Environmental Aspects of Thermal Power

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Environmental Aspects of Thermal Power

Coal is the only natural resource and fossil fuel available in abundance in India. Consequently, it is used widely as a thermal energy source and also as fuel for thermal power plants producing electricity. India has about 90,000 MW installed capacity for electricity generation, of which more than 70% is produced by coal-based thermal power plants. Hydro-electricity contributes about 25%, and the remaining is mostly from nuclear power plants (NPPs).

The problems associated with the use of coal are low calorific value and very high ash content. The ash content is as high as 55–60%, with an average value of about 35–40%. Further, most of the coal is located in the eastern parts of the country and requires transportation over long distances, mostly by trains, which run on diesel.

About 70% oil is imported and is a big drain on India’s hard currency. In the foreseeable future, there is no other option likely to be available, as the nuclear power programme envisages installing 20,000 MWe by the year 2020, when it will still be around 5% of the installed capacity. Hence, attempts are being made to reduce the adverse environmental and ecological impact of coal-fired power plants.

The installed electricity generating capacity has to increase very rapidly (at present around 8–10% per annum), as India has one of the lowest per capita electricity consumptions. Therefore the problems for the future are formidable from ecological, radio-ecological and pollution viewpoints. A similar situation exists in many developing countries of the region, including the People’s Republic of China, where coal is used extensively.

Hydroelectric Potential

2700 TWH Hydroelectric  Power is generated every year. Hydropower supplies at least 50% of electricity production in 66 countries and at least 90% in 24 countries. The hydropower potential of India is around 1,45,000 MW and at 60% load factor, it can meet the demand of around 85, 000 MW. Around 26% of Hydropower potential has been exploited in India.

The estimated economically exploitable hydro potential in India is assessed at 84,000 MW (@ 60% load factor) with a suggested installed capacity of 1,48,700 MW. About 26% of this has been exploited with the existing hydro power plants. The study is an effort to bring out vividly the past, present and future of hydro energy in India; some relevant aspects of the global situation are also discussed.

Relevant policies of the central government have been touched upon as required while discussing the bottlenecks encountered in accelerating hydropower sector development. India has the capacity to play a lead role in energy security if it were able to harness all the exploitable hydro energy in the region, including Himalayas in collaboration with its neighbouring countries.

With the completion a few world class hydro projects of challenging nature such as the Tehri Dam and power plants, Naptha Jhakri Hydro Project, etc. in recent decades, the engineering community in India is well-poised to focus on the development of hydro energy in challenging sites, mostly in the Himalayas, and accomplish the realization of the balance available energy potential that is sizeabl
Hydro Energy Sector in India: The Past, Present and Future Challenges (PDF Download Available). Available from: he first systematic and detailed study to assess the hydroelectric power potential of the country was undertaken during 1953-59 by the Government of India in the then Central Water & Power Commission (CW&PC). This was on the basis of the then prevailing technology, available topographical and hydrological data. The study carried out by CW&PC (Power Wing) placed the country’s power and annual energy potential, respectively as 42,100 MW at 60% load factor corresponding to annual energy generation of 221 billion units.

A total of 845 schemes were identified to yield 442 billion units of electricity. In addition, 56 sites were also identified in various regions of the country for the development of pumped storage schemes with an assessed aggregate installed capacity of about 94,000 MW.

Though the country ranks fifth in terms of available hydropower potential globally, much remains to be achieved despite their timely identification. This is a challenge while one takes pride in what could be achieved in a developing country with financial resource limitations soon after gaining its independence. Some 177 hydro power stations with a station capacity above 25 MW (having 617 generating units) provide a total installed capacity of about 38,748 MW that are operational; and, about 50 projects with an installed capacity of 15,065 MW are under execution as of December 2011. The latest assessment reveals the hydro share percentage to the grid in India as just 19%. The potential harnessed within India remains at about 15%, with yet another 7% in various stages of development. The balance potential of about 78% remains unharnessed due to many issues and barriers, with more and more new challenges creeping in before their development.

The estimated economically exploitable hydropower potential in India is about 84,000 MW at 60% load factor with a suggested installed capacity of 148,700 MW. The Indus, the Ganga and the Brahmaputra, basins together in the administrative boundary of India could contribute about 80% of the hydropower. The majority of India’s hydropower development potential lies in the key basins of Brahmaputra Basin (66 GW), Indus Basin (34 GW), Ganga Basin (21 GW), and the rivers of South India (24 GW). From a total hydropower potential of 149 GW, India can currently develop only 40 GW of the assessed potential.

Should the development of the regional resources that can be pooled together with cooperation from India’s neighbouring countries such as Bhutan and Nepal, the hydropower potential figures (149 GW) could increase further by over 50 GW; this can make South Asia’s energy position quite enviable. The share of hydro energy will then really boost the desired grid security of the entire region as a whole even under extreme variations in the load pattern in summer and winter.

Efforts by India in this direction under international cooperation mechanism can ensure the overall welfare of the region, which lags behind many others such as South East Asia. The hydropower sector in India today is considered to be at crossroads as the decline in its share is impacting the energy grid and its stability. The hydropower’s share was at a high of 40% in the 1970s and one wonders if the same could ever be reached again in the future. In hindsight, even in 2006, hydropower shared about 26% of the installed capacity of the then total energy generation that stood at 124 GW. The balance is tilting adversely with the passage of time. A mid-course correction in our energy policy for an enhanced focus on hydro energy option with all encouraging policies, as rapidly as possible, is a requisite now and this has to consider several new factors that surfaced after the announcement of liberal policies two decades earlier to bring in the private sector with some encomiums. What is crucial is that the energy segment too is given an impetus and hydropower potential unique to regional development obtains the requisite support, not only from the national budgets but also from international funding agencies.

 

Up gradation of hydro plants

The acute shortages in power supply in the country, both the energy and peaking, is a matter of grave concern, as economic development of the country crucially depends on availability of adequate and reliable power.

The broad strategy of the Government has been both supply side and demand side management to meet these shortages. On the supply side, however, the emphasis has primarily been on addition of generation capacity. However, one important area which could not receive desired attention was the upkeep of these plants. As a result, the efficiency of these plants gradually deteriorated and PLF’s plummeted to alarmingly low levels.

The Government did successfully implement the Renovation & Modernisation Programmes in the Seventh Plan period and spectacular results were obtained. But this thrust could notbe sustained primarily due to acute shortages of funds with our utilities. There is no gain saying the fact that Renovation &Modernisation (R&M) offers a much cheaper and quicker way to add capacity and, therefore, deserves the highest priority. While the greenfield projects would invariably involve long gestationperiods, R&M offers a quick remedy to the power shortages to a considerable extent.

With the announcement of the private power policy in October, 1991, private investment became possible in all areas of the power sector. It consequently opened up a new avenue of financing of R&M of power plants.

The policy envisages three practical and feasible alternative options, viz.

(i) Lease, rehabilitate, operate and transfers (LROT)

(ii) Sale of plants

(iii) Joint venture between SEB’s and private companies.

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