Coalbed Methane
Commentaries
Commentaries Coalbed Methane: A New Source of Energy and Environmental Challenges Alvin L. Young Visiting Professor, Institute for Science and Public Policy, Sarkey Energy Center, The University of Oklahoma, Norman, Oklahoma, (current address – Cheyenne, Wyoming) USA (
[email protected]) DOI: http://dx.doi.org/10.1065/espr2005.11.002 Travel Notes – 23 August 2005: It is about 500 km north from Cheyenne, Wyoming, to the coalbed methane (CBM) wells near the city of Gillette, in Campbell County, in Northeast Wyoming. It has taken me about 7 hours to drive the large sports utility vehicle I have rented. I passed Wyoming's latest Wind Farm of 250 one-megawatt windmills as I left the Cheyenne area. Approximately 100 km north of Cheyenne, I passed the first methane-fired Power Plant, but did not see the first methane wells until I was about 350 km north of Cheyenne in the southern tip of the Powder River Basin. In the Basin there are now almost 32,000 CBM wells, and as you pass through the Basin, you can see the hundreds of access roads and the accompanying pipelines. The country is relatively flat, with few trees, and the land is sparsely covered with grasses and sagebrush. Most of the land belongs to the US Bureau of Land Management. I've only seen a few ranches, and very few sheep or cattle; however, I have seen hundreds of deer and antelope grazing on the prairie, and when I passed the National Grasslands, I saw a herd of about 2,000 buffalo. The only river I've crossed in the 500-km journey is the Platte River, mapped and named by Lewis and Clark in 1805. For the last 200 km before Gillette, the highway followed the railroad system. In a onehour time period, I counted 13 fully loaded coal trains, each 2 km long, and each heading in directions away from the 14 massive open pit coal mines in Campbell County. The mines and trains operate 24 hours a day, 7 days a week. These low-sulfur coal mines now provide almost 80% of the coal for the US. The entire Powder River Basin is underlined with coal beds, and hence, a major source of methane gas. I'll spend the next 3 days examining coalbed methane ponds, created by the CBM wells.
Introduction
During the past three years, I have had the opportunity to research some of the environmental impacts of a new source of energy for the United States. The new source of energy is coalbed methane (CBM). As noted in my Travel Notes for 23 August 2005 (above), the Powder River Basin is a vast region of high plains in Wyoming and Montana known for producing low-sulfur coal. The area is also becoming a primary source of CBM, America'a fastest growing resource for natural gas [1]. The exploration of this new resource is not without controversy. Like many developed and developing countries, the demands for new energy sources are outstripping their availability. In the August 2005 issue of National Geographic, Michael Parfit asked the question: Where will the world get its next energy fix? Parfit viewed the problem by stating: "Oil, no longer cheap, may soon decline. Instability where most oil is found, from the Persian Gulf to Nigeria to Venezuela, makes this lifeline fragile. Natural gas can be hard to transport and is prone to shortages. We won't run out of coal anytime soon, or the largely untapped deposits of tar sands and oil shale. But it's clear that the carbon dioxide spewed by coal and other fossil fuels is warming the planet." I don't know that I agree
318
Travel Notes – 24 September 2005: It is about 500 km southeast of Heidelberg, Germany, to Bad Ischl, Austria. Its taken me about 7 hours by train. I left Heidelberg at 11:14 on Die Bahn IC 2297 and arrived at Salzburg, Austria, at 16:03, and transferred to the train going to Bad Ischl. What a wonderful train system, no need for an automobile here. It has been an incredible view from the train. I've never seen such carefully tended and managed forests and agronomic fields as I have seen on this trip. The landscape of the countryside is manicured through generations of use. How different from my home state of Wyoming. Outside of Munich I saw two massive wind power generators, far larger than those in the wind farms of Wyoming. I counted 4 large coal-fired power plants, and (I believe) one nuclear power plant. All of the power plants were located within communities; there certainly doesn't seem to be a 'not in my backyard syndrome' here. When the train stopped in Munich, hundreds of young people got off the train to attend the Octoberfest. The Depot was packed with young people in 'traditional dress' coming or going from the festive activities. Obviously, these young people represent generations who have grown up with a transportation system (trains) that caters to rapid mobility for large numbers of people. No need of a sports utility vehicle here. The hundreds of tightly constructed houses and villages that I have seen along the way are connected by an elaborate and efficient railroad system. I don't know how we could build such a system in the Western United States; too few people and towns, and too far apart. Germany is approximately 357,000 km2 with a population of 84 million people, while the State of Wyoming is approximately 254,000 km2 with a population of 470,000 people. I have also noticed many large rivers and lakes along the train route. I can't imagine such a wonderful river system with so much water available for energy, industry, municipalities, recreation, and travel. I'll be in Austria for a few days before returning to the States via Frankfurt am Main.
