How big a solar battery do I need to store *all* my home's electricity?
6 hours ago
- #battery storage
- #solar energy
- #energy self-sufficiency
- A homeowner in suburban London with solar panels generating 3,800kWh annually seeks to determine the battery size needed for complete energy self-sufficiency.
- Analysis of a typical summer day shows a peak excess of 13kWh, indicating the need for a larger battery than just the daily excess due to mismatched solar production and household usage patterns.
- Using real data from March 2024 to March 2025, the cumulative difference between solar production and household usage suggests a need for approximately 1,068kWh (1MWh) of battery storage to cover annual energy needs.
- The exercise highlights impracticalities, including high costs (estimated £100k-£500k), environmental concerns, and inefficiencies in battery usage.
- Future possibilities include falling battery prices (e.g., sodium ion batteries at US$10/kWh) and increased solar panel efficiency, potentially making home energy self-sufficiency more feasible.
- The discussion acknowledges the ecological imprudence of large domestic batteries and suggests reliance on grid-scale renewable sources as a more sustainable alternative.