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NFE metering strategy + Glen Street-EMS

Purpose

OrientAuthoritative thepage team onfor NFE's meteringrole +in behind-the-meterthe controlIEEE strategy:Smart whereVillage meshEMS / Street-EMS initiative. Compiled 2026-08-10 from the Element room "Smart Village Energy Interest Group" (full history back to 2026-04-24), the ISV Dev Kit BOM sheet, isv.wiki, and the Rev B/C line diagrams. No customer PII or financial ledgers on this page by policy.

What it cameis

from,

Not whata runsstandalone today,NFE product. It is NFE's seat in an IEEE Smart Village (ISV) open-source initiative called meshEMS, hardware-branded Street-EMS, started at an IEEE / NESL hackathon in April 2026. Hardware and Glen'sfirmware customare open-hardwareled "STREET-EMS"by thatGlenn Algie (10power.com / NESL); the software and standards side is led by Adam Sauer (ISV Tech Committee chair). The working venue is the nextElement/Matrix step.room Compiled"Smart 2026-08-09Village fromEnergy theInterest BOM sheet, the July 25 and June 2 check-ins, and the meter evaluation. Sections marked (to confirm with Glen) are inferred from the BOM/one-line diagram and need his sign-off before they are treated as design.Group".

The evolution (three generations)

  1. Calin / Kalin Chinese prepaid meters (early pilot).meshEMS Claimed prepaid + postpaid, but the vendor did not expose meter data directly: you had to go through their proprietary cloud middleware API. That caused reliability issues, token-lockout problems (needing overseas tokens just to unlock a customer's meter), slow support, and MOQ pressure. Abandoned.

  2. CHINT DDSU666 postpaid meters (current, since March 2026). Locally sourced, postpaid-only, expose data directly via RS-485 / Modbus into a Raspberry Pi (the pi2 logger), internet via modem. This removed the vendor dependency and the token risk, and gave direct data. An OpenEMS plugin reads the meter usage in real time. The meters are physically clustered in one PDU, so wired connectivity is practicalopen-source forfirmware this dense, apartment-style site (would not suit dispersed rural). This is what feeds billing today.

  3. Custom "STREET-EMS" (Glen's build, in procurement). Instead of buying meters that only measure, buildon an open-hardware unit that meters AND controls each customer, integrated with OpenEMS. This is the next generation.

Division of labour (agreed direction)

  • OpenEMS = monitoring: meters, battery/inverter, solar. (Already has the meter plugin.)
  • MPM (EnAccess) or the NFE billing engine (MBE) = business: billing cycles, invoicing, payment links, customer/account management.
  • The edge meter/EMS = measure + control at the point of supply. The principle from the EnAccess call: integrate, don't rebuild. Battery/solar data that affects billing is the gray area to model carefully.

Glen's STREET-EMS (to confirm with Glen)

A cabinet-mounted, multi-tenant meter + controller. From the BOM + the July 25 one-line diagram review (multi-channel metering, residual-current monitoring, relays/contactors, EV charging):

  • Metering core: CircuitSetup Expandable 6-Channel ESP32 Energy Meter (main + add-on boards), ATM90E32-based, CT current sensors per tenant/phase + voltage reference. Open hardware (ESPHome/Arduino).
  • Controller: ESP32-S3 / ESP32-P4 module doing OpenAMI two-way metering and control over secure MQTT into OpenEMS. Deployed as a street-pole or pedestal low-voltage feeder cabinet that meters AND controls every tenant, it is designed to replace the per-tenant DIN-rail meters and the OpenEMS Raspberry Pi with a single integrated 9x15 cm EMS board.

    card,

    How Ethernetit fits NFE

    • Today (Wiznetpilot): W5500),CHINT 18650DDSU666 batterysmart backup.meters plus a Raspberry Pi gateway over Modbus RTU / RS485, feeding OpenEMS. Current pedestal cabinet is roughly 80 x 60 x 25 cm, about USD 150 locally.
    • Per-Next generation: the Street-EMS cabinet folds the 3-phase meter, the per-tenant control:meters and the Pi into one EMS board plus an SSR bank, shrinking the cabinet (cheaper, fits indoor locations, easier to secure from theft and weather) and adding per-tenant remote control and local energy-policy automation.

