A community-scale microgrid shares energy generation, storage, and distribution infrastructure among multiple households. This is fundamentally more efficient than individual off-grid systems: shared battery banks can be sized for the statistical diversity of loads (not every household needs power at the same moment), shared generation can be optimally sited on the best solar or wind resource on the site, and shared inverter and control systems reduce per-household equipment costs.

The basic components of a community microgrid are: a central generation cluster (solar array, potentially supplemented by small wind turbine or micro-hydro if available), a central battery storage bank (typically lithium iron phosphate at community scale), a bidirectional inverter-charger that converts DC storage to AC distribution, and a distribution network that brings AC power to each building’s main panel.

Community microgrid design must address load management: the discipline of scheduling high-consumption activities (water pumping, washing machines, power tools, EV charging) to match generation availability. In a well-designed community microgrid, load management is supported by smart metering, time-of-use pricing signals, and community agreements about high-load scheduling.

Community Microgrid Sizing Approach

1. Conduct load analysis for each household (see Book 7: Off-Grid Energy Systems)

2. Sum daily household loads and add common area loads (community building, pumps, workshop)

3. Apply diversity factor of 0.7-0.8 (not all loads peak simultaneously)

4. Size solar array for 120% of total average daily load (accounting for seasonal variation)

5. Size battery bank for 2-3 days of autonomy at 80% depth of discharge

6. Size inverter-charger for peak demand load (typically 1.5-2× average load)

7. Design distribution network for <3% voltage drop at full load