The recently released AgriSolar Best Practices Guidelines by Solar Power Europe officially recommends module-level power electronics for Agri-PV safety and supports other recent such documents that have been recently released, such as the Installation Guidelines for Agri-PV in Japan. This, of course, is not news to us at SolarEdge where module-level power electronics  (MLPE) is at the core of our PV system architecture and a key enabler for our advanced multilayer safety features.  Agri-PV (also called Agrivoltaics), for the uninitiated, is the dual use of land for agricultural and solar energy production Solar installations can be placed on trackers to ensure complete control of the amount of sun reaching the plants and maximum benefit to both solar and crop production. “… it is recommended to apply Module Level Power Electronics in Agri-PV systems to reduce risk of electric shocks and fires” Solar Power Europe (SPE), Best Practices Guidelines for Agrivoltaics Below, you can find a review of safety suggestions offered by the SPE Best Practices Guidelines, as well as “Agrivoltaics in India, Challenges and Opportunities”, as well as additional safety recommendations in a guideline document prepared by Japan’s New Energy and Industrial Technology Development Organization (NEDO). Why is “Safety” critically important in Agri-PV? Safety is of course important in every PV installation. Maintenance staff, installers, and first responders must be able to work safely on a property. Similarly, the people and property populating both commercial and residential sites, require protection. In an Agri-PV installation, however, the situation is compounded by the combination of two ventures sharing one piece of land. Many ground-mount PV installations are gated to ensure that no outside individuals enter the site and interact with equipment or cabling. However, in agrivoltaic sites, farmers work in close proximity to the PV products using large machinery and irrigation, making gating impossible and increasing the potential risk of electrical shock. In some installations, animals share their grazing lands with PV panels, possibly leading to cable damage. This is significant, as the deterioration of cabling can result in fire risk. As a nascent industry, ensuring safety in Agri-PV is even more important. As the Best Practices Guidelines explains: “… incidents of fire and electric shocks could be detrimental to the growth and public acceptance of Agri-PV, especially in the early stages of the market, when dedicated binding standards and regulations are yet to be published or enforced.” Before regulation is enacted, the industry must self-regulate so it can grow effectively.  This is also emphasized by the recently published “Agrivoltaics in India, Challenges and Opportunities” document. One of the seven key findings in the document determines that: “on the agricultural side, farmers’ safety concerns due to the proximity to high voltage cabling, as well as constraints on the mobility of farm equipment, are the main challenges.” What can impact safety in Agri-PV? As in any electrical plant, electrical shock and fire are the two main safety risks in PV installations. As explained above given the dual-usage of land in Agri-PV sites, there is an increased risk of fire and electrical shock. Electric shock can occur when an individual (or animal) touches a high-voltage element. While the risk of fire is minimal in a PV plant, it can be caused by the creation of an electric arc. This can occur if there is a small gap in a connection, or when an electric current jumps between two wires, for example when the insulation is frayed or damaged. As mentioned, an Agri-PV site provides more opportunities for damage to the equipment, therefore leaving it open to additional safety challenges. Why is MLPE considered superior for safety? 1 – Visibility and control In conventional PV installations, solar modules are attached to each other in a string and interact with the inverter through that string. In such installations, there is no visibility of each module’s performance and it’s not possible to automatically identify the location of a fault if one occurs. This can waste valuable time when troubleshooting a safety issue and require costly on-site visits With MLPE, O&M staff are appraised of the exact location of any fault or issue, ensuring quick resolution, often remotely. The ability to monitor and manage each individual module provides important control of the entire system, which means that the system can be shut off when needed. With an agrivoltaic installation, the aim is to have as little intrusion as possible by maintenance staff, so as not to interact with the crops or interfere with farm operation. Because of the module-level visibility provided in MLPE systems, when intervention is necessary, the location is pinpointed and limits onsite maintenance visits. 2 – Arc fault detection The ability to determine the exact fault location and address it directly is critical in maintaining system safety. With MLPE, it is possible to determine the location of an arc and mitigate it. Japan’s New Energy and Industrial Technology Development Organization (NEDO) explains the value of MLPE in Agri-PV installations very well: “...even if the electric circuit is opened in these locations [solar plants based on string inverters, nb], the solar cells will continue to generate power as long as the solar cells are exposed to sunlight. Voltage continues to be applied to the array side. Also, if a ground fault or short circuit accident occurs, a closed electrical circuit may form, and current may continue to flow. Therefore, even if you open the electric circuit in the connection box or stop the inverter, risk of electrical shock or fire remains. In order to prevent electric shock, it is necessary to reduce the voltage to, for example, 60 V or less. Methods for this include shielding the solar cells from light and using MLPE (Module Level Power Electronics) in which equipment is attached to each solar cell module.” SolarEdge improves on basic MLPE system safety We often say that safety is part of the SolarEdge DNA. When SolarEdge split the functionality of the inverter with the invention of the Power Optimizer, the key motivator was to make sure each module performs at its maximum potential But another equally important goal was increased system safety. Essentially, SolarEdge designs for safety, taking optimal advantage of MLPE with these features: SafeDC™ and Rapid Shutdown SafeDC™, integrated into every SolarEdge system, automatically brings the system to a touch-safe voltage level whenever the inverter is shut down. Why is this important? In conventional solar systems, shutting the inverter down with a safety switch or other device leaves high voltage on the modules and in the cabling as long as the sun is shining. In a SolarEdge system with SafeDC™, each panel is quickly reduced to 1V during grid failures or AC power shutdown, removing the risk of electric shock to maintenance workers, farmers or first responders. The feature also prevents secondary events. For example, if cabling has lost some insulation and an arc develops, SafeDC™ will operate automatically and prevent the arc from becoming a safety hazard. This is the only feature on the market that can handle such events. Sense Connect Sense Connect is one of the most significant safety features in the SolarEdge safety suite, embedded in S-Series Power Optimizers. They are designed to prevent arcs from forming. Before an arc can develop, the temperature in the connector will increase. Sense Connect is able to detect that change of temperature and alert the inverter to shut off. Coupled with the SolarEdge Monitoring Platform that indicates the location of the fault, this early warning system helps keep agrivoltaic installations safe. Temperature sensing in SolarEdge inverters enables monitoring the AC and DC side interface installation as well as aids in detecting bad connections before they turn into an arc. When abnormal temperatures are detected, the system will even shut down the inverter. Temperature sensing in inverter and Smart Reconnect Mechanism SolarEdge inverters are also equipped with temperature sensing to help identify a hazard and prevent it from escalating. Temperature sensing in SolarEdge inverters enables monitoring the AC and DC side interface installation as well as aids in detecting bad connections before they turn into an arc. When abnormal temperatures are detected, the system will even shut down the inverter. The smart reconnect mechanism can get the inverter up and working when safe, for minimal system downtime. Other important Agri-PV best practices for safety In addition to critical site protection as described above, several other practices should be adopted to keep Agri-PV safe. Signage Sometimes low tech is critical. Installing signs around the site can help maintain awareness of the installation and remind farmers and other site visitors to pay attention to their environment in order to protect themselves, the installation and crops. Cable placement Cables can be buried deep in the ground in order to keep them safe from roaming animals or machinery (and to keep the animals and machinery safe from them). Of course, plant roots and irrigation needs must be taken into consideration when determining placement. According to an Indian study, cabling for most of their pilot projects was installed overhead to avoid interaction with it. They concluded that it’s important to ensure that the overhead cables remain taut. Module height Placing modules at specific a height over the crops is important for ensuring plant crop health but also to keep the machinery safe. What’s the next step? When safety issues are addressed in the planning stages of an Agri-PV installation, the addition of solar energy production to an agricultural site can be an excellent opportunity for farmers to extract more value and profit from their land.

  Constructing a vast ground mounted solar system and making it financially viable is hard enough. Add another layer of threats from Mother Nature and you’ve got a mega challenge. One sizzling hot example of this is a large-scale ground mounted PV plant that was recently installed at an abandoned salt production site in Taiwan using SolarEdge PV solutions. The plant has installed  77 MW of solar arrays— the size of 78 soccer fields. But besides  its considerable size, its location presents one of the world’s most challenging environments for solar. Typhoons and heavy rains lash the island each year, causing severe flooding and pounding it with strong sea winds that carry sand, dust and salt. And when the rain subsides, huge migratory seabirds flock to the wetlands. SolarEdge stepped up to the plate to overcome these extremely difficult conditions. The Big Idea of Large-Scale Solar Solar farms are emerging in all shapes and sizes, as solar PV becomes the lowest-cost option for new electricity generation in most of the world. One of the main types of solar installations increasing in popularity is the large-scale ground mounted solar farm. Ground-mounted PV plants are generally divided into categories according to the amount of power they can produce: Large-scale commercial: Over 1 MW Medium commercial: 100.1 kW-1 MW Small commercial: 10.1-100 kW   78 Soccer Fields of PV Power Shinfox Energy, an investment firm in Taiwan focusing on renewable energy, is a subsidiary of the Foxlink group which builds and provides O&M services for renewable power plants. Shinfox recently signed a 20-year lease agreement for a vast piece of land owned by the Taiwanese government, as part of Taiwan’s Feed-In-Tariff (FIT) incentive program. The plot, near the popular scenic spot of Qigu Mountain just outside of Tainan City, spans more than 550,000 square meters. What was once the site of a 300-year-old abandoned salt