Airport Renewable Energy Projects Inventory and Case Examples (2020)

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5 Renewable sources of energy provided 17.6% of total electricity generation in the United States in 2018—a total of 742 million megawatt-hours (MW-h), which represents a near double increase from just 10 years earlier. The U.S. Energy Information Administration (EIA) predicts that nonhydroelectric renewable energy resources, such as solar and wind, will be the fastest growing source of U.S. electricity generation for at least the next 2 years (EIA, 2019a). The components of renewable energy reported by EIA are shown in Figure 1. Overall growth has been fueled by a number of factors, including • Significant improvements in the technology and infrastructure necessary to generate and distribute renewable energy, • Programmatic incentives designed to diversify energy supplies and to reduce air emissions, and • Market forces resulting in significantly reduced costs associated with both the manufacture of renewable energy equipment and the broader development of renewable energy projects. As renewable energy production is predicted to grow, so is the demand for air travel. Passengers on U.S. carriers reached an all-time high at the start of 2020, an increase of 4.1% from the previous year and 12.3% over a 3-year period (Bureau of Transportation Statistics, 2020). The number of passengers at the largest U.S. airports is projected to grow by 2.1% annually through 2045 (FAA, 2017). Figure 2 shows long-term changes in passenger enplanements, with steady growth apparent since the world economic recession in 2008. Plans for this growth should take into account a wide array of environmental impacts. Airports can minimize environmental impacts through tools such as sustainability plans, increased energy efficiency, and the development of renewable energy projects. These practices can result in a decrease in greenhouse gas (GHG) emissions. While up to 90% of GHG emissions attributed to air travel come from the transit of aircraft and ground transportation (Cooper et al., 2016), airport operations offer clear opportunities for mini- mizing GHG-associated emissions. As complex hubs for commerce and travel, airports are major consumers of energy: large terminals and buildings require electricity, heating, and cooling; runways and taxiways require electricity for lighting; and ground transportation fleets require fuel and electricity for operation. Furthermore, the projected growth in air travel will trigger an even greater demand for reliable energy at airports to support the traveling public. In response, airports are seeking ways to (1) manage growing energy needs more effectively in an effort to minimize costs, (2) reduce local environmental impacts of their growth and energy use, and (3) address increasing concerns about GHG emissions and their role in global climate change. Renewable energy is one concrete option that helps meet these multiple objectives. To provide guidelines for airports looking to implement renewable energy projects, and to record the number and range of existing projects as a baseline for future research, this synthesis presents the current state of practice for airport renewable energy development as it stands in C H A P T E R 1 An Introduction to the State of Renewable Energy at Airports

6 Airport Renewable Energy Projects Inventory and Case Examples 2020. Current trends in the development of renewable energy at airports have been influenced by both (1) the broader expansion of renewable energy development across the country, and (2) the specific interests of individual airports as they consider best practices for lowering long-term operating costs, decreasing environmental impacts, meeting the objectives of renewable energy programs, and serving customers. The report is organized as follows: • Chapter 1 outlines the report scope, provides a general review of the literature, and presents the general context for renewable energy development at airports. • Chapter 2 describes the specific issues that airports must consider when developing renewable energy given their broader mandate to deliver safe and efficient air transportation. • Chapter 3 summarizes the data from the airport Renewable Energy Projects Inventory included as Appendix A. • Chapter 4 details 10 specific case examples of airports using renewable energy. • Chapter 5 summarizes the report conclusions and research needs. Figure 1. U.S. renewable energy generation by resource, 2016–2020. Note: M = millions. Figure 2. U.S. commercial airline passenger enplanements, 2003–2019.

