This paper was written as part of the 2011 Alaska Oceans Sciences Bowl high school competition. The conclusions in this report are solely those of the student authors.
Potential Effects of the All Alaska Pipeline on the Ecosystem of Prince William Sound
Team Copper River Reds
An all Alaska gas pipeline has been in the works for over 20 years. In this paper we try to analyze whether this project should be taken on by our state. We cover some of the possible impacts the construction of the pipeline will have on the marine environment of Prince William Sound and suggestions possible concerns and solutions to these concerns. Such projects can be controversial but we hope this short paper may cause dialogue about the possible direction our state should take in deciding our long-term commitment to such a plan.
Anthropomorphic Effects on an Ecosystem—The All Alaska Pipeline
A. The Pipeline
The All Alaska Pipeline proposition was proposed under the Alaska Gas line Inducement Act (AGIA), which was passed in 2007. It is primarily held under the control of the Alaska Gasline Port Authority (AGPA), which was established in 1999 and is one of 140 of such organizations existing in the U.S. The proposed pipeline is 806 miles in length and will transport Alaska Natural Gas (ANS) from the wellhead at Prudhoe Bay, AK to its termination point at Valdez. Also, a spur line leading off of Glennallen will extend to Anchorage. Its planned diameter will range from 44 to 48 inches. The pipeline's design has been fully planned and costs have been estimated; the total cost predicted for the project is $23.650 billion.
The natural gas drilled at Prudhoe Bay will be refined or separated into gas and oil through a process involving the repetitive cooling of it. Next, any water and condensates will be extracted to decrease the likelihood of the formation of gas hydrates in the stream. Large particles will also be removed in a process known as scrubbing. Carbon dioxide, dihydrogen sulfide, mercury and other contaminants will also be filtered out the solution. The method used to extract the corrosive compound H2S is known as sweetening. The gas will then be cooled to 26 degrees Fahrenheit and compressed through the pipeline at an exceptionally high pressure of about 2220 psi.
At Valdez, a liquefaction plant will be constructed for the purpose of removing certain hydrocarbons from the gas, or fractionating it into Liquefied Natural Gas (LNG). The plant will load a series of tankers, each with a holding capacity of 147,000 to 177,000 cubic meters, for export to Asian countries such as China and Japan and other parts of the United States. Several MOL (Mitsui O.S.K. Lines) companies that have agreed to support the Port Authority's cause will assume responsibility of this action. The Port Authority's objective through this project is to promote "maximum distribution of natural gas" across Alaska to its residents and natural gas industries in the state, and other parts of the world; to provide for cheaper gas by pipeline, to create jobs throughout the building of the pipeline, and to provide as much economic benefit as possible.
The construction of the pipeline will be economically important to southcentral Alaska, whose gas economy is in recession and continuing in a steady decline. It has already caused several companies associated with natural gas to go out of business. The supplication of cheap, abundant gas to this area may help avoid unintended harm to the environment that may arise if an environmentally friendly option is not found. A real fear may be that if the pipeline isn't constructed, natural gas in southcentral Alaska could be substituted with a dirtier, more polluting, and less efficient source of fuel or energy. However, other clean and environmentally safe forms of energy exist, such as wind and solar power and diligence should be taken to determine if such options may not better suit the southcentral region. Electrical power is mandatory for industry and consumers alike and is consumed in Alaska in great amounts. To satisfy this demand Alaska may have to use all the alternatives that are available and the natural gas that will be transported through the All Alaska Gas pipeline may be one such alternative.
B. The Sound
An ecosystem is a group of species interacting with each other and with the environment where they reside, involving the interaction between biotic (living) and abiotic (nonliving) elements in the ecosystem. Examples of abiotic elements are: nutrients, heat, sunlight, water, rocks, minerals, and dissolved salts and gases. Biotic elements are all the organic matter in the environment, including the living organisms. All of these elements are impacted in some way by natural and manmade phenomena. These include climate, wind patterns, and changing nutrient levels, pollution, harvesting of wildlife, and tourism. All of these interact and result in a healthy vibrant system, a decrepit contaminated system, or one that is somewhere in between. As stewards of our environment we must make sure that we provide for a clean, safe and viable ecosystem. This suggests that we must consider all factors including biotic, abiotic, and anthropomorphic factors when interacting with the environment. With this in mind we should insure that the activities undertaken by residents take into account all the possible outcomes that may result.
Prince William Sound, or "the Sound" as locals call it, is a semi-enclosed bay in the Gulf of Alaska created by uplift of the surrounding mountains—the Chugach Range—and its extensions on the Kenai Peninsula. It is accessed by a major shipping channel through the shallow Hinchinbrook Entrance. The Port of Valdez is at the north end of the Sound, accessed through a shallow, narrow channel (the Valdez Arm). The Sound has many spectacular natural formations along its 2,700 mile long coast line, among which are: forested islands, off shore islets, sea stacks, fjiords, valleys, expanding glaciers, temperate rainforest, and coastal wetland. Perhaps the most prominent feature is the Chugach Mountains which includes six of the highest mountain peaks in the world, with nine peaks over 16,000 feet.
