Abstract—Increase in aircraft travel has led to increased greenhouse gas emissions and an increased impact on the global environment. While aircraft represent a small portion of the greenhouse gases emitted on a global scale, these emissions occur in high concentrations at high altitudes surrounding airports which has lead to increased concern by local communities. There is no current legislation in the United States which regulates greenhouse gas levels for stationary and non-stationary sources at airports. There exists a need for a system to ensure compliance and accountability to future legislation for greenhouse gas emissions regulations at airports. The proposed Airport Inventory Tool (AIT) is the first step toward carbon neutrality, used to establish current emissions levels at airports in order to identify sources which can be optimized to reduce emissions and move toward complete carbon neutrality. The AIT utilizes fuel consumption and fuel burn rates to compute CO2output data for each source at the airport. The system design can feasibly be integrated at any major airport in the United States to be used to assess current greenhouse gas emissions in order to advise and guide airport authority in making critical changes to reduce overall emissions. (Abstract)

I. INTRODUCTION

A. ContextConcerns continue to increase over potential effects of

anthropogenic (or human-made) activities on earth’s climate particularly those activities contributing to the rising concentrations of greenhouse gas (GHG) emissions. Looking at emissions since the industrial revolution in 1850, there has been an increase in carbon dioxide concentration and an increase in global temperature relative to this carbon dioxide level. This data can be seen in Figure 1: Global Temperature and Carbon Dioxide Concentrations.

Figure 1: Global Temperature and Carbon Dioxide Concentrations

Aviation is currently responsible for 3.63% of United States greenhouse gas emissions (EPA) and 2% of global

Manuscript received December 5, 2011 This work was supported in part by Dr. Lance Sherry, George Mason University Systems Engineering and Operations Research Department and Dr. Terry Thompson, Metron Aviation.

CO2 emissions (IPCC, 2004). While this is a small percentage of the GHG emissions globally, the emissions from aviation related activities has a direct impact into the atmosphere and are concentrated in high traffic area.

Political and community concerns have grown in response to these studies. Internationally, the primary response to these concerns is the Kyoto Protocol. The Protocol is an environmental treaty with the goal of reducing climate change through the stabilization of anthropogenic emissions. The Protocol commits to reduce or trade emissions and represents a promise by the participating governments to reduce GHG emissions by an average of 5.2% of the 1990 levels. These GHG’s emissions include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), sulfur hexafluoride (SF6), hydrofluorocarbons (HFC), and perfluorocarbons (PFC). The targets set by the Kyoto Protocol included aviation emissions, but only those related to domestic travel. As of September 2011, around the world, 193 parties (192 States and 1 regional economic integration organization) are a part of the Kyoto Protocol. The United States has been involved in the Protocol legislation since the creation but remains a signatory and has not ratified the treaty. Over the past Presidential administrations, there has been a commonly accepted understanding that the United States would not ratify the treaty until there are quantitative emissions commitments for developing countries, such as China1. Since the limits are based on the size of a country’s land, carbon trading may become financially advantageous to geographically large countries with low population density, such as Russia. Most of the provisions in the treaty only apply to developing countries which is a direct violation of the Byrd-Hagel Resolution wherein the US cannot sign any agreement that does not have fair guidelines for all countries (STERN, 2007). In the United States, federal legislation has yet to be developed to regulate mobile aviation-related GHG emissions. State and local governments have responded to concerns by developing policies to control the amount of GHGs generated by airport operations. Voluntary registries, such as The Climate Registry, on the national and regional level have been established to promote meeting Kyoto goals.

Several states have developed state-based laws that require inventories of greenhouse gas emissions. In 2006, the California Air Resources Board (CARB) was created with the goal of reducing GHG emissions in California through 2020 (ARB Mission and Goals, 2009). The first part was setting caps for emissions levels in major industries and requiring participation in the California Climate Action Registry (CCAR). Other legislation includes the Massachusetts Environmental Policy Act (MEPA), and Washington State’s Environmental Policy Act (SEPA). These policies have led to discussions about who has

The Design of a Carbon Neutral AirportJoel Hannah, Danielle Hettmann, Chris Saleh, Naseer Rashid, Cihan Yilmaz

authority to regulate GHG emissions. In 2007, it was declared by the U.S. Supreme Court that the United States Environmental Protection Agency (USEPA or EPA) has authority over GHG regulations and that the USEPA must begin to exercise the authority. This ruling increased pressure on the USEPA to regulate emissions under the Clean Air Act (CAA).