An Introduction to the State of Renewable Energy at Airports 7 The Renewable Energy Projects Inventory is included as a standalone product, both as part of the report in Appendix A and as a searchable online database available on the TRB website. Quantitative data compiled for the inventory matrix were obtained through a combined methodology of online research, which was cross-referenced with FAA construction permit- ting applications and, in some cases, visual verification through Google Earth. As a starting point, 700 commercial service U.S. airports (Zeducorp, 2019) were reviewed for their current renew- able energy projects at the end of 2019. Following this review, additional research was conducted through publicly available sources to confirm project details and identify previously unrecog- nized projects. The resulting inventory was then sent to more than 300 airport personnel for confirmation and additional input. With any research, a margin of error is anticipated, and— in regard to this report’s inventory matrix—the researchers are aware that quickly developing projects or technologies may have been either inadvertently excluded or incorrectly included (if a project was not seen through to completion). Qualitative data collected for the case examples were gathered through a specific process of (1) background research, (2) telephone interviews with relevant airport staff involved with the documented renewable energy project, and (3) e-mail follow-up, clarification, and final review of the text by airport staff for all highlighted case examples. This collection of data and information has been synthesized into the following document with the intent to provide an accurate overview on the current state of renewable energy projects at airports. This compendium complements existing ACRP research such as ACRP Report 141: Renewable Energy as an Airport Revenue Source (Barrett et al., 2015), ACRP Report 151: Developing a Business Case for Renewable Energy at Airports (Barrett et al., 2016), and ACRP Research Report 197: Guidebook for Developing a Comprehensive Renewable Resources Strategy (Shaw et al., 2019). 1.1 Power for the Airport: The Fit for Renewable Energy 1.1.1 Energy Needs Airports, varying in size from large international travel centers to small general aviation facilities, serve as transportation hubs for the region where they are located. As such, they are typically connected to the regional energy infrastructure to ensure the supply of adequate power for the wide array of airport operations, which are highlighted in Figure 3. Such operations include but are not limited to the heating, cooling, and electrical needs of airport buildings; lighting the airfield and parking areas; aircraft servicing and maintenance activities; airside operation; passenger management, ticketing, and baggage services; retail, restaurant, and comfort facilities; and corporate tenants and private airport businesses (Alba and Manana, 2016). As significant consumers of energy, airports depend on electricity provided by a utility-fed electrical grid. The capacity of the regional electrical infrastructure correlates to the amount of electricity consumed, with large airports served by large capacity lines and smaller airports served by smaller lines. Additionally, larger airports routinely install on-site emergency genera- tors that can be temporarily drawn on to offset a grid failure caused by natural disasters or infrastructure malfunctions. Fifty large airports across the United States are categorized as continuous power airports (CPAs), with FAA-installed standby engine generators that main- tain, at a minimum, power for air traffic control and other national airspace systems in the event of a utility-grid power outage (FAA, 2019). Lighting is among the most significant electricity demands at airports, with extensive lighting needs in terminals and outbuildings, on runways and taxiways, in air traffic control towers, for signage, along inter-airport roadways, and in parking areas (Lau, Stromgren, and Green, 2010, p. 50). Electricity demands for these lights can be reduced by installing LED and other

8 Airport Renewable Energy Projects Inventory and Case Examples energy-efficient lighting options (Barrett, 2019); however, continuous power for lighting is considered critical for the safe operation of aviation services, as emphasized by FAA’s (2019) electrical power policy. Other major sources of electricity consumption include passenger moving systems, such as airport trains and ground transportation systems, baggage handling systems, and a wide array of terminal support services. Interruption or loss of electricity can impact far more than essential lighting requirements; it can halt or disrupt heating and cooling, inter-airport transport, and sanitation services, among other fundamental operations. Therefore, in addition to representing a critical public safety issue, a reliable electricity supply is also a necessity for airport operations and requires a broader evaluation regarding the importance of on-site energy generation and storage. On-site, renewable electricity generation and battery storage can both reduce dependence on grid-supplied electricity and provide an additional power source to help sustain crucial airport systems and maintain optimal operation of airport services. The heating and cooling needs of airports are typically powered by a combination of fossil fuels and electricity. The exact combination often varies with the energy options available in the region. Traditional boilers and furnaces that provide building heat may be fueled by heating oil, propane, or natural gas (Edwards, 2005). Air conditioning systems may be powered by natural gas or electricity, and the mechanisms that move the conditioned air (either heated or cooled) are also often electrically powered. Alternative thermal systems (e.g., geothermal, solar thermal, and biomass), as well as renewably generated electricity, may be options for providing more cost-effective and efficient heating and cooling at airports. Implementation of geothermal and biomass technologies varies by region, however, as these technologies are somewhat dependent on local climate and availability of local resources. Fueling vehicles used for on-airport transport is another major category of energy use. Most airport vehicles currently run on fossil fuels, with ground support equipment (GSE) often operating on diesel fuel. Road vehicles, including passenger shuttles and emergency service vehicles, currently run on a variety of fuels such as gas, diesel, and compressed natural gas, with electric vehicles even operating in some airport fleets. In the near term, airports’ GSE, ground transportation vehicles, and work fleets will see an increasing level of electrification Figure 3. Airport power demands.

