»Energy Storage Inspection 2023«: Clear Advantages for Li-Ion Batteries

The Solar Storage Systems Research Group of the German University of Applied Sciences Berlin (HTW) has presented the new edition of its »Energy Storage Inspection«. For the first time, saltwater and high-temperature batteries were also analyzed here in cooperation with the Karlsruhe Institute of Technology KIT. The results showed that the market-dominating lithium-ion technology is »currently still clearly superior« to the alternative battery technologies. The storage losses of sodium nickel chloride batteries are »seven times higher«, and their power output is also »in need of improvement« and, moreover, decreasing linearly with downward state of charge.
The Energy Storage Inspection also looks at the battery storage market. According to the report, around 200,000 systems were installed in Germany in 2022 (44 percent more than in the previous year), 98 percent of which were lithium-ion-based. Here again, lithium iron phosphate batteries have achieved a market share of just under 70 percent. Systems with hybrid inverters show a »rapid market development«, about three quarters of all storage systems have been realized with DC-side connection of the battery storage last year.
In the actual evaluation, HTW Berlin tested 18 storage systems from eleven suppliers; companies that provide technical data and measurement results for the inspection participate every year. The overall efficiency of the storage systems was evaluated as a »System Performance Index« in two categories – 5 kW and 10 kW – in both of which systems from German RCT Power GmbH of achieved the best results. In total, seven systems received a rating of the highest efficiency class A. In addition to RCT Power, systems from Varta (highest battery efficiency, lowest standby consumption) and Kaco (shortest inverter »settling time«) were also rated as »outstanding«.
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