The National Ambient Air Quality Standards (NAAQS) was established under the CAA to set limits on concentrations of particulate matter in outdoor spaces. The limits are set on pollution sources and vary depending on geographic location and air flow conditions. The NAAQS are set for six pollutants defined as “criteria” pollutants: carbon monoxide, lead, nitrogen dioxide, ozone, particulate pollution, and sulfur dioxide. Inventories are taken annually. Compliance to the standards makes a region an “attainment” area. Non-compliance earns the title of “non-attainment”. Non-attainment areas are required to implement a plan to meet NAAQS or risk losing federal financial assistance.

These policies are a response to public concern of the effects of increasing energy consumption on the planet. The end goal of the policies referring to GHG emissions is carbon neutrality, where the net GHG emissions in an area created by human activity is close to zero, relative to a determined baseline level. Airports have to report air quality statistics from stationary sources under NAAQS. Trends in policy indicate a move towards controlling byproducts of energy consumption, including GHG emissions, from both stationary and non-stationary sources.

B. Airport OperationsFrom the surrounding communities, passengers and

employees flow-in to the airport through the use of personal cars, public transportation, and airplanes. Passengers then leave on similar sources, through personal cars, public transportation, and airplanes. The case study of this project will be Washington Dulles International Airport (IAD) of the Metropolitan Washington Airports Authority (MWAA). IAD consists of 127 airline gates with five concourses: A, B, C, D, and Z. The airport always operates an AeroTrain system and mobile lounges to transport passengers and employees between the concourses. IAD has a total of four runways to accommodate the increasing traffic off aviation (Metropolitan Washington Airports Authority, 2011).

Dulles International Airport is serviced by two major roadways: VA-route 28 and the Dulles Toll Road (VA-Route 267). Ground access vehicles include: personal vehicles, taxis, and public transportation such as buses and other mass transportation. All of the economy and some of the employee parking lots are serviced by MWAA controlled shuttle buses. Employees have 7 parking lots: North, East, East Reserve, West Reserve, Cargo, CBP, and L S G (in-flight service provider). Public parking lots include: Economy, Daily Garage 1, Daily Garage 2, Hourly, and Valet. There are 24,000 total public parking spaces available at Dulles. (Metropolitan Washington Airports Authority,

2011)Bottle necks occur during airport operations in the flow of aircraft and ground access vehicles. With aircraft there are delays which include: gate push back, departure congestion, and taxi times. For ground access vehicles delays include: congestion on roads servicing airport and increased idling time at arrivals/departures. Bottlenecks cause an increase in emissions through the increased engine use of both aircraft and ground access vehicles. Optimization of airport flow would assist in overall reduction of GHG emissions.

II.STAKEHOLDER ANALYSIS

A. Stakeholder OverviewThere are three levels of stakeholders involved in airports

with regards to GHG emissions. The first level of this is the decision makers, including the federal government, local government, and non-government organizations (NGO). The second level of stakeholders follows the decisions made by the first level. This level includes airport management, air carriers, air service providers, ground transportation, and airport services. The third level of stakeholders is the bystanders. These bystanders, or victims, are not decision makers or those who conform to the decisions, but rather the people or entities who perform the day-to-day operations implied by the actions of the first and second level stakeholders. These stakeholders include passengers, employees, and surrounding communities.

Within the primary stakeholders, there are two main points of view: business decision verse an environmental decision. The business decision focuses on lowering cost, increasing revenue, and maximizing profit. An environmental view of a decision focuses on minimizing the effect of a decision on the community. This effect also includes an emphasis on environmental impact. These two views create tension as the two views often do not produce the same results. Another issue arises when identifying whose responsibility it is to consider the environmental decision. A business decision produces the more desirable immediate, tangible result. Consequently, environmental impacts have a long, intangible result and are given little weight when considering changes to airport operations.

To emphasize the value of environmental decisions the Social Cost of Carbon (SCC) is a valuable metric. The SCC is a notional value for emitting an extra ton of CO2 at any time. The average cost is $43 per metric ton of CO2 per person. This impact includes changes in agricultural productivity, human health, property damages, and other ecosystem changes. Monetizing the impact of CO2¬ emissions allows for analysis based on benefits of environmental decisions. (Intergovernmental Panel on Climate Change, 2007)

B. Airport Stakeholder Model

Figure 1: Stakeholder Interaction Diagram

The model of airport organization is shown through boundaries between different entities of airport operations. Such boundaries include the airport organizational boundary, airport service boundary, capital improvement bill payers, and local economy and community. The airport organization boundary is controlled by the airport management which is partly controlled by the airport board. The airport management has control over the infrastructure of the airport and operational procedures. They do not have control over services provided within the airport infrastructure. The airport service boundary is all of the services provided at an airport regardless of the organization that has responsibility and control over that service.

