• Energy Research
• National Science Foundation close
• 11. Sustainability close
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Urban vacant lots are often a contentious feature in cities, seen as overgrown, messy eyesores that plague neighborhoods. We propose a shift in this perception to locations of urban potential, because vacant lots may serve as informal greenspaces that maximize urban biodiversity while satisfying residents’ preferences for their design and use. Our goal was to assess what kind of vacant lots are ecologically valuable by assessing their biotic contents and residents’ preferences within a variety of settings. We surveyed 150 vacant lots throughout Baltimore, Maryland for their plant and bird communities, classified the lot’s setting within the urban matrix, and surveyed residents. Remnant vacant lots had greater vegetative structure and bird species richness as compared to other lot origins, while vacant lot settings had limited effects on their contents. Residents preferred well-maintained lots with more trees and less artificial cover, support of which may increase local biodiversity in vacant lots. Collectively, we propose that vacant lots with a mixture of remnant and planted vegetation can act as sustainable urban greenspaces with the potential for some locations to enhance urban tree cover and bird habitat, while balancing the needs and preferences of city residents.

Abstract Building energy consumption is vulnerable to climate change due to the direct relationship between outside temperature and space cooling/heating. This work quantifies how the relationship between climate change and building energy consumption varies across a range of building types at different spatiotemporal scales based on estimates in 925 U.S. locations. Large increases in building energy consumption are found in the summer (e.g., 39% increase in August for the secondary school building), especially during the daytime (e.g., >100% increase for the warehouse building, 5–6 p.m.), while decreases are found in the winter. At the spatial scale of climate-zones, annual energy consumption changes range from −17% to +21%, while at the local scale, changes range from −20% to +24%. Buildings in the warm-humid (Southeast) climate zones show larger changes than those in other regions. The variation of impact within climate zones can be larger than the variation between climate zones, suggesting a potential bias when estimating climate-zone scale changes with a small number of representative locations. The large variations found in the relationship between climate change and building energy consumption highlight the importance of assessing climate change impacts at local scales, and the need for adaptation/mitigation strategies tailored to different building types.

Family and caregiving leave are increasingly important dimensions for careers in academic science, and for vital, sustainable institutional structures. These forms of leave are intended to support equity, and particularly gender equity. A key question is how the actual use of leave affects critical milestones of advancement for women—compared to men—in (1) time to tenure and (2) the odds of promotion to full professor. We address this question with descriptive statistics and event history analyses, based on responses to a survey of 3688 US faculty members in 4 scientific fields within a range of Carnegie institutional types. We find that leave that stops the tenure clock extends time to tenure for both men and women—the effect is gender neutral. Promotion to full professor is another matter. Being a woman has a strong negative effect on the likelihood of promotion to full professor, and women are especially disadvantaged in promotion when they used tenure leave years earlier. These findings have implications for a life-course perspective on gender and advancement in academic science, the roles of caretaking and leave, and the intended and unintended consequences of leave policies for equitable and sustainable university systems.

Abstract Using a parametric modeling approach, we evaluate economic and environmental life cycle trade-offs of medium-duty electric trucks in comparison with nine non-electric technologies (e.g., conventional diesel, biodiesel, compressed natural gas, etc.) for U.S. model year 2015. Life cycle results for electric trucks vary strongly with weighted positive kinetic energy, whereas those for non-electric trucks vary the most with average trip speed. Our parametric life cycle assessment models explain 91%–98% of the variability in life cycle inventory and impact assessment results, revealing “how” and “why” the trade-offs of truck electrification change with different input conditions. In terms of cost, whether total cost of ownership or also including health and climate impact costs, model year 2015 battery electric trucks in severe applications such as urban driving provide positive and robust net benefits in many areas of the U.S. However, for typical operations, petroleum diesel with idle reduction or hybrid-electric technology provide the largest overall life cycle cost benefit. Battery electric, idle reduction, and hybrid trucks emit lower life cycle greenhouse gas emissions across the board in comparison with the other technologies. Despite lower carbon-intensity, electric trucks tend to be water-intensive because of cooling water consumption for thermo-electric power plants. Hybrid trucks create higher NOx emissions and thus larger associated environmental impacts. Idle reduction is beneficial to urban-type applications. Compressed natural gas trucks are the least water-intensive but may not reduce greenhouse gas emissions. Using marginal rather than average factors for electric grid emissions calculations doesn't change the overall life cycle comparisons. Improving driving behavior has universally positive effects for which the exact magnitude and sensitivity depend on environmental impact indicators and technologies.

Load shedding enjoys increasing popularity as a way to reduce power consumption in buildings during hours of peak demand on the electricity grid. This practice has well known cost saving and reliability benefits for the grid, and the contracts utilities sign with their “interruptible” customers often pass on substantial electricity cost savings to participants. Less well-studied are the impacts of load shedding on building occupants, hence this study investigates those impacts on occupant comfort and adaptive behaviors. It documents experience in two office buildings located near Philadelphia (USA) that vary in terms of controllability and the set of adaptive actions available to occupants. An agent-based model (ABM) framework generalizes the case-study insights in a “what-if” format to support operational decision making by building managers and tenants. The framework, implemented in EnergyPlus and NetLogo, simulates occupants that have heterogeneous thermal and lighting preferences. The simulated occupants pursue local adaptive actions such as adjusting clothing or using portable fans when central building controls are not responsive, and experience organizational constraints, including a corporate dress code and miscommunication with building managers. The model predicts occupant decisions to act fairly well but has limited ability to predict which specific adaptive actions occupants will select.

