Page 24 - Mines and Minerals Reporter eMagazine - Volume October 2021

TECHNOLOGY

iness level. Finally, as wells become mature and production fulfill the additionality criteria (Prusty et al, 2009). Kholod et
begins to decline, CBM sites may also be treated as sinks for al (2020) also indicate that emissions from abandoned mines
may be significant globally. However, no field-level data ex-
ists on quantification of such emissions or mitigation potential
from abandoned mines in India. It is recommended that fu-
ture work look at such areas.

Mitigating emissions
from the power sector

As discussed, coal combustion is the key contributor to In-
dia’s GHG emissions. There is a risk of stranding of existing
coal facilities due to their underutilization in the future due
to climate constraints. Malik et al (2020) project that strand-
ing of 133-237 GW capacity may occur post-2030 if ambitious
CO2 sequestration which could also increase the overall recov- climate policies are introduced. This risk may be somewhat al-
ery of methane. leviated by early policy strengthening. In fact, the government
is already taking steps to retire old and inefficient units. State-
While VCBM is critical in reduction of overall GHG emissions, ments from the power ministry indicate that several plants
it would not contribute to reductions in operational mines. have already been retired with the likelihood of retiring 29
As such, coal mine methane (CMM) recovery has been con- more plants and replacement with low-carbon infrastructure.
sidered as a technological mechanism for simultaneous uti- In 2020, India commissioned 2.0 GW of coal power. Taking
lization of coal and methane through premining drainage of into account 1.3 GW of retirements, India’s coal fleet grew by
methane. A demonstration CMM project was carried out with only 0.7 GW in 2020—the lowest since 2004 and much below
joint funding of the United Nations Development Program, China’s 38.4 GW new capacity additions in 2020. Coal power
the Global Environment Facility and the Ministry of Coal in commissioning in India fell steeply in 2016 and shows no signs
the Moonidih mine of the Jharia coalfield. While there is no of rebounding (Global Energy Monitor, 2021). The PLFs have
currently operational mine with active CMM recovery, there is also been running around 60% for several years, indicating a
high viability of CMM recovery in several existing mines in the gap in supply and demand. There have also been efforts at ef-
Damodar Valley coalfields (Table 2). Utilizing this mechanism ficiency enhancement for coal boilers. Since 2011, the Nation-
would not only lead to availability of gas and reduction in al Thermal Power Corporation (NTPC) has commissioned sev-
greenhouse gas emissions, it would also enhance mine safety eral units of supercritical boilers. In the last couple of years,
conditions. Thus, utilization of CMM could be considered in two units of 660 MW each have also been commissioned by
light of several sustainable development goals. NTPC at their Khargone station. This power plant has an esti-
mated efficiency in excess of 41% which is almost 10-percent-
age points higher than the average coal fleet in India. While
the efforts to reduce emissions through efficiency enhance-
ment, retirement of old units and reduction of transmission
and distribution losses could be tangible, compatibility with
the 2/1.5°C target would require near-certain deployment of
CO capture and storage (CCS). CCS involves capture of CO2
2
from large point sources, its transportation and injection into
deep geological formations. Because the concentration of
CO2 in the flue gas from a typical pulverized coal plant is only
12-14%, its separation to >90% purity involves large energy
penalty. The prior analyses (Singh et al, 2017) carried out on
existing facilities showed that this energy penalty could be
disproportionately high in Indian subcritical units (32-53% of
Recovery of ventilation air methane (VAM) may also be consid- the gross power generation). At such levels, CO2 capture could
ered in some mines. Previous analysis at the Moonidih mine be deemed infeasible at these units and the retrofitting pos-
indicated a reduction potential of 0.6 Mt-CO2e/year. It is also sibility with CO2 capture would be limited. However, due to
notable that CMM and VAM projects may be considered for the efficiency enhancement, there may be a significant scope
incentives under the Clean Development Mechanism as they for CCS deployment at the supercritical and ultra-supercritical

22 MINES & MINERALS REPORTER / OCTOBER 2021