Figure 3: Stakeholder Interactions – Emissions

There are several system loops in the airport stakeholder model. The first is an emissions feedback track, seen in Figure 3: Stakeholder Interactions - Emissions. Emissions are generated within the airport service boundary from airport operations, airport infrastructure, and service providers. These emissions directly affect the local economy and community through increased noise and pollutants entering the environment. For the purposes of this study, only emissions will be considered, not noise. These local communities hold voting power over the local government which governs the airport board. This airport board directly affects the airport organizational boundary through airport

management and operations. The airport organizational boundary dictates the capacity for service providers to operate within the airport service boundary which cycles back to the amount of operations generating emissions. This cycle is designed to have a very weak feedback loop through the stakeholder model since emissions have a slow effect on the surrounding environment and the time needed for these effects to be felt through the election process and into airport management is a very long cycle.

Figure 4: Stakeholder Interactions - Business

There is also a financial or business decision feedback loop that exists in the airport stakeholder model, seen in Figure 4: Stakeholder Interactions - Busines. Airports depend on both capital and operating revenues to pay for capital projects and operating expenses. The feedback loop has interactions between passengers, local economy and communities, and businesses. This feedback loop is the strongest in response time due to financial decisions and can have runaway growth since other loops are weak.

Figure 5: Stakeholder Interaction - Legislation

The final feedback loop shows the legislative interaction with the stakeholders, seen in Figure 5: Stakeholder Interaction - Legislation. This shows the government/capital improvement funding. MWAA serves as the airport manager for Dulles International Airport. The MWAA Board of Directors consists of 13 members. Five members are

appointed from the Governor of Virginia, three from the Mayor of the District of Columbia, two from the Governor of Maryland, and three from the President of the United States. Regulators, which include: FAA, TSA, Federal Government, Local Government, and NGOs, provide legislation for aviation which must be enforced. The conflicting objectives create tension between stakeholders in decision making. This feedback loop also includes the elections and government stakeholders. These stakeholders create tension in the feedback loop through decisions that can impact funding available through the capital improvement finds to the airport. The feedback loop has a very slow response time.

III. PROBLEM AND NEED STATEMENT

A. Problem StatementExisting legislation in the United States, including the

Kyoto Protocol and NAAQS, require the monitoring of air pollutants in stationary sources in aviation to improve the air quality with respect to a target fixed by legislation. Presently, there is no legislation for aviation in the continental United States which imposes caps for greenhouse gas emissions from stationary and non-stationary sources involved in aviation. Analysis of policy from Europe regarding capping of emissions suggests that the increasing awareness of global energy use and its impact on the environment will prompt the United States to create similar laws for emissions from aviation. Since there is currently no legislation against all of the sources of emissions from aviation, there is no way to assign penalty for those sources with the largest amount of emissions and assign fines to these specific sources. With no feedback loop for penalties, there is a conflicting stakeholder opinion of who should own the overall problem. No ownership of the identified problem leads to no one absorbing the cost and time to make changes and no significant changes can occur.

As the global economy becomes more aware of the impact of greenhouse gas emissions from both stationary and non-stationary sources within aviation, there will be a desire to reduce the impact of greenhouse gas emissions from these sources. To achieve a reduced impact on the environment, the aviation sector of industry will work toward a carbon neutral state in which there is no net emission of greenhouse gases. This implies that the total amount of gases emitted will be equal to the total amount of gases sequestered or offset. Due to the lack of legislation currently in place, there is not a tool which allows for the collection and analysis of stationary and non-stationary emissions.

B. Need StatementIn order to reach a carbon neutral state for airports, the

total amount of CO2 emissions must first be determined. A system to collect and report total CO2 emissions for stationary and non-stationary sources at airports is needed.

This system should be able to receive input, calculate CO2 emissions, analyze data to identify sources to reduce emissions output and verify compliance with emissions caps.

As the global economy becomes more aware of the impact of greenhouse gas emissions from both stationary and non-stationary sources within aviation, there will be a desire to reduce the impact of greenhouse gas emissions from these sources. To achieve a reduced impact on the environment, it is projected that the aviation sector of industry will work toward a carbon neutral state in which there is no net emission of greenhouse gases. This implies that the total amount of gases emitted will be equal to the total amount of gases offset. Due to the lack of legislation currently in place, there is not a tool which allows for the collection and analysis of stationary and non-stationary emissions. There exists a need for a tool to collect and report GHG emissions of stationary and non-stationary sources at airports.

