Solar size & savings calculator

Generation: 3.4–4 units per kWp per day in West Bengal and Bihar, 3.0–3.4 in Sikkim; south-facing, shadow-free, 90–100 sq ft per kWp on a flat roof. Factories and businesses in West Bengal and Bihar are sized to the units outside the 5–11 pm peak, which surplus solar cannot offset there. Savings: for factories, the demand charge for a contract demand typical of the bill stays on the bill, since solar does not reduce it, and each solar unit saves its energy charge and duty under the state’s current industrial tariff; for other connections each solar unit is valued at 90% of your average rate, because fixed charges stay on the bill. Savings in Bihar are a further 16% lower, where solar hours are billed at 80%, and are capped at what you consume. 0.71 kg CO₂ per grid unit. Indicative only — the survey replaces every number here.