The emission standards for thermal power plants in India are being enforced based on Environment (Protection) Act, 1986 of Government of India and it’s amendments from time to time.A summary of emission norms for coal and gas based thermal power plants is given below in Tables
Environmental standards for coal & gas based power plants | ||
Capacity | Pollutant | Emission limit |
Coal based thermal plants | ||
Below 210 MW | Particulate matter(PM) | 350 mg/Nm3 |
210 MW & above | 150 mg/Nm3 | |
500 MW & above | 50 mg/Nm3 | |
Gas based thermal plants | ||
400 MW & above | NOX(V/V at 15% excess oxygen) | 50 PPM for natural gas; 100 PPM for naphtha |
Below 400 MW & up to 100 MW | 75 PPM for natural gas; 100 PPM for naphtha | |
Below 100 MW | 100 PPM -naphtha/natural gas | |
The norm for 500 MW and above coal based power plant being practiced is 40 to 50 mg/Nm and space is provided in the plant layout for super thermal power stations for installation of flue gas desulphurisation (FGD) system. But FGD is not installed, as it is not required for low sulphur Indian coals while considering SO X emission from individual chimney
Stack height requirement for SO2 control | |
Power Generation Capacity | Stock Height (Metre) |
Less than 200/210 MWe | H = 14 (Q)0.3 where Q is emission rate of SO 2 in kg/hr, H = Stack height in meters |
| 200/210 MWe or less than 500 MWe | 200 |
| 500 MWe and above | 275 (+ Space provision for FGD systems in future) |
However the norms for SOx are even stricter for selection of sites for World Bank funded projects. For example, if SOx level is higher than 100 ? g/m 3, no project with further SOx emission can be set up; if SO X level is 100 ? g/m 3, it is called polluted area and maximum emission from a project should not exceed 100 t/day; and if SOx is less than 50 ? g/m 3, it is called unpolluted area, but the SOx emission from a project should not exceed 500 t/day. The stipulation for NOX emission is that its emission should not exceed 260 gram s of NOX per Giga Joule of heat input.
In view of the above, it may be seen that improved environment norms are linked to financing and are being enforced by international financial institutions and not by the policies/laws of land.
