Microgrids and Their Application for Airports and Public Transit (2018)

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1 Airports and public transit services are critical infrastructure with significant power demands and emission reduction goals. These features make them the ideal candidates for exploring the opportunities that microgrids can offer. Traditionally a way of generating electricity at a remote location with no access to the wider electrical grid, microgrids have more recently become popular as a supplement to a utility grid connection. A microgrid can be described as a collection of loads, on-site energy sources, local energy storage sys- tems (ESSs), and an overarching control system. Developments in control technologies have seen advanced microgrid controllers expand microgrid functionality to create new value streams and revenue opportunities, increasing microgrid viability to many more sectors. The purpose of this synthesis is to capture the benefits, challenges, costs, revenue streams, and ownership structures relevant to airports and public transit entities. It will also highlight knowledge gaps and feature success stories from within and outside of the airport and public transit industry. Study Methodology Information for this synthesis was gathered by a review of existing literature, reviews of documented case studies, and data collected via surveys and interviews from three air- ports, one airline, three public transit entities, two universities, and the U.S. Department of Defense (DOD). Case examples have been collected to highlight successful installations and to share lessons learned and business case insights. Particularly useful details have been highlighted in shaded callout boxes throughout the report. Background Examples of operational airport and public transit microgrids are limited. Currently, backup power generally is provided by the traditional method of multiple diesel generators combined with simplistic controls. Although diesel generators generally are under-utilized assets, issues with their use include many cases of operation failure in disaster situations, hefty maintenance requirements, liquid fuel supply issues, inability to power operations, and significant environmental drawbacks. Modern, advanced microgrids can provide the advantages of continually used assets, monetization of assets through grid services, and energy cost reductions. For airports and public transit agencies, the driving factors for microgrid implementa- tion are resilience and reliability. On December 17, 2017, Hartsfield–Jackson Atlanta Inter- national Airport experienced an 11-hour power outage that resulted in 1,150 cancelled flights S U M M A R Y Microgrids and Their Application for Airports and Public Transit

2 Microgrids and Their Application for Airports and Public Transit and affected 30,000 travelers. The cause of the outage was a fire in an electrical utility service tunnel, which cut off power to both the primary and redundant feeders to the airport. In this situation, a microgrid would have provided clear benefits, but they are difficult to quantify to develop a business case, and additional research in this area would be highly beneficial. Each microgrid is unique. The size, composition, functionality, and feasibility of the microgrid depends on many factors, including electricity price, natural gas price, solar resource, wind resource, building use, time of use, occupancy levels, climate, access to incen- tives and grants, local construction costs, owner goals, site-specific constraints, remoteness, and existing or new-build infrastructure. Successful business cases will depend on the right combination of utility pricing, fuel cost, carbon cost, generating asset cost, and access to provide ancillary services. State and federal subsidies and grants also play a critical role in the viability of projects, especially in supporting lower emission solutions. Current airport and transit microgrid operators include the Southeastern Pennsylvania Transportation Authority (SEPTA), the Massachusetts Bay Transportation Authority (MBTA), and Denver International Airport, all of which participate in a microgrid part- nership contributing land for solar photovoltaic (solar PV) carports. At time of writing, the New Jersey Transit Corporation (NJ Transit) microgrid is in the planning and design stage, and San Diego International Airport is in the procurement phase for a battery energy storage system (BESS) to supplement their on-site solar arrays and 12 kV distribution system. In Vermont, Burlington International Airport is working with the Burlington Electric Department to appoint a contractor to deliver their microgrid design. In New York State, known feasibility studies have been undertaken for Albany International Airport in Albany County and Stewart International Airport in New Windsor. In Illinois, Chicago’s Rockford International Airport and in California the John Wayne Airport in Orange County also are looking at options for constructing a microgrid. Interest in microgrids in the airport and transit sectors will likely increase significantly in the coming years. Drivers for Adoption The main drivers for increased adoption of microgrids across all sectors will include significant cost reductions in battery storage technology, increases in electricity rates, regulatory changes, climate goal mandates, and more frequent and severe weather events. Persisting barriers that need to be overcome to facilitate this market movement include the regulatory and interconnection process, and policies that need to continue evolving to support microgrid adoption. Several state task forces have been formed to investigate microgrid integration into the existing energy mix. Such committees consistently recom- mend that policy and energy markets be brought up to speed with the technology. Increased communication with utilities and continued development of partnerships between the public and private sectors also will foster industry growth. Even today, many projects can realize financial benefits from microgrid adoption; how- ever, this is not true across the board. For example, although a feasibility study showed a breakeven point for Stewart International Airport at 0.4 days of electrical outages per year, a study conducted for the Eighth Avenue Manhattan commercial microgrid indicated that financial viability would require outages totaling 22 days per year. The value of avoided out- ages often is a determining factor and makes the case for many microgrids in defense and university applications. Microgrids that fall into the category of “community” and “critical assets” also receive more support and have access to more grant funding. Successful funding models for airports

Summary 3 and transit entities are likely to follow the success of public-private partnerships (P3s) and third-party asset ownership models in conjunction with varying degrees of owner financing. Microgrid system costs vary widely because system sizes, equipment components, and configuration are unique to the individual project needs. Generation and storage assets represent the greatest portion of the cost, so airports and transit entities with existing assets can expect an improved business case due to lower up-front costs and improved utilization of existing systems. Further Research Although design standardization opportunities are limited outside of system equipment design, further research is desirable regarding the financial impacts of power usage and momentary power quality issues. Further research can contribute to the development of guidance on monitoring of power disturbance frequency and consequences to assist air- ports and public transit entities in developing microgrid business cases. Airports and public transit entities would benefit from a centralized resource for tools and guides to aid the microgrid planning, including success stories in microgrid planning and development as practice matures. The industry also would benefit from a central resource for tools and guides in relation to the microgrid planning and development process.