Energy Efficiency in Power Sector Alok Mathur General Manager (ARP) BHEL New Delhi
3rd India –Japan Energy Forum 15-16 February 2010
Importance of Increasing Efficiency in Power Sector y y y y y
Less fuel burnt per unit Less CO2 and other pollutants per unit Conserves non‐renewable fuel Reduces cost of generation Reduces requirement of fresh capacity addition
Predominance of Coal • Coal is predominant source of energy for power generation – 40% in world – 70% in India • Coal likely to remain mainstay of India's electricity generation for next twenty five years • With explosive growth in energy demand, the consumption of coal is slated to increase many fold
Strategies to Improve Efficiency in Power Sector y Multi‐pronged strategy has to be adopted: y Improvements in existing technologies such as subcritical power plants and hydro power plants y R&M of aged power plants y Introduction of supercritical and ultra supercritical power plants y Introduction of advanced technologies such as Integrated Gasification Combined Cycle (IGCC) y Reduce losses in power transmission
Improvements in Steam Turbines • For every 1 kcal/ kWh reduction in TG cycle heat rate, coal consumption per year reduces by – 300 tonnes for 210 MW sets – 700 tonnes for 500 MW sets • Since 1977, heat rate of BHEL’s steam turbines has reduced – 210 MW by 5.4% – 500 MW by 3.1% • Efficiency of steam turbines is being improved by – More efficient aerodynamic blade profiles – Re‐designing inlet and outlet sections – Reduction of primary and secondary heat losses – Effective inter‐stage sealing – Using higher steam parameters especially reheat steam temperature
New 500 MW Steam Turbine • New variant of 500 MW steam turbine introduced by BHEL – Reheat steam temperature raised from 537°C to 565°C – Flow paths of HP, IP and LP turbines redesigned – Advanced class blade profiles • Reduction of heat rate by 10 kcal/kWhr • Thermal performance 0.6% better than conventional cycle • New cycle adopted for NTPC Dadri, Simhadri, Ennore, Aravali, etc.
New Rating of 600 MW • New unit rating of 600 MW developed – Uses existing HP and IP turbine modules of 500 MW – LP turbine changed from N30‐2 x 10.0 to N30‐4 x 6.3 (two LP turbines of 250 MW) • Two alternatives – 6‐heater cycle and 537 °C reheat temperature – 7‐heater cycle and 565 °C reheat temperature • Lower cost per MW • One percent improvement in heat rate over conventional 500 MW • Saving of 24,000 tonnes of coal per year • First 600 MW plant being installed at North Chennai, with a 7‐ heater cycle
Auxiliary Power Consumption • Aerofoil bladed PA fans, with inlet guide vane control in place of damper control, has helped reduce fan losses • Replacement of worm gear by planetary gear in pulverisers has improved energy efficiency. • Efficiency of boiler feed pumps being enhanced by one percent through thermo hydraulic re‐design • Use of variable speed drives with ID fans and BFPs can reduce energy losses at part loads • Use of efficient motors such as H‐compact can increase drive efficiency by 0.6%
Control & Instrumentation • Modern distributed control systems help to run all power plant equipment at close to their optimum operating points • PADO (Performance Analysis, Diagnosis and Optimisation) software provides online guidance to run the plant with minimum losses and downtime • Smart wall blowing system can optimise steam blowing cycle for soot blowers – Improving the heat absorption in boiler surfaces – Reducing the consumption of auxiliary steam
Supercritical Power Plants • Power plant cycle above critical pressure (221.2 bar) • Offers advantage of ‘burn less fuel for the same output’ and low emissions • Current steam parameters in India: 250 bar, 568 °C main steam and 593 °C hot reheat temperature • Steam parameters are expected to be raised further, in line with global trends • During the 12th Five Year Plan, over 50% of the capacity expansion will be through supercritical power plants
Ultra Supercritical Power Plants • Worldwide, Ultra Supercritical (USC) plants with steam parameters up to 280 bar and 620 OC have been set up • Development of USC plants with steam parameters of 300 bar and 700 OC is in progress • The first such plant is expected by 2015
USC Technology in India y India also plans to shift to USC steam parameters over the next few years y India also plans to develop USC technology with 300 bar and 700 OC y The key challenges y Development of suitable materials y Development of an optimum thermodynamic cycle y Development of major equipment such as steam generators, steam turbines and their auxiliaries
Integrated Gasification Combined Cycle (IGCC) y Important technology in the context of climate change y Emission of CO2 per MW less than for conventional plants y Potential efficiency (~45%) higher than that of sub‐critical (~37%) and super‐critical (~40%) y Capture of CO2 is easier in the case of IGCC y Low NOx and SOx emissions y Low water consumption y Fuel flexibility: coal as well as refinery residues y Syn Gas can be used for conversion to oil, chemicals, fertiliser and hydrogen
IGCC vs. Conventional Coal Plant Conventional Coal Plant
IGCC
Plant y y y y y y y
NOx 350 ppm SOx 600 ppm SPM 50 mg/Nm3 CO2 Emission High CO2 capture ready No Fuel consumption High less Water consumption High