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38 This chapter discusses emerging technologies, innovative project delivery, and policy trends that will impact energy effi- ciency at airports in the future. Unique or innovative practices and those with long-term payback included solar PV, wind energy systems, and high-performance windows. EMERGING TECHNOLOGIES Solar Thermal and Photovoltaics As identified more than 20 years ago in the Bruntland report, the technology for solar thermal and solar electric technolo- gies is constantly improving and âit is likely that their con- tribution [to energy production] will increase substantiallyâ (Bruntland 1987, p. 144). The need for a steady transition to a broader and more sustainable mix of energy sources is beginning to become accepted. Renew- able energy sources could contribute substantially to this, partic- ularly with new and improved technologies, but their development will depend in the short run on the reduction or removal of certain economic and institutional constraints to their use (Bruntland 1987, p. 145). Airport terminals possess distinct advantages that position them well for implementation of solar technologies in the future including large roof areas and limited shading from vegetation. FresnoâYosemite and Phoenix Airports have installed large, greater than 1 MW, projects. Although prices for electricity from photovoltaics may not become widely competitive with wholesale prices for electricity from con- ventional generating technologies within the next 25 years, they may be competitive with high retail electricity prices in sunny regions (EIA and DOE 2009). Power Purchase Agreements for Photovoltaic Systems In addition to owner-installed and managed roof-top PV instal- lations, alternative leasing models are being tested across the country, with one of the largest being initiated by the utility, Southern California Edison and their Solar Roofs Program. Southern California Edison or a private corporation will âown, install, operate and maintainâ rooftop systems on existing commercial or public rooftops, leasing space from and sell- ing power to building owners through contracts known as power purchase agreements. This strategy takes advantage of large, underutilized roof areas within the established electrical grid and uses them for electrical production (Coughlin 2009). With large roof areas on terminal buildings, hangers, and parking structures, and very little shade from surrounding buildings, airport terminal roof tops are often prime can- didates for large-scale PV installationsâespecially as panel efficiencies increase and costs decrease (Seidenman and Spanovich 2008). Quoting California Public Utilities Commission Commis- sioner John A. Bohn, âUnlike other generation resources, these projects can get built quickly and without the need for expen- sive new transmission lines. And since they are built on exist- ing structures, these projects are extremely benign from an environmental standpoint, with [limited] land use, water, [and] air emission impactsâ (California Public Utilities Com- mission 2009, p. 2). Because a private investment group and solar developer pay for installation, all up-front capital costs are avoided; how- ever, agreements are legally complicated and usually require an agreement to purchase power at a fixed rate for 20 years or more (Coughlin 2009). Geothermal or Ground-Source Heat Pumps Ground-source heat pump (GSHP) is the name for âa broad category of space conditioning systems that employ a geother- mal resourceâthe ground, groundwater, or surface waterâ as both a heat source and sink. GSHPs use a reversible refrig- eration cycle to provide either heating or coolingâ (DOE 2007). By replacing old or inefficient direct expansion mechanical systems with GSHP, significant savings and additional flexi- bility within the system can be achieved. Very limited use was noted in the survey with only one major airport providing cost data. These data indicated a 2- to 5-year payback and medium level of investment. Other sources indicated longer payback terms of 4 to 13 years and savings of 25% to 30% on energy consumption (Turner et al. 2007, p. 14; DOE 2008). Ongoing improvements at the JNU airport include the addi- tion of GSHP systems and envelope retrofits. Although the $1 million cost of the GSHP system is close to 20% of the annual operations budget, a combination of grants, legisla- CHAPTER EIGHT NEW TECHNOLOGIES, INNOVATION, AND LONG-TERM PAYBACK
39 other airports, including Toronto, which built a âthree turbine cogeneration plantâ (Schwartz 2009). The âuse of cogeneration is not a simple decision because of fluctuating natural gas and electric prices and high capital costsâ (Turner et al. 2007, p. 6). Micro Wind Turbines Small-scale wind turbine installation, such as PV installation, has been considered as a supplemental energy source for air- port terminals. Currently, their implementation is challenged by low electricity rates, which can significantly extend pay- back periods. As a test case, on-site, parapet-mounted wind turbines were recently installed at MSP Airport. Although long-term data are not yet available, payback periods of greater than 10 years are expected at this time (see Figure 14). Peak Shifting Thermal Storage To avoid paying peak demand charges for energy during the most intensive months and days of the year, some airport respondents utilize peak-shifting thermal storage. This prac- tice takes energy at off-peak times to heat or cool a material Box 17 Implementing Geothermal Space Conditioning Juneau International Airport ( JNU) and the surrounding community typically heat with diesel fuel owing to the land- locked geography and therefore are very sensitive to fuel prices. When the airport began evaluating a terminal reha- bilitation and expansion, fuel prices were rising, which made operating costs a determining factor in the decision to install a ground source heat pump or geo-thermal system, one of the first systems in the area. With this system coming on line in the late fall of 2009, the airport is already looking ahead to future improvements. Another geothermal system, this one a horizontal loop field, was installed for a future main- tenance building as the building site was disturbed during a separate earthwork project (see Figures 12 and 13). Bemidji Regional Airport (BJI), located in northern Min- nesota, is taking a similar approach, and utilizing large land areas that airports have available to plan for a geother- mal system. This system will be a vertical well-field installed adjacent to taxiways to serve an expanded terminal build- ing, as well as a renovated Aircraft Rescue and Fire Fighting (ARFF) facility. FIGURE 12 Geothermal well field. Well fields installed below existing pavements at Juneau International Airport (Courtesy: JNU). FIGURE 13 Geothermal system installation. tive appropriations, and facility fees coupled with expected savings of at least $80,000 per year in energy costs, mean an expected payback of just over 6 years (Martin 2009). Geo- thermal ice and snow melt systems in exterior pavements are expected to bring additional savings owing to reduced equip- ment maintenance costs, labor, and ice removal chemical expenses (Martin 2009). Cogeneration of Heat and Electricity The survey found no use of cogeneration technology by sur- vey respondents. Literature sources indicated utilization at
