Floating photovoltaic (FPV) systems, also called floatovoltaics, are a rapidly growing emerging technology application in which solar photovoltaic (PV) systems are sited directly on water. The water-based configuration of FPV systems can be mutually beneficial: Along with providing such benefits as reduced evaporation and algae growth, it can lower PV operating temperatures and potentially reduce the costs of solar energy generation. Although there is growing interest in FPV, to date there has been no systematic assessment of technical potential in the continental United States. We provide the first national-level estimate of FPV technical potential using a combination of filtered, large-scale datasets, site-specific PV generation models, and geospatial analytical tools. We quantify FPV co-benefits and siting considerations, such as land conservation, coincidence with high electricity prices, and evaporation rates. Our results demonstrate the potential of FPV to contribute significantly to the U.S. electric sector, even using conservative assumptions. A total of 24 419 man-made water bodies, representing 27% of the number and 12% of the area of man-made water bodies in the contiguous United States, were identified as being suitable for FPV generation. FPV systems covering just 27% of the identified suitable water bodies could produce almost 10% of current national generation. Many of these eligible bodies of water are in water-stressed areas with high land acquisition costs and high electricity prices, suggesting multiple benefits of FPV technologies.

Microgrids are being increasing deployed to improve the operational flexibility, resilience, coordinated-energy management capabilities, self-adequacy, and increased reliability of power systems. This strong market growth is also driven by advances in power electronics, improved control systems, and the rapidly falling price and increased adoption of distributed energy generation technologies, like solar photovoltaics and storage. In the event of grid outages, microgrids can provide a backup source of power; providing resilience to the critical loads; however, this requires that the microgrid itself is resilient to physical and cyber threats. Building highly resilient microgrids requires a methodological assessment of potential threats, identification of vulnerabilities, and design of mitigation strategies. This paper provides a comprehensive review of threats, vulnerabilities, and mitigation strategies and develops a definition for microgrid resilience. The paper also develops a methodology for designing resilient microgrids by considering how microgrid designers and site owners evaluate threats, vulnerabilities, and consequences and choose the microgrid features required to address these threats under different situations.

Executive SummaryLike many island communities, the U.S. Virgin Islands (USVI) is almost 100% dependent on fossil fuels for electricity and transportation. This total reliance on oil leaves the territory vulnerable to global oil price fluctuations that can have devastating economic effects on individuals and businesses. USVI electricity costs are over four times the U.S. average, making energy price spikes extremely difficult for ratepayers to absorb. And like other island communities around the world, the U.S. Virgin Islands are among the first to feel the impact of the environmental threats associated with fossil fuel-based energy sources-rising sea levels, intense hurricanes, and widespread loss of coral reefs due to ocean acidification.Such risks and hardships incurred by islands offer mounting evidence that the status quo is unsustainable. In the USVI and other island communities, this has created a sense of urgency around the need to dramatically transform the way energy is sourced, generated, and used. In response, islands around the globe have adopted some of the most aggressive clean energy goals. The USVI's goal is to reduce fossil fuel use 60% from business as usual by 2025. Source: NRELAs islands reduce their fossil fuel usage, they have an opportunity to lead the rest of the world in transforming our shared energy future. This report describes one area in which islands may lead: integrating a high percentage of renewable energy resources into an isolated grid. In addition, it explores the challenges, feasibility, and potential benefits of interconnecting the USVI grids with the much larger Puerto Rican grid.vi The overall objective of the interconnection study is to explore the most economical mix of fossil fuel-based and renewable power generation technologies that can be deployed to enable the USVI to reach its goal. This report focuses on the economic and technical feasibility of integrating renewable energy technologies into the USVI transmission and distribution systems. The report includes three main areas of analysis:• The first area of analysis (Sections 3 and 4 of the report) examines the economics of deploying utility-scale renewable energy technologies, such as photovoltaics (PV) and wind turbines, on the islands of St. Thomas and St. Croix.• The second (Sections 5, 6, and 7) focuses on the potential sites for installing roof-and ground-mount PV systems and wind turbines and investigates the impact renewable generation will have on the electrical subtransmission and distribution infrastructure.• The third (Section 8) summarizes the results of a study to determine the feasibility of a 100-200 megawatt (MW) power interconnection of the Puerto Rico, USVI, and British Virgin Islands (BVI) utility grids via a submarine cable system. Economic AnalysisThe National Renewable Energy Laboratory (NREL), in partnership with HOMER Energy LLC, developed two models using the Hybrid Optimization Model for Renewable Energy ( The results of the analysis demonstrate the following:• Wind is cost effective at...

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NOTICEThis report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof.Available electronically at http://www.osti.gov/bridge Available for a processing fee to U.S. Department of Energy and its contractors, in paper, from: U.S. Department of Energy Executive SummaryWith high energy costs, isolated grids, and abundant renewable energy resources, island communities around the world are exploring alternatives to fossil fuels. Many small island states have set ambitious targets to reduce oil consumption-the primary fossil fuel consumed on islands. The U.S. Virgin Islands (USVI) has emerged as a leader in the effort to reduce oil imports and stabilize electricity costs via the deployment of energy efficiency and renewable energy technology. In 2010, a partnership among the USVI, the U.S. Department of Energy (DOE) who funded this report, and the U.S. Department of the Interior (DOI) was formed under the guidance of DOE's Energy Development in Island Nations (EDIN) initiative. This partnership is tasked with developing and implementing a plan to achieve a 60% reduction in business-as-usual (BAU) fossil fuel demand by 2025 (60x25).This report lays out the strategy envisioned by the stakeholders in the USVI, DOE, and DOI to achieve this ambitious goal within the electricity sector (the full 60x25 goal also includes fossil fuel consumption in the transportation sector). The results presented here do not identify or quantify all power system or rate impacts. Instead, this work and supporting analysis provides a framework within which decisions can begin to be made, a concrete vision of what the future might hold, and a guide to determine what questions should follow. MethodologyThe path forward articulated here was developed through four primary efforts:• A review of existing initiatives and activities that are currently focused on decreasing oil consumption in the power sector• A review and analysis of energy efficiency potential within specific sectors of the USVI economy• A screening for technical and market potential of renewable technologies• The development of a model that allows basic assessments of the relative impact and cost effectiveness of each efficiency and renewable energy opportunity.This analysis combined the re...