production plant is now a 77 MW large-scale commercial solar site that produces renewable electricity (see Case Study). This green electricity will be sold to the utility company for 20 years of dependable revenue. Reduced Module Mismatch Effects and More Energy When Shinfox decided to finance the project, they looked for a PV solution that could yield maximum energy output, minimize operating costs, and keep service crews safe. Finding a solar energy system that could deliver the most amount of electricity at such a large site was easier said than done, given the typically high module mismatch rate. Tens of thousands of modules meant potentially significant revenue loss. The SolarEdge DC-optimized solution was chosen for its proven ability to maximize energy yield by minimizing power losses caused by module mismatch. The SolarEdge inverters and Power Optimizers continuously track MPPs (Maximum Power Points) and adjust current and voltage at module level. With this built-in module mismatch mitigation mechanism, underperforming modules don’t affect other modules on the same string, which results in higher energy production. By contrast, with central or traditional string inverters, underperforming modules reduce the output of all other modules on the string. SolarEdge addressed several module-mismatch scenarios related to Taiwan’s weather and environment: Partial shading from clouds, dust, salt and sand carried by the South China Sea winds, especially during tropical cyclones, all accumulate on the panels and over time reduce their performance. Another stubborn and aggressive form of soiling comes from birds, due to the plant’s location along a main migration route. Thermal mismatch: The lower the temperature of the module’s surface, the greater its output, which can affect output efficiency by as much as 10-25%. Each module’s temperature can differ according to its position on the row. Uneven module aging: Over the 20-year FIT period, normal wear and tear will inevitably degrade each module at different rates, which increases mismatch power losses. Most module manufacturers specify that during the warranty period, degradation reduces the power output of each module by as much as 20%. The drops in output cause mismatches in a string, which could lead to inconsistent production. Micro-cracks: With fluctuating temperatures and heavy winds, modules are subjected to thermal and mechanical stress, which can cause micro-fractures in the silicon wafers, decreasing power generation.   Remote, At-a-Glance Troubleshooting Saves O&M Costs   Maintaining the modules was another major concern for Shinfox, which needed to secure the highest long-term return on their investment. To do that, they had to minimize operating costs. Typically, thermal imaging drone cameras are used at large solar sites for inspecting and diagnosing PV panels. SolarEdge avoided these high expenses, saving potentially up to 50% in overall O&M costs. The SolarEdge Monitoring Platform, accessed remotely from any computer, receives granular data from the Power Optimizers, each automatically tracking the performance of every four modules and of the inverters. By receiving real time notifications, O&M personnel can quickly pinpoint faulty modules and troubleshoot remotely, which translates into fewer and shorter site visits. The modular design of the Three Phase inverter with Synergy technology saved further costs. If one inverter unit should fail, the others are unaffected and will continue to operate independently until the faulty unit is replaced. These units are lightweight, requiring only two people to lift them, making forklifts unnecessary. SolarEdge also saved more on DC cabling and combiner boxes by supporting as many as 60 modules per string. This reduces incidents of insulation faults associated with moisture (which is common in warm and humid climates), resulting potentially in up to 40% increase of BOS savings. Keeping People and Assets Safe During the Rainy Season   Service crew safety was a top priority, especially because of the heavy rainstorms that cause flooding during the East Asian rainy and typhoon season when the site turns into a huge retention pond. While the basin helps limit overflowing of the surrounding streams, floodwater reaching knee level or higher could pose a serious electrical hazard to maintenance crews. SolarEdge technology, safe and reliable by design, complies with stringent international safety standards. The SolarEdge IP65-rated inverters are water and humidity resistant with a wide temperature range, and they comply with the UL 1699B standard for Arc Fault Circuit Protection. In addition, the built-in SafeDC™ feature can automatically reduce the output voltage of each module to a touch-safe level of 1V within up to 5 minutes, providing extra protection to maintenance and firefighting crews. The automatic Arc Fault Detection prompts the inverter to shut down when an arc fault is detected, reducing the risk of fire due to faulty or improperly connected cables. Sunny Future Ahead for Supersized Solar Farms Net zero is the internationally agreed upon goal to reduce global warming by the second half of this century. The IPCC (International Panel on Climate Change) concluded the need to reach net zero CO2 emissions by 2050 in order to limit global warming to 1.5°C. To achieve this important goal urgent action is needed, and in the energy sector this will require major transitions. The world will have to generate on average 25% more solar PV each year from 2022 to 2030. That’s a serious undertaking, given the limited available areas that are suitable for large-scale solar farms. One solution will be to utilize areas with sub-optimal soil and weather conditions for large-scale ground mount solar farms. SolarEdge, in addition to its installations in Taiwan, has vast experience in large-scale PV all over the world, such as in the U.S., the Netherlands, Poland, Japan, Turkey and Israel.