By Andrew Oliver, Chief Technology Officer, RES
By 2030, solar is poised to have the largest installed power capacity of any technology in the world. This incredible rise has been made possible by the sector's unrelenting commitment to innovation which has driven down costs right across the project lifecycle. More recently, automation has begun to play a leading role in successful innovation. With the potential to increase solar farm profitability by millions of dollars, RES has invested in and continues to explore the use of automation across design, construction, operations, and maintenance to the benefit of its customers.
Automation in design
Solar farm design might look quite simple to the untrained eye: typically arranged in neat, evenly spaced rows. However, small differences in design can create large differences in the construction cost and energy output. Pack a farm too tightly with solar modules (panels) and you may have issues with shading, but too much space costs more in electrical wiring and real estate.
Sola Max - software developed by RES - automatically analyses thousands of potential site designs and equipment choices to either minimise the power price delivered, or maximise the project value. On one project, the software achieved a power price reduction of around 3% or $1.50 / MWh - equivalent to millions of dollars over the project's lifetime.
Automation can also be used to decide to what extent a project should be overbuilt' (the ratio of DC module power to the project's nameplate AC power) based on the project's generation profile, available grid connection, financial model, and electricity market it will participate in.
Automation in construction
RES is currently trialling a modern factory-in-a-field' approach to construct the 168MW White Wing Ranch solar facility in Arizona. The technology we are trialling is part of an interconnected digital and automation platform that has been designed to accelerate the deployment of utility-scale solar by automating the assembly of PV modules and trackers with robots.
The technology combines a digital twin of the project site, advanced supply chain and inventory management systems, an on-site wireless digital command centre, a field-deployed robotic assembly line, and specialised installation rovers. The approach has several benefits including increased safety, improved quality control, the ability to operate 24/7, and installation productivity that exceeds that of traditional methods.
This builds on our previous trials using autonomous robots to move pallets of solar modules around the job site and take the packing materials away.
Solar farm operation and drones
While drones have been in use on solar farms for several years now, their capabilities continue to expand as the technology improves and we experiment with different integrations.
For example, traditionally it could take technicians 2-3 person-hours to manually identify faults using a hand-held device. Using a drone equipped with a thermographic camera, this time can be reduced to less than half an hour. At RES, we are taking this a step further by innovating the technology to give preliminary inspection results in just a matter of minutes.
On many of our solar sites, drone-mounted infrared cameras are already being used to identify modules for replacement. From the digital twins of the sites we manage, we see that, on average, around 2% of modules are faulty at any one time. This is a clear opportunity. On a 200 MW project, replacing just half of these modules can result in a revenue increase in excess of $200,000 per annum, depending on location and power price.
Eventually, we will see the introduction of autonomous drones being placed permanently on larger sites, or housed on the back of trucks with pre-programmed flight details for a series of sites. However, current regulations in most jurisdictions do not allow autonomous flights to take place without a human pilot or observer.
Automating warranty claims
On a project with 500,000 solar modules, it might cost $100,000 to manually gather the module serial numbers necessary for a warranty claim.The serial numbers identify the manufacturing batch, allowing us to prove a serial defect. Instead, RES is innovating a drone that is fitted with a very high-resolution camera that allows the module serial numbers to be read by machine. We expect that this innovation will reduce costs by over 90%.
Use of digital twins on solar farms
Digital twins can come in many different types, which has sometimes led to confusion about what is a digital twin and what is simply a digital representation of a physical asset. If we take the example of a wind turbine, a digital twin could be as simple as monitoring the power output, or it could be a full engineering model describing how the aerodynamics and loading behave in differing wind and atmospheric conditions, while operating in the wake of another turbine. A twin can even be a simulator that a technician can be trained on virtually before heading out to site.
A lot of the innovations in drone technologies go hand in hand with a solar digital twin. For example, once a drone has identified issues with solar modules, an electrical twin' (a model of the specific electrical layout of the site) allows us to calculate expected production losses, and therefore target the areas with the largest losses first.
In Australia, RES has been trialling the use of digital twin to monitor asset performance and automatically notify any issues that require further inspection. As an example, during COVID-19 when few manual site inspections were taking place, the digital twin identified an underperforming inverter that had not been flagged by the OEM's SCADA alarm.
If the issue had remained undiscovered, the damage would have cost the client A$8,000 per month and may have taken up to a year to uncover in standard reporting. The damage was fixed, and the site was returned to 100% production within a week, reducing the cost of the incident by over 90%.
These are just a small selection of some of the automation technologies that RES is trialling and developing to maximise the return on investment of solar projects. There are many more use cases including mixed reality headset use, automated module cleaning and grass cutting, theft prevention - and many more to come in the future as we continue to develop and trial the best in novel automation technologies.