An Introduction to the State of Renewable Energy at Airports 9 (KB Environmental Services, 2015, p. 141). In addition, aircraft serviced at the airport are increasing their use of on-board electricity for at-gate turnover purposes. The modernization of airport vehicles with more efficient technologies, through retrofitting, replacement, or new design, provides an opportunity to integrate alternative and cleaner energy options that, in turn, will increase the airport’s electricity demands (Barrett, 2019). In light of these energy demands and the projected move toward greater airport electrifi- cation, airports are evaluating aggressive energy efficiency projects followed by a long-term program of renewable energy integration to reduce future energy costs. Alternative renewable energy technologies are becoming increasingly relevant options for providing on-site power. At large commercial service airports, where 70% to 90% of carbon-related impacts result from electricity consumption, the generation of renewable electricity on site can support the growth of air travel while reducing GHG emissions and other environmental impacts (K. Russell, personal communication, December 10, 2019). 1.1.2 Energy Distribution Renewable energy provides new sources of power for airports through use of on-site resources as an alternative to more traditional grid-drawn electricity and temporary backup emergency generators (see Figure 4). Renewable energy technologies that produce electricity, such as solar PV and wind power, can be connected directly to the existing electricity infrastructure, adding immediate power to the current electricity flow serving the airport or other nearby consumers. When renewable electricity projects are connected directly to the airport’s electrical infrastructure, the airport uses all of the power generated by the renewable source and then simply purchases the remainder from the grid, at a cost savings comparable to that before renewable energy was installed. If the renewable energy is instead connected to a larger, regional electrical grid, the renewably generated power serves the airport as well as other nearby customers drawing from the grid. Adding batteries and energy storage on site can give the airport more control over the availability of power and allow for more independent energy use. Figure 4. Airport electricity sources.

10 Airport Renewable Energy Projects Inventory and Case Examples Heating and cooling (or thermal) facilities at airports are traditionally designed to run on fossil fuels such as oil, diesel, or natural gas (when powered by non-electricity sources). These systems depend on an off-site fuel distribution network that imports the fossil fuel by pipeline or ground delivery. Some renewable thermal technologies can lessen an airport’s dependence on off-site distribution networks, thereby enhancing the on-site reliability of its heating and cooling systems. Additionally, airports can limit their exposure to fluctuating or escalating costs of fossil fuels by replacing traditional systems with those that are fueled by renewable energy (e.g., swapping out a heating oil furnace with a comparably sized furnace fueled by biomass), or by supplementing heating and cooling demands with renewable systems (e.g., solar thermal and geothermal heat pump systems). If an airport’s heating and cooling are generated by electricity, then renewable electricity technologies, such as those discussed earlier, can be used to power thermal systems, further reducing or eliminating dependence on fossil fuels. An airport’s work fleet, including GSE, often requires its own fueling network. As airports increasingly convert to electric GSE (eGSE) fleets, fueling stations can readily be replaced with a new electric charging infrastructure that connects to the airport grid. In conjunction, airports can begin to couple renewable electricity generation with their electrification projects so that new electric vehicles are powered by renewables and do not lead to increased electricity costs. 1.2 Drivers and Incentives: Pathways to Renewable Energy The United Nations Intergovernmental Panel on Climate Change (IPCC) has stated the goal of reducing carbon dioxide emissions by 45%—from a 2010 baseline—by 2030 and reaching net zero carbon by 2050 (Masson-Delmotte et al., 2018). In recognition of this goal, airports around the world are taking action to directly reduce carbon emissions generated on site and are collab- orating with tenants and airline partners to facilitate further emissions reductions (FAA, 2020a). Though the dependable, continuous power that airport operations will always require has customarily been supplied through conventional fossil fuels, new opportunities are available. Airports can supplement and replace existing systems with on-site renewable energy genera- tion, increased efficiency, and storage technologies. These measures increase energy reliability and support other airport strategic goals such as reaching net zero carbon. Renewable energy is key to this transition, but which factors are driving airport decision making toward renewable energy and enabling a feasible business case for renewable energy development? 1.2.1 Renewable Energy Framework One reason for the current shift toward renewable energy across many fronts is the determi- nation by federal, state, and local governments that renewable energy is beneficial; in response, governments have created programs designed to increase energy independence and reduce overall energy consumption (Congressional Research Service, 2019). Columbia University’s Earth Institute identified the benefits of renewable energy as they specifically relate to developers of public programs: • Economic: local economic development, job creation, utility cost savings, and secure energy futures. • Environmental: climate change concerns, defense against natural disaster, preservation of local environment and wildlife, and climate leadership. • Public health: clean air and water, and pollution prevention. • External: regional partnerships, existing state policies, existing or prior municipal policies or initiatives, and nonprofit partnerships. (DeFrancia, 2018)

