The basic use for solar arrays in the New Zealand environment is to cover some of the cost of energy usage during the daylight hours that a plant or installation is running.
For a solar array installation to be efficient there must be more electrical load that solar capacity installed, this is due to the low compensation rated provided for solar generation back into the local electrical grid network.
In the case of Well 8, it generally only runs during daylight hours, so was well suited.
Key Information:
Project Size
- 3-4 Millennium teams
- $50,000 on Budget Value
- Programme on time and on budget
- Building roof surface area - 11800mm x 9050mm
- New steel support frame extended by 6m on the rear of the building
- This would result in a total installation of 50 solar panels rated @ 440WPP
- The solar panels will be installed at between 20 to 25 degrees angle to the horizontal. This is Considered a good angle for natural cleaning by rainwater
- Solar capacity to approximately 22.0KW
Cost Benefit Analysis
Well 8 roof structure can accommodate 3 rows of 10 panels and the pergola can accommodate 2 rows of 10 panels configured into 2 strings of 30 and 22 Solar panels. The panels are each rated at 440 Watts and have a spacing of 1.25M between rows.
The inverter installed would be a 20KW inverter and would allow for the 22.0KW of connected panels.
Based on the geographical position of the station and building orientation to the north the output of the above installation would harvest in the vicinity of 28.43 Mega Watt Hours of energy over a calendar year.
At the current rate of energy cost ($0.22820/ Unit) the net harvested energy cost would be $6,487.73 per annum.
Thus, the payback time frame for the installation was 6 years and 6 months based on the current NIWA weather and atmospheric data over the past 10 years.
With the panels having a 25-year minimum service life span and the inverter having an advertised minimum service life span of 10 years we were able to calculate the cost benefits over 10, 20 and 30 years.
Automation
The inverter stores running information, fault records, etc. and parameters are set via phone App to change the requirements of the device or optimize its performance.
Standard RS485 port is connected for remote monitoring of the device and PV system. Separate Energy meter and CT’s were installed to remotely check on the performance of the inverter, energy in vs energy exported, this was integrated onto the existing SCADA network.