with all the comments by Parfit, but what is clear is that the worldwide demand for energy will require that all potential sources of energy be explored and exploited. The day may come when all of our energy sources are renewable, but that day is far into the future. What is also obvious is that the sources of energy for one country may not be appropriate for another, whether for political, social, geographic, or economic reasons. As my Travel Notes for 24 September 2005 records, I cannot imagine that all of the energy sources and distribution systems essential for train systems in Europe would be practical in the Western United States, nor could I imagine the magnitude of the open pit mining in Wyoming being acceptable in today's Western Europe. There are many articles to be found in ESPR- Environmental Science and Pollution Research on the atmospheric impacts of anthropogenic sources. Some of these focus on the impacts of increased ozone [2,3] or greenhouse gases [4,5,6]. However, some of these sources are natural [7,8], or generated in unique circumstances, e.g., during military operations [9,10]. Many of the studies focus on urban or regional emission sources [11,12,13]. Many researchers now believe that an increase in greenhouse gas may change the heat budget of the atmosphere and lead to an increase in the average
ESPR – Environ Sci & Pollut Res 12 (6) 318 – 321 (2005) © 2005 ecomed publishers (Verlagsgruppe Hüthig Jehle Rehm GmbH), D-86899 Landsberg and Tokyo • Mumbai • Seoul • Melbourne • Paris
Commentaries surface temperature of the earth [6]. Carbon dioxide is considered to be the most important greenhouse gas, but other trace gases of anthropogenic origin such as methane (CH4) and nitrous oxide (N2O) also contribute to the 'global warming potential' [6]. Thus, it is appropriate that nations invest in new technologies and new sources of energy that will leave less of an environmental 'footprint' than coal or oil, and be more sustainable. Smith [14], however, has discussed the problems in defining 'sustainability', particularly as it applies to bringing modern energy services to the one-third of humanity whose development and survival requirements suffer from the lack of them. He argues that if all of the 2 billion people who lack modern energy services shifted to liquefied petroleum and natural gases for household fuels, it would add less than 2% to global greenhouse gas emissions from fossil fuels. He concludes that in terms of human health, a shift to these sources would actually result in a net reduction of human exposures to air pollution that would be substantially larger than today's total exposure from all fossil fuel emissions [14]. Thus, a case for coalbed methane development! The impact of the recent two hurricanes in the Southern United States has promoted the US Congress to re-examine the Nation's energy policy [15]. Oil production worldwide is estimated at 84 million barrels per day, of which the United States now uses 22 million. Much of the Nation's distribution, refining infrastructure, and production of gasoline is concentrated on the Gulf Coast. The hurricanes temporarily shut down nine Gulf refineries and halted most production of crude oil and natural gas in the region [15]. The new Energy Policy of the US addresses the need for further development of refining and distribution systems for oil and gas, but also stresses the importance of developing clean coal technology, and further development of energy from geothermal, wind, solar, biomass, hydropower, oil shale, uranium/nuclear, and tar sands [16]. Currently, 95% of total electricity generation in the US is from coal, nuclear energy, natural gas, and hydropower; oil and renewable energy contribute the remainder [16]. Coalbed natural gas from public lands has been identified as a major new source of energy for meeting increasing energy demands. 1
Coalbed Methane and How it is Obtained