An Introduction to the State of Renewable Energy at Airports 11 In response to these drivers, public initiatives have been designed to encourage renewable energy development. Such initiatives include the following: • Tax credits that decrease the installation or production costs of renewable energy generation; • Delivery mandates that require utilities to purchase a percentage of the total amount of electricity delivered to customers from renewable sources; • Purchasing mandates that require a minimum amount of the power consumed by a govern- ment entity (federal, state, county, or local) to be generated by renewable sources; and • Surcharges on customer utility bills used to fund projects that encourage the development of renewable energy. (National Renewable Energy Laboratory, 2011) While the two most prevalent federal tax credits for renewable energy development projects are currently being phased out (Center for Climate and Energy Solutions, 2019a), a growing number of states are creating financial incentives designed to increase the generation and consumption of renewable energy. In 2019, for instance, policy makers and regulators in 46 states enacted legislation or issued decisions promoting distributed solar, according to the 50 States of Solar Annual Report published by the North Carolina Clean Energy Technology Center (2020). In 2018, Berkeley Lab’s annual status update on U.S. renewable portfolio standards (RPSs) reported that “roughly half of all growth in U.S. renewable electricity (RE) generation and capacity since 2000 is associated with state RPS requirements” (Barbose, 2018, p. 3). Cities and municipalities are also promoting the deployment of renewable energy by piloting demonstration projects, leasing government-owned land for privately owned renewable energy installations, and updating local regulations to facilitate private renewable energy investments (Center for Climate and Energy Solutions, 2019b). As a result of these and other incentives, market demand for renewable energy has expanded, creating a robust supply chain of associated industries and businesses. These include but are not limited to manufacturers of renewable energy and associated technology, engineers for designing projects, installation and construction companies to build the projects, financiers to assess invest- ments and risks, legal experts to interpret the law, and energy market experts and consultants to assess opportunities for public and private clients. As these associated markets expand and competition among developers increases, the costs to produce renewable technologies are decreasing. The result is a significant reduction in the overall project costs and price of power generated on a per-unit basis (Barbose et al., 2016). Increased growth and the corresponding decrease in price are illustrated by activity in the U.S. solar industry in Figure 5. The overall decrease in the cost of renewable energy has enabled its broad adoption throughout society (International Renewable Energy Agency, 2019), from private residences, to government buildings—such as schools and emergency service centers—to nonprofit institutions—such as hospitals and higher education campuses. Corporations and individual businesses are actively integrating renewable energy as they build, move, or modernize their facilities (Business Renew- ables Center, 2018). Developers of private renewable energy who profit from new development projects offer services to these customers, enabling them to supply cost-competitive renewable energy. With renewable power incentivized by public programs and generated at prices close or comparable to market rates, airports are identifying more affordable and viable ways to partici- pate in this broader renewable energy marketplace. 1.2.2 Implementing Public Programs After developing public initiatives for renewable energy, governments seek locations at which to build and entities to implement the new programs. Airports, which are operated and

12 Airport Renewable Energy Projects Inventory and Case Examples maintained either by municipal or county governments or by state authorities, are often identi­ fied as potential sites for renewable energy projects encouraged by government initiatives (Overdevest and Proudfoot, 2016). When implementing a renewable energy program, government agencies most often start by setting a goal, such as consumption of 25% of all government electricity from renewable sources by 2020 (Trumbull et al., 2019). Goal­setting may be followed by the development of a strategic plan to assess ways for the government entity to achieve its goal. For example, an option might be for the government entity to develop renewable energy projects on government­owned prop­ erty; subsequently, the possibility of siting renewable energy development projects on airport property might be identified. States with aggressive renewable energy purchasing programs are shown in Figure 6. Though the “top­down” approach to renewable energy projects—initiated by public program developers, as described earlier—is a common driver of renewable energy development, another common driver is airports’ identification of their own initiatives. As revealed in this report’s featured case examples (see Chapter 4), many airports have identified a beneficial path whereby renewable energy emerges as an outcome of their long­term planning efforts. Often, the airport first develops a master plan that identifies economic and environmental objectives. In conjunc­ tion with the master plan, the airport develops a capital improvement plan that identifies funding priorities for specific improvement projects over a 5­year period. With the public program incen­ tives described earlier, strengthened by FAA’s direct support (for federal funding opportunities and agency guides, see Appendix C), airports are bolstering their master and capital improvement plans with renewable energy projects that, among other things, can (1) reduce the long­term cost of energy, (2) improve local air quality, and (3) decrease overall GHG emissions. Regardless of whether ideas for incorporating renewable energy originate with a government executive or an enthusiastic airport professional, airports are making use of their planning processes to capture renewable energy opportunities. 1.2.3 Renewable Options at Airports Renewable energy projects located on airport property require three fundamental elements: (1) an adequate connection to the electrical grid, (2) an entity to purchase or use the renewably Figure 5. Growth in the U.S. solar industry and reduction in costs, 2010–2019.