Lying in a transition zone between temperate and subarctic biomes, Prince William Sound is influenced by many ecological and geological happenings. Among these natural fluctuations are glaciation caused by valley and continental glaciers, erosion, changing ocean currents, and plate movement to name just a few. All of these forces work together to affect habitat diversity and quality, and ecosystem sustainability.
The sound is an amazing place for many varying species. Among such species are: 300 species of fish, 220 species of birds, 30 species of terrestrial mammals, approximately 12 species of marine mammals, two amphibious species, and many marine invertebrates. Some of the endangered species include: 130 resident orcas, humpback, fin, sei and minke whales, stellar sea lions, harbor seals, and sea otters. Two hundred thousand resident seabirds spend the summer season in the Sound, using its resources to fuel themselves for their journey south for the winter. The Sound also makes an important wintering area for many various ducks numbering 80,000 or more.
Anthropogenic activities have been a major concern for threatened, endangered, and specially-managed species. U.S. Fish and Wildlife Service (USFWS) lists 12 threatened or endangered species in Alaska. Of these, one is a plant and 11 are vertebrates. Seven marine animals and four bird species make up the 11 vertebrates. USFWS listed no fish species as endangered as of late. Among the most threatened species are the humpback whale (Megaptera novaeagliae), fin whale (Balaenoptera physalus), Steller sea lion (Eumetopias jabatus), and northern sea otter. These species have been reduced in several areas of the Gulf of Alaska. In response to such concerns we as stewards must insure that any new proposed pipeline should have negligible effects upon the sound and its inhabitants.
C. The Potential Problems
In this section, we will address two general problems that could arise as a consequence of the construction of the pipeline and potentially harm the marine environment. The first subtopic will state the accidents that could occur associated with the potential of explosions of the LNG plant and spills associated with the LNG tankers. The second portion will explain how noise generated by the tankers may disrupt the underwater communication of marine species.
The composition LNG after its dehydration, fractionation, and liquefaction, will be primarily methane. At its liquid state, the gas will be devoid of odor and will possess an inability to explode. Natural gas tends to explode only in its gaseous form when exposed to air at 5-15% concentration, since exposure to certain amounts of oxygen is required for it to combust. These conditions are likely to be attained if the vaporized gas is located in a congested or confined area. Accidents involving LNG include the disaster in Cleveland, Ohio on 1944, when an LNG tank with little amounts of nickel in its steel composition ruptured and spilled gas into a sewer, resulting in a catastrophic explosion when the gas evaporated, killing 128 people.
Besides accidents caused by leaks or ruptures, another area of concern is the general operation of the LNG plant. A plant in Maryland was destroyed in 1979 due to the accidental release and ignition of gas vapors. In 2004, the Sonatrach LNG plant in Skikda, Algeria was severely damaged when the ethane and propane stored in the plant exploded due to the malfunction of its boiler system, killing 27. These occurrences indicate that there is a potential that the LNG plant in Valdez will explode if it isn't safely managed or kept under control. Any plan that is proposed must address these vital issues to ecosystem and public safety.
Only nine LNG spills have occurred during the past 45 years, which indicates that these spills are significantly less frequent than that of oil tankers. Of the very few LNG tanker spills that have occurred, only minor consequences have resulted. Since the area surrounding the tanker is unconfined, no explosions have arisen from the gas dispersed in these incidents. Studies on the spilling and dispersion of LNG have indicated that, if existing in an unenclosed area, the gas will form a low level cloud generally with a height of 12 meters and variable spreading distance. The extreme rarity of LNG spills is partly due to the considerable design tactics of the tankers intended to reduce the possibility of such accidents; for instance, LNG tankers are constructed of double hulls for maximum exterior protection and the tanks containing the gas, which is kept at the equivalent of atmospheric pressure, are specially constructed to hold LNG.
Interference with Mammal Migration
While an increase in tanker traffic will have several consequences there are two potential problems that may have the most negative impact on the Sound. These include: the production of damaging and or high frequency sounds that affect the migration routes of marine mammals and alteration or interference to migration routes.
The noise levels in the sound will certainly rise as tanker traffic increases, but the degree or impact of it needs to be researched. Studies on TAPS determined that the places in the sound most frequently visited by tankers, cruise ships, fishing boats, recreational boats, and ferries have been drastically affected by the increase of noise pollution. The masking of significant sounds at moderate to low frequencies includes and results in social communications, echolocation, and hunting of prey. The most likely to be affected are fish and mysticete whales, which hear and communicate at frequencies overlapping the greatest energy from ship noise. It takes an average of 22 hours and 20 minutes for a tanker to complete its visit at the Port of Valdez. This includes berthing, loading crude oil, and deberthing. Noise from these ships could multiply if the gas line is built. The noise from ships is likely to be greatest in the central basin of the Sound.