    The cabinet (Rev C, 9-tenant, 3-phase LV feeder)

    Signal flow left to right:

    • Incoming LV feeder RCBO Type-A breakersL1/L2/L3 + modular contactorsN + 8-channelPE. SSRsEach forphase: remotea connect/disconnect63A main breaker (postpaidQF1/QF2/QF3), enforcement);a phase-transfermains-usage contactors.
    • Safety: residual-current monitoringCT (RCM/RCB)CT4/CT10/CT16), withthen leakage-sensora CTsUKK80 terminal block fanning out to up to 6 tenant ways per phase.
    • EVThree charging:Ivy RCMs Etek(RCM1/2/3), EVSEone chargeresidual-current controllersmonitor (Typeper 2,phase, 32A,for Modecontinuous 3)leakage +and Typeneutral 2insight. cable.Modbus UART to RS485 adaptor.
    • Enclosure:Nine contactors K1..K9 FRP/NEMA-4X(3 IP66tenants cabinets.per Customphase) power-supplyfor PCBsper-tenant remote connect/disconnect, each with a tenant-usage CT (Myrra 230->9V, XP Power / HiLink 5V)CT1,2,3,7,8,9,13,14,15).
    • Sizing:Controller eachon the cabinet servesdoor: ~"Street-EMS w RGBW" = 3 tenantsstacked equipped,CircuitSetup wired6-channel forCT upmeters to= 9,18 3-phase.channels (9 tenant + 3 mains + 6 spare).
    • Two 8-channel opto-isolated zero-crossing SSRs drive the 9 contactor coils (9 control lines, 3x3 per phase, 240 Vac sensitive).
    • Backplate Power PCB: fused, TVS surge protected, 3x Myrra 44122 240-to-9 Vac, giving 5V 2A and 12V 1A.

    Net:Legend a(Rev ~$100/EMSB openwith unitlegend): thatQF meterscircuit eachbreaker, customer,CT cancurrent disconnecttransformer, themK forcontactor, non-payment,UKK80 addsdistribution terminal block, RCM residual current monitor, SSR solid-state relay, PCB printed circuit board, EVSE EV charging,charger. and1P+N speaksone Modbus/Ethernetphase toplus neutral. RS485 / Modbus UART / I2C communications.

    Decisions ratified in the NFE stack, replacing per-unit commercial smart meters.

    Procurementroom (from the BOM sheet)

    2026-07-25):

    • Total1P ~$2,377over 1P+N for tenant breakers and contactors (1P is cheaper; do not switch neutral except for EV).
    • 80A over 63A rating, chosen to leave room for a future EV station at a new location later this year.
    • Rev B to Rev C added the firstlegend; batch.the Orderingdiagram waves:is Augdeemed 7complete =with only a few unlabelled wires to clarify at the workshop.

    Still open: the make-before-break 80A neutral / phase-transfer balancer ("neutral rebalancer transfer method and apparatus") and the EVSE port are marked spare-room / in-progress.

    Firmware and energy-policy vision (Glenn)

    Local, IFTTT-style per-tenant automation in C/C++ on the ESP32, not just remote on/off:

    • Triggers: prepaid-token expiry, over-voltage, over-current, over-kW, over-kWh, over-generation, over-storage.
    • Actions: SSR disconnect (normally-closed contactor coil), SMS alert, RGBW LED or e-paper warning at the tenant box, a flash-warning cadence before cutoff, and a graceful post-sunset lighting-only allowance (about 10-20 W for a few hours from battery when storage allows).
    • Policy model: each tenant has a JSON "mode" (safety vs prepaid-shutdown automations) stored in ESP32 SPIFFS or SD as a persistent energy-model cache.
    • Grid insight: continuous per-phase leakage detection, neutral-imbalance alerts, phase-loss detection.

    Cloudless village

    An ESP32-P4 with its own Ethernet NIC acts as a per-feeder aggregation node. Street-EMS units LAN-hop along the feeder ("feeder hops") to run an in-village pay-go portal and full UX with no broadband. Optional LoRa / Meshtastic mesh and power-line communication on top; optional low-cost village camera / audio snapshots.

