The 2023 evaluation report for HTW HOME-ESS products, released by the Berlin University of Applied Sciences, offers a comprehensive analysis of the residential photovoltaic battery system market in Germany. The report covers four main areas: market analysis, comparative test results, SPI scores, and an analysis of sodium-ion and sodium nickel chloride battery systems. Here’s a detailed look at the key findings.
1. Analysis of the German Residential Photovoltaic Battery System Market
In 2022, Germany experienced a significant growth in the adoption of HOME-ESS systems, with 197,000 new installations—a remarkable 44% increase from the previous year. By the end of 2022, the cumulative number of HOME-ESS systems reached 526,000, totaling 4.3 gigawatt-hours (GWh) of installed capacity. The average usable capacity of these systems was 8.4 kilowatt-hours (kWh), with an average charge-discharge rate of 0.6C.
A notable trend is the dominance of DC-coupled systems, which utilize hybrid inverters. These systems represented 75% of the newly installed HOME-ESS systems in 2022, reflecting a shift towards more efficient energy management solutions.
2. Comparative Test Results of Evaluated Products
The report evaluates various HOME-ESS products, presenting them in an alphanumeric format. Key findings include:
- Usable Capacity Deviation: The average deviation between the actual measured usable capacity and the promised capacity is -0.2 kWh (-2.2%). The most significant deviation recorded was -14.7%, although the brand associated with this deviation was not disclosed.
- Efficiency Testing: The system efficiency is tested across several stages including PV→AC, PV→Battery, AC→Battery, and Battery→AC. The highest discharge conversion efficiency observed was 97.8%.
- Standby Power: Standby power consumption varies depending on the battery’s charge state. Systems typically show higher standby power when the battery is empty compared to when it is full. Most products had a standby power consumption below 10W, with one exception showing a notably high 37W standby power for Battery Management System (BMS).
3. SPI Score
The SPI (System Performance Index) scores are categorized by inverter power levels: 5kW and 10kW. Key points include:
- Top Performers: The RCT brand leads in both the 5kW and 10kW categories, demonstrating superior performance across different power levels.
- BYD Battery-Box Series: The BYD Battery-Box series consistently ranks in the top three across various evaluations, indicating robust performance and reliability.
4. Analysis of Sodium-Ion and Sodium Nickel Chloride Residential Energy Storage Systems
The report compares sodium-ion and sodium nickel chloride battery systems with traditional lithium-ion batteries. Key insights include:
- Energy Density and Efficiency: Lithium-ion batteries outperform sodium-ion and sodium nickel chloride batteries in terms of energy density and various technical indicators. This performance advantage highlights the ongoing dominance of lithium-ion technology in residential energy storage.
Conclusion
The 2023 HTW HOME-ESS evaluation report provides valuable insights into the current state of the residential photovoltaic battery market in Germany. With a significant increase in installations, the dominance of DC-coupled systems, and notable advancements in efficiency and performance, the market is poised for continued growth. The comparative analysis of products and the SPI scores underscore the competitive landscape, while the examination of alternative battery technologies highlights the ongoing advantages of lithium-ion batteries.
The data and findings from this report are crucial for industry stakeholders, consumers, and researchers aiming to understand the latest trends and performance metrics in home energy storage solutions.
