Page 25 - Mines and Minerals Reporter eMagazine - Volume October 2021

TECHNOLOGY

CO2 avoidance costs at ultra-supercritical units with>40% ef- lations requirement retrofitting of existing plants with these
ficiency could be $30-40/t-CO2 (Hu and Zhai, 2017) which is controls by 2017, the deadline has now been extended to
economically competitive with provision of CCS incentives. 2022 with provision of a penalty.

An important consideration in the development of CCS is the Opportunities for coal sector
conceptualization of so-called clusters or hubs. These are ar-
eas with large number of large point sources in close proxim- diversification
ity with sinks of large potential. Our analysis for Indian point
sources indicates the presence of eight such clusters where While the major utilization of coal in India occurs in the pow-
mitigation of 800 Mt-CO2 could be possible (Garg et al, 2017). er sector, there is also an opportunity for diversification of
This existing analysis could be further evolved as and when ca- coal, primarily through gasification. Two routes of gasification
pacity estimates for sinks that have the potential to deliver in- are being considered: underground coal gasification (UCG) -
cremental hydrocarbon recovery are resolved. Our estimates where coal is gasified in-situ - and surface gasification – where
indicated that the average cost of mitigation would be ~$60/t- coal is gasified post-mining. Regardless of the where the reac-
CO2 but with provision of enhanced oil recovery or enhanced tor is located, coal gasification leads to formation of carbon
CBM (Figure 1), this could reduce below $45/t-CO2 if there is a monoxide and hydrogen. Due to the higher concentration of
sustained price support for such fuels. One of the prospective CO2 (40-60%), the energy penalty associated with CCS reduc-
clusters or hubs is near the Jharia coalfield where there is a es considerably. Moreover, there is a significant co-benefit in
concentration of infrastructure (power, steel, cement, fertil- terms of reduced air pollutants. The hydrogen produced from
coal gasification could provide for a blue hydrogen pathway
without import dependence.

UCG could provide an opportunity to utilize deep-seated coal
deposits that would otherwise be unrecoverable. Lignite re-
serves in Gujarat, Rajasthan and Tamil Nadu could be poten-
tially viable for UCG because of the high reactivity of these
deposits (Jain, 2017). UCG also offers
the advantage of negligible
fugitive methane emis-
sions. There have been
efforts for a pilot-scale
project at the Vastan
Mine with the joint
venture between
izers and petrochemicals). As discussed in section 3, there is ONGC and GIPCL.
a scope of large-scale CBM extraction along with CO2 injec- Due to multiple
tion in the latter stages of such projects. Figure 2 shows the reasons, this was
sub-clusters that could prospectively be conceptualized in this withdrawn in 2016
region that could deliver overall cost reduction of $10-20/t- after detailed site
CO2 to the baseline avoidance cost of CCS in India. characterization
studies were carried
There are significant technological constraints for CCS de- out. A site-selection
ployment in Indian power plants even with efficiency im- study has also been
provement. For instance, water limitations are anticipated to carried out by Tata
shutdown power capacity in the order of tens of gigawatts in Steel and Ergo Exergy
the United States (Liu et al, 2019). In India, there have been Inc at Jamadoba in the
observed cooling water shortages during summer months for Jharia coalfield. Their
existing power plants. Implementation of CCS could further pre-feasibility analysis
exacerbate this. Accordingly, technological development in showed availability of 400 Mt
India should focus on low-water consuming technologies. For of coal resources for in-situ gasifi-
instance, membrane-based capture could offer lower water cation (Blinderman, 2019). The Gov-
consumption as compared to the conventional amine-based ernment also has a substantial thrust
capture. CCS also requires installation of flue gas desulfuriza- on surface gasification, primarily to
tion (FGD) and selective catalysis reaction (SCR) equipment for power the ‘methanol economy’.
management of SO2 and NOx. While the environmental regu- There is a target to gasify 100 Mt

OCTOBER 2021 / MINES & MINERALS REPORTER 23