Low-cost, high-cycle efficiency home sodium battery (household sodium battery), household electricity bills greatly reduced. Crustal abundance of sodium resource is 440 times higher than lithium (sodium 2.74% compared with lithium 0.006%), raw material sodium carbonate price just ¥3,000/ ton (peak price of lithium carbonate ¥600,000/ ton), cost per kilowatt-hour (kWh) of sodium batteries 30% to 40% less than lithium batteries. Taking 10kWh residential energy storage system as an example, the cost of sodium battery is around ¥15,000 (lithium battery ¥25,000, lead-acid battery ¥8,000), and kilowatt-hour cost (LCOS) is ¥0.06 (lithium battery ¥0.12, lead-acid battery ¥0.28) based on 5,000 cycle life. The whole life cycle can store 50,000kWh of electricity, saving electricity costs of about ¥42,000 (calculated by using the residential electricity price of ¥0.6/kWh).
Peak-valley price arbitrage increases the profit. Evenings, families in Germany charge with sodium batteries inexpensive electricity (€0.15/kWh) to be used during the daytime (cost of electricity €0.35/kWh), €4.2 per day arbitrage benefit (10kWh system), €1,533 yearly profit, and 5-year return period (lithium batteries 8 years). After the home installation of sodium batteries in a residence in Jiangsu, China, the utilization rate for peak-valley price difference was 92% (65% for the lead acid system alone), and the yearly electricity bill reduced by ¥3,600.
Security and maintenance-free characteristics reduce hidden costs. Home sodium battery thermal runaway temperature is 300 ° C (150 ° C for ternary lithium battery), and UL lab test reveals that its failure rate is only 0.0003% (0.02% for lithium battery). California home test reveals that sodium batteries never need a cooling system, and maintenance cost is ¥0/year (¥500/year for lead-acid batteries to replace the electrolyte). Seismic areas of Japan users reported that the sodium battery system maintained refrigerators (150W) and medical equipment (300W) running for 48 hours in case of loss of power, and fuel costs were 89% lower than with diesel generators.
Low-temperature performance maintains power supply for harsh weather conditions. Sodium battery capacity retention rate is 85% (65% lithium battery) when stored at -20℃, and domestic use measurement in Harbin, China, sodium battery still provides 1.5kW ground heating for 8 hours in -30℃ temperature (only 3 hours with lithium battery), and saves the heating electric charge by ¥2,400/ month. Statistics from the Norwegian Light Storage project show that the daily discharge of the sodium battery during polar night is 18% more than that of lithium batteries, and system availability is 99.5% (82% for lead-acid systems).
Environmental protection and recycling advantages contribute to economy. The carbon footprint of the production of sodium battery is 12kg CO₂/kWh (ternary lithium battery 35kg CO₂/kWh), and the recovery process is also streamlined: sodium can be recovered through aqueous solution method (98% recovery rate), whereas lithium battery needs high-temperature melting (recovery rate < 70%). The EU subsidizes sodium batteries for €50 per kWh, which lowers the net cost of a 10kWh system to €3,000 (€4,500 for lead-acid systems) and a 40% (15% for lead-acid batteries) recovery rate.
In-the-field experiences validate the viability. By 2023, 20kWh sodium battery systems will be installed in homes by Cape Town, South Africa, which will work together with the average daily power generation by photovoltaic of 65kWh, save 94% of the electricity purchased from the grid, and save the average electricity bill from ¥1,200 to ¥72 monthly. In the Tesla sodium battery pilot program, American households reduced their average annual electric bill by $1,800, with an ROI of 22% (8% for lead acid systems).
Cost reductions are driven by market trends. BNEF anticipates sodium battery price to fall to 80/kWh in 2030 (120/kWh in 2023) since the price of 10kWh systems is being driven to ¥8,000, and the share of domestic electricity saving must exceed 95%. When Ningde Times publicly announced the mass production of the second-generation sodium battery (8,000 cycle lives), this resource-abundance-driven energy revolution and technology is transforming the economic model of home electricity consumption.