IV. CONOPS

A. Statement of WorkIn order to move towards a carbon neutral airport several

aspects of the airport must be explored. First you have to see how much is currently being put out. To do this, previous inventory methods and results have to be surveyed. The tools used in these inventories also have to be surveyed. From there an inventory tool has to be developed to account for stationary and non-stationary aviation emissions. This tool will be used to the current status of total emissions and to identify emissions by source. Those results will be used to set goals for emissions reduction. Various strategies will be considered for reducing GHG emissions from all sources. The strategies will be analyzed to determine the most effective and beneficial solution.

B. Mission RequirementsMission requirements derived from the sponsor statement

of work are as follows: • The system shall report total aviation related CO2

emissions for stationary and non-stationary sources• The system shall account for aviation related emissions

within the boundary of the landing/take-off (LTO) cycle around the airport.

• The system shall report GHG emissions by source.• The system shall calculate emissions within 1.1%

accuracy for each emissions source.*• The system shall provide structure for additional GHGs

to be calculated.*Based on magnitude of sample calculations.

C.ScopeThe scope of the project is decomposed into geographic,

operations, and emissions scope. The scope of this project is geographically limited to

airport operations within the landing and take-off (LTO) cycle below mixing altitude. The mixing altitude is the where pollutant mixing and chemical reaction occurs in the

atmosphere. Above the mixing altitude, pollutants do not mix with ground level emissions and have little effect on ground level concentrations. The geographic scope covers a radius of 12 nautical miles (22 km) and an altitude of 3,000 feet within the LTO cycle. The LTO, detailed in Figure 6: Landing Take - off Cycle, is divided into five main operational modes:

1. Approach: the portion of flight from the time the aircraft reaches the mixing height or 3,000 ft altitude and lands and exits the runway;

2. Taxi/idle-in: the time the aircraft is moving on the taxiway system until reaching the gate;

3. Taxi/idle-out: from departure from the gate until taxied to the runway;

4. Take-off: the movement down the runway through lift-off up to about 1,000 ft; and

5. Climbout: the departure segment from takeoff until exiting the LTO cycle.

Figure 6: Landing Take - off Cycle

Within the airport boundary, this project will account for all stationary and non-stationary sources of GHG emissions. Stationary sources include: Boilers (facility, heating, and fuel), airport fire department training fires, waste management devices (waste disposal and incinerators), and construction activities. Non-stationary sources are broken up into 3 additional areas: Aircraft, Ground Support Equipment (GSE), and Ground Access Vehicles (GAV). Aircraft accounts for all aviation related emissions including their Aircraft Power Units (APU). GSE accounts for emissions for airport related activities including: tugs, catering trucks, transporters, fuel tankers, and passenger boarding stairs. GAVs include all non-airport related emission activities including: personal passenger vehicles, and public transportation such as taxis, buses, and trains.

This project will only measure the output of Carbon Dioxide (CO2), based on Figure 7: Greenhouse Gas Decomposition, CO2 accounts for 83% of the total United States GHG emissions. Because the majority of GHG emissions are CO2 the tool will be limited to outputting CO2 measurements. To calculate CO2 emissions, the tool will convert total fuel consumption and fuel economy into tons of CO2 using predefined equations.

83.0%

10.3%

4.5% 2.2%

2009 Greenhouse Gas Emissions by Gas(percentages based on CO2 equivalent)

CO2 CH4 N2O HFCs, PFCs & SF6

Figure 7: Greenhouse Gas Decomposition

V. METHOD OF ANALYSIS

In order to evaluate solutions for reduction of GHG emissions, a tool is needed to evaluate the current state of emissions. The Airport Inventory Tool (AIT) is used to inventory stationary and non-stationary aviation-related GHG emissions within the LTO boundary around an airport.

Figure 8: Airport Inventory Tool

An overview of the AIT is in Figure 8: Airport Inventory Tool. The AIT calculates total carbon emissions based on fuel consumption and the appropriate emissions index. There are two methods for finding the amount of fuel consumed by non-stationary sources. The first method is the most preferred method. It uses total fuel consumption from stationary, GAV, GSE, and aircraft sources. If fuel consumption data are not available, a second method may be

used. The second method for calculation is uses fuel economy information and distance travelled to calculate emissions from GAV, GSE and aircraft sources. Emissions indices are based on the type of fuel consumed by the source and are provided by, the Energy Information Administration (EIA), Environmental Protection Agency (EPA), and Department of Energy (DoE).

