INGENIEUR
INGENIEUR
●●
Increased generation turndown capabilities when loads are low ( e . g . due to a spike in VRE generation );
●●
Faster generation start-ups with less damage to plant equipment when loads are high ( e . g . due to a decrease in VRE generation );
●●
Faster load changes to allow for flexible load-following due to the variable output of VRE ; and
●●
Reserve shutdown at minimal cost . Cold , and to a lesser extent warm , starts can significantly add to coal-fired generation costs , including variable O & M costs , when compared with consistent generation .
Coal-fired Power Generation
Coal-fired electricity generation will remain a substantial part of the Asia-Pacific region , as well as global , energy mix for decades to come . Coal remains the most abundant fossil fuel on earth , with proven global reserves of nearly one trillion metric tons . At current consumption rates , this would allow for another 150 years of generation . Reserves of coal are much greater than those of natural gas and oil in terms of energy content as well . Recoverable reserves of coal are present in over 75 countries and mining and combustion have remained relatively inexpensive , which has led to coal being an important component of the global energy mix for many decades .
As of 2012 , coal-fired generation accounted for approximately 55 % of electricity production in the Asia-Pacific region , up from 32 % in 1990 . More than 92 % of this electricity is generated using hard coal – bituminous , some anthracite and a small portion of coking coal . In absolute terms , coal-fired generation increased from 1,207 TWh in 1990 to 5,888 TWh in 2012 , a compound annual growth rate ( CAGR ) of 7.47 %. Over this period however , generation from VRE sources increased from 38 GWh of electricity production in 1990 to nearly 164,000 GWh ( 164 TWh ) in 2012 , a CAGR of 46.3 %. Total electricity production from all sources nearly tripled from 3,743 TWh in 1990 to 10,739 TWh in 2012 .
The majority of power plants using coal in the region use pulverised coal ( PC ) combustion technology , which encompasses subcritical , supercritical , USC and A-USC . A number of countries in the Asia-Pacific region , including China , India , Indonesia , Japan , Republic of Korea and Thailand , are using fluidised bed combustion ( FBC ) technology . Integrated gasification combined cycle ( IGCC ) technology can be found in select countries in the region including China , Japan and the Republic of Korea .
With respect to PC combustion technology , the main parameters to consider when profiling the global stock of CFPPs are size ( nameplate power generation capacity in MW ), age ( based on when the power plant was built ) and performance level ( combustion technology differentiated by temperature ). The typical maximum efficiency can vary significantly depending on site-specific factors such as weather conditions , extent of maintenance and type of operating regimes .
High-efficiency , low-emissions coal-fired Power Generation
Average global coal-fired plant efficiency rests at around 33 %, as of 2012 ( IEA , 2013b ). In order to increase these efficiencies , a transition towards more efficient HELE coal-fired generation should take place . HELE coal-fired generation includes supercritical , USC and A-USC PC technologies , typically in the range of up to 42 % for supercritical , 45 % for USC and up to 50 % for A-USC ( IEA , 2013b ). The aim of deploying HELE technologies is twofold : to increase conversion efficiencies and to reduce CO 2 emissions . Both supercritical and USC technologies are available now , with even higher efficiencies possible when A-USC becomes more readily available .
Poorer quality or low-grade coals ( such as lignite ) are candidates for more efficient generation , notably by employing pre-combustion drying . Global shares of supercritical and USC coal-fired generation rest at approximately 28 % as of 2012 . With coal-fired generation comprising 55 % of electricity production in the Asia-Pacific region as of 2012 , addressing more efficient coalfired generation is a necessity .
66 VOL 67 JULY-SEPTEMBER 2016