    Standards and interoperability (OpenAMI)

    OpenAMI is the "actionable energy telemetry" layer, the utility-facing layer above a village feeder. Built on DLMS/COSEM (IEC 62056), SunSpec Modbus/JSON, MQTT, IEEE 1547-2018 (DER interconnection) and IEEE 2030.5 (Smart Energy Profile). Village Metering goals: billing, remote disconnect, theft detection. EnAccess Foundation is extending the OpenAMI codeset. Reference: isv.wiki (repo github.com/overview-solutions/isv-ai-wiki, MIT).

    The workshop (immediate driver of the ISV Dev Kit BOM)

    IEEE ISV awarded Glenn and Adam a 4-session, 9-hour hands-on workshop (assemble an EMS +in 1about cabinet15 (3minutes tenants,each, assemble a cabinet, run code challenges). IEEE funds the parts BOM. Plan: build 15-20 EMS units and 3-phase,5 readymultitenant cabinets for 9);participants Augto 14-21take =home 10(about EMSUSD +50 2each). cabinets.

    • Parts
  • Logistics split: China-side items pre-ship to Albert, the ISV lead in Nairobi (AliExpress ->China Kenyato (Nairobi);Nairobi direct; small PCB parts hand-carriedcarried, byPSUs Glen,prebuilt whoon arrivessite). ~4BOM daystotal earlyabout USD 2,377 per batch (see the ISV Dev Kit BOM sheet).

    Venues: PAC2026 Nairobi (September) and prebuildsOSEAS Kigali, Rwanda (October, about EUR 50).

    NFE attendance (as of 2026-08-10): Dansturn and Dismas are going to Kenya (Nairobi). Aaron, now back in Uganda, could join them. Kigali remains a possibility. Glenn asked NFE to co-lead the 3-phasecabinet PSUsbuilds.

    on

    People site.and orgs

    Glenn Algie (10power.com / NESL / IEEE ISV, hardware + firmware; also WMAC.CLOUD New Zealand, REI Cameroon). Adam Sauer (ISV Tech Committee chair, meshems software + OpenAMI, runs isv.wiki). Aaron Tushabe, Hillary Arinda, Dansturn, Dismas (NFE). Albert places(ISV theNairobi orders.lead). Abiodun Okunola (ISV Africa regional lead). EnAccess Foundation, EPRI Open Source, NESL.

    Sources

    • Element room "Smart Village Energy Interest Group" (#smartvillage:matrix.nearlyfreeenergy.com), full history from 2026-04-24.
    • ISV Dev Kit BOM (Google Sheet 1AeAUrfL-Fu_j3xsBPjY555B0huxV0nnMtRjkDTFPjTE).
    • Line diagrams saved at NFE/smart village energy interest group/ (Rev B with legend, Rev C editable + PDF).
    • isv.wiki; github.com/energy-iot.

    Open questions / actions (from July 25 check-in)items

    • FinishConfirm the KenyanRev smart-meter provider investigation (pricing, product, contact) - build-vs-buy is still an open comparison against Glen's custom unit.
    • Review the one-line diagramC legend + component labels (clarify RCM vs RCB, feeder labels, meter-channel assignments); send consolidated questionsback to Aaron for the designer.
    • Nansana field issue: cable heating under inverter/EV load - schedule on-site tests, collect temperature dataGlenn (temperaturehe gun)asked).
    • Grant/partnerDecide work:and GreenVotermobilize /the RegenerateNFE Africaworkshop panels; Women-in-Business grantattendance (needsNairobi company-ownershipconfirmed legalfor change)Dansturn + Dismas; Aaron + Kigali possible).
    • PowerFill Africa 2026 workshop participation (sponsorship, travel, equipment shipping; possible Kigali follow-up).

    Gap

    Glen'sthe detailed design (the one-line diagram, channel map, firmware behaviour) is NOT yet written up here - theper-tenant "Behind the MeterMeter" Connection"companion pagepage.

    • is
empty. This overview should be confirmed with Glen and expanded into a real design page (schematic, channel assignments, firmware, OpenEMS integration).

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