Solar carbon savings calculator
Every unit your panels generate is a unit the grid does not have to produce. Enter your system size or yearly generation to estimate the carbon dioxide you avoid each year and over 25 years, using the Central Electricity Authority’s published Indian grid emission factor.
How it works
- If you enter kW, yearly generation = kW × 126 units × 12 months.
- Units (kWh) ÷ 1,000 = MWh.
- CO₂ avoided per year = MWh × 0.710 tonnes CO₂ per MWh.
- 25-year total = yearly CO₂ avoided × 25.
Assumptions
- Grid emission factor: 0.710 tCO₂/MWh — weighted average including renewable energy, FY 2024-25, CEA CO₂ Baseline Database for the Indian Power Sector, Version 21.0 (November 2025). Source: https://cea.nic.in/cdm-co2-baseline-database/?lang=en
- Average generation of 126 units (kWh) per kW per month (1,512 units per kW per year).
- Emission factor and generation are held constant for 25 years. The grid is getting cleaner and panels degrade slowly, so the long-term figure is indicative.
- Indicative only; formal ESG or BRSR reporting should use metered generation and the CEA version your framework specifies.
Frequently asked questions
Which emission factor does this calculator use?
We use 0.710 tonnes of CO₂ per MWh (0.71 kg per unit), the weighted average emission factor of the Indian grid for FY 2024-25, including renewable energy. It comes from the Central Electricity Authority’s CO₂ Baseline Database for the Indian Power Sector, Version 21.0 (November 2025).
How is CO₂ avoided calculated?
Yearly generation in units (kWh) is divided by 1,000 to convert it to MWh, then multiplied by 0.710 tonnes of CO₂ per MWh. For a system entered in kW, yearly generation is estimated as kW × 126 units × 12 months. The 25-year figure simply multiplies the yearly result by 25.
Will the savings really stay the same for 25 years?
Probably not exactly. India’s grid is getting cleaner as more renewable power is added, which lowers the emissions each solar unit displaces, and panel output also declines slowly with age. Holding the factor and generation constant gives a simple, transparent estimate rather than a forecast of the future grid.
Can I use this number for ESG or BRSR reporting?
Use it only as an indicative estimate. Formal reporting should rely on metered generation data and the CEA factor version your framework or auditor specifies. For a commercial or industrial plant, use the generation recorded by the inverter or meter rather than the average yield assumed by this calculator.