Micro Energy Systems

Grid connect photovoltaic solar power systems are the most cost effect way of using solar energy to power your home, school, office or commercial facility. They can be scaled up or down to meet anything from a portion of a household’s power requirements to the power requirements of large industrial facilities.

In a grid connected photovoltaic solar power system, the solar panels generate high voltage DC power which is then fed through a grid connect inverter which converts it into grid compatible 240V AC power which feeds into your switchboard. During the day, the solar electricity feeds any power requirements of the building with any shortage drawn in from the grid. If the solar array is producing more power than the building is using, then the excess solar electricity is fed out through the switchboard into the grid. At night when there is no solar power being produced, electricity is drawn in from the grid as per usual.

Grid connected solar power systems have many advantages. These systems are much cheaper than the equivalent stand alone system as they do not include expensive battery banks and do not require the solar array to be oversized to account for the worst case (peak load) situation, as the grid will provide power during any period when PV system output is insufficient.

Also these systems are much easier to operate and maintain. The end user does not need to do anything to make the system work and will notice no change at all in their electricity supply. The only difference is solar panels on the roof, an inverter next to the switchboard and a lower electricity bill.

In the event of a blackout, the grid connect system is required to shut down. This is to avoid energising part of grid which would be a safety risk for line workers. This can be avoided by installing a battery backup system which allows the system to disconnect from the grid and run on battery power during a blackout. This does add to the cost significantly however as batteries, charge regulator and a second, stand alone inverter is required.

Since a grid connect system runs in parallel to the grid rather than separate to it, it is not necessary for the solar to provide all of your electricity requirements. You may wish to choose a system which covers a certain percentage of your electricity based on budget, available roof space or a range of other factors. The amount of electricity you use on average is shown on your electricity bill in kilowatt hours (kWh) per day. As a rule of thumb, an unshaded, north facing solar array will produce roughly 4-5kWh per kilowatt of capacity per day in Perth. A 2kW system will produce approximately 8-10kWh per day of electricity when averaged over a year.

Average energy used by homes in Perth varies widely, in more affluent areas where large houses incorporating swimming pools multiples of split air conditioners or large ducted air conditioners and electric hot water systems, consumption can average as much as 100kwh per day and more.

The majority of suburban households however fall within the 16 -25kW/h per day bin. This can usually be reduced through energy efficiency measures to around 10-16kWh per day. This is what is referred to as a standard energy efficient household. Buildings which are designed to be energy efficient can reduce this amount of energy further still and can also be more comfortable to live in.

 Perth is blessed with one of the mildest climate ranges of any urban centre; there is no reason that the average energy use per household should be higher than any other centre in Australia. If basic efficiency measures are observed and larger appliances considered carefully before purchase or upgrading, i.e. air conditioning systems, hot water systems, refrigeration, the average energy consumption by Perth house holders should be amongst the lowest in the nation.

A well designed home incorporating passive design efficiencies and energy efficient appliances can easily support 4 -5 people’s electrical energy needs with a 2kW grid connect system if they are careful about minimising wastage.