by Harshavardhini Varagunan, Researcher - Environment and Climate Change
Use of land at the proposed site of a thermal power plant is a prime concern to communities living in the vicinity and the project proponent. Optimal use of land should be considered in order to ensure operation and maintenance flexibility. Hence, for efficient use of land and other resources (water, coal, and vegetation), proper and prior field and technical study should be done. Land required for a power plant depends on factors like:
- type of coal (indigenous or imported)
- location of the plant (pithead or coastal)
- coal storage capacity
- mode of coal receipt
- water storage capacity planned depending on the source of water and its availability
- type of condenser cooling system
- greenbelt required
- capacities of water and wastewater treatment plants
Land requirement for a thermal power plant is generally divided into inside plant land requirements and outside plant land requirements. The former includes main plant area (boiler, turbine generator and transformer yard), coal handling system, raw water reservoir, water system (water & wastewater treatment and water requirement for the cooling tower), switchyard, ash handling system, FGD system, roads, landscaping and green belt. Outside plant land requirements are ash pond, raw water pumping house including desilting plant, a corridor for ash slurry, and raw water pipelines and township.
Figure A Figure B
Figure A shows the land required for a 5 x 800 MW thermal power plant using indigenous coal and figure B shows the land required for a 5 x 800 MW thermal power plant using imported coal. In both the figures, the areas to the left of the red line represent the land required outside the plant and those on the right side represent the land required inside the plant.
In both the cases, inside the plant, the maximum land is required for the green belt cover, which can’t be reduced, given its environmental importance. Other land intensive operations are coal handling and water systems.
Outside the plant, the maximum land is occupied by the ash pond, a significant part in a power plant. This area can’t be compromised accounting for its environmental importance as it stores and dries the ash before disposing the ash or closing the pond instead of disposing of it with no treatment.
Land requirement for coal handling depends on the location of the plant, type of coal unloading, quality of coal, and storage requirement. Storage land required by pithead power plants is less compared to indigenous and imported coal-dependent power plants.
In water systems, land required for raw water reservoir depends on: a) specific water consumption, b) capacity of the plant, c) quantity of water to be stored, d) depth of the reservoir. Specific water consumption is the quantity of water consumed by the plant to produce 1 MWh power. As per MoEF&CC EIA notification 2015, 2.5 m3/MWh is the upper limit for water consumption, storage capacity in the water reservoir shall be for 10 days and the depth of the reservoir can be between 5 m to 12 m depending on the soil strata. In acutely space-constrained areas, the water storage can be part underground and part over the ground. In such cases, breaching issue should be addressed immediately.
Land requirement for switchyard can be reduced by adapting to new technologies, such as the Gas Insulated Switchgear Switchyard (GIS). GIS is a compact metal cased switchgear and the total space required for this is 10% lower than the conventional switchgear. Instead of abandoning areas allocated for pre-construction activities, they can be converted into green belt areas after the construction activities are completed.
Outside the plant, land required by township can be reduced by tailoring multi-storey type residential buildings.
These are the major areas where land is being acquired for a thermal power plant. Selection of a plant site not only has a significant impact on the design, construction and operation costs of the power plant but also influence the output of the project. As the increase in the amount of solid waste from power plants creates a serious environmental issue, optimally and safely using land resources, a power project can dexterously produce output.