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.

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Cities in the United States are increasingly taking action to improve the sustainability of their jurisdictions. Clean energy and energy efficiency must be a central component of these efforts. This analysis uses a sample of 20 U.S. cities to explore how cities incorporate data in energy decision-making in terms of planning, implementation, and evaluation. Many programs and tools related to city energy needs are available to decision makers (Appendix A, Figure A-1). This work identified over 30 government, foundation, non-profit, and private programs and frameworks for cities to use in energy planning. These programs provide a myriad of case studies, best practices, frameworks, and support for clean energy programs, but few align metrics with GHG reduction goals or identify clear methodologies for plan implementation and measurement of programmatic impacts. In addition to these external resources, cities are creating sustainability, energy, and climate plans that vary in scope (e.g., city operations or community-wide), specificity, timeframe, data collection, and reporting. City staff interviewed for this research indicated that a lack of standardization in measuring impact and prioritizing actions can impede effective energy decision making. Developing and implementing plans helps communities address their specific energy and climate priorities. The heterogeneity of plans creates a barrier, however, to understanding the plans' impacts on climate and energy goals and the broader impacts of the plans and actions on national energy use. To address this, a nomenclature system (Figure ES-1) was designed to compare climate, sustainability, and energy plans across cities. Figure ES-1. City energy decision-making framework Goal • Clearly stated vision or objective for city energy use, typically aimed at a specific sector (e.g., buildings and efficiency, renewable power, or transportation and planning) • Example: Support alternative commuting modes Action • Specific implementable efforts, policies, or programs aimed at acheiving energy goals • Examples: Create bike lanes or complete street policies Metric • A measurement (units can vary) for understanding impacts of actions and progress toward energy goals. Some cities refer to metrics as indicators. • Example: Miles of added bike lanes or mode share by bike Data • Observation that can be used to inform measurement of actions and progress toward energy goals. • Example: Bike counts vii This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications. Data collection from city plans and interviews with representatives of 20 cities provided a survey of city goals, the actions employed to meet those goals, and measurement strategies to track progress. Common city energy-related goals focus on reducing carbon emissions overall (and specifically from transportation), improving energy efficiency across sectors, increasing renewable energy, and increasing biking and walking. Categorizing the plans according to Figure ES-1 and compar...

The potential for energy efficiency to simultaneously address economic development, energy security, and environmental protection in countries around the world is well known. Energy efficiency can have even more pronounced impacts in developing countries, where citizens need increased access to energy, utilities might struggle to keep up with demand, and public and private capital to expand availability of energy and improve quality of service is scarce. Especially among low-income residents, energy efficiency has a host of beneficial attributes that can help achieve the United Nations' Sustainable Development Goals, including those associated with economic opportunity, improved health, gender equity, and better environmental and climate-related outcomes. Although energy efficiency faces barriers even in the most favorable environments, the time to consider energy-efficiency programs for low-income households might never be stronger. Non-low-income 90,000 2.3 Low-income multifamily (≤80% area median income, 5 or more units) 21,996 5.0 Non-low-income multifamily 71,982