Generally speaking, PV systems are safe to use if they are properly installed and regularly maintained. Still, more can be done to make them even safer, more reliable, and more intelligent. Continuous improvements in the safety of PV systems is obviously something welcomed by system operators and end-users. “There is no compromise to safety,” said Owen Tsai, director at SolarEdge Technologies Taiwan.
As a global provider of inverters and other advanced technologies for PV projects, SolarEdge stands out from its competitors by offering comprehensive solutions that maximize power output. The company also has the strong advantage of having developed its own proprietary rapid shutdown and arc fault detection mechanisms for inverters. For large or commercial end-users in Taiwan, SolarEdge presents a solution that is able to mitigate safety risks and bring a more prudent approach to the adoption of PV generation.
In the recent years, the government of Taiwan has introduced a series of legislative amendments and policy incentives to promote the installation of renewable generation systems across the island. Taiwan’s Renewable Energy Development Act, which was just revised last year, mandates that large end-users whose electricity demand exceeds a capacity limit of 5MW (or 5,000kW) are required to have “green energy” account for 10% of their electricity supply. The definition of green energy not only covers equipment related to renewable generation and energy storage but also power purchased through renewable energy certificates (RECs). Alternatively, large end-users can fulfill this requirement by paying a special levy to support the development of the domestic renewable sector.
The green energy mandate, which is officially in force as of January 1, 2021, is expected to affect more than 600 local companies engaging in many of the island’s key industries such as semiconductor, steel, chemicals, textile, car assembly, etc. To ease the impact of the new law on businesses, the government has set a five-year grace period. Instead of forcing companies to fully comply with the decree by next year, the government has established annual targets and incentives for early adoption. Also, the progress made by enterprises and industries will be reviewed every two years. With the rule and its implementation mechanism that are now in place, Taiwan’s installed capacity for PV generation is projected to increase by 1GW over the next five years. In other words, around 200MW will be added annually during the grace period.
While government support will encourage enterprises to install solar panels, the safety risk associated with the electrical equipment deployed at PV projects will also be a concern that cannot be ignored. While well-maintained PV systems pose no inherent danger to system operators and end-users, nevertheless, preventing and responding to emergency events is a critical part of risk management for PV projects. Tsai pointed out that large end-users such as manufacturing firms place far more value on their production equipment and their property than on the solar panels installed on the roofs of their factories. Hence, safety and reliability are the major considerations for an enterprise that is deciding on whether to acquire PV systems to fulfill its green energy obligation.
SolarEdge has long been focused on the development of fire safety technologies and other protection mechanisms for safeguarding the operation of PV systems. In this respect, it believes that the further advancement of safety functionality within the industry is important for the continued proliferation of PV.
When there is an accidental fire at a PV project, for their own safety, firefighters cannot immediately enter the equipment room that houses the inverter. They remain at a safe distance until the public utility Taipower severs the connection between the system and grid or shuts down some of the on-site equipment including the inverter. Even when the inverter is shutdown however, high-voltage power can still be present in the PV array and the DC lines connected to the inverter. Generally, the module can generate electricity as long as there is sunshine, and the DC voltage output is from 600 volts to 1500 volts. Since first-responders are unable to spray water or a chemical agent to extinguish the fire, there is often a lag in the response to a fire at a PV project.
For large end-users that will have to comply with the green energy mandate, SolarEdge presents an integrated solution with advanced inverter technology and power optimizers. The Power optimizers turn solar panels into smart panels, increasing the system’s energy output and enabling module level monitoring and control. No less important, they provide enhanced safety. The built-in safety functions of a SolarEdge inverter can reduce the response time for fires and other emergencies. The safety functionality, as well as a remote monitoring, can help raise the efficiency of the response without sacrificing the safety of the first-responders. In addition, an integrated solution with built-in functionality also helps to avoid the extra cost of installing safety-specific hardware - reducing installation time and room for error.