An Introduction to the State of Renewable Energy at Airports 13 generated power, and (3) a feasible on-site location that is in accordance with airport operations. Of these requirements, grid connection is often the most straightforward element of the initial siting process. Because airports require significant power to operate, there is often commensurate electrical grid infrastructure nearby to accommodate the necessary grid connection, though site-specific analysis is always necessary. The purchase of power, the second project component, is determined by project type and agreement structure. Financial aspects of each project depend on whether the airport, a utility, or a private entity owns or operates the project. Many renewable energy projects are designed to offset the airport’s energy demands, producing both on-site power and cost savings, while other projects are designed primarily to generate a direct revenue stream for the airport through lease structures or other agreements. Location, the third requirement for a successful renewable energy project, is often more complex than the first two because of the multiple considerations involved in the siting of projects on airport grounds. Among additional requirements, an appropriate site must 1. Meet all safety and operational requirements of the airport, 2. Ensure the project can attain energy production targets and financial goals, and 3. Allow for maintenance and access as necessary. In addition to complying with all FAA regulations and airport operations (both existing and planned), project location must also comply with local zoning regulations and use of adjacent land. Thus, siting renewable energy projects at airports can be advantageous because airports are already dynamic land users with nearly constant activity related to aircraft takeoff and landing, ground transportation, and power line and utility networks, as well as a variety of nonaeronau tical activities (U.S. Government Accountability Office, 2013, 60). Therefore, renewable energy projects sited at Figure 6. States with renewable energy targets.

14 Airport Renewable Energy Projects Inventory and Case Examples airports are often less intrusive than those proposed for less active or quieter areas. What becomes the most significant siting consideration, then, is ensuring that a renewable energy project is compatible with aviation activity and meets all airspace safety regulations and requirements. Compatibility depends on the type of technology proposed. Large structures located on or near airports can extend into airspace and represent a hazard to air navigation, as illustrated in Figure 7. Wind energy is particularly affected by this limitation. Wind farms, which generate large amounts of electricity in appropriate sites (generally more than 5 miles from airports), typically have turbines that extend 500 feet into the air. As wind turbines are sited closer to airports, their height must decrease to meet FAA regulations (FAA, 2012a). Decreasing a wind turbine’s height, how- ever, also significantly decreases its production capacity. Most wind turbines on airport property are small units that are located on the ground and attached to buildings. Compared to the large turbines on wind farms, these designs generate only small amounts of supplementary energy rather than acting as dependable energy producers. Thus, there is limited potential to develop meaningful wind power at airports. Other renewable energy options may not be limited by height or airspace constraints, but rather by the availability of or access to a natural power source. Biofuels have significant poten- tial for renewable energy use, but only at airports with local access to these fuels (e.g., wood waste as a byproduct of timber harvest in the Pacific Northwest and other forested regions). For airports with less proximity to these resources, biofuel projects require additional infrastruc- ture or development considerations. In the case of hydropower, large infrastructure systems are required to convert the energy of moving water into electricity, making it difficult for airports to practically access this power source (Alba and Manana, 2016). In contrast to these more limited options, the following renewable energy technologies have demonstrated that they work well within the airport landscape and are thus the greater focus of this report: • Solar technology—both PV and thermal—is generally suitable for any terrain, though energy production can vary significantly with climate. Additionally, given the low profile of solar panels and their modular construction, solar projects can be integrated in a variety of loca- tions across the airport campus. Figure 7. Airspace impingement of various objects.

