Solar EPC, Mini-Grid & Commercial C&I Clean Energy ERP: Engineering BoQ Design, Inverter/Smart-Meter IoT Telemetry, Power Purchase Agreement (PPA) kWh Billing, and Carbon Credit Auditing

Across East Africa, commercial factories, tea estates, shopping malls, hospitals, and off-grid communities are rapidly adopting Commercial & Industrial (C&I) Solar + Battery Energy Storage Systems (BESS) and EPRA-licensed rural mini-grids. Yet clean-energy developers struggle when engineering Bills of Quantities (BoQs) live in spreadsheets, serialized Tier-1 solar panels and hybrid inverters are tracked manually in warehouses, inverter telemetry lives in fragmented vendor clouds (Huawei, SMA, Victron, Sungrow, Deye), and monthly Power Purchase Agreement (PPA) or lease-to-own kWh billing is calculated by hand.

At devManue, we engineer end-to-end Solar EPC, C&I PPA & Mini-Grid ERP platforms that unify load-profile sizing, serialized PV/BESS warehouse dispatch, field installation commissioning, real-time MQTT/Modbus inverter and smart-meter telemetry, automated dual-tariff kWh invoicing with M-Pesa Daraja / KRA eTIMS integration, and auditable carbon-offset (tCO₂e) ledgers.

1. Bridging EPC Project Delivery and 15-Year PPA Asset Operations

• Serialized Tier-1 Panel, Inverter & Lithium BESS Warranty Traceability: Every solar module, string/hybrid inverter, and LiFePO4 battery rack is scanned by manufacturer serial number from container arrival at Mombasa through site installation—linking 10-to-25-year OEM warranty timelines directly to the client’s site digital twin.
• Automated C&I PPA Dual-Source Tariff Billing: Under a solar PPA or energy-lease model, the factory or mall pays per kilowatt-hour (kWh) of solar energy consumed on-site (often indexed at a 20%–35% discount to the prevailing utility grid tariff plus fuel/forex adjustments). Our ERP ingests 15-minute interval smart-meter registers to bill exact solar self-consumption vs. grid import.
• Prepaid PAYGO Mini-Grid Token & Tariff Tiering: For rural mini-grids, customers top up via M-Pesa STK Push or USSD, and the ERP instantly pushes STS prepaid tokens or remote relay commands to smart meters across lifeline, commercial, and anchor-load tariff bands.

2. C&I Solar PPA Billing, Performance Ratio (PR) & Carbon Offset Engine

Our clean-energy billing engine computes monthly PPA invoices from interval smart-meter telemetry, verifies contractual Performance Ratio (PR) guarantees against plane-of-array (POA) solar irradiance, and calculates verified grid-displacement carbon emissions saved:

from decimal import Decimal, ROUND_HALF_UP

class SolarPpaBillingAndCarbonEngine:
    """
    Computes C&I Solar PPA monthly kWh billing, contractual Performance Ratio
    (PR), and verified grid-displacement carbon credits (tCO2e).
    """
    @staticmethod
    def compute_monthly_ppa_statement(
        solar_generated_kwh: Decimal,
        exported_or_curtailed_kwh: Decimal,
        ppa_tariff_kes_per_kwh: Decimal,
        benchmark_grid_tariff_kes_per_kwh: Decimal,
        installed_dc_capacity_kwp: Decimal,
        poa_insolation_kwh_per_m2: Decimal,
        grid_emission_factor_tco2_per_mwh: Decimal = Decimal("0.42"),
    ) -> dict:
        billable_self_consumed_kwh = (solar_generated_kwh - exported_or_curtailed_kwh).quantize(
            Decimal("0.01"), rounding=ROUND_HALF_UP
        )
        ppa_invoice_net_kes = (billable_self_consumed_kwh * ppa_tariff_kes_per_kwh).quantize(
            Decimal("0.01"), rounding=ROUND_HALF_UP
        )
        client_grid_savings_kes = (
            billable_self_consumed_kwh * (benchmark_grid_tariff_kes_per_kwh - ppa_tariff_kes_per_kwh)
        ).quantize(Decimal("0.01"), rounding=ROUND_HALF_UP)
        theoretical_dc_yield_kwh = installed_dc_capacity_kwp * poa_insolation_kwh_per_m2
        performance_ratio_pct = (
            (solar_generated_kwh / theoretical_dc_yield_kwh) * Decimal("100")
            if theoretical_dc_yield_kwh > 0 else Decimal("0.00")
        ).quantize(Decimal("0.01"), rounding=ROUND_HALF_UP)
        co2_abated_tonnes = (
            (solar_generated_kwh / Decimal("1000")) * grid_emission_factor_tco2_per_mwh
        ).quantize(Decimal("0.001"), rounding=ROUND_HALF_UP)
        return {
            "billable_self_consumed_kwh": billable_self_consumed_kwh,
            "ppa_invoice_net_kes": ppa_invoice_net_kes,
            "client_monthly_savings_kes": client_grid_savings_kes,
            "plant_performance_ratio_pct": performance_ratio_pct,
            "verified_co2_abated_tonnes": co2_abated_tonnes,
        }

3. Proactive O&M Dispatch: Soiling Loss Detection & String Fault Alerts

When dust accumulation (soiling) or a tripped DC combiner string causes a plant’s Performance Ratio to dip below its pyranometer baseline for 48 consecutive hours, the ERP automatically dispatches a field O&M technician with mobile checklist photos and spare-part barcodes.