Solar companies struggle with net‑metering & GST invoicing — automated, compliant billing

About 200,000 small solar installers, O&M providers and EPCs in India are currently burdened by manual net‑metering reconciliations, state-by-state GST invoicing rules, wheeling settlements and time-of-use tariff complexity, causing revenue leakage, delayed cash flows and audit risk. These operators typically lack affordable, sector‑specific billing systems and cannot absorb high ERP customization costs, so they default to error-prone spreadsheets or ad hoc tools. You could build a compliance‑first SaaS billing platform that automates net‑metering and wheeling reconciliations, generates GST‑compliant e‑invoices, ingests smart‑meter interval data, supports configurable tariff and credit rules by state, and exposes APIs for ERP/payments and O&M workflows. The market is attractive now because rapid rooftop solar growth, a large installed base of small vendors and the smart‑meter rollout make usage‑based and export billing both necessary and technically feasible; with an addressable base of ~200,000 customers at a realistic $3,000 annual contract value the immediate market size is roughly $600M. To stand out you should emphasize a state‑aware regulatory rule engine, prebuilt integrations with major meter vendors and utility portals, auditable reconciliation algorithms, and white‑label options coupled with SLA‑backed remittance workflows—differentiators that matter more to installers than basic invoicing. That said, execution risks are real: you will need continuous regulatory monitoring, deep integrations with fragmented utility systems, and a sales motion tailored to low‑capex customers, but the recurring revenue profile and medium competitive intensity make this a viable business if you can solve compliance and trust at scale.