Energetica India Magazine: september 2020

ENERGY STORAGE Tips and Tricks to Select the Ideal Energy Storage System System integration technology is critical to the stable operation of solar-plus-storage project, while there are huge challenges. Few companies have proven solar-plus-storage system integration capabilities, though many com- panies do well in individual fields such as PV inverters, batteries, Power Conversion System (PCS), and Energy Man - agement System (EMS). 40 energetica INDIA- September_2020 Given the increasing concerns about global warming and environmental im- pacts of burning fossil fuels, policymak- ers pay more attention to energy stor- age solutions than ever before. Apart from having the ability to address the in- termittent supply of renewable energy, energy storage assets can also offer a multitude of uses consisting of frequen- cy regulation and ancillary service. An increasing number of countries released incentives to spur the inte- gration of PV and storage. In China, energy storage is compulsive in many of the renewable energy projects, aim- ing to meet the demand of frequency regulation and grid stabilization. For markets like the US and Europe, the so- lar-plus-storage applications are highly recognized as ancillary services or a buffer in the large-scale solar and wind integration in the existing power sys- tem. DC-coupled and AC-coupled so- lar-plus-storage solutions The first step to any successful so - lar-plus-storage solutions is to figure out what requirements you need and which technologies are able to meet these requirements at the highest efficiency. The DC-coupled and AC-coupled de- signs are undoubtedly typical solutions. The AC-coupled design means that an energy storage system connects to a solar system via AC side. As we know, the electricity from a solar system is generated in the form of DC which is then turned into the AC by PV inverter. The energy storage system is general- ly better suited to flexibly participate in a wider array of ancillary services and can be connected to the low voltage side or the high voltage side, ideal for the large-scale solar-plus-storage proj- ect. Respectively, DC-coupled systems can have a small but significant cost advan - tage over AC-coupling, depending on system size and characteristics, with the primary benefits including the re - duction of power conversion equipment required and the ability to recapture DC energy that would otherwise be clipped by the inverters. The pre-assembled storage interface on the PV inverter is essential, which enables an energy storage system be easily added to the existing solar system without recon- structing the entire system. Both types can leverage the ITC (In- vestment Tax Credit) and benefit from shared installation and operational costs. Industry chaos System integration technology is critical to the stable operation of solar-plus-stor- age project, while there are huge chal- lenges. Few companies have proven solar-plus-storage system integration capabilities, though many companies do well in individual fields such as PV inverters, batteries, Power Conversion System (PCS), and Energy Manage- ment System (EMS). Given the condition that different appli- cations put different requirements on energy storage systems, there is no uni- fied standard for energy storage system design and cost management.This vari- ability leads to a grey zone due to the uneven integration capabilities and the low price competition. “The most critical aspect of energy stor- age system integration is the safety of battery system,” commented a spokes- person from the energy storage indus- try. A qualified system protection de - sign can monitor the operating status of cells, modules, battery clusters, battery management system (BMS) in real-time, enables pre-alarm and faults localiza- tion. If a fault occurs, it can protect the system by fast-breaking and anti-arc protection. Otherwise, minor faults can easily evolve into major problems. Most of the 30 fire accidents that occurred in South Korea in recent years were caused by defects in the electrical system design and failure of the protection system.