In this portion we will take the problems previously addressed and propose solutions to them and determine how they can or should be mitigated.
Construction-Pipeline and Refining Plant
As historical evidence has revealed, plants containing natural gas are prone to the possibility of explosion. For natural gas to combust, it only requires exposure to air at a certain concentration in a congested area. If the gas is accidentally released, a severe disaster could occur depending on the conditions. To help prevent the LNG plant in Valdez from exploding, several precautions must be taken, and an emergency plan must be established. In the case of an explosion, the location of the plant will certainly determine the extent of the damage to objects outside of the perimeter. If the plant is built near the forest, there is a potential that a forest fire would be ignited if it explodes, therefore devastating the environment. If is it constructed over water, the effects of any explosions would be less drastic towards the surrounding area. The plant should be isolated from any buildings or structures in addition to the shore in order to prevent the spreading of the incineration. A solution to handling the natural gas in an exploded LNG plant is to either bury or contain it in a secure place so that if there was an explosion minimum damage would be caused. If an explosion were to happen and the tanks were buried the chances of the natural gas affecting the ecosystem would be reduced, because underground the gas vapors cannot spread as drastically as above ground. Whereas, above ground, the gas vapors would spread drastically and possibly harm the ecosystem. Fire is also a major concern following explosions. Underground there is a better chance that the gas would not cause harm to the ecosystem by ways of fire. They earth would smother the flames before they could potentially become harmful.
Merchant ships tend to have sound frequencies that interact with marine life in most places of the sound. They effect the communication and migration of many species of marine animals, such as that of whales. Whales are capable of communicating over incredibly long distances through echolocation, as the sound generated by whales can travel through water very easily. This can be easily disrupted by noises produced by tanker traffic, as recent recording based studies on the effects of the noise on whale calls have revealed. Due to the abundance and continuing increase of tanker traffic, communication for whales is becoming increasingly difficult; it is estimated that 80 to 85 percent of all calls are bleached or erased. The large amount of ship traffic has resulted in many cases in which ships have collided with whales. A possible way to help prevent ships from harming species is to map out the areas of their migration and aggregation and determine where it is environmentally safe for the tankers to travel and where it is not. Routes for the tankers could be established that avoid the high risk areas, limits could be established on the speed of the ships at those locations to minimize cavitation and/or reduce the possibility of collision. Another solution is to somehow change the noise levels of the tankers. If they were changed to something that did not interact with marine animal communication there might be less effect on marine species. Underwater noise created by ships is caused by machinery, hull movement through water, and by the propeller. A major factor contributing towards the noise generated by tankers is the cavitation, or submersion of air that the propeller creates. The amount of cavitation is dependent upon the ship's wake flow and the propeller's shape or design. The depth at which the rudder is submerged, a factor that depends upon the amount of cargo transported by the ship, also affects noise. Cavitation is unavoidable at high speeds, but capable of avoiding at low speeds. Special propellers have been designed that begin to cavitate at a faster speed than that of conventional propellers, but are however often relatively inefficient. In order to help mitigate the effects of tanker traffic on species such as whales, considerable research needs to be done on the hydrodynamic interaction between the species and the vessels in terms of behavior. Also, the majority of research on the migration of whales is done on that of the Atlantic Ocean, and more study should be performed on these patterns in the Pacific Ocean also particularly in that of Prince William Sound. We should also work to develop technology that more accurately tracks the locations of migrating and aggregating whales, which will in essence reduce the likelihood of collisions.
No proposition issued entails only benefits or advantages, for nothing can be completely perfect and all ideas are bound by some flaws and disadvantages. When the pros and cons of an issue are almost equally competing, debates emerge, creating the essence of controversy. The All Alaska Gasline proposal, for instance, will be beneficial economically, since it offers the opportunity to provide for years of cheap and fuel efficient natural gas, and yet is also weighed down by drawbacks which exist in the possible negative environmental problems that it creates. Since both poles of the issue are located at separate standpoints, it will result in a persistent controversy. To resolve the conundrum, either the sides of the issue should be leveled out, or the parts of the project associated with the negative consequences will have to be carefully considered to ensure that they are minimally intrusive. Since the second option is certainly a feasibility, we believe that the All Alaska Gasline should be constructed for the sake of the economy and preventing dirtier sources of fuel and energy from replacing natural gas in Alaska and contaminating the environment, provided that the potential effects of the pipeline marine life in the Prince William Sound is considered extensively by the Port Authority, and that it will put forth maximum effort to mitigate these concerns.