Investigating Safety Impacts of Energy Technologies on Airports and Aviation (2011)

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33 As described in this report, energy developments are expand- ing nationwide as a result of increasing energy demand and development of new and innovative technologies. Although many of these projects result in a decrease in air and water emissions and support national policies including energy secu- rity and climate change, many are introducing potential con- flicts with existing uses including airports and aviation. This report has reviewed new energy technologies and their poten- tial impacts with the purpose of defining the current state of knowledge and suggesting future research. The following impacts have been identified and the exist- ing base of knowledge presented. • Physical Penetration of Airspace—All of the energy technologies discussed in this report have the potential to penetrate airspace depending on their proximity to airports. However, wind turbines are the most common energy technology with a potential impact because util- ity-scale wind turbines can exist more than 300 ft above ground level. Power towers from particularly concen- trated solar power facilities are being proposed at more than 450 ft in height. • Communication Interference—Again, it is possible that any of the energy technologies assessed could interfere with aviation radar. However, wind farms have been iden- tified as producing the most significant impact owing to the amount of clutter or false radar signals that are picked up by navigation and weather radar. • Visual Impact from Glare—This impact is specific to solar technologies that have the potential to reflect sunlight from its surfaces. Concentrating solar power facilities, which use mirrors to actively reflect sunlight to concentrate it and boil water, pose the greatest risk of visual impairment from glare. • Thermal Plume Turbulence—This impact is specific to power generation that boils water to run a steam turbine, which is accomplished either by firing fossil fuels or biofuels or with a concentrated solar power facility. The thermal plume is produced by those facilities that use dry cooling (e.g., an air-cooled condenser) to cool the steam for reuse. • Vapor Plume Visual Impact—As with the thermal plume, the vapor plume is a product of steam turbine electric- ity generation. However, the vapor plume is produced by units that utilize evaporative wet cooling to cool the steam for reuse. • Wind Turbine Rotor Turbulence—Downwind of a wind turbine the air can be destabilized, producing turbulence that can impact aircraft. This study found that a significant amount of research has been conducted, particularly over the past year, on energy tech- nologies and their safety impacts on airports and aviation. In 2010, the FAA completed Technical Guidance for Evaluat- ing Selected Solar Technologies on Airports, which generated new information associated with solar photovoltaic panels and farms. The California Energy Commission has conducted a review and issued decisions for the Blythe Solar Power Plant and the Ivanpah Solar Electric Facility that provide updated guidance on impact assessment of concentrated solar power projects. The DOE’s Sandia National Laboratories has produced information on potential glint and glare from concentrating solar power technologies. The U.S. Trans- portation Command has issued a report in association with Travis Air Force Base and three private wind energy devel- opment companies on the effect of farm construction on radar performance. Furthermore, the FAA is actively administering airspace reviews to assess the potential impact of new energy projects. Where most effective, these reviews are being completed under a systematic and coordinated federal–state environmen- tal review process such as those completed by the Bureau of Land Management and California Energy Commission for concentrated solar projects in Southern California. Wind tur- bine projects have been more difficult to coordinate as a result of the sheer volume of applications. Although each wind tur- bine receives an independent review, a cumulative assessment becomes more difficult given the volume of applications and time constraints on reviews. Cooperation between federal agencies and in concert with state agencies have helped identify gaps in the knowledge base and reach consensus on high-profile projects as well as a more coordinated review strategy. Mitigation measures have been developed by regula- tory agencies to minimize the impacts of energy technol- ogies. The mitigation measures identified included the following: • Marking and lighting of wind turbines, power towers, transmission towers, and other tall structures. CHAPTER EIGHT CONCLUSIONS

• Operations and maintenance procedures for concentrat- ing solar power facilities to avoid inadvertent glare. • Use of anti-reflective coatings and roughened surfaces to minimize glare from solar photovoltaic sources. Formal notices to airmen and updates to nautical charts alerting pilots to potential hazards of thermal uplift and glare posed by concentrating solar power and air-cooled condensers. • Monitoring plans to assess the potential impact of glare on sensitive receptors. • Upgrading of radar infrastructure and software to filter out radar clutter. • Preservation of a flight buffer of 1,000 ft above energy facilities. Based on this information, we suggest the following data collections be conducted to enhance the existing knowl- edge base: 34 • Develop a comprehensive inventory of energy facilities to establish a baseline for implementing planning and conducting cumulative impact assessments. • Conduct a survey of pilots to collect more experiential information about their understanding of potential energy impact issues and document their experiences. • Conduct a detailed review of aircraft accidents to quan- tify energy technology components. • Prepare siting and planning guidance for each energy technology. • Conduct a risk assessment for each energy technology and opportunities for aviation adaptation. • Assess cumulative impacts for each technology. • Develop predictive glare assessment tools that more actively and consistently quantify glare impacts expe- rienced at existing facilities. • Collect field data on thermal plume turbulence to sup- port an impact assessment threshold.