The Battery-Box system by BYD Co Ltd, one of the world’s largest manufacturer of rechargeable batteries, has been ranked as the most efficient energy storage system in the latest system evaluation by the Berlin-based University of Applied Sciences (Berliner Hochschule für Technik und Wirtschaft – HTW) the Stromspeicher-Inspektion 2019. This is the second consecutive time BYD’s Battery-Box not only achieved the top ranking but also dominated the top-10 ranked system combinations – claiming six positions together with inverter systems by partners such as KOSTAL and SMA.
In addition to examining the overall system efficiency of energy storage systems, the researchers also pursued the question of whether the combination of photovoltaic systems and battery systems in residential buildings could really effectively reduce CO2 emissions. The HTW team examined the CO2 balance of the power supply for various residential buildings with very efficient and less efficient photovoltaic energy storage systems. The results demonstrated that the contribution to climate protection and reduced CO2 emissions was highly dependent on overall system losses.
“This finding makes the availability of reliable data and transparency in regard to the overall system efficiency all the more important for end users aiming to contribute to a greener environment in addition to finding an efficient and cost effective solution to utilize renewable energy,” said Julia Chen, global sales director for BYD Batteries. “The vendors participating in the Stromspeicher-Inspektion received a seal, showing their contribution for more transparency in the market.”
The Energy Storage System Inspection survey, supported by the German Federal Environmental Foundation (DBU), is aimed at providing more transparency and comparable data to help installers and consumers choose the best solution based on reliable facts. Vendor datasheets often provide limited data, make it hard to compare specifications and also cannot provide the total efficiency of a complete system including battery storage and inverter system. The HTW test results show that high battery efficiencies are no guarantee for the highest overall system efficiency. Decisive factors also included low conversion and low standby losses of entire storage systems. More than 60 manufacturers and suppliers of the PV storage systems brands most active in Germany were invited to participate in the study. Not every vendor followed the invitation by providing the necessary transparency for participating in the survey so only 16 systems entered the final research phase.
“We are delighted to be recognized as the most efficient energy storage system for the second consecutive time together with our inverter system partners,” added Chen. “The survey data provided by HTW Berlin demonstrates how important it is to provide full transparency in regards to a system’s overall efficiency, the efficiency level during charging and discharging cycles and standby losses. Only with this full transparency and reliable data can installers and end-users can choose the most suitable system.”