Joint Scientific Statement
Question 1:
Definition: Natural gas is a flammable gas, consisting largely of methane and other hydrocarbons, occurring naturally underground and used as fuel.
Natural gas is a mixture. It contains mixtures of hydrogen and carbon. Natural gas can be used to create electricity, heat buildings and homes, cook food, dry clothes, and power manufacturing operations. Natural gas also contains methane, ethane, propane, pentanes, and butane
Chemical formulas
Methane- CH4 wt. %- 80-90
Ethane- C2H6 wt. %- 5-15
Propane- C3H8 wt. % < 5
Butane- C4H10 wt. % <5
Question 2:
CH4 + 2O2 -> CO2 + 2H2O+ 891 kJ (the combustion reaction)
That is, one molecule of methane combined with two oxygen molecules; react to form a carbon dioxide molecule two water molecules and 891 kilojoules of energy. Natural gas is the cleanest burning fossil fuel. Coal and oil, the other fossil fuels are more chemically complicated than natural gas and when combusted they release a variety of potentially harmful chemicals into the air. Burning methane releases only carbon dioxide and water. Since natural gas is mostly methane the combustion of natural gas releases fewer byproducts than other fossil fuels.
Question 3:
Natural gas processing consists of separating all of the various hydrocarbons and fluids from the pure natural gas to produce what is known as pipeline quality dry natural gas. Major transportation pipelines usually impose restrictions on the makeup of the natural gas that is allowed into the pipeline. That means that before the natural gas can be transported it must be purified. While the ethane, propane, butane, and pentanes must be removed from natural gas this does not mean that they are all waste products. In fact associated hydrocarbons known as natural gas liquids (NGLs) can be very valuable by-products of natural gas processing. NGLs include ethane, propane, butane, iso-butane, and natural gasoline. These NGLs are sold separately and have a variety of different uses; including enhancing oil recovery in oil wells, providing raw materials for oil refineries or petrochemical plants, and as sources of energy.
Question 4:
A natural gas power plant can either be classified as either a simple cycle, or combined cycle system. Both systems follow the same basic design. It begins with the combustion of the natural gas. The energy released will turn into the electricity used. The first way this energy is harnessed is through steam. There is water in pipes that run through the combustion chamber. The heat released converts this water into steam. This steam becomes pressurized and spins a steam turbine. The turbine powers a generator which then converts the energy to electricity which is sent out to the local community. The spent steam is sent to a condenser, there it is converted back to water so that it can continue on through the closed system. A cooling tower surrounds the condenser with cold water to cool it down. The other way the energy is harnessed is through the combustion of the gas. Air is brought in to the plant and then forced through a compressor. This compressed air is mixed with the natural gas and combusted. The pressure this combustion creates spins a gas turbine. The turbine is connected to a drive shaft to a generator, which converts the energy into electricity. If either of these systems are used on their own then they are considered single cycle systems. If both are used then they are considered a combined cycle. The combined cycle is about 50% more efficient.
Question 5:
Gas shales are generally fine grained, organic-rich, sedimentary rocks that contain natural gas. Gas shale rocks normally have small pores that contain natural gas but because the rock is so impermeable the gas cannot flow unless natural or artificial fracturing occurs creating channels in between the pores. Gas shale rocks are so impermeable that geologists have said it makes marble feel spongy.
Coal bed methane (CBM) is formed during organic decomposition. The CBM in reservoirs is stored in a very different way than conventional gas, it is attached to the surface in micropores as opposed to filling spaces in between grains of sand. CBM is not produced until large amounts of water are present.
Question 6:
The goal of fracking is: “Hydraulic fracturing, or fracking, wrenches open rock deep beneath the Earth's surface, freeing the natural gas that's trapped inside. Proponents argue that fracking-related gas recovery is a game changer, a bridge to the renewable energy landscape of the future. ” This is done using long pipes that are put into the ground and then fracking fluids are pushed down the pipes. The hole for the pipe is done using horizontal drilling, horizontal drilling is where workers dig very deep straight deep down and at a slight angle start to make a curve and turn. The drill does this with a series of many gears and motors. These fluids can be many things typically, fracturing fluid is 90% water and 9.5% sand with the chemical additives accounting to about 0.5%. The process of fracking is fairly simple. Water, sand, and chemicals are mixed at the surface and pumped at high pressures down the pipe or wellbore. The fracturing fluid flows through the cracked area of the wellbore and into the surrounding shale formations. Shale formations are the target formations when fracking, as is coal bed methane. Fracturing it while carrying the sand into the cracks to hold them open the chemicals do a number of things from keeping the pipe clean and also help get into the cracks. The pressure is constantly being monitored. This process is typically completed in multiple sections of the wellbore, often referred to as stages. Typically stages are isolated using a plug to allow pressure to be applied to a smaller portion of the formation to help maximize the fractures created in the target formation. The plugs are removed from the wellbore and the well’s pressure is reduced during the “flowback” process, leaving the sand in place to prop open the cracks and allow natural gas and/or oil to flow freely. Usually produced water, collected during the “flowback” process and throughout the life of the well, is properly disposed of or treated and reused in the next hydraulic fracturing operation. The final state of the land after fracking varies from case to case. The longer you frack a well the more chance there is of large water pockets underground forming. If fracking is done in a timely way and is monitored there is little damage to the land or drinking water.in rare cases the land can be over fracked and there can be slight shifting of the land. if the pipe is too close to ground water, meaning the people who installed the pipe did not dig deep enough. the chance of a leak in the pipe is near impossible with very strong steel and many layers of concrete are surrounding the drill and fluid it will not escape the pipe.