In the past, people thought of SolarEdge as an ideal solution for shade. However, the SolarEdge DC optimized solution has many other benefits. As well as advanced built-in safety functionality, the SolarEdge DC optimized solution also helps with energy loss due to mitigation of all types of module mismatch, such as panel aging, damage, shade, soling, different tilts & orientations. The SolarEdge solution can mitigate the issue because of Maximum Power Point Tracking (MPPT) of the power optimizers. Since SolarEdge is an internationally leading and stable company, publicly traded on NASDAQ, warranties are provided from SolarEdge HQ to avoid “Orphan”PV station and are the longest warranty in the industry, which helps protect the system owner’s long-term investment.
A SolarEdge inverter automatically switches to safety mode in any one of these cases:
[1] The inverter is turned off due to installation, maintenance, or emergency
[2] The AC connection is shut down due to previously mentioned instances
[3] An arc fault has been detected
[4] A temperature above 85˚C has been detected by the thermal sensors of the power optimizers that are attached to the PV modules
Once the safety mode kicks in, power output is cut off, and the output voltage of each PV module is reduced to just 1V, which is harmless to the human body. Hence, firefighters and rescue personnel that have arrived at the project site can take a proactive approach in dealing with the situation that they are facing. They can spray water directly onto the equipment room, or they can enter the equipment room to suppress the fire at its source without the fear of electrocution.
For end-users that need to deploy a sizable PV array to meet their green energy obligation, SolarEdge has developed a new 120kW, three-phase inverter system, expected to acquire Voluntary Product Certification (VPC) by the first quarter of 2021. The 120kW inverter makes solar energy more economically attractive to businesses. It features increased power output and overall system performance, improved scalability, ease of installation, pre-commissioning for early stage system inspection and validation, 150% inverter oversizing and decreased price per watt. The system itself consists of three 40kW inverters that are strung together but operate independently of each other. For example, if one malfunctions and has to be turned off, the other two can still keep working. This 120kW inverter system also comes with an improvement in operational efficiency, rising from 98.1% to 98.3%. Moreover, it supports applications that require a connection to a 480V grid.
Tsai stated that the compatible grid-connection voltages of the 120kW inverter system include 380V, 440V, 460V, and 480V. Thanks to its scalability, the inverter system can work with residential PV systems as well as PV arrays that power office buildings and factories of various sizes. Tsai further boasted that deploying this single 120kW inverter, which can meet all kinds of demands, will lead to an estimated saving of over NT$300,000 in costs of purchasing a voltage transformer.
SolarEdge also provides customized solutions for existing PV projects around Taiwan. Many older PV installations now need an upgrade because of aging, pollution, and shading. Take a PV project at a poultry farm in Changhua County as an example: Its previous inverter had long passed its warranty period. Lack of proper maintenance also led to the deterioration of the PV modules deployed at the project site. Consequently, the project was operating at loss with the performance dropping to 2kWh per kWp. An overhaul was necessary to turn this situation around. The old inverter was replaced with a SolarEdge solution, and power optimizers were added to the modules. After this refurbishment, the project’s performance rose above 3kWh per kWp.
SolarEdge has also helped built the rooftop PV array that powers Je-nong Coop in Miaoli County. The rooftop of this building has different angles and tilts, which limits the capacity. With a traditional inverter, its estimated generation capacity would be limited to just 150kW. Since it adopts SolarEdge’s solution that enables longer strings and hence a more flexible design and more modules on the roof, its capacity is able to reach a capacity of 190kW.
Regarding future plans, Tsai acknowledged that the recent COVID-19 pandemic and policy changes by the government have impacted Taiwan’s solar market. However, he also stressed that SolarEdge has been performing remarkably well despite the market headwinds and expects growth results that are several times higher compared with the previous year.
SolarEdge is optimistic that the installed PV capacity in Taiwan will continue to grow in the future as government pushes forward with its renewable energy initiatives and enforces the green energy mandate for large end-users. At the same time, the major industries on the island are starting to pay more attention to the safety of PV systems as they pursue energy transition. For enterprises that opt to set up their own PV projects to power their office buildings and factories, they need to protect their assets and establish a working environment where safety is prioritized for not only their employees but also emergency personnel and PV specialists (e.g., system installers and O&M personnel).
(Photo Credit: TechNews)