For GAV and GSE sources, the total of emissions is calculated using the number of vehicles, amount of fuel burned, and the appropriate emissions index. If it is known, the actual amount of fuel consumed is calculated. If the amount is not known, the amount of fuel consumed is calculated using the distance travelled and average fuel burn rate for each vehicle or vehicle class.

Equation 1: Emissions = ∑^i〖fi*Ei〗where fi: GAV/GSE fuel consumed; Ei: Emissions Index

Aircraft emissions are calculated using the amount of fuel burned and the fuels appropriate emissions index. If fuel consumption data is not available, the amount of fuel used can be calculated using averages based on the model or type aircraft and the number of landings and take-offs. Obtaining the fleet mix of the airport in question is important in calculation aircraft emissions under the alternative method. In the event the fleet mix is not available, accepted distributions of aircraft types may be obtained using the Seattle-Tacoma emissions inventory.

Equation 2: Emissions = ∑^j 〖 fj *Ej 〗 + ∑^k 〖 fk *Ek〗

fj: landing aircraft fuel consumed; Ej: landing aircraft emissions index; fk: take-off aircraft fuel consumed; Ek: take-off aircraft emissions index

Stationary source emissions are only calculated using the total fuel consumption method because NAAQS requires annual reporting of stationary source emissions and fuel consumption. The total emissions for each stationary source will be calculated using the total fuel consumed and the appropriate emissions index. If there are multiple fuel types being consumed by one source, each fuel input is considered treated as a separate input in the AIT.

Equation 3: Emissions = ∑^m〖fm*Em〗 fm: stationary source fuel consumed; Em: stationary

source emissions index

B. RiskThe risks associated with emissions inventories are data

availability and data reliability. Specific data related to fuel consumption and airport

operations is not publically available for use in the development of the AIT. After development, the process of data collection will be outside of the scope of the AIT and

will be the responsibility of the airport manager. Therefore, data is needed to validate the AIT development to ensure that emissions indices and fuel usage data are correct. To validate these values, acceptable distributions from previous inventories performed at Seattle-Tacoma and Denver International Airports will be used to determine fleet distributions and ground access vehicle distributions as well as accepted averages for aircraft and associated ground service equipment fuel consumption.

Some of the input, calculations, and emissions indices used in the tool may not be accurate enough to meet accuracy requirements for the system. To mitigate this risk, previous inventory inputs and results, such as Seattle-Tacoma and Denver International Airports, will be compared to AIT results. Since data specific to Dulles International Airport cannot be released for public use, inventory results based on Dulles International Airport will be presented to the airport managers, MWAA for validation. The AIT will also be turned over to MWAA for data entry and validation, with results being returned to the team without specific data included.

C. LimitationsCarbon Dioxide emissions account for 83% of total GHG

emissions by CO2 equivalency (IPCC, 2004; Brian Kim, 2009). Due to CO2 being such a large percentage of greenhouse gas emissions, the AIT focus is a Level-1 Inventory tool as defined in ACRP, which focuses on CO2 emissions, and does not include Methane (CH4), Nitrous Oxide (N2O), Sulfur Hexfluoride (SF6), Hydrofluorocarbons (HFC), and Perfluorocarbons (PFC).

The purpose of the analysis is to identify emissions sources contained within the airport operational boundary. Therefore dispersion is not included in the analysis. The analysis follows the IPCC LTO methodology for calculating aircraft emission which does not include helicopters in the inventory model. In the case of Dulles International Airport, there are less than 10 helicopter landings and takeoffs per year.

VI. DESIGN ALTERNATIVES

A. Carbon Neutrality StrategyThe long term goal of carbon neutrality is to achieve a

zero carbon footprint relative to a baseline amount. To create a carbon neutral airport, a tiered approach will be used to reduce carbon emissions through the use of renewable energy sources and energy efficient technologies. Figure 9: Carbon Neutral Strategy shows the project strategy to reach carbon neutrality.

Figure 9: Carbon Neutral Strategy (Source: The Carbon Neutral

Company)

The first step of the strategy is to reduce energy need for airports in order to minimize total carbon emissions at airports. The second step of the carbon neutral strategy is to maximize energy efficiency in order to minimize energy waste at airports. The third step of the strategy is to focus on renewable energy and new energy technologies in order to produce electricity in all or part of the airports. The fourth step of the strategy is to share offset studies in order to share existing and future offset programs for carbon neutral airports. The reduction strategies are based on the emissions source classifications: Ground Access Vehicles (GAV), Ground Support Equipments (GSE), Aircrafts (including APUs), and Stationary Sources.

