As India gears towards introducing a National Mission on Clean Coal, the author in the following article discusses the current status and challenges associated with India's largest source of energy.
India seems to be in a bind as it develops a sustainability strategy: planners are faced with a tough choice of whether to go for clean coal, which costs more and needs to be imported from outside or focus more on harnessing domestic coal reserves and thus go for quantum rather than its quality. With a growing concern over energy security and sustainability, coupled with concerns about climate change and greenhouse gas emissions from coal combustion, the long term generation of coal-based thermal power by India will require the use of cleaner coal. On the other hand the energy starved country needs to meet the massive demand-supply gap, if it is to compete with its next door neighbour China in the run to be the next super-power.
The Situation on Ground
India is the 5th largest consumer of electricity in the world and accounts for roughly 4% of the global energy consumption. Though on one hand, the National Action Plan on Climate Change (NAPCC) has been aggressively promoting the usage of renewable energy sources, about 65% of the electricity consumed in India is still generated by thermal power plants with hydro-electric power coming a distant second at 21%. More than half of India’s commercial energy demand is met through its vast coal reserves of 285 billion tons out of which only 0.5 billion tons is mined per year. The debate that perennially plagues the domestic coal market is the choice between the abundance of coal reserves in the country versus the poor quality of coal that is quarried here. Indian coal is of poor quality and often contains 30-50% ash as compared to 10% in imported coal. The conundrum here is whether “More coal should take precedence over clean coal”, given the acute shortage of electricity in the country vis-a-vis the abundance of untapped coal reserve that the country has to offer.
The next decade or two would definitely see many developing countries around the world take advantage of coal’s low cost, its abundance and its proven technology for their energy needs. Yet at the same time, increasing fears over global warming and coal’s impact on the environment and human health have led to calls for coal to be replaced by cleaner energy sources. These factors considered together create an opportunity for clean coal technologies, which aim to reduce the harmful by-products of burning coal. The clean coal technologies’ market is likely to see a substantial increase in spending over the next decade as a number of national governments and private players seek to invest in this growing market.
Over time the calorific value and the ash content of thermal coal in India has deteriorated owing to depletion of better quality reserves and prevalence of rampant surface-mining activity. This poses significant challenges as transporting large amounts of ash-forming minerals wastes energy and creates shortages of rail cars and port facilities. The high ash content in Indian coal also creates problems for power stations, including erosion in parts and materials, difficulty in pulverization, poor emissivity and flame temperature, and excessive amounts of fly ash containing large amounts of unburned carbons.
On the other hand, using beneficiated coal leads to massive reductions in erosion rates and maintenance costs in power plants, increases thermal efficiencies and leads to reduction in CO2 emissions. Beneficiation of thermal coal is a relatively new development in India, as much of the new cleaning capacity was installed in response to regulations promulgated in 2001 by the Ministry of Environment and Forest (MoEF). These regulations mandate that raw coals be cleaned to less than 34% ash-content if transported more than 1,000 km or if burned in environmentally sensitive areas.
Addressing the Challenge
The threat that looms large over the future of Indian thermal power generation is to identify newer avenues of generating cleaner thermal energy without drawing flak from the MoEF. There are presently 2 solutions to the problem in hand:
1.Cleaning the poor quality coal to remove its impurities – Coal Beneficiation
2.Improving the efficiency levels of the generating plants – Integrated Gasification Combined Cycle
A cost-effective and significant step towards improving power plant efficiency and reducing the GHG emissions from the coal-fired power plants would be to increase the availability of clean beneficiated coals using appropriate beneficiation technologies. Coal beneficiation (or cleaning) is widely viewed as the lowest-cost option to address these goals as increasing the quality of coal is an essential step toward the deployment of the state-of-the-art Clean Coal Technologies (CCTs) in India. The general impacts and benefits of using beneficiated coal within a power generation process are (i) it produces higher quality coals that can be burned more cleanly and with greater efficiency, (ii) it reduces the amounts of emitted fly ash and associated hazardous air pollutants, (iii) it minimizes capital, operating and maintenance costs associated with coal fired power generation, (iv) it lowers costs and free up capacity on the overburdened saturated network of Indian railways; (v) it reduces the need to import higher-quality coals and (vi) it improves health and safety and mitigates environmental degradation
Integrated Gasification Combined Cycle (IGCC)
An alternative to achieving efficiency improvements in conventional pulverised coal-fired power stations is through the use of gasification technology. IGCC plants use a gasifier, where coal is combined with oxygen and steam to produce the syngas, which is mainly H2 and carbon monoxide. The gas is then cleaned to remove impurities, such as sulphur, and the syngas is used in a gas turbine to produce electricity. Waste heat from the gas turbine is recovered to create steam which drives a steam turbine, producing more electricity – hence a combined cycle system. IGCC efficiencies typically hover around the 40-50% mark.
The step forward
India has been keeping pace with changing times and has commenced work on the country’s first and biggest IGCC power plant that would come up at Vijayawada in Andhra Pradesh. The 182 MW, 2500 crore plant is a joint venture between Bharat Heavy Electricals Ltd (BHEL), Department of Science and AP Genco, a state-owned power generator in Andhra Pradesh.
National Thermal Power Corporation (NTPC) recently joined hands with BHEL to set up a 100 MW IGCC power plant at Dadri near Ghaziabad in Uttar Pradesh at an estimated cost of 600 crores.
The expansion of coal beneficiation capacity and use of IGCC in India, in order to achieve a significant potential benefit to energy security and environmental protection, is not fundamentally a technical problem. Policies need to be adopted that address the institutional barriers preventing widespread adoption of such technologies in India. Necessary changes will require the coordination of various ministries that influence the coal mining, preparation, transportation and use, including the ministries of coal, oil and gas, and power, and environment and forest. The context for this was rightly set by Dr. R R Sonde, EVP- Thermax Limited through his statement ‘We have to find the balance between new versus existing technology through frugal engineering’ during his speech at the Clean Coal India Conclave 2011.
The author, Sandeep Roy is an Associate at a sustainability consulting firm cKinetics.