Abstract With the increasing effects of climate change and high costs of energy, many rural Alaska communities are working to implement local alternative energy solutions to improve energy security. Integrating renewable energy systems can reduce reliance on fossil fuels and subsequently improve food, energy, and water (FEW) security. In this study, wind energy modeling techniques using local airport meteorological data were convolved with community loads to determine the most cost-effective combinations of wind turbine technology and dispatchable loads for improving FEW security in a southwestern Alaska village. This approach is different from wind assessments that exclusively analyze wind resources. A 100 kW wind turbine was determined to be suitable for the community, resulting in a capacity factor of 16.7% and levelized cost of energy (LCOE) of $1.15/kWh, with diminishing returns for higher wind turbine capacity. The results from the dispatchability study indicated that dispatchable loads could handle the intermittency of the wind resource with up to 86% of their annual load met. More work is needed to understand the impact of integrating and scheduling dispatchable loads into the grid in practice.

Abstract Beginning in the 2000s, the Dallas-Fort Worth metropolitan region became home to the world's largest and longest experiment in urban shale gas production, with 25,182 drilling permits issued from 2000 to 2016 in the Barnett Shale. Urban hydrocarbon governance centered on establishing statutory setback distances between drilling sites and nearest houses or other protected uses. Here we analyze qualitative interview data obtained with a rigorous sampling frame to examine processes and outcomes of municipal-level hydrocarbon governance. We find that early municipal responses (2001–2002) revealed lack of technical expertise to respond to unconventional drilling and production. Controversial wells, which residents considered too close to houses, focused governance debates in several municipalities. Municipal policymakers reported that protecting public health and safety were top priorities in determining setbacks. After 2003, policymakers copied ordinance language from neighboring municipalities and established task forces and working groups to reduce political tensions. The role of the hydrocarbon industry included frequent claims seeking to exploit the longstanding separation of mineral and property estates, which encouraged municipalities to reduce setbacks and lower potential exposure to regulatory takings lawsuits. Over time, municipal regulatory power in hydrocarbon governance decreased while industry power increased, offering several implications for corporate responsibility and social license debates.

“Modern energy for all,” an internationally supported initiative to connect populations to electricity services, is expected to help reduce poverty-induced vulnerabilities. It has become a primary strategy for meeting sustainable development goals, especially in sub-Saharan Africa. However, when electricity is supplied by a capacity-constrained grid to a resource-constrained population, the service quality can vary both spatially and temporally. This research explores the quality of electricity services based on a case study of Unguja, Tanzania. Using 1) open-ended interviews, 2) detailed electricity-systems monitoring, and 3) household surveys, we show how voltage quality varies significantly, even within highly localized settings. Fluctuations result in dim lights at best and power outages and broken appliances at worst, denying many Unguja residents the expected benefits of access to modern energy. By combining an extensive understanding of the physical system together with interviews and surveys, this work presents a unique mapping of voltage quality in a system that is financially and physically constrained and highlights the consequences of poor-quality service for poor users.

The sharing economy has upset the market for housing and transportation services. Homeowners can rent out their property when they are away on vacation, car owners can offer ridesharing services. These sharing economy business models are based on monetizing under-utilized infrastructure. They are enabled by peer-to-peer platforms that match eager sellers with willing buyers. Are there compelling sharing economy opportunities in the electricity sector? What products or services can be shared in tomorrow’s smart grid? We begin by exploring sharing economy opportunities in the electricity sector, and discuss regulatory and technical obstacles to these opportunities. We then study the specific problem of a collection of firms sharing their electricity storage. We characterize equilibrium prices for shared storage in a spot market. We formulate storage investment decisions of the firms as a non-convex non-cooperative game. We show that under a mild alignment condition, a Nash equilibrium exists, it is unique, and it supports the social welfare. We discuss technology platforms necessary for the physical exchange of power, and market platforms necessary to trade electricity storage. We close with synthetic examples to illustrate our ideas.

Tropical reforestation (TR) has been highlighted as an important intervention for climate change mitigation because of its carbon storage potential. TR can also play other frequently overlooked, but significant, roles in helping society and ecosystems adapt to climate variability and change. For example, reforestation can ameliorate climate‐associated impacts of altered hydrological cycles in watersheds, protect coastal areas from increased storms, and provide habitat to reduce the probability of species' extinctions under a changing climate. Consequently, reforestation should be managed with both adaptation and mitigation objectives in mind, so as to maximize synergies among these diverse roles, and to avoid trade‐offs in which the achievement of one goal is detrimental to another. Management of increased forest cover must also incorporate measures for reducing the direct and indirect impacts of changing climate on reforestation itself. Here we advocate a focus on “climate‐smart reforestation,” defined as reforesting for climate change mitigation and adaptation, while ensuring that the direct and indirect impacts of climate change on reforestation are anticipated and minimized.