India is gradually replacing coal with renewable energy sources, aiming to reach 450 gigawatts of renewable capacity and net zero emissions by 2070. The transition involves increasing investments in solar, wind energy, and green hydrogen, while also addressing the challenges of land acquisition for solar parks. Despite the ongoing reliance on coal for power generation and steel production, advancements like underground coal gasification present potential economic and environmental benefits.

1. Coal Mining

2. Gradual replacement of coal with
Renewable energy
• Reduction of coal consumption is not a one-day
process and India has a long-term plan to gradually
replace coal with renewable energy
• A long-term plan where we will replace coal with
renewable energy slowly to achieve the goal
announced by the prime minister to reach 450
gigawatt
• We have already 80 gigawatts renewable energy
replace coal in last 5 years

3. India’s clean energy transition is rapidly underway,
benefiting the entire world
• India’s announcement that it aims to reach net zero
emissions by 2070 and to meet fifty percent of its electricity
requirements from renewable energy sources by 2030 is a
hugely significant moment for the global fight against climate
change.
• Renewable excluding hydroelectricity will contribute 5-6% in
India's energy by 2031-32 (Planning Commission).
• India aims to produce five million tonnes of green hydrogen
by 2030 which will produce 125 GW of renewable energy
capacity.
• 57 solar parks with an aggregate capacity of 39.28 GW have
been approved in India.
• Wind Energy has an off-shore target of 30 GW by 2030, with
potential sites identified.

4. Benefits of Renewable Energy Use
• Less global warming.
• Improved public health.
• Jobs and other economic benefits.
• Stable energy prices.
• Reliability.

6. Green Hydrogen
Emissions of CO2 from steel and iron industry
2Fe2O3 + 3C = Fe + 3CO2
Use of green hydrogen in place of carbon.
Fe2O3 + 3H2 = 2Fe + 3H2O
• Solar energy to electrolyse water that can generate
hydrogen at scale and replace carbon to a significant extent.
• carbon capture and sequestration

7. Solar Park

8. Solar Energy
• A strong network of storage battery is required to ensure full
utilisation of captured solar energy…costs need to come
down
• However, a related problem with solar energy is the large
land area required. Acquiring large area of land is a challenge
in India and will be more so in the next 10-20 years as the
population grows and urbanisation expands
• This can be mitigated to some extent if the efficiency of solar
panels improves from the current 19-21%.Upgradation and
expansion of grid capacity.

9. Solar Park
• The world's
largest 30,000
MW solar-wind
park is under
construction
at Khavda in
Kutch district,
which will be
completed in
December 2026.
90 thousand
crore to 1 lakh
crore rupees are
being invested.

10. • Coal still supplies just over a third of global
electricity generation even though it is the
most carbon-intensive fossil fuel.
• While coal is being gradually replaced in most
countries for power generation, it will
continue to play a crucial role in iron and
steel production until newer technologies are
available.

14. How do we get coal out of the
ground?
• Surface Mining:
– Typically occurs at depths above 180 ft.
– Most common for coal production
• Underground Mining
– Typically occurs at depths below 300 ft.
– Accounts for huge amount of world coal production as
coal deposition below far depth of surface is huge

20. Opencast Mining
• The technology is very advanced.
• Large Shovels, Bulldozers and bucket wheel excavators
are used .
• The top soil is first progressively removed and placed
on one side exposing the coal seams, which are then
progressively extracted .
• This involves the restoration of the land after
extraction of the coal.
• More than half of the coal in India is raised by open
cast mining .
• Productivity per man-shift in cast mining is more than
five times then that in underground mining .

41. Underground Mining
• Board and pillar are used specially in medium to
thick seams at relatively shallow depth. Tunnels
are driven by blasting along and across the
extension of the coal seam. Coal is moved
underground by conveyor belt and brought to
the surface by lift .
• Long wall, a method adaptable to most mining
condition but which is the sole technique for
mining at greater depth . The main machinery on
a long wall method consists of a cutter-loader,
conveyor belt and a set of powered supports .

42. Underground Mining

56. Where does the coal go after it leaves
the mine?
• The coal is shipped by train or barge to its
destination.
• The coal may be refined before shipping
– Washing with water or a chemical bath to remove some impurities
• When the coal arrives at the power plant, it is
pulverized into a heavy powder that is
suitable for burning.