Coalbed methane (CBM) is a naturally occurring gas bound by water pressure in underground coal seams. It is the same as natural gas. Water wells are drilled into the coal deposits. As the water is released through the well, water pressure is decreased, which releases the natural gas. The natural gas flows to the surface within the well bore where it is captured, minimally compressed, and piped to a larger compression station. The water is drawn from the coal seam through a water line and piped into newly constructed retaining ponds or reservoirs. The well bore is equipped with oxygen sensors that will shut the pipelines if any oxygen is detected. This prevents any underground spontaneous ignition of coal. Approximately 60% of the wells are drilled to a depth of less than 335 meters, with the remaining wells greater than that depth. Typically a new CBM well will discharge about 45 liters per minute of water. After about a year of production, the water discharge is reduced to about 30 liters per minute. The typical half-life of a CBM well is
ESPR – Environ Sci & Pollut Res 12 (6) 2005
Coalbed Methane 13 years. During that period a typical CBM well will produce 11.3 million cubic meters of methane gas [16,17]. Fig. 1 is a photograph of a typical new CBM well that has just been drilled. Note the required piping and pumping systems for both gas and water recovery. The wells do not emit any volatile organic compound to the atmosphere. The small compressor engines for recovering the methane are fueled by natural gas re-circulated from a larger compressor station. The red bin in the background contains all of the supporting materials required for construction and is required by regulations until all of the drilling and construction activities are completed and the site is cleaned up. Well covers or housings are placed over the unit to protect the pumps and compressors from the weather and livestock (Fig. 2). The well pumps for recovering the water are run by electricity. Frequently, companies will install solar panels to produce the electricity to run the water pumps. The companies that own the wells check each unit on a weekly basis. Fig. 3 is a photograph of a water recovery operation where the water is pumped into a tank for livestock use. Sometimes it is necessary to filter the water through crushed limestone to purify and clarify it (Fig. 4). The water is then drained into a retaining pond where it can be used for irrigation or to provide water for domestic livestock and wildlife (Fig. 5).
Fig. 1: A new CBM well with piping and pumps being installed in the Powder River Basin, Wyoming, USA, August 2005
Fig. 2: An operating CBM well with housing and fencing to protect pumps, pipes, and compressor from the weather and livestock, Powder River Basin, Wyoming, USA, August 2005
319
Coalbed Methane
Fig. 3: A CBM water recovery system where the water is being pumped directly into a tank for use by livestock. The overflow of the water is drained into the pond in the background, Powder River Basin, Wyoming, USA, August 2005
Commentaries resources associated with coal. While many areas of the US are experiencing declining natural gas reserves, the Rocky Mountain resources are largely untapped and the amount of newly discovered gas in the area is increasing on a daily basis. In the five-state region most of the coalbed methane wells are located on public lands managed by the US Department of Interior's Bureau of Land Management (BLM). The BLM currently controls and manages 106 million hectares of public land in the Western US. But more importantly, the BLM controls the subsurface mineral rights (including CBM) on more 280 million hectares of lands in the Western US [16]. This means that although CBM wells are frequently drilled on private land, the mineral rights to that gas most often belong to the Federal Government, and the companies must lease the mineral rights from the Federal government, while being required to pay the private landowner for access to develop the wells. This requires the companies to rent the land on which the wells, roads, and pipeline and electric power rights-ofways are constructed, and any compressor stations that may be built on that land. The states also get their share of income from the CBM wells by establishing a state tax on quantity of gas produced. When the wells are drilled on public lands managed by BLM, each CBM company must negotiate similar leasing and rental agreements with BLM. The Powder River Basin (Fig. 6), which is located in Northern Wyoming and Southeastern Montana, is known to hold at least half of the 1.5 trillion cubic meters of undiscovered natural gas resources [1]. Currently, there are more than 32,000 operating CBM wells in the Basin. The projection is that there will be more than 100,000 operating CBM wells in the near future [17]. In many areas of the basin, wells are