An Introduction to the State of Renewable Energy at Airports 15 • Geothermal heating system components are located either in the airport building or under the ground, presenting no issues to airspace safety. In addition, geothermal projects can be sited in almost any location because the technology draws on the constant temperature maintained below the frost line, where the earth is isolated from temperature variation. While solar and geothermal options are good candidates for airports, each has important siting considerations. Solar projects must avoid significant impacts on glint and glare in accordance with FAA’s (2013) interim policy, “FAA Review of Solar Energy System Projects on Federally Obligated Airports.” Siting of geothermal projects depends more on an airport’s geophysical features and buildings systems. These and other specific renewable technologies are examined in more detail in Chapter 2. 1.3 Renewable Energy Development: Implementing Projects Airports consistently undertake significant planning to both improve short-term operations and identify capital projects that can accommodate long-term growth. Initial interest in devel- opment of a renewable energy project at an airport is often driven by this planning process, which can be led by individual staff members, airport leadership, or both. Regardless of who leads the planning process, the first step to advancing renewable energy projects is to take stock of an airport’s extensive planning framework. Figure 8 includes specific steps that can serve as a guide for moving through the process of developing an airport renewable energy project. An accompanying checklist is included in Appendix B. Figure 8. Practical steps for developing airport renewable energy projects.

16 Airport Renewable Energy Projects Inventory and Case Examples 1.3.1 Planning for a Renewable Energy Project Airports are required by FAA to prepare and keep current airport layout plans (ALPs) that depict existing facilities and planned development. From the ALP, many airports then prepare an airport master plan, which details air traffic forecasts, facility improvements to accommodate future demand, and environmental issues that must be addressed as part of project planning and implementation. Additionally, FAA requires that major airports develop capital improve- ment programs to identify expected capital needs over a 5-year period; this step is a prerequisite for submitting funding applications through the Airport Improvement Program, broadly known as AIP (FAA, 2020b). With increasing focus on energy and the environment, FAA launched its Sustainability Master Plan Pilot Program in 2010. FAA has also made AIP funds available to airports specifically for the development of sustainability plans, which include detailed assessments of energy use and asso- ciated emissions (FAA, 2012b). More recently, some airports have prepared individual energy plans in recognition of the central importance of energy use to airport operations and budgets, and to obtaining funding for energy efficiency assessments that are presently eligible under AIP grants. Each of these plans feeds back into an airport’s overall strategic plan and vision statement. When airports identify renewable energy projects in their strategic planning documents, they specify long-term objectives in relation to energy and the environment. One such goal may be to reach “net zero carbon,” the point at which airport building operations are highly efficient and fully powered by on-site renewable energy sources, off-site renewable energy sources, or a combination (World Green Building Council, 2020). This is best achieved through a hierarchy of actions that begins with an aggressive reduction in energy consumption, continues with conver- sion to low- or no-impact energy sources, and ends with carbon offsets (National Renewable Energy Laboratory, n.d.). When an airport’s net carbon dioxide emissions over the course of an entire year are zero, it can obtain an overall certification of carbon neutrality through the Airport Carbon Accreditation (ACA) program. Alternative accreditation standards, such as the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) certification or the Institute for Sustainable Infrastructure’s Envision program, can be applied to individual airport building projects in recognition of advancement toward this net zero target. Not all renewable energy initiatives need be this ambitious, however. Renewable energy can be plugged into the planning process in the form of shorter-term projects that help meet long-term goals. For instance, solar thermal projects can immediately reduce heating costs while supporting the airport’s overall sustainability goals of energy reduction. One of the key benefits of renewable energy is its flexibility. Renewable energy can be integrated directly into capital and improvement projects as they are being built, or it can be incorporated into planning and design elements that allow for the addition of renewable energy in the future. Renewable energy projects can also be dismantled or redesigned at the end of their useful life, allowing for the airport to consider the best use of its land over time. 1.3.2 Organizational Champions Even feasible and beneficial projects require effective messengers to facilitate successful implementation. For an airport’s renewable energy project, this messenger can be anyone on the airport staff who believes the project will benefit the airport’s long-term goals and who can successfully communicate those benefits to the internal and external stakeholders involved in financing and approving the project. Ultimately, the airport’s executive team will need to back the project, or it is unlikely that the project will secure the resources necessary for its success. Initial opportunities, however, are often identified by one informed champion or a small group of individuals.