60. But… Coal is DIRTY!!!!!!

61. There are several negative externalities attributed to the
combustion of coal, including:
- sulphur and acid rain,
- carbon Dioxide, and
- general destruction to the environment due to the actual
coal mining.
A 500 megawatt coal power plant will produce 10,000 tons of
Sulfur dioxide, 10,200 tons of nitrogen dioxide and 3.7 million
Tons of carbon dioxide per year.
OVERBURDEN
When mining, “overburden” is left over. Mining one ton of
coal leaves 25 tons of overburden. Pyrite is contained in
overburden; when pyrite is exposed to water and air, it forms
dangerous substances like sulfuric acid and iron hydroxide.
When this mixes with water, it forms acid lime drainage which
is highly destructive to the environment. So sad ☹.

63. This is a very clean method, as only gas is removed from the ground,
leaving all the overburden and ash underground.

64. • On 28 February 2022, the Central Bank of Russia was blocked
from accessing more than $400 billion in foreign-exchange
reserves held abroad and the EU imposed sanctions on
several Russian politicians.
• NATO Sent weapons to Ukraine, Russian cut off gas to six
countries and reduced supplies to six more.
• Russia supplied some 40% of Europe’s natural gas before the
war. That has dropped to around 15%.

65. Underground coal gasification
• Underground coal gasification (UCG) is an in-
situ gasification process, carried out in non-mined coal
seams using injection of oxidants and steam.
• The high pressure combustion is conducted below
1,200 feet at temperature of 700–900°C (1,290–
1,650 °F), but it may reach up to 1,500 °C (2,730 °F).
• The predominant product gases
are methane, hydrogen, carbon monoxide and carbon
dioxide.
• Ratios vary depending upon formation pressure,
depth of coal and oxidant balance.

66. • Gas output may be combusted for electricity production.
Alternatively, the gas output can be used to produce
synthetic natural gas, or hydrogen and carbon monoxide can
be used as a chemical feedstock for the production of fuels
(e.g. diesel), fertilizer, explosives and other products.

67. Advantages
• There are a number of significant economic benefits associated
with UCG that include:
• No need for the coal to be mined, No need for coal handling, No
need to transport the coal, No need to prepare the coal to be fed
into a reactor, No need for disposing of ash or slag
• Significantly lower capital cost for project development than that
of above ground plants
• There are also a number of environmental benefits with UCG:
• Minimal land use
• Significantly reduced use of groundwater or freshwater
Underground saline water is used
• No environmental impacts traditionally associated with coal
mining and handling
• Coal seams being gasified are below the fresh drinking water
supplies
• No landfill disposal required for ash or slag

69. Indian Scenario
• BHEL, GAIL, IOCL, and Neyveli Lignite
Corporation set up coal gasification units
• To produce methanol, ammonia, ammonium
nitrate, urea
• Fertiliser industry identified as major
consumer & proposed for ammonia and
ammonium nitrate
• Centre has targeted 100 MT of coal
gasification capacity by 2030

70. Problem 5
• Coal containing C 67.9% H 4.4% S 0.8% N 16%
O 7.9% Ash 4.5% and water 12.9% is burnt in
a furnace. The product of combustion dry gas
analyses CO2 14.5% O2 4.7% and N2 rest.
Calculate
• A) the theoretical volume of air used for the
complete combustion of 100kg of coal
• B) the percent excess air used

71. Solution 5
• Basis 100 kg of wood
• Oxygen balance C + O2 = CO2 -- I
• S + O2 = SO2 -- II
• H + 1/4 O2 =1/2 H2O -- III
• O2 required for carbon = 67.9x1/12 = 5.66 kgmolO2 required for, H2 = 4.4/2 X1/2=
1.1 kgmol
• O2 required for S = 0.8 X 1/32 = 0.025 kgmol, Total O2 required = 6.785 kgmol
• O2 present = 7.9/32 = 0.247
• O2 to be supplied= 6.785-0.247 = 6.538 kgmol
(a) Air to be supplied = 6.538x 100/21 = 31.13 kgmol= 31.13x 22.4 = 697.4 m3 at NTP
(b) Let y = mol of gas obtained
Carbon in flue = 0.145y = 5.66, y = 39.03 kgmol
N2 in flue gas = 100-(14.5+4.7)=80.8%
Amount of N2 = 39.03 X0.808 = 31.54Kgmol
N2 from air = Total N2-Fuel N2= 31.54-16/28= 30.97 Kgmol
Air supplied = 30.97x100/79 = 39.2 Kgmol
% Excess air = % Excess oxygen = O2 Supplied-O2 Required/O2 Required
= (39.2x0.21) -6.538/6.538 x100= 25.9