Wednesday, August 5, 2015

Benchmarking Thermal Efficiency of Coal Based Plants in India with Mature Systems in Other Countries

Economic Times Editorial of 4 August 2015

For a Tech Boost to Energy Efficiency

Revving up efficiency in the energy economy cannot but focus on dirty but abundant, coal. The fuel conversion efficiency in state electricity board-owned plants is abysmally close to 30%. In contrast, in the mature power systems abroad, thermal efficiency levels approach 50%. It follows that by raising thermal efficiencies, we could generate up to two-thirds more power with the same amount of coal, reducing the carbon intensity of growth, besides pollution. This is achievable using existing technology. India needs to invest in coal gasification and integrated gasified coal combined cycle technologies, to utilise our natural endowment of coal while clamping down on green gas emissions.

Report of CSE's Study - Study of 47 Thermal plants

Old technologies, poor maintenance worsen performance

India’s landscape is dotted with many inefficient plants; its fleet is among the least efficient in the world. Improving efficiency is key to meet India’s energy needs, consume fewer resources and have the least impact on the environment.

A quarter of the total capacity under the study had exceeded operational life. Second, just 1 per cent of the power sector’s capacity in 2012 comprised supercritical (SC) or ultra supercritical (USC) plants, which operate with efficiency that is 3-7 percentage points higher than that of “subcritical” technology, the most commonly used. In comparison, 25 per cent of Chinese capacity was SC/USC. Around a third of plants under the study had efficiencies of less than 32 per cent. The worst performers typically have small capacity units, poor technology and are old..

Over half the plants in the study were found to be running inefficiently due to bad operation and maintenance practices. A particularly poor performer is MPPGCL, Birsinghpur, a 13-year-old plant, whose efficiency was 22 per cent below design. On the other hand, well-maintained plants like Reliance-Dahanu had a deviation of 3.8 per cent from design.

Only four plants in the study experienced less than 15 days of outages, which is considered a desirable level of availability. Poor maintenance, which results in increased outages, meant that average availability was low for the sample—11 plants experienced an average annual outage of more than 73 days during 2010-13. Even some new private plants such as Adani-Mundra and Maithon Power experienced outages as high as 95 days.

Auxiliary Power Consumption (APC), the power consumed by the plant’s own equipment, in most cases was almost 50 per cent higher than global best practices—APC of 12 of them was over 10 per cent. Higher APC means less power supplied to the grid.  Most plants in India do not monitor APC for individual equipment, which makes it impossible to identify areas of excess consumption.

The government launched the Perform, Achieve and Trade (PAT) programme to encourage efficiency improvement in eight industrial sectors, including thermal power generation.

GRP study exposed weaknesses in the PAT scheme. Of the 31 plants that were analysed, five achieved target efficiency in 2010-11 (even before the scheme started) while four more did so in 2011-12.

Shortcomings like these meant that plants like UPRVUNL, Obra, whose efficiency was 27 per cent during baseline period, achieved their PAT target after R&M—but its present efficiency at 31 per cent is still quite low.

Low efficiency is directly related to high CO2 emissions. The average emission rate of plants was 1.08 tonne CO2/MWh, which is seven per cent higher than the global average and 14 per cent higher than China’s. In 2012, coal-based power generation accounted for half of India’s total CO2 emissions from fuel combustions. During 2011-12, India’s total CO2 emissions grew by six per cent which was mostly on account of coal in energy production.

JSEB, Patratu, was again the worst performer with an unacceptably high emission of 1.80 tonne CO2/MWh (see ‘Specific CO2...’). There were just 13 plants in the study whose average emissions were lower than the global average. No plant conformed to the global best values. Even super critical plants in the study had emissions 35 per cent higher than the global best. It is estimated that a one percentage point improvement in efficiency can reduce CO2 emissions by 2-3 per cent. Apart from improving efficiency of existing plants, adopting state-of-the-art technologies can help achieve big cuts in emission rates.

See for more details and figures of efficiencies

21 February 2015
Efficiency of India's Power Plants way below global standards

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