With reference to two non-conventional energy sources called ‘coalbed methane’ and ‘shale gas’, consider the following ‘statements: (1) Coalbed methane is the pure methane gas extracted from coal seams, while shale gas is a mixture of propane and butane only that can be extracted from fine-grained sedimentary rocks. (2) In India abundant coalbed methane sources exist, but so far no shale gas sources have been found. Which of the statements given above is/are correct?
Neither 1 nor 2
Understanding Coalbed Methane and Shale Gas
Let's break down the two statements given about coalbed methane (CBM) and shale gas, which are both important non-conventional sources of energy.
Analysis of Statement 1: Composition of Coalbed Methane and Shale Gas
Statement 1 says:
- Coalbed methane is the pure methane gas extracted from coal seams.
- Shale gas is a mixture of propane and butane only that can be extracted from fine-grained sedimentary rocks.
Let's look at each part:
- Coalbed Methane (CBM): This is indeed primarily methane ($\text{CH}_4$) gas that is adsorbed within coal seams during the process of coal formation. While it's mostly methane, it can contain minor amounts of other gases. The first part of the statement is largely accurate in saying it's pure methane gas extracted from coal seams, though 'pure' should be understood in the context of being predominantly methane.
- Shale Gas: This is natural gas found trapped within shale formations, which are fine-grained sedimentary rocks. However, shale gas is also predominantly methane ($\text{CH}_4$), similar to conventional natural gas and CBM. It can contain varying amounts of other hydrocarbons like ethane, propane, and butane, but it is not *only* a mixture of propane and butane. Methane is the main component.
Because shale gas is primarily methane and not just propane and butane, the second part of Statement 1 is incorrect. Therefore, Statement 1 as a whole is incorrect.
Analysis of Statement 2: Availability in India
Statement 2 says:
- In India abundant coalbed methane sources exist.
- But so far no shale gas sources have been found.
Let's examine the situation in India:
- Coalbed Methane in India: India has significant reserves of coal, and consequently, abundant potential resources of coalbed methane have been identified in various coalfields across the country, such as those in Jharkhand, West Bengal, Madhya Pradesh, Chhattisgarh, Andhra Pradesh, Rajasthan, and Maharashtra. Exploration and production activities for CBM are ongoing in India. So, the first part of Statement 2 is correct.
- Shale Gas in India: While India's shale gas potential is still being assessed and developed, potential shale gas reserves have been identified in several sedimentary basins. Notable basins with identified shale gas potential include Cambay (Gujarat), Krishna-Godavari (Andhra Pradesh), and Cauvery (Tamil Nadu). Exploration efforts by public and private sector companies have been undertaken. Thus, the statement that "so far no shale gas sources have been found" in India is incorrect.
Because shale gas sources have been identified in India (even if full potential is under assessment), the second part of Statement 2 is incorrect. Therefore, Statement 2 as a whole is incorrect.
Conclusion
Based on the analysis of both statements:
- Statement 1 is incorrect because shale gas is primarily methane, not just propane and butane.
- Statement 2 is incorrect because shale gas sources have been identified in India.
Since neither Statement 1 nor Statement 2 is correct, the correct option is 'Neither 1 nor 2'.
| Feature | Coalbed Methane (CBM) | Shale Gas |
|---|---|---|
| Source Rock | Coal seams | Shale (fine-grained sedimentary rock) |
| Primary Composition | Mainly Methane ($\text{CH}_4$) | Mainly Methane ($\text{CH}_4$) |
| Occurrence in India | Abundant resources identified, exploration/production ongoing | Potential resources identified, exploration ongoing in select basins |
Revision Table: Coalbed Methane and Shale Gas Key Points
| Concept | Description |
|---|---|
| Coalbed Methane (CBM) | Natural gas (primarily methane) trapped in coal seams. Extracted by dewatering coal seams. |
| Shale Gas | Natural gas (primarily methane) trapped within dense shale rock formations. Extraction often requires hydraulic fracturing. |
| India's CBM Status | Considerable identified resources in various coal basins. Production activity underway. |
| India's Shale Gas Status | Potential resources identified in major basins like Cambay, KG, Cauvery. Exploration and resource assessment are ongoing processes. |
Additional Information: Non-Conventional Energy Sources
Coalbed methane and shale gas are examples of unconventional gas resources, meaning they are trapped in formations that are not traditional porous reservoirs where conventional natural gas is found. Extracting these resources often requires different techniques compared to conventional gas fields.
- Unconventional sources like CBM and shale gas are becoming increasingly important for meeting energy demands globally, including in India.
- The extraction processes for these resources, particularly hydraulic fracturing for shale gas, have environmental considerations that are subject to ongoing research and debate.
- Exploring and developing these resources helps diversify a country's energy basket and can potentially reduce reliance on imports.
Important Questions from Sources of Energy
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1. Production of algae based biofuels is possible in seas only and not on continents.
2. Setting up and engineering the algae based biofuel production requires high level of expertise/technology until the construction is completed.
3. Economically viable production necessitates the setting up of large scale facilities which may raise ecological and social concerns.
Select the correct answer using the code given below:
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