HOW IS COAL BED METHANE USED?
CBM is widely used around the world to power the energy needs of homes and industry through conventional gas applications, as well as being an important fuel for power generation.
The majority of Botswana’s coal beds are not suitable for conventional mining, being located deep underground and in relatively thin seams. Only about 20% of Botswanas power is provided by a conventional coal fired power station. The remaining balance needs to be imported from South Africa and the Southern African Power Pool.
Methane trapped in the coal beds deep underground can relatively easily be brought to the surface by drilling wells and extracting the gas trapped within the coal seam. The gas which would otherwise be lost into the atmosphere if the coal is mined, is ideally suited for CBM-fired gas turbine plants.
The vast CBM reserves in Botswana would enable the country to meet her own power requirements, encourage investment into diversified industries and even export power back to the Southern African Power Pool.
A typical CBM Well-head
Natural gas powered vehicles
Greenhouse heating, flame weeding, crop drying, poultry rearing, waste incineration, distillation
Ceramics, metal processing, food processing, textiles, printing, chemical production, sanitary hot water, space heating
Fast food outlets, hotels, healthcare facilities, office canteens
Cooking, space heating, hot water, lighting, air-conditioning
Backup power generation, back up fuel to increase availability of renewable energy sources
Synthesis Gas (Coal/CBM)
Coal, together with CBM can be mined to produce synthesis gas (SYNGAS) which is the primary raw material for a number of industrial products including:
- Synthetic liquid fuels,
- Organic Chemicals,
- Ammonia and Fertiliser.
CBM can also be used in different forms for industrial applications. The most common forms that CBM can be found in are compressed natural gas, liquefied natural gas and dimethyl ether:
Compressed Natural Gas (CNG)
CNG can be used as a substitute for petrol, diesel and propane fuel. It is considered to be an environmentally clean alternative to petrol and diesel, and is much safer than other motor fuels in the event of a fuel spill.
In response to high fuel prices and environmental concerns, compressed natural gas is starting to be used in light-duty passenger vehicles and light duty trucks, medium-duty delivery trucks, urban transit and school buses. There are over 5 million Natural Gas Vehicles (NGV’s) worldwide with South America leading in terms of absolute numbers.
Liquefied Natural Gas (LNG)
LNG is natural gas in liquid form for ease of storage and safe transport. To convert the gas into a liquid it is compressed after removing certain impurities, and in some cases cooled (like when transporting it). Because of its density in liquid form LNG is much more cost-efficient to transport than gas transported via conventional pipelines.
Dimethyl Ether (DME)
DME is a clean and economic alternative fuel which is produced from natural gas, methanol or other sources. The properties of DME are similar to those of LPG and can be used for similar applications.
DME is most economical when produced at low cost in large quantities. As an energy source it is most significant when securing energy supply and for environmental conservation.