Designing M&E Systems for Off-Grid Public Infrastructure
Monitoring is the cheapest insurance an off-grid program can buy — yet most programs ship without it. A reference architecture for hardware, telemetry, and accountability.
- 01
M&E hardware adds 2–4% to system cost and pays back within 9 months through preventable-failure avoidance.
- 02
GSM-based telemetry covers 78% of Sudan's PHC network; satellite fallback closes the remainder for under $40/month per site.
- 03
Three KPIs (daily kWh delivered, battery SoC floor, inverter fault count) detect 89% of degradation events at least 30 days before failure.
What M&E actually has to do
An effective M&E system on an off-grid public asset answers three operational questions, in priority order: Is the system delivering the energy it was funded to deliver? Is anything degrading on a trajectory toward failure? Who is responsible for acting on the answers? Most installed monitoring stops at question one and stalls there.
Reference hardware stack
| Layer | Component | Indicative cost (USD) |
|---|---|---|
| Measurement | DC + AC energy meters, battery shunt, temperature probes | 180–260 |
| Logging | Edge controller with 30-day local buffer | 120–180 |
| Transport | GSM modem with SIM and failover to LoRa or satellite | 90–140 + airtime |
| Backend | Time-series DB with alerting, hosted regionally | $0.40–$0.90 / site / month |
The three KPIs that matter
- Daily kWh delivered vs. design expectation — flags PV-side issues and shading
- Battery state-of-charge floor over rolling 7 days — flags load growth and battery aging
- Inverter fault and restart count — flags grounding, harmonics, and inverter-end issues
Across 38 sites where we instrumented retroactively, these three KPIs flagged 89% of subsequent degradation events at least 30 days before a user-visible failure. The remaining 11% were sudden physical events (lightning, theft) that no telemetry would have predicted.
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