Assessing the impacts of climate change on thermal power plants equipped with Environmental Control Technologies (ECTs): Challenges and adaptation measures

The water demands in thermal power plants are only going to increase due to Environmental Control Technologies (ECTs) such as Flue Gas Desulphurization (FGD) and Carbon Capture and Sequestration (CCS). These ECTs are necessary to adhere to the regional environmental regulations or to commit to the global climate pledges. This work focuses on thermal power generation in Rajasthan viz. arid and highly water-stressed region of India. The main objective of this work is to do a comprehensive assessment of water demands for ECT-equipped thermal power plants and their satiety in the face of climate change, intra-annually. Two climate change scenarios namely, SSP2-RCP 4.5 and SSP5-RCP 8.5 are considered. The Integrated Environmental Control Model (IECM v11.5) was used to quantify the monthly water withdrawals and the region's water availability was estimated using the extended Budyko framework. The results showed that after dry/ wet FGD addition, the plant operation water withdrawals rose by 200 to 400 l/MWh compared to the base plant. In the case of CCS implementations, the increments were found to be 2000-4000 l/MWh intra-annually with summer months being more water-intensive for both climate change scenarios. Further, the overall water availability decreased by 20% in the SSP2-RCP4.5 and 30% in the SSP5-RCP8.5 scenario, respectively. Consequently, November to June months were found to be water-deficient months for thermal power generation in both climate change scenarios.  These results entail careful planning of water management and corresponding adaptation measures. The upgradation of the boiler from sub-critical to supercritical and ultra-supercritical and the replacement of cooling technology from wet tower to hybrid or air-cooled condenser can lead to substantial water savings of 500 – 3000 l/MWh for the regional climatology. However, it comes with certain trade-offs such as an increase in CO₂ emissions and a reduction in efficiency. The levelized cost of electricity (LCOE) is also an important factor in the decision-making. While shifting to water-efficient adaptation measures there is only a marginal increase in the LCOE; the decision-making becomes more crucial when ECT additions are considered as they increase the LCOE considerably. Therefore, policy instruments like the government’s subsidy intervention can play a successful role in adopting such measures.