An Introduction to the State of Renewable Energy at Airports 17 The success of project champions will be determined in part by their ability to integrate renew- able energy into the airport’s strategic plans. It is in the initial discussions and negotiations of setting plan priorities that conversations about sustainability and renewable energy often begin. These concepts are then specified in the plan and brought to the airport’s executive staff for consideration, review, and approval. If project champions can successfully demonstrate how renewable energy meets the long-term economic and environmental objectives of the airport’s development, then the renewable energy concept becomes (1) a component of the airport’s plan and (2) a priority that can be referred to in subsequent conversations about capital programs and airport operations. If, however, renewable energy objectives do not make it into an airport’s plan- ning documents, it will be difficult for project champions to advocate for individual projects unless some new, unanticipated opportunity arises. Ultimately, the goal for internal champions of renewable energy is to incorporate implementa- tion goals either directly into planning documents (as discussed earlier) or, by broader inference, into the airport’s strategic plan, as the latter document guides the long-term decision making of the airport’s executive team and its board members. For example, some airports have identi- fied net zero carbon in their airport strategic plan, which requires adoption of renewable energy technologies. Another long-term goal that is in the interest of the airport and its tenants is emer- gency planning, as well as the subsequent opportunities associated with developing an energy microgrid that addresses emergency energy needs. When renewable energy is a core element of the airport’s strategic plan, the approval of projects that contribute to renewable energy goals is prevalidated; this facilitates approval of appropriate renewable energy projects that help ensure the airport’s progress toward its stated strategic objectives. 1.3.3 Responding to a New Opportunity For some airports, it is difficult to strategically plan for renewable energy opportunities. This is particularly true for small, nonhub, and general aviation airports that may lack the staffing and financial resources to actively pursue alternatives to current business and operational structures, especially when those airports are running without any unusual problems or difficulties. While many large airports are preparing strategic plans and weighing the business case for renewables, it is more common for managers of smaller airports to be approached by developers of renewable energy projects with an opportunity to host a project on airport land. Under such circumstances, airport staff members must quickly learn about the proposed project—and about similar projects at similar airports—to be able to adequately assess a wide range of considerations, including revenue generation, energy cost savings, financial investment, infrastructure renovations, mainte- nance, staff time, customer relations, and public sentiment. These circumstances are particularly relevant to solar PV energy (Barrett et al., 2016). Given the solar incentive programs being authorized by state legislatures and the renewable energy mandates being established by state energy offices, private solar companies are actively seeking locations for their incentivized projects. Solar developers seek key features that help ensure cost-effective electricity production, which in turn allows their projects to be developed with predictable costs and schedules. Airports frequently emerge as prime locations because their flat, cleared buffers of nonaeronautical land make construction easier and provide access to the existing electrical grid infrastructure. Thus, airports are being directly approached by private solar companies that have identified underused airport lands, with developers often seeking to sign a short-term (e.g., 2-year) “option” agreement to explore solar project development. When a project progresses to the implementation phase, private developers will complete construction of their solar project; then, developers typically convert their option agreement to a long-term lease of the airport property. This structure provides the airport with a reliable, mutually agreed- upon monthly or annual revenue payment that supports aviation business.

18 Airport Renewable Energy Projects Inventory and Case Examples Unanticipated opportunities for renewable energy projects may also arise from newly created or existing grant programs made available through federal and state sources. Determining the potential costs and benefits involved in pursuing such projects may require some research by an internal champion or airport consultant. However, learning from other airports and industry peers that have pursued and capitalized on such opportunities is a valuable approach for champions of renewable energy projects to take; numerous ACRP reports, including this document, feature detailed case examples and lessons learned from renewable energy projects that interested parties can leverage for their own benefit. 1.3.4 Key Role of Stakeholders Renewable energy projects are complex, and an evaluation of their suitability requires the consideration of many interested parties with different areas of expertise. New projects must be vetted by a variety of internal and external stakeholders, who assess how the projects both measure against organizational goals and are in regulatory compliance. Maximizing input from stakeholders can help project champions identify potential hurdles and build consensus for optimal outcomes (Schaar and Sherry, 2010). Stakeholders fundamental to the successful develop- ment of a renewable energy project are shown in Figure 9. The first layer of stakeholder engagement is typically limited to internal airport staff, including those with expertise in energy, sustainability, planning, and engineering. It focuses on the project idea and conceptual plan, among other fundamental considerations. The staff members involved will vary depending on the size of the airport, its resources, and its organization. Smaller airports, with limited staff resources, may coordinate closely with city and county officials and critical tenants from the outset. Figure 9. Stakeholders of an airport renewable energy project.

