What is Coal Bed Methane?

Coal Bed Methane is basically methane gas, which is exactly the same as natural gas. Most people have heard of CBM from mining accidents. Factually CBM is a byproduct liberated along with coal during its formation underground. Most gas in coal is stored in the internal surfaces of organic matter. Because of its large internal surface area, coal can store a much larger volume of CBM. It remains entrapped between various coal seams under pressure. Since CBM travels with ground water in coal seams, extraction of CBM involves pumping water from the seam in water to reduce the water pressure that holds gas in the seam. CBM is having very low solubility in water and so it is easily liberated sooner the water pressure is reduced. Thus extraction of CBM involves pumping out of enormous volume of water. Management of large volume of water is done in such a manner that the underground equilibrium is not disturbed. Most of the water pumped out is reintroduced into the coal seam aquifers. A portion of the water if not saline, can however, be utilized for irrigation purposes.

Utilisation of CBM

Methane concentration in CBM varies from 60 to 98% depending upon the quality of coal. Coal Bed Methane basically being methane (CH4), is an ideal fuel to generate electricity. It can be used as a fuel in small & big boilers, as an alternative motor fuel in the form of compressed natural gas (CNG), as a domestic fuel in the form of piped natural gas (PNG) and above all CBM can be used as the basic raw material for the production of value added products like methanol and Urea.

CBM – International Scenario

In the United States, CBM accounts for between 3 and 4 % of all gas production. Basically about 10 years back itself CBM production in USA was 1.25 trillion cubic feet (TCF) from its the then 10 production centers. Comparatively, in other countries, the progress in CBM exploration is negligible. Practically it was during the beginning of this century only; CBM has got the distinction of being considered as an alternative source of energy.

Peoples Republic of China being the world’s largest coal producer is also having a large potential of CBM. The estimated resource of CBM is 1000 to 2800 TCF, many times more than its conventional gas potential. China has produced 1.4 billion cubic meters (BCM) of gas during 2006 which was around 3% of the country’s over all gas production.

In Indonesia the gas potential is 453 TCF which is double the natural gas resource of the country.

India’s CBM resource potential has been estimated at 280 TCF, again far surpassing its conventional gas endowment.

The tempo of CBM exploration has increased significantly in Australia since the entry of major international CBM producers such as Amoco and Conoco. Governments of Philippines and Zimbabwe have constituted special cells for exploration of CBM. Bangladesh too has a large potential of CBM but there seems to be lukewarm response of the Government. The East European countries have reported to have met with mixed success in the exploration of CBM.

Why Coal Bed Methane ?

Now it is time for all coal rich nations to explore the possibility of utilising this alternate source of energy specially in view of drying up of the conventional natural gas resources. Depending upon the quality of coal methane percentage in CBM varies between 60 & 98%, where as in natural gas, methane percentage is around 92%. After combustion, CBM does not emit any polluting dust particles and carbon di-oxide emission is hardly 50% in comparison to coal. Hence, methane, be it sourced from natural gas or from CBM, has established itself as a much superior fuel.

Search for alternative energy sources is an everlasting exercise. Initially it was only forest wood and then gradually came coal, mineral oil and natural gas. Tapping of non-conventional energy through wind, wave, solar and hydel power continues. Then came the theory of bio-diesel and it became a craze especially in advanced countries to promote cultivation of corn, wheat and zetropha for production of bio-diesel exclusively. Now it is the time for CBM and underground coal gasification (UCG).

Advancement of CBM in India

Regrettably, due initiative from the government was not available initially. Potential of this alternate energy is yet to be fully estimated. Who knows where and in which coal area, how much quantity of CBM is entrapped. There are several deep abandoned mines with good quantity of untapped coal reserves as well. Technology for gasification of this abandoned coal for production of synthesis gas to be used as raw material for Methanol or Ammonia production is readily available. It is needless to say that government initiative in this direction is still on paper and a lot more is required to be done in this field.

Government thinking on this line was first initiated during 1995-96. It was during December 1999 a policy document “India Hydrocarbon Vision – 2025″ was framed and CBM, for the first time found its place at 5.1(c) of its objective part and it was written, attempt would be made “To tap unconventional sources of natural gas like coal bed methane, natural gas hydrates, underground coal gasification etc.” To fulfil this objective as a medium term policy, it was written at para 5.3 (viii) of the document that “operationalise the coal bed methane policy with a time bound programme” and finally keeping parity with the Government’s new economic and liberalization policies, it was noted at para 8.1, 8.2 and 8.3 of the document that industrial restructuring and disinvestment would be made to maintain long term profitability and strengthen competitive edge of the concerned companies to ensure that the consumers are benefited.

It was however much before the adoption of CBM policies; M/s Essar Oil was engaged for CBM exploration in Mehsina area of Gujarat’s Cambay Basin. Mineral Exploration Corporation Ltd., in its 1998-99 annual report confirmed a CBM reserve of 471 Billion Cubic Meter (BCM) in the 7 coal field areas of our country. Later M/s Reliance Gas Company, after geological analysis of various coal and lignite basins of the country, announced availability of 800 BCM of CBM. India Hydrocarbon Vision 2025 was possibly adopted based on these reports only. Latest reports confirm availability of 280 Trillion Cubic Feet equivalent to 8000 BCM of CBM.

Soon after the India Hydrocarbon Vision 2025 was announced, union government adopted the New Exploration Licensing Policy. Global tenders were invited for exploitation of oil, gas and CBM in various fields of the country. In case of CBM, by the year 2004 through NELP I, II & III; 26 coal blocks in West Bengal, Jharkhand, Madhya Pradesh, Maharastra, Chattisgarh, Rajasthan & Gujarat were awarded to various bidders like Great Eastern Energy Corporation (GEEC), M/s Essar Exploration & Production Ltd. (EEPL), M/s Reliance Industries and public sector ONGC. It was declared that the then natural gas production of 69 MMSCMD has to be enhanced to 120 MMSCMD through exploration of CBM. A few more coal blocks are likely to be awarded to stake holders through the next rounds of NELP ( Few blocks of CBM were awarded for exploration during recently held round of NELP).