Samoa 2.36MW solar power plant

Utility scale grid-connect solar case study

Solar design in the south pacific

Samoa Solar Power Project Samoa Solar Power Project Samoa Solar Power Project Samoa Solar Power Project Samoa Solar Power Project Samoa Solar Power Project

The islands within the south pacific region have expressed a greater need for renewable energy to supplement and offset the cost and impact of current diesel power systems.

Solar photovoltaic panels have a demonstrated success in cost effective power generation, but the pacific region imposes a complex coastal wind dynamic subject to uncertainty in wind behaviour and a recorded history of tropical cyclone activity, intense low pressure systems and heavy rain.

This case study outlines how Harelec Solar identified the risks associated with solar power generation in the southern pacific island of Samoa and developed a ground mounted solar system that overcame this to meet the design and project delivery outcomes of the client.

Wind

Harelec project design team utilised computer space frame analysis software to identify how significant localised negative wind pressures impacts the exposed edges of the low pitched structures intended for the site.

Structure

A series of posts supports, horizontal front and rear pipe supports, rod tie down and aluminium extruded rails were designed to withstand the imposed actions for the site thereby ensuring that the system would not be damaged during a cyclonic event.

Ground Support

Geotechnical investigations identified high strength volcanic rock shallow beneath the silty gravel soils of Samoa. High wind speeds required reliability of performance and efficiency in installation. These key criteria meant that galvanised steel screw piles were adopted based on smaller machinery requirements and greater control of installation into the ground.

Primary Rail Support

The varying levels of terrain required the design of a uniaxial support system that could also accommodate the temperature induced expansion and contraction associated with spanning 135m across the site.

Panel Rails

Harelec engineering team analysed numerous panel rail systems that existed on the market to identify which system would best provide the surest safety for inevitable cyclonic conditions that would occur. No system was identified that provided the security that was required at this site. Harelec engineering and design team designed, tested and manufactured a proprietary rack and railing system that would survive the strongest cyclonic event.

Panels

The high wind speeds required a panel that served both as solar collector and as a durable and strong frame. A specific design life and warranty also needed to address the increased load and higher performance requirements of the site. A 305 watt panel was chosen to maximise yield whilst minimising required material cost with its frame and glass infill increased in depth to meet serviceability criteria.

Product Delivery and Service

The challenge was the ability to deliver, construct and maintain a remotely located renewable energy project. Detailed documentation and coordination of skilled based industries was identified as the key to successfully overcoming these obstacles. A more efficient, less labour intensive system would ensure less downtime in required maintenance and minimise waste on site while providing a high performance, durable structure able to resist fatigue, corrosion, varying ground conditions and erosion. Sovereign, environmental and statutory requirements of Samoa were also paramount in development with every component subjected to rigorous review to ensure delivery of the solar project.

Construction

Work on the site commence mid November 2014.

  • During November 2014, surveying, clearing and levelling of the site was commenced. Fencing was carried out and some roadwork constructed
  • The first container of components was landed in Samoa with subsequent containers arriving during the following two months.
  • The first 500kW was commissioned in March 2015, four (4) months after taken control of the site.
  • A total of 1 Megawatt was commissioned in April 2015.
  • A total of 1.5 Megawatts was commissioned in May 2015
  • Currently 1.77 Megawatts has been commissioned and completion for the 2.36 Megawatt solar project is on track for September 2015.
  • Contract period for practical completion is April 2016, therefore, project completion is on track to achieve a timeline eight (8) months ahead of schedule.
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