An Introduction to the State of Renewable Energy at Airports 19 Essential external stakeholders will likely be included in the next layer of engagement, which— for an airport renewable energy project—would include the FAA regional office contact as well as the airport utility provider. Upon initial introduction of the project concept, these key stake- holders can confer with their specialty staff to provide more extensive feedback. For example, FAA may request staff members involved with airspace safety and environmental compliance to provide information on issues of concern and to review the overall project processes and time- lines. The utility can provide information on current energy usage and patterns, grid access and infrastructure matters, and renewable energy incentives and rebates. As the project evolves, additional internal, external, and community stakeholders may be consulted to further vet feasibility and design issues. For example, the airport fire and rescue department may have comments on design and shutoff to ensure compliance with existing safety codes. Local and state energy officials may be aware of grants available for implementation of renewable energy projects. Local chambers of commerce and economic development organizations may wish to weigh in on opportunities for regional workforce and local businesses’ participation. While the array of stakeholders will vary by project and location, it is critical that airports identify appropriate parties and partners early in the project development process. 1.4 Industry Progress to Date Progress in renewable energy at airports is summarized in this report as well as numerous other publications. Industry reports specific to airport renewable energy development are available through FAA, the International Civil Aviation Organization (ICAO), and the National Renewable Energy Laboratory, as well as in detailed articles appearing in industry publications such as the Journal of Airport Management and Aviation Pros magazine. A list of further resources and suggested guides accompanies this report (Appendix C). As a general archive of airport renewable energy projects completed to date, this report— ACRP Synthesis 110: Airport Renewable Energy Projects Inventory and Case Examples—includes a comprehensive inventory matrix of renewable energy projects that have been developed on airport property in the United States by airports, tenants, FAA, utilities, and private developers. It also includes case examples that illustrate different technologies, ownership structures, and financing models at airports of varying size around the country. The inventory (Appendix A) shows that airports have been developing an increasing variety of renewable energy projects that continue to expand in size and scope. For instance, the largest solar PV project located on a U.S. airport property to date was recently constructed at Tallahassee International Airport in Tallahassee, Florida. Energized in January 2020, the solar project, operated by a private solar company through a lease of airport land, has a capacity of 55 MW (direct current) of renewably generated electricity fed into the utility grid. Of similar note, the largest-ever geothermal cooling project in North America was completed at Nashville International Airport in 2016. This innovative renewable energy project uses cool lake water to reduce the airport’s air conditioning costs in summer by an average of 1.3 million kW-h each year, saving the airport approximately $430,000 per year (McGee, 2015). To more closely examine this range of airport renewable energy progress, the case examples in this report include varying models of solar PV development, two different types of geothermal heating and cooling, deployment of biomass and anaerobic digestion technology, an innovative renewable energy purchasing program, and battery storage that supports other renewable energy sources. Progress in the airport industry is evidenced by the development of policies and tools such as the FAA solar policy and the Solar Glare Hazard Analysis Tool (SGHAT) to improve safe and

20 Airport Renewable Energy Projects Inventory and Case Examples compatible project siting, and funding programs such as the Section 512 energy efficiency program to support energy planning and implementation of renewable energy projects. Technological improvements have also been made to the electrical efficiency of solar panels, with typical silicon modules having increased power output by a third since 1995 (National Renewable Energy Labo- ratory, 2020). Power output has increased, in part, through antireflective design, which reduces reflections off the panels, thus reducing the potential impact of glare. Similarly, technological advances in combustion and control automation, as well as widespread production of wood pellets, have improved the economics of biomass boilers (General Services Administration, 2014). Performance and “success” are difficult to measure and depend on the airport’s objectives in implementing the project, as well as unique project conditions and characteristics. Some projects were primarily funded with government grants, including so-called shovel-ready projects under the federal stimulus program, or ARRA. These projects resulted in “free” electricity and lower utility bills, a relatively simple measure of success. Other projects may have required the airport to execute a long-term power contract to purchase clean energy; if market rate power subsequently decreased, such projects may in retrospect have been a costly choice. Notwithstanding shifts in market prices, these projects would have achieved previously identified and articulated carbon- reduction and environmental goals, with the prospect for better economics as market forces change during the project life of 20+ years. Each of the 10 case examples provides project benefits and lessons learned to illustrate these issues for a group of individual projects. From a high-level perspective, the sheer volume of projects (219 projects at 146 different airports) suggests that renewable energy has been successfully integrated into the airport environment. In aggregate, the data show that airports are adopting renewable energy in a variety of ways, with industry forecasts indicating continued renewable energy growth (International Energy Agency, 2019). As the economic viability and benefits of renewable energy expand, and as new programs to regulate carbon emissions are implemented (such as ICAO’s Carbon Offsetting and Reduction Scheme for International Aviation, or CORSIA), airports are increasingly turning to renewable energy projects to meet economic and environmental objectives. From generating on-site power to creating additional revenue streams, from creating energy resiliency to reducing carbon emissions, the industry of renewable energy at airports continues to grow in a flexible manner that is likely to benefit airports of all sizes and in locations across the country.