Question 7:
Potential hazards of horizontal drilling and hydraulic fracturing are the pollution of water supplies. Horizontal drilling is when the pipe bends to drill along a horizontal axis. The main concerns with the fracking is the possibility of polluting our water supply. One of the concerns is that when fracturing, you are exposing water supplies to the chemicals in fracking fluid. Fracking is the fracturing of shale formation by pressurizing the hydraulic fluid (which consists of mostly sand and water but a small percentage of chemicals) until it fractures. However, the fracking process has an incredibly low chance of actually affecting the drinkable water table because of the depth difference. The drinkable water table is found at around 100-500 feet while the fracking process takes place around 10,000 feet. The other concern is that fracturing will pollute drinkable water but the possibility of that actually happening is very minute. The possibility of it happening is minute because the geologic tables that can have an impact on humans and nature have several casings to ensure there is no fracture in the casing or the pipe in this area. What companies are trying to do is reuse the 15% of fracking fluid that they get back from the fracking process. The rest of the the fracking fluid stays in the rock formation but at a depth at which it will not affect drinkable water. It will not affect the drinkable water because the drinkable water is separated by an impermeable rock layer. But in some incidents the fracking fluid will affect drinkable water table by having a leak into the drinkable water table. According to the Department of Environmental Protection Well Record and Completion Report, fracking fluids consist of: hydrotreated light petroleum distillate, tributyl tetradecyl phosphonium chloride, ammonium chloride, guar gum, sodium persulfate, hemicellulase enzyme, hydrochloric acid, monoethanol amine borate, and ethylene glycol. Some of the substances are known to cause cancer. According to Fracking of America the long term effect of leaving fracking fluid in the ground is unknown.
- Personal interview with Steve Dobbs
Question 8:
The greenhouse effect is a process by which energy from the sun is trapped in earth’s atmosphere which raises the overall temperature of the earth. The energy from the sun enters our atmosphere as UV, visible, or near IR light. This energy is absorbed by the earth’s surface. It is then released as IR light. The gases in our atmosphere which are called greenhouse gases will absorb the Infrared light. When it is released again it will be released in all directions, so that some will be directed back to the earth. This energy will increase the temperature of the earth.
The greenhouse gases that cause the greenhouse effect are: H2O, CO2, and Methane. Ozone and CFCs are also greenhouse gases, but the three previously listed are much more prevalent. Greenhouse gases are extremely important for our survival, without them we would either be like Mars or Venus, and without life. However, currently there is worry over the increase of these trace gases. According to Scripps Institution of Oceanography, the current amount of CO2 in the atmosphere is at 398.44 ppm, compared to 280 ppm prior to the industrial revolution. As mentioned earlier, as light enters our atmosphere in the visible spectrum it may pass through the greenhouse gases. For a greenhouse gas to be effective its structure must allow for this movement of light. As the light is reradiated as infrared the greenhouse gases absorb it. To do this the structure of the molecules must be bound loose enough to allow the molecules to vibrate with the increase of energy. When the light is released, it is released in all directions. H2O, CO2, and Methane are all gases that are capable of performing this process. “Of equal or even greater importance than molecular structure to the effectiveness as a greenhouse gas are the abundance of the gas and the lifetime of the gas in the atmosphere.” Said David R. Cook, Meteorologist at the Argonne National Laboratory, “CO2 and methane have very long lifetimes, and so are also important.”
The combustion of fossil fuels is directly related to global climate change. All of the energy sources we burn contain carbon, so that when they combust a product will be CO2. As discussed earlier this gas will cause global warming to occur. As we burn more fossil fuels, we increase the amount of CO2 in the atmosphere. As mentioned above, CO2 is an effective greenhouse gas. Carbon dioxide is the greenhouse gas that is responsible for 63 percent of the warming attributable to all greenhouse gases, according to the National Oceanic and Atmospheric Administration’s Earth System Research Lab.
When natural gas is combusted, it releases 117,000 pounds of CO2 per billion btu of energy input, while oil and coal release 164,000 and 208,000 pounds of CO2 per billion btu of energy input respectively. Nuclear energy does not release greenhouse gases in its energy production process. However, the creation of the plants and the harvesting of the fuels do. These are called life-cycle emissions. The maximum life-cycle emission found for nuclear power was 59 grams of carbon dioxide-equivalent per kilowatt hour. The only other energy source lower than this was hydropower, according to a study by the International Energy Agency.
Question 9:
This website has a bunch of info and percentages about what the financial cost is for natural gas it in all the states per month. there are graphs on it to.
In 2008 the cost per kilowatt-hour was $0.10. The weighted average cost is $0.022.. The production cost of natural gas is $0.081. The cost for a natural gas power plant is $4.15 per KWH as of thursday April 11th, 2013. The levelized cost for natural gas in a conventional combined cycle is $66.1. The total cost for levelized energy of conventional combined cycle for natural gas is
A levelized cost is the net cost to install a renewable energy system divided by its expected lifetime energy output.
Question 10:
Natural gas is a fossil fuel that is formed when plants and animals are buried and exposed to extreme pressure and heat over thousands of years. Throughout the years these organisms have gotten buried deeper and deeper. The sun’s energy is stored in these plants and animals as carbon. Natural gas gets trapped in shale and coalbed methane when the animals and plants decompose completely leaving only the gases. Natural gas is a nonrenewable resource because it cannot be replenished on a human time frame.
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