Idea Bank — Request for Climate Startups
Rooftop Solar Aggregator
Aggregate rooftop solar installations into a financed, maintained portfolio — the Pakistan playbook for Bangladesh.
The ask
Build a rooftop solar aggregator that finances, installs, and operates solar panels on commercial and residential rooftops under a long-term lease or net-metering PPA — replicating Pakistan's 2022–24 rooftop surge in Bangladesh.
Why now
Pakistan installed an estimated 12–17 GW of rooftop solar in 2023–24 driven by currency devaluation, grid tariff spikes, and cheap Chinese panels — proving South Asian urban consumers will adopt solar rapidly when economics align. Bangladesh's BPDB grid tariff crossed ৳12/kWh for commercial users in 2024 after subsidy reform. Chinese panel prices have fallen below $0.10/W, making a financed rooftop system cash-flow-positive from month one for most commercial customers.
Why Bangladesh
Dhaka and Chittagong have millions of flat concrete rooftops sitting idle. Bangladesh's solar irradiance averages 4.5–5 kWh/m²/day — slightly better than Germany, where rooftop solar already accounts for 60 GW. Net metering regulations (BPDB Circular 2022) allow export to the grid, though approval is slow. The real short-term market is commercial off-takers (factories, cold chains, shopping centres) who need reliable daytime power and will sign 10-year PPAs.
As a business
Revenue is monthly PPA payments from building owners — typically ৳8–10/kWh against a ৳12–15 grid tariff, giving the building owner a guaranteed discount and the aggregator a spread. Capital is raised via green bonds or asset-backed facilities secured against the PPA revenue streams. The aggregator earns on installation margin (10–15% of system cost), O&M fees, and the wholesale-retail tariff spread over the PPA life.
Economics
Move the sliders to model your own rooftop solar aggregation business. Defaults are order-of-magnitude estimates — pressure-testing them is part of what a founder pitches us.
Model a rooftop solar aggregator
Does not break even within 5 years at these inputs — adjust the sliders. Hover or tap the chart for any month.
Illustrative model — defaults are order-of-magnitude estimates from public data, not a forecast. Pressure-test every number before you build.
What ZEPH would back
A founder with energy finance and project development experience who can close the first ten commercial PPAs before raising significant capital. We want the operator who treats the PPA contract as the product, not the solar panel — the hardware is a commodity. Co-investment with a green infrastructure fund is expected from Series A onward.
Impact
A 30 kW system on 80 commercial rooftops generates roughly 10 GWh/yr of solar electricity, displacing around 7,800 tCO₂e annually versus Bangladesh's grid emission factor of 0.78 kgCO₂e/kWh. At 300 sites (3.75x scale), annual avoided emissions reach ~29,000 tCO₂e and the project displaces an estimated $2.4 million in LNG imports per year. Each additional rooftop creates roughly 0.5 FTE in installation, O&M, and monitoring roles — keeping skilled solar jobs local.
Also being built elsewhere
Companies proving the model in other markets.
Asia's leading distributed C&I solar aggregator with 2.1 GWp across 350+ firms — the exact PPA aggregator model being proposed for Bangladesh.
Third-party owned rooftop solar under long-term PPAs for commercial and industrial customers; demonstrates scalable aggregator unit economics.
Pakistan's rooftop solar aggregator EPC/IPP; proof that the South Asian aggregator model works in a comparable regulatory environment.
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