40 (usually water) that is then used for heating or cooling energy during peak times. A second method of peak shifting involves switching power generation to on-site diesel or natural gas powered generators or PV arrays, which reduces demand for utility-provided power. If generators are used, local air qual- ity may be affected. Considerable cost savings can be realized with thermal storage technology if utility rate schedules have penalties for high peak electrical demand (Turner et al. 2007, p. 12). Ther- mal storage retrofits have an estimated payback of 3 to 10 years (Turner et al. 2007, p. 14). Windows Future window technologies will continue to improve the insu- lating properties of window systems and increase the respon- siveness of building envelopes to daily changing climatic conditions. Ways that windows may continue to contribute to build- ing energy efficiency include: â¢ Insulation Filled GlazingââThere are several options for highly insulating windows with aerogel, honey- combs, and capillary tubes located between glazing panes. These materials provide diffuse light, not a clear viewâ [Center for Sustainable Building Researchâ University of Minnesota (CSBR-UMN) 2007]. â¢ Dynamic âSmartâ WindowsââThese facade systems include switchable windows and shading systems such as motorized shades, switchable electrochromic or gaso- chromic window coatings, and double-envelope window- wall systems that have variable optical and thermal properties that can be changed in response to climate, occupant preferences and building system requirementsâ (CSBR-UMN 2007). â¢ Building Integrated PhotovoltaicsââPhotovoltaic vision glass integrates a thin-film, semitransparent photovoltaic panel with an exterior glass panel in an otherwise tradi- tional double-pane window or skylightâ (CSBR-UMN 2007). âGreenâ or Renewable Power Two survey respondents indicated that renewable power was purchased by the airport in substitution for carbon-based power. This arrangement may reduce utility costs during peak periods and supports greater investment by utilities in renew- able power systems. EMERGING PROJECT DELIVERY As energy efficiency and sustainable design become more integrated into new and existing buildings, project delivery methods are adapting to accommodate the added complexity of energy systems and building management. Integrated Design and Building Simulation Integrated design is a departure from typical design and construction processes that brings disciplines together early in the process, holistically evaluating the design in terms of energy performance and other factors. It can âenhance air quality, lighting, thermal environment and other key aspects of a buildingâs indoor environmentâ (Griffith et al. 2007, p. 9). The integrated team requires collaboration between all stakeholders. âThe expansion of the âefficiency resourceâ is also accel- erating as designers realize that whole-system design inte- gration can often make very large (one or two order-of- magnitude) energy savings cost less than small or no savings, and as energy-saving technologies evolve discontinuously rather than incrementally. Similarly, rapid evolution and enor- mous potential apply to ways to market and deliver energy- saving technologies and designs; research and development can accelerate bothâ (Lovins 2004, pp. 384â385). FIGURE 14 Micro scale wind turbines. Parapet mounted turbines mounted on the airport fire station at MSP.
41 EMERGING POLICY Emerging Energy Guidelines Federal regulations within the Energy Policy Act of 2005, as well as state-level high-performance energy codes, will con- tinue to push private and public sector buildings to improve energy efficiency. Federal standards noted here by literature sources represent one future direction that could have signif- icant impacts on buildings such as airport terminals. â¢ EPACT Section 103âall federal buildings must be metered by 2012. â¢ EPACT Section 1251ânet metering. â¢ EPACT Section 1331âsupport for $1.80 per square foot tax deduction for sub-metered properties (Millstein 2008). State by state, policies regarding energy efficiency for build- ings and utilities continue to develop rapidly. The American Council for an Energy-Efficient Economy has identified major issues regarding energy efficiency in most states. WEBLINKâState Energy Efficiency Policy Database American Council for an Energy-Efficient Economy: http://www.aceee.org/energy/state/index.htm ZEBâNet Zero Energy Buildings âDesigning a building in such a way that energy efficiency and on-site production convert it from an energy consumer to an energy producer lies at the heart of the zero-energy build- ing (ZEB) conceptâ (Griffith et al. 2007, p. 1). Studies by the National Renewable Energy Laboratory on ways to achieve net zero energy building âindicate that the amount of energy that can be saved by efficiency measures is comparable to the amount that can be generated by rooftop PV panels and that pursuing both is important for reaching the ZEB goalâ (Griffith et al. 2007, p. 64). Because of the many energy-intensive systems at airport terminal buildings, they may be challenged to achieve net zero energy status. Interviewees indicated that strategies learned from the ZEB concept will enable airport managers to better control the escalating costs of energy. Chapter Summary The following practices were identified within literature and survey data as emerging technologies, policies, and trends that will impact energy efficiency at airports in the future. â¢ Renewable and on-site energy technologies such as solar PV and geothermal space conditioning coupled with innovative financing and purchasing agreements have already reduced energy costs at some airports. â¢ Envelope materials and mechanical systems are becom- ing more adaptable and responsive to changing envi- ronmental conditions. â¢ Design delivery methods for new or complex proj- ects often include integration of analysis and energy modeling. â¢ Federal and state energy guidelines continue to endorse and require energy efficiency. â¢ Airport terminal buildings will continue to be challenged to manage energy use in the face of escalating energy costs and demands for energy neutral buildings.