Fig. 4: A limestone filtering system for water from a CBM well, Powder River Basin, Wyoming, August 2005
Fig. 5: A large CBM reservoir created and maintained by the water from many CBM wells, Powder River Basin, Wyoming, USA, August 2005
2
The Current Locations in the US for Coalbed Methane Wells and Their Potential Production Capacity
Coalbed methane currently accounts for 10% of the total natural gas being produced in the United States. However, the Rocky Mountain States of New Mexico, Utah, Colorado, Wyoming, and Montana are estimated to hold more than 1.5 trillion cubic meters of undiscovered natural gas
320
Fig. 6: The Powder River Basin
ESPR – Environ Sci & Pollut Res 12 (6) 2005
Commentaries being placed and drilled on every 32-ha plots. It is anticipated that there will be more than 400,000 operating CBM wells in the five-state area by 2010. Although both state and Federal regulatory agencies have require that BLM and coalbed methane companies have approved Environmental Impact Statements (a process requiring public input), the development of such an enormous program nevertheless has many adverse environmental impacts [17]. 3
The Environmental Challenges Associated with Development of Coalbed Methane
The major environmental issues identified with the development of coalbed methane are: • The management of the co-produced water, • The significant soil disturbance from construction of wells, roads, and the associated pipeline and electric power rights-of-ways, and • The impact on wildlife. A primary concern with CBM development in the Powder River Basin is that coal seams serve as primary aquifers for agriculture and domestic uses [17]. Removal of CBM co-produced water has the potential to deplete landowner well water, and to contaminate long-establish farm ponds and lakes from the disposal of potentially saline-sodic-enriched waters. Total CBM water produced in the basin in 2006 is expected to peak at a volume that would cover 525 square kilometers to a depth of 1 meter [17]. The removal of this much water during the production of CBM wells may have a significant impact on current aquifers. Thus, the use and disposal of CBM waters is one of the primary environmental concerns of the public. Complex site-specific environmental factors such as topography, land use, soil types and quality, existing salinity levels, soil hydrologic characteristics, water quality, application rates, and vegetation types must be considered when evaluating the options for use and disposal of CBM waters [17]. The CBM waters that are discharged into unlined reservoirs or impoundments allow water to leach into the subsurface environment or percolate into the surrounding soil. This disposal method has been identified by BLM as the primary process for disposal in the Powder River Basin [17]. However, much of the current CBM waters in the Basin are being used for land applications on rangeland, for production agriculture, and for supporting increased herds of domestic livestock. The destruction of land surfaces is significant due to the construction of wells, roads, rights-of-ways for pipelines and power lines, and supporting compressor facilities for processing the methane for pipeline distribution [18]. In some locations where wells are densely placed on every 32-ha plots of land, approximately 25% of the land has been disturbed destroying vegetation and causing significant wind erosion. However, CBM companies are required to replant much of this land [17,18]. This disturbance has adverse effects on wildlife. One report noted that in the Powder River Basin, road building associated with drilling has fragmented winter habitat for some of the West's largest and longest-migrating herds of pronghorn antelope and mule deer, while reducing breeding and nesting areas for sage grouse and other valued bird (fowl) species [18]. My own research has focused on the coalbed methane ponds as breeding grounds