B. Proposed Alternatives for Ground Access Vehicles (GAV)

Ground access vehicles are private and commercial motor vehicles used by passengers and airline & airport employees to travel on airport roadways and in parking lots. The first proposed alternative for GAVs is to reduce energy need. The first alternative method for energy reduction is a carpooling program in order to consolidate the number of GAV emissions sources per passenger. The second alternative method for energy reduction is establishing a combined rental car shuttle. For example, there are currently eight rental car companies at Dulles International Airport which each run their own shuttles to pick up rental customers from the main terminal. Instead of running eight different shuttles, one energy efficient shuttle could be implemented for rental car companies. The second proposed alternative for GAVs is investment in better public transportation in order to encourage passengers to leave their cars at home and utilize public transportation. Two alternatives for public transportation are Metro (Dulles Metro, scheduled to open 2013) and hybrid busses. Carpooling programs and better public transportation will decrease the total number of GAVs at airports and will lower passengers’ total carbon emissions.

C. Proposed Alternatives for Ground Support Equipment (GSE)

The strategy for determining alternatives for ground support equipment is categorized into two major groups

based on fuel type (gasoline or diesel) and on-road (vehicles or trucks) or off-road (tugs, tractors or loaders). GSEs provide services (fuel & baggage loading or transportation of passengers) to aircrafts between flights. The majority of existing ground support equipment use gasoline or diesel fuel. The proposed alternative for GSEs is to invest in new energy technologies. Alternative energy technologies for GSEs are electric, hybrid, hydrogen and liquid propane. The new technologies will minimize fuel consumption and will lower GSEs’ total carbon emissions.

D. Proposed Alternatives for Aircraft and APUA majority of existing aircrafts and APUs use aircraft fuel

(Jet A-1). The first proposed alternative for aircrafts is to invest in alternative fuels. The first alternative is hydrogen-powered aircrafts. Hydrogen is an environmentally friendly gas fuel for future aircrafts. It shows a significant promise as fuel and it is a potential replacement for current aircraft fuel, Jet A-1. The most significant advantage of hydrogen is that it does not produce any GHG emissions. It is lighter than Jet A-1 and thereby maximizes energy efficiency and minimizes carbon emissions for each flight. The second alternative fuel type is compressed natural gas (CNG). It is a fossil fuel substitute for gasoline, diesel and propane. It shows a significant promise as fuel and it is a potential replacement for current aircraft fuel, Jet A-1. The most significant advantage of CNG is that it produces less greenhouse gases and is more environmentally friendly than the current fuel, Jet A-1. CNG is lighter than current aircraft fuel, Jet A-1 therefore it maximizes energy efficiency and minimizes carbon emissions for each flight. The third alternative fuel type is biodiesel. It is also called vegetable fuel and being used for diesel engines. In 2007, the first biodiesel military aircraft was tested in Nevada. The second proposed alternative for aircrafts is fixed ground power. It is an alternative method to provide aircrafts’ energy consumption on gateways. It provides 400 Hz gate power and pre-conditioned air therefore aircrafts can switch off their engines and APUs while at the gate. The largest advantage of fixed ground power is that it is clean energy source and is environmentally friendly. This technology will significantly reduce the use of APUs and related carbon emissions. The third proposed alternative for aircrafts is developing more efficient air traffic management. One option is utilizing continuous descent approach (CDA) for air traffic management. It is an optimized landing strategy for aircrafts. It minimizes engine and fuel usage. Unlike the traditional landing method, CDA minimizes engine trust at 7000 FT and 25 miles away from landing point and does not add any additional trust on engines at 3000 feet above ground level. This new landing strategy minimizes fuel waste and lowers aircrafts’ total carbon emissions. Another alternative for reducing aircraft GHG emissions is minimizing taxiing times. Taxi time is the total time of an aircraft movement on the ground between the gate, terminal, ramp or runway. Delays, previously discussed as bottlenecks, can increase

Reduce energy need

Maximize energy efficiency

Renewable Energy

Off set

taxiing times for aircrafts increasing the emissions expelled into the atmosphere. Shortening taxiing times minimizes the total time of an aircraft between the gates, terminals, ramps and runways and therefore minimizes fuel waste and unnecessary carbon emissions.

