Coalbed Methane

Coalmine and coalbed methane are two excellent sources that can be utilized by Prometheus’ proprietary purification and liquefaction systems.

Methane is a naturally occurring gas that is adsorbed onto coal. There are two ways to extract the methane from the coal. Conventional drilling rigs can be used to drill into the coal bed and fracturing techniques allow the methane to escape. This is useful when the coal beds cannot be economically mined and are rendered stranded. The other extraction technique is more passive.

CoalMine Methane

Coalmine methane (“CMM”) is methane gas released from coal or surrounding rock strata during the process of coal mining. It is estimated that CMM vented to the atmosphere is responsible for approximately 10% of global methane emissions. In the US alone, coalmines produce more than 150 billion cubic feet (“bcf”) of methane each year. Of that amount, only 50 bcf of CMM is recovered and used as fuel while 100 bcf is emitted into the atmosphere. Due to its harmful effects as a potent greenhouse gas (approximately 21 times more potent than carbon dioxide on a 100 year basis) reduction of CMM emissions is a primary concern for the EPA. The EPA’s Coalbed Methane Outreach Program (“CMOP”) was implemented in 1994 to promote the capture of CMM for use in a variety of applications.

All coal mining, whether done underground or at the surface, releases methane. However, nearly 75% of CMM emissions in the US come from underground coalmines due to the geological characteristics associated with the coal formation (coalification) process. Deeper deposits tend to generate more methane and retain more of the gas for longer periods of time. These underground mines use mine ventilation systems for safety purposes. If a high concentration of methane (generally, 5-15%) is mixed with air, it becomes explosive. Subsequently, the dilution of methane through the use of ventilation fans that mix large volumes of air with extremely low concentrations of methane (0.3-2%) help to avoid potentially hazardous situations. These ventilation systems actually emit significant amounts of methane into the atmosphere in low concentrations.

The ventilation systems may also be supplemented by degasification systems (wells or boreholes) in particularly gassy mines. The degasification systems may be used in advance of or during mining activity or after mining has occurred. Degasification systems, also commonly referred to as drainage systems, employ vertical and horizontal wells to recover methane. In 2001, ten coalmines in the US collected 44 bcf of methane from degasification systems and sold 99% of the gas to pipelines. The wells typically drain gas containing 30% to 80% methane. Pre-mine boreholes drilled from the surface prior to mining or in coal seams that will never be mined contain more than 90% methane.

The emerging market for CMM presents opportunities for billions of dollars in profitable projects world-wide. With its innovative, distributed-scale purification and liquefaction technology, Prometheus Energy Company (“Prometheus”) is well-positioned to exploit the emerging CMM market. The majority of CMM currently being recovered is in the eastern US where the recovered gas is injected into natural gas pipelines. However, CMM can only be sold to natural gas pipelines if the mines are located in close proximity to existing pipeline infrastructure. The market for CMM is expanding quickly and as a result, projects are rapidly diversifying. The production of liquefied natural gas (“LNG”) from CMM is a viable option for remote mines with excess gas. LNG is a superior commodity due to its higher energy content, which makes it is easier to transport and store than natural gas. Prometheus can cost-effectively produce anywhere from 5,000 to 25,000 gallons per day of high-value LNG from a variety of underutilized or stranded CMM sites.

CoalBed Methane

There is a large domestic resource of methane that has taken the limelight since “energy security” has become a much more important domestic issue in the last three years. Prometheus Energy’s technology has the capability to convert the methane presently adsorbed on coal into high-value LNG at numerous sites.

U.S. Coalbed Methane Proven Reserves

Coal in its various forms is the most abundant carbon-based energy substance in the world. Major reserves exist in many countries and ~90 % of the world’s known reserves are in Canada, China, Russia, and the United States. Coal is a microporous solid containing carbon with large internal surface areas that adsorb compounds such as methane and carbon dioxide under sub-terrain pressures. Coalbed gas released from coal seams via drilled wells is a mixture primarily of methane, carbon dioxide, and nitrogen with minor concentrations of light hydrocarbons and oxygen. The gas is generally saturated with water and may contain a variety of other trace components. In naturally occurring reserves of coalbed gas, the composition varies depending upon the particular field. These huge quantities of methane captured in coal are a valuable energy source if they can be economically recovered via environmentally compatible means. Both methane and carbon dioxide are greenhouse gases that are associated with recovery and processing of coalbed gas. The handling of underground water, which saturates many coal beds, is an additional important environmental concern.

Coalbed methane proven reserves are considered in the US Energy Information Agency’s natural gas resource estimates. Known reserves are steadily increasing as better estimation technique evolve and the accumulated proven reserves of 15,708 bcf (billion cubic feet) of coalbed methane shows an increase of 19 % from 1999 levels with an estimated 13,229 bcf of accessible reserves. Coalbed methane accounts for ~9 % of all estimated dry natural gas reserve.

State-by-state production of coalbed methane estimates show that opportunities in the western US states of Wyoming, Texas, New Mexico and Colorado have increased drastically in 2000 as compared to 1989. This is a result of nurturing of the concept of coalbed gas reserves as unconventional sources of natural gas supply by the Gas Research Institute. Their forward-thinking research programs were implemented in terms of exploration and identification of new gaseous sources of energy to meet the nations growing energy needs.

The success of coalbed methane reserve identification and utilization programs in the Western US, not only as a pristine alternative fuel for residential and commercial sectors but also as a major source of pipeline and utility electric energy production, can be readily translated to similar programs in the Eastern US and abroad as a viable source of clean alternative fuel energy supply for both central and distributed energy projects.