The application scope of energy storage systems currently covers all aspects of the energy value stream, including conventional large-capacity power generation, renewable energy power generation, power transmission, distribution networks, and power management at the user end. In practical applications, energy storage systems need to connect the low DC voltage they directly generate to the high AC voltage of the power grid through inverters. At the same time, inverters are also required to maintain the grid frequency in the event of frequency interference, so as to achieve grid connection of energy storage systems. At present, some countries have issued relevant standard requirements for grid-connected energy storage systems and inverters. Among them, the grid-connected standard systems issued by the United States, Germany, and Italy are relatively comprehensive, which will be introduced in detail below.

the United States

In 2003, the Institute of Electrical and Electronics Engineers (IEEE) of the United States released the IEEE1547 standard, which was the earliest standard for distributed power grid connection. Subsequently, the IEEE 1547 series of standards (IEEE 1547.1~IEEE 1547.9) were released, establishing a complete grid connection technology standard system. The definition of distributed power in the United States has gradually expanded from the original simple distributed power generation to energy storage, demand response, energy efficiency, electric vehicles and other fields. At present, grid-connected energy storage systems and inverters exported to the United States need to meet the IEEE 1547 and IEEE 1547.1 standards, which are the basic entry requirements for the US market.

European Union

EU Regulation 2016/631 Establishing A Network Code On Requirements For Grid Connection Of Generators (NC RfG) stipulates the grid connection requirements for power generation facilities such as synchronous generation modules, power regional modules and offshore power regional modules to achieve an interconnected system. Among them, EN 50549-1/-2 is the relevant coordinated standard of the regulation. It is worth noting that although the energy storage system does not fall within the scope of application of the RfG regulation, it is included in the scope of application of the EN 50549 series of standards. At present, grid-connected energy storage systems entering the EU market generally need to meet the requirements of the EN 50549-1/-2 standards, as well as further requirements of relevant EU countries.

Germany

In early 2000, Germany promulgated the Renewable Energy Act (EEG), and the German Energy Economics and Water Management Association (BDEW) subsequently formulated medium-voltage grid connection guidelines based on the EEG. Since the grid connection guidelines only put forward general requirements, the German Wind Energy and Other Renewable Energy Development Association (FGW) later formulated a series of technical standards TR1~TR8 based on the EEG. Afterwards, Germany released a new edition of the medium voltage grid connection guideline VDE-AR-N 4110:2018 in 2018 in accordance with the EU RfG regulations, replacing the original BDEW guideline. The certification model of this guideline includes three parts: type testing, model comparison and certification, which are implemented in accordance with the standards TR3, TR4 and TR8 issued by FGW. For high voltage grid connection requirements, VDE-AR-N-4120 shall be followed.

Italy

The Italian Electrotechnical Commission (COMITATO ELETTROTECNICO ITALIANO, CEI) has issued corresponding low-voltage, medium-voltage and high-voltage certification standards for energy storage system grid connection requirements, which are applicable to energy storage devices connected to the Italian power system. These two standards are currently the entry requirements for grid-connected energy storage systems in Italy.

Other EU countries

The grid connection requirements for other EU countries will not be elaborated here, and only the relevant certification standards will be listed.

China

China started late in developing energy storage system grid-connected technology. Currently, national standards for energy storage system grid-connected are being formulated and released. It is believed that a complete grid-connected standard system will be formed in the future.

Summary

Energy storage technology is an inevitable component of the transition to renewable energy generation, and the use of grid-connected energy storage systems is accelerating, expected to play a greater role in future grids. At present, most countries will release corresponding grid connection requirements based on their own actual situation. For energy storage system manufacturers, it is necessary to fully understand the corresponding market access requirements before designing products, so as to more accurately meet the regulatory requirements of the export destination, shorten product inspection time, and quickly put products into the market.