ESPR – Environ Sci & Pollut Res 12 (6) 2005
Coalbed Methane for Culex tarsalis, the species of mosquito that transmits West Nile virus. I am currently evaluating bio-based larvicides made from soybeans as a means of controlling infestations of mosquitoes in Powder River Basin CBM ponds. 4
The Future of Coalbed Methane as a New Energy Source
Although coalbed methane production is occurring primarily in the Western United States, the technology and experience being developed in this five-state region can readily be transferred to other nations. For example, China and Russia have significant coal reserves that undoubtedly can be tapped for coalbed methane. This new form of energy may give many nations the opportunity to develop a ready source of energy, albeit fossil fuel energy, while they invest in more sustainable and globally-friendly forms of energy. References [1]
[2]
[3] [4] [5] [6] [7]
[8]
[9] [10] [11] [12] [13]
[14] [15] [16] [17]
[18]
US Department of Energy (2002): DOE Study Raises Estimates of Coalbed Methane Potential in Powder River Basin. Online US Department of Energy Publications at web site: . For the above publication add: Katsambas A, Varotsos C, Veziryianni G, Antoniou C (1997): Surface Solar Ultraviolet Radiation: A Theoretical Approach of the SUVR Reaching the Ground in Athens, Greece. ESPR – Environ Sci & Pollut Res 4 (2) 69–73 Kondratyev KY, Varotsos C (2001): Global Tropospheric Ozone Dynamics. Part I: Tropospheric Ozone Precursors. ESPR – Environ Sci & Pollut Res 8 (1) 57–62 Lammel G, Grassl H (1995): Greenhouse Effect of NOX. ESPR – Environ Sci & Pollut Res 2 (1) 40–45 Veerkamp W, Wolff C (1996): Greenhouse Gas Induced Climate Change. ESPR – Environ Sci & Pollut Res 3 (2) 91–95 Hegerl GC, Cubasch U (1996): Greenhouse Gas Induced Climate Change. ESPR – Environ Sci & Pollut Res 3 (2) 99–102 Renner E, Munzenberg A (2003): Impact of Biogenic Terpene Emissions from Brassica nupus on Tropospheric Ozone over Saxony (Germany): Numerical Investigation. ESPR – Environ Sci & Pollut Res 10 (3) 147–153 Laturnus F, Fahimi I, Gryndler M, Hartmann A, Heal M, Matucha M, Schöler HF, Schroll R, Svensson T (2005): Natural Formation and Degradation of Chloroacetic Acid and Volatile Organochlorines in Forest Soil. Challenges to Understanding. ESPR – Environ Sci & Pollut Res 12 (4) 233–244 Unkasevic M, Vukmirovic Z, Tosic I, Lazic L (2003): Effects of Uncontolled Particulate Matter Release on Precipitation under Warfare Conditions. ESPR – Environ Sci & Pollut Res 10 (2) 89–97 Young AL (2003): Responding to the Environmental Impact of a New Gulf War. ESPR – Environ Sci & Pollut Res 10 (3) 141–142 Harnisch J, Hohne N (2002): Comparison of Emissions Estimates Derived from Atmospheric Measurements with National Estimates of HFCs, PFCs, and SF6. ESPR – Environ Sci & Pollut Res 9 (5) 315–320 Harnisch J, Jager D de, Gale J, Stobbe O (2002): Halogenated Compounds and Climate Change: Future Emission Levels and Reduction Costs. ESPR – Environ Sci & Pollut Res 9 (6) 369–374 Lopez-Mahia P, Muniategui-Lorenzo S, Lopez-Moure M, Pineiro-Iglesias M, Prada-Rodriguez D (2003): Determination of Aliphatic and Polycyclic Aromatic Hydrocarbons in Atmospheric Particulate Samples of A Coruna City (Spain). ESPR – Environ Sci & Pollut Res 10 (2) 98–102 Smith KR (2002): Editorial – In Praise of Petroleum? Science 298, 1847 Hess G (2005): Government and Policy: Katrina Renews Energy Debate. C & EN – Chemical and Engineering News, September 12, 2005, p 11 US Department of Interior (2004): Energy Facts: Onshore Federal Lands. Bureau of Land Management. Vance G, King L, Ganjegunte G (2004): Coalbed Methane Co-produced Water: Management Options. Reflection Magazine, College of Agriculture, The University of Wyoming, Laramie, WY 82071, USA, pp 31–34 Harden B (2005): Gas-Drilling Permits in Rockies Outstrip Ability to Tap Resources. The Washington Post, National News, Thursday, April 28, 2005, p A3
321