E. Proposed Alternatives for Stationary SourcesStationary sources include facilities sources such as power

generators, steam boilers, heaters or waste incinerators. Fire training, waste management, and construction activities are other aviation-related stationary sources. The majority of existing stationary sources use gasoline, oil or electric. The first proposed alternative for stationary sources is renewable energy technologies. Solar energy is the most available renewable energy source to produce electricity through photovoltaic cells at airports. Solar energy can also be used for heating. Based on the specific area and locations, airports might be able to provide total or part of energy consumptions by solar energy. Wind energy is the second best available renewable energy source to produce electricity by wind turbines at airports. Wind turbines convert kinetic energy to mechanical energy to produce electricity. Depending on the area and locations, airports might be able to provide total or part of energy consumptions by wind energy. For example, Denver International Airport is able to produce enough electricity by wind and solar farms in order to provide their energy consumption (Associates, Rocondo &, 2005). Innovative design in energy efficient terminals & buildings could be another solution used to reduce or eliminate energy need and maximize energy efficiency. These designs also include high efficiency boilers, heating and cooling systems with effective waste management techniques. The most important step for innovative designs is to reduce energy need and generate energy with environmentally friendly methods. These new technologies will minimize fuel consumption and will lower stationary sources’ total carbon emissions.

VII. DESIGN OF EXPERIMENT

The design of experiment for Greenhouse Gas Emissions Project is comprised of four main steps. The first step of our design of experiment is to plug in aviation data in Aviation Inventory Tool (AIT) in order to collect total carbon emissions from stationary and non-stationary sources. The second step of our design of experiment is to analyze emissions data from AIT in order to determine the largest contributions of emissions at airports. The third step of our design of experiment is to implement proposed alternatives into AIT in order to reduce emissions from inputs. The fourth step of our design of experiment is to provide recommendations based on results from third step in order to optimize airports. The design of experiment for Greenhouse Gas Emissions Project has three weights: Payoff, Difficulty and Cost. We will retrieve weights based on discussion with MWAA and our stakeholders. The weights will be combined with proposed alternatives in order to provide

recommendations for system optimization and to determine the best proposed alternative for overall reduction of greenhouse gas emissions and a step toward carbon neutrality for the airport.

DEFINITIONS AND ACRONYMNS

ACRP: Airport Cooperative Research ProgramAIT: Airport Inventory ToolCarbon Neutral: no net release of carbon dioxide to the atmosphere by balancing a measured amount of carbon released with an equivalent amount offset relative to a baseline quantityClimate Change: major changes in temperature, rainfall, snow, or wind patterns lasting for decades or longer due to human-made and natural factorsDispersion: process of air pollutants spreading over a wide area in the ambient atmosphereDOE: Department of EnergyEIA: Energy Information AdministrationEPA: USEPA, United States Environmental Protection AgencyFAA: Federal Aviation AdministrationGAV: Ground Access VehicleGHG: greenhouse gas, a gas that traps heat in the atmosphereGSE: Ground Support EquipmentICAO: International Civil Aviation OrganizationInventory: accounting of the amount of GHGs emitted to or removed from the atmosphere over a specific period of timeKyoto Protocol: a protocol to the United Nations Framework Convention on Climate Change (UNFCCC or FCCC), aimed at fighting global warmingMWAA: Metropolitan Washington Airports Authority, Dulles International Airport and Reagan National Airport managersNAAQS: National Ambient Air Quality Standards

REFERENCES

1. AIRPORTS COUNCIL INTERNATIONAL. (2009). GUIDANCE MANUAL: AIRPORT GREENHOUSE GAS EMISSIONS MANGEMENT.

2. ARB MISSION AND GOALS. (2009, DECEMBER 8). RETRIEVED 2011, FROM CALIFORNIA ENVIRONMENTAL PROTECTION AGENCY AIR RESOURCES BOARD: HTTP://WWW.ARB.CA.GOV/HTML/MISSION.HTM

3. ASSOCIATES, ROCONDO &. (2005). DENVER INTERNATIONAL AIRPORT EMISSIONS INVENTORY. DENVER, CO.

4. BRIAN KIM, I. A. (2009). ACRP REPORT 11 GUIDEBOOK ON PREPARING AIRPORT GREENHOUSE GAS EMISSIONS INVENTORIES. WASHINGTON, DC: TRANSPORTATION RESEARCH BOARD.

5. DAVID SCHARR, L. S. (2010). ANALYSIS OF AIRPORT STAKEHOLDERS. INTEGRATED COMMUNICATIONS NAVIGATION AND SURVEILLANCE CONFERENCE .

