The MicroFIT Grid Tie system (w/o battery backup) is also known as a Grid Dependant system. The main components are the Solar Photovoltaic (PV) array, Grid Tie Inverter or Micro-inverters and Generation meter (mG). The Electrical Safety Authority (ESA) will require an AC disconnect be installed between the Grid Tie Inverter / Micro-inverter and the Generation meter. Currently, this distributed generation system can only be connected to the local grid in parallel or on the line side of the Load meter (mL). In a parallel connection, the solar power is not used for your own home consumption before it goes out onto the local grid. This means 100% of the solar power (not the excess) is fed onto the local grid as in a Feed-In Tariff program.

Along with a MicroFIT Contract you will also be required to obtain a Connection Agreement with your Local Distribution Company (LDC). All the PV generated power received on the grid is measured at the Generation meter (mG) in kilowatt hours (kWh). For rooftop mounted solar PV systems, the LDC will send you a payment of 80.2 cents per kWh of power received on the grid. Ground mounted solar PV systems will be paid 64.2 cents per kWh. See our ROI and Payback calculation for more detailed information on this lucrative incentive.

The wattage rating of the inverter is dependant upon the quantity and performance specifications of the solar PV panels being used in the array. Certain solar panel types will be "matched" to the inverter in providing the best overall operating range and efficiency of the system. In most cases you could oversize the inverter if you decide to add more solar panels later or simply add more solar panels with a micro-inverter system. Micro-inverters are now becoming more popular for residential applications. The Micro-inverter is a mini grid tie inverter installed on the mounting rack beneath each solar panel. All grid tie inverters and micro-inverters also have a feature known as Maximum Power Point Tracking (MPPT). The MPPT is designed to take power from the solar panels at a voltage where it can put out the most power (it's Maximum Power Point). MPPT allows a solar array to deliver up to 30% more power to the inverter.

For the solar PV system to export power onto the local grid, the grid tie inverter converts (or inverts) the higher DC voltage of the overall solar array (or from each individual solar panel as in the Micro-inverter system) and converts it to an equivalent AC voltage and waveform. This AC voltage is then either stepped up or down or synchronized and phased to that of the utility grid. This is known as the Power Factor component of the inverter. The higher voltage and phased frequency is what enables the power to be exported or "received" onto the local grid. 

An important feature of the grid tie inverter should also be mentioned here; for safety reasons, grid dependant or grid interactive systems are not able to export power onto the local grid in case there is a local grid blackout. When the grid tie inverter detects a blackout or severe voltage drop from the grid that lasts for more than a few seconds, it will immediately shut itself down and cease to export power.  If it were able to continue exporting power during a blackout, this condition would be known as 'islanding'. All grid tie inverters must incorporate an 'anti-islanding' feature which is primarily designed to protect utility workers from serious injury if they happen to be working to resume power to a blacked out area of the grid. 

The solar panels (PV modules) are commonly mounted on a south facing roof. They can also be ground or pole mounted if a good south facing roof exposure is not available. The solar array should be mounted at an angle equal to the latitude co-ordinate of the site location. In most cases a common 6:12 roof pitch (app. 27 degrees) is quite adequate. The solar array should also receive an unobstructed exposure to the sun between the hours of 9 am to 3 pm minimum. In some cases where shade issues exist, then utilizing Microinverters is a more practical approach. Each solar module is controlled independantly as opposed to connecting from 8 to 12 modules in a series string therefore allowing better power production without causing an entire string array to be affected.

Solar trackers are used with pole mounted solar arrays and will follow the sun's path from east to west throughout the day. Depending on location, they're able to increase an array's output anywhere from 10% in the winter to 25% in the summer. Sometimes the extra cost and ongoing maintenance of a tracker would not be cost effective compared to a fixed array system. Simply increasing the overall array size for less money could provide better results in terms of not only power output but in ROI and payback.

If you require round the clock backup power during a blackout situation, then you'll need to incorporate a battery bank or generator to supply that power to your essential or critical loads in the home. Battery backup systems cannot be installed upstream of the generation meter (mG). With a battery bank or generator, this system now becomes what is called a grid interactive system (see below). 

For a step by step guide on the MicroFIT application process, please click here.

A grid-interactive system is basically the same as the grid-dependant type. The main difference is that the grid-interactive system has a battery bank incorporated to provide backup power to your critical loads during a grid blackout.
 
When the utlity supply is active, electricity is imported and exported in the same manner as in a grid-dependant system. When there is a grid failure or blackout, the inverter will disconnect itself from the grid utlity and reconnect to an essential or critical loads sub-panel. While in backup mode, the inverter cannot export power onto the grid as well.
 
The energy stored in the battery bank or from any other renewable energy sources will produce sufficient power to operate these connected loads until the grid utility comes back online. Once it does, your renewable energy source will recharge the battery bank so it'll be ready to provide backup power for the next blackout.
 
As a fail safe option, a generator can be installed to provide power to the critical loads as well or if the battery bank becomes too depleted. For Off Grid systems, the generator can also be connected to the input of a charger (built into the Off Grid Inverter) to keep the battery bank charged when there are extended periods of a lack of sun and/or wind.
 
A hybrid system is a combination of renewable energy sources such as solar, wind and micro hydro systems. Where possible, we recommend a solar PV (photovoltaic) and wind hybrid system for the simple reason that on sunny days there may not be quite as much wind blowing. Whereas on cloudy days, there tends to be more wind and sometimes at greater speeds. Therefore the two systems will compliment each other and provide power where the other may not produce as much. Since solar PV panels can only provide power during daylight hours, the wind generator is capable of producing power any time of day. In some cases you can use a wind generator exclusively for all your power needs if you are located in a good wind area and are already energy conscious and use power sparingly.