,000 investment at today’s interest rate will yield a gain of $500. Depending on your tax requirement this will net $375 per year.
The investment in your solar system will net you $328 per year tax free.
A 20% increase in electricity cost will make the investment in a solar grid system a better proposition and earn more money and with every further rise the earning will increase.
However the investment in a solar grid system is a long term commitment and this will be ultimately the key factor influencing your decision.

For more information contact:

Sustainable Energy Enterprise Pty Ltd
www.crestaustralia.com.au
Tel.: (08) 8267 2366 , mobile: 0427672366 or e-mail: heinzrechten@crestaustralia.com.au