Background: Queensland experiences frequent summer thunderstorms and has an aging power grid, with 3–5 power outages per year, each lasting up to 8 hours.

User Profile: A retired couple living at home with an oxygen concentrator (medical device), requiring extremely high power supply reliability.

Pain Point: During power outages, the oxygen concentrator cannot operate, posing a life-threatening health risk. Food in the refrigerator has also been spoiled multiple times.

Solution:

• Configuration: 13.5kWh all-in-one residential energy storage system (with off-grid switching) + 6.6kW PV

• Strategy: Perform peak shaving and valley filling during normal conditions. During a power outage, automatically switch to off-grid mode, prioritizing power supply to medical equipment, the refrigerator, and lighting.

Results:

• The oxygen concentrator continued to operate during every power outage, ensuring the elderly couple's health and safety

• Maintained basic electricity supply for 8–10 hours during outages

• Annual electricity costs reduced by approximately 65%