6. DEXINGER. (2009). DEXINGER. RETRIEVED FROM AIA INTRODUCES 2030 COMMITMENT PROGRAM TO REACH GOAL OF CARBON NEUTRAL BY 2030: HTTP://WWW.DEXIGNER.COM/NEWS/17758

7. ENERGY INFORMATION ADMINISTRATION. (2011). VOLUNTARY REPORTING OF GREENHOUSE GASES PROGRAM. RETRIEVED 2011, FROM INDEPENDENT STATISTICS & ANALYSIS U.S. ENERGY INFORMATION ADMINISTRATION: HTTP://WWW.EIA.GOV/OIAF/1605/COEFFICIENTS.HTML

8. ENVIRO.AERO. (2011). AVIATION'S ROLE IN CLIMATE CHANGE. RETRIEVED 2011, FROM ENVIRO.AERO: HTTP://WWW.ENVIRO.AERO/AVIATIONSROLEINCLIMATECHANGE.ASPX

9. FEDERAL AVIATION ADMINISTRATION. (2011). PASSENGER BOARDING (ENPLANEMENT) AND ALL-CARGO DATA FOR U.S. AIRPORTS. RETRIEVED 2011, FROM FEDERAL AVAITION ADMINISTRATION: HTTP://WWW.FAA.GOV/AIRPORTS/PLANNING_CAPACITY/PASSENGER_ALLCARGO_STATS/PASSENGER/INDEX.CFM?YEAR=ALL

10. FIRST ENVIRONMENT, INC. . (2008). WESTCHESTER COUNTY AIRPORT AIR EMISSIONS INVENTORY.

11. INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE. (2007). 3.5.3.3 COST-BENEFIT ANALYSIS, DAMAGE COST ESTIMATES AND SOCAIAL COSTS OF CARBON - AR4WGII CHAPTER 3: ISSUES RELATED TO MITIGATION IN THE LONG-TERM CONTEXT. IPCC.

12. IPCC. (2004). PUTTING AVIATION'S EMISSIONS IN CONTEXT.

13. MASSECHUSETTS EXECTUIVE OFFICE OF ENVIRONMENTAL AFFAIRS. (2009). MASSECHUSETTS ENVIRONMENTAL POLICY ACT (MEPA). RETRIEVED 2011, FROM THE OFFICIAL WEBSITE OF THE EXECUTIVE OFFICE OF ENERGY AND ENVIRONMENTAL AFFAIRS: HTTP://WWW.ENV.STATE.MA.US/MEPA/

14. METROPOLITAN WASHINGTON AIRPORTS AUTHORITY. (2011). FACTS ABOUT WASHINGTON DULLES INTERNATIONAL AIRPORT. RETRIEVED 2011, FROM METROPOLITAIN WASHINGTON AIRPORTS AUTHORITY: HTTP://MWAA.COM/DULLES/663.HTM

15. METROPOLITAN WASHINGTON AIRPORTS AUTHORITY. (2010). TOTAL OPERATIONS, PASSENGERS, MAIL, & FREIGHT ACTIVITIES. WASHINGTON, D.C.

16. OFFICE OF ENVIRONMENT AND ENERGY. (2000). CONSIDERATION OF AIR QUALITY IMPACTS BY AIRPLANE OPERATIONS AT OR ABOVE 3,000 FEET AGL. WASHINGTON, DC: US DEPARTMENT OF TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION.

17. PORT OF SEATTLE. (2008). PORT OF SEATTLE SEATTLE-TACOMA INTERNATIONAL GREENHOUSE GAS EMISSIONS INVENTORY 2006. SEATTLE, WA.

18. SCHAAR, D. (2011). INTRODUCTION TO AIRPORT FINANCE.

19. STERN. (2007). STATUS OF KYOTO PROTOCOL RATIFICATION.

20. THE CLIMATE REGISTRY (TCR). (2008). GENERAL REPORTING PROTOCOL. LOS ANGELES, CA.

21. U.S. DEPARTMENT OF STATE. (JUNE 2010). U.S. CLIMATE ACTION REPORT 2010. WASHINGTON, DC: GLOBAL PUBLISHING SERVICES.

22. U.S. ENVIRONMENTAL PROTECTION AGENCY. (2011, APRIL 20). CLIMATE CHANGE - GREENHOUSE GAS EMISSIONS. RETRIEVED 2011, FROM U.S. ENVIRONMENTAL PROTECTION AGENCY: HTTP://WWW.EPA.GOV/CLIMAGECHANGE/EMISSIONS/INDEX.HTML