Case Study – SunPower, Off Grid Solar Tracking system – Victoria
The Green Power Company supplied, designed and installed an off grid SunPower solar power system using single axis solar trackers on a rural property in eastern Victoria. The off grid solar system was designed to completely cater for the electrical demands of the property, without the requirement of mains grid connections. We aimed to maximise the amount of solar energy available by tracking the sun via the two single axis solar trackers. We used SunPower solar panels because they are the most efficient in the market at 327W for a frame 1m x 1.6m. Each solar tracker was able to fit 8 x SunPower 327W solar panels equaling 2.616kWp, and a combined total of 5.232kWp.
Solar trackers will generate 25% more power than fixed array, static systems. They will also start producing power earlier in the morning and later in the evening than a static system.
Off grid power system basics
HOW IT ALL WORKS
Solar is fed into the German made Kaco inverter(s) (AC coupled inverters, http://www.selectronic.com.au/kaco/) which are connected to the Australian made SP PRO (inverter charger, http://www.selectronic.com.au/catalogue/).
Loads (appliances in the house) are first serviced by the solar then the batteries and, if required, the generator fitted with autostart can contribute by itself or in parallel with the SP PRO (ideally generator only comes on during prolonged extreme low light conditions) all automatically and seamlessly.
Loads of up to 7500 watts can be handled constantly with the ability to handle additional surges.
A well-designed off grid system is based on the customer filling out an average daily load sheet and then certain assumptions are made in regards to:
- Constant loads, this determines inverter charger capacity
- Fossil fuel contribution, how often will the generator turn on
- Renewable energy/fossil fuel ratio, more solar, same load, less generator run time
- Battery sizing, days of autonomy for cloudy weather
- Existing infrastructure, is there a shed to mount the panels or ground mount, pole mount with trackers
Off Grid Solar Tracker Components
System proposed is based on supplied information and assumptions as mentioned above. Have assumed an average daily load of approximately 11 – 13 kWh, corrugated sloped North facing roof, and internal inverter battery room with correct ventilation.
The generator component has not been included in this quote:
- 1x 7500 watt inverter charger Selectronic SP PRO SPMC482-AU
- 1 x 5000 watt inverter Kaco Powador 6600
- 1 x 1000 ah @ 48 volts, 48 kWh Battery Bank, PowerCharge X-Cell
- 1 x PRAMAC S9000 generator fitted with remote autostart
- 1 x Battery enclosure to suit
- 1 x 5232 watt SunPower solar panel array, 16 x 327 watt
- 2 x East West automated pole mounted trackers each holding 8 x 327 watt
- 1 x 5000 watt framing and mounting kit for the trackers
- 1 x Battery fuse kit, AC/DC enclosures, circuit breakers
- Installation of 1 x SP Pro
- Installation of 1 Kaco Inverter
- Installation of new 5232 watt SunPower PV array to tracker.
- Installation of 1000 ah @ 48 volt battery bank
- Supply and installation of 1 x PRAMAC S9000 generator fitted with remote autostart
- Generator connected to inverter charger system
- System configured to accept generator
- Pole mounts for PV array
- Enclosure for Battery Bank
- Load Analysis
- Load Balancing
- Miscellaneous items
- Circuit breakers
- Fully installed and certified.
- Independently inspected by an Electrical inspector
The PRAMAC S9000 specs are as follows:
- 9 kW output
- Electric start with remote autostart fitted
- 24 litre tank
- At 75% loading, 12 hour run time