eSolar® is extremely proud to be part of Sundrop Farms’ first commercial greenhouse facility in Port Augusta, South Australia which officially opened on October 6th. There have been several excellent articles (see list below) published which give a great overview of Sundrop Farms and this particular site–this article is different. This article focuses on how the eSolar’s Solar Collector System (SCS) plays a pivotal role at Sundrop Farms Port Augusta and what enables eSolar to build the lowest-cost, easiest to install, easiest to maintain, and highest-reliability SCS in the industry.
eSolar’s Solar Collector System is made up of a few main parts. The most obvious and visible part is the thousands of heliostats, or powered mirrors, which rotate on two-axis. Controlling the field of heliostats is eSolar’s control system, known as Spectra™, which knows precisely where each heliostat is, can compute a unique path for each heliostat, and can integrate with the rest of the plant.
In late 2014 Aalborg CSP, developer and turnkey supplier of the energy system in Port Augusta, invited eSolar to bid on a 50,000 square meter solar field for a concentrated solar power (CSP) plant. At the time it was unclear what the final application would be, but eSolar got started the way all projects start, optimizing the plant layout. A key part of eSolar’s product portfolio is its plant modelling software. The core of the modelling software is a proprietary, highly-parallelized ray-tracing and solar flux analysis toolset which allows eSolar to optimize the plant design before any ground is cleared away or heliostats are placed. Beyond plant optimization, this also allows eSolar to provide options to our customer, allowing them to see the trade-offs of size, performance and costs as various options are considered. eSolar’s modelling software has been compared against months and years of actual plant output to validate that plant predictions match actual plant output.
Once the plant layout was established, an order for parts was made and production began. eSolar has a set of prequalified vendors ready to build the parts of eSolar’s SCS. eSolar provides quality assurance software and test harnesses to many of our vendors so that they can test the parts they build and ensure the parts meet our standards before sending them on to the next stage or to the plant. The Sundrop Farms plant was built with our current prequalified vendors, but eSolar’s hardware is designed for manufacturability and localization – so eSolar can train and qualify new vendors to build eSolar parts with in-country companies.
Installation of a solar field is always a big task, but eSolar’s small heliostat and its unique design make the big task easily achievable with local unskilled labor. eSolar constructed the field of nearly 24,000 heliostats in just 4 months with a small field team all of whom were local and trained on site. See the images below. Some example of how easy eSolar makes it to install the field: only a single sized ratchet wrench is required to construct the heliostats on site, heliostats are prewired and snap together, and GPS is used to ensure that that rows and columns are aligned properly. Another unique element in eSolar’s approach and its emphasis on quality assurance is that as each row is completed the heliostats are operationally checked out again using eSolar’s Mobile Heliostat Controller, helping to identify any heliostat which may not operate properly for early removal or repair.
In order to acheive the accuracy required, eSolar needs to know the precise position and orientation of each heliostat after installation. Our process to do this is called calibration which is another key component of Spectra™. eSolar does not have to wait until the field installation is complete: calibration can begin immediately on an installed heliostat while others are still being installed. Also, eSolar’s patented calibration can be conducted both day and night. This way eSolar can ensure that once the field is completed, it will be ready to capture solar energy as soon as the customer is ready for it.
While field construction and calibration are underway, plant integration can also proceed. A key design feature of Spectra™ is its flexibility to integrate with the rest of the plant using industrial automation standards. eSolar and its customer agree upon the exchanged data and control mechanisms and eSolar can customize Spectra™ for each plant’s specific needs. Once the plant has its control systems in place, eSolar and the plant operators conduct testing of that integration.
When the field installation, calibration, and plant integration testing are complete, and the plant has completed constructing its key elements like the solar receiver, the real interesting testing can begin. We posted an article back in June on the initial parts of that testing. We tested various safety mechanisms, and then we tested putting solar flux on the receiver and slowly ramped up until we created steam.
Today the plant is fully operational. Each day eSolar’s SCS ensures the sun’s rays are directed at the receiver as the plant requires. That heat captured there generates steam which is used to desalinate sea water and generate electricity and heating for Sundrop Farms’ 20-hectare greenhouse. This plant is a world-first as it combines the aspects of a concentrating solar power and desalination plant with a greenhouse farm.