Analyzing the repetitive pattern of historical lead poisoning that to present-day has shaped our legislatorial systems regarding lead consumption, this work focuses on creating awareness and caution toward lead halide perovskite commercialization while concurrently pointing out considerations and ambiguity in policies and regulations.

Lead halide perovskites have caused a paradigm shift in state-of-the-art photovoltaic technology half a decade ago and have gained tremendous momentum ever since. Given their seemingly imminent commercialization, rigorous scrutiny regarding their potential environmental impact is becoming increasingly relevant. In light of the current need for sustainable energy resources, several start-up and spin-off companies have been established, initially promising modules on the market by the end of 2017. On the downside, lead representing approximately one third by weight of the absorber layer in such photovoltaic devices is enough reason to become wary about the potential environmental impact of their large-scale implementation. Whilst many have wondered where the acceptable boundaries lie regarding lead consumption, it remains a focal point in many discussions, as it seems almost unattainable to ban lead usage from our society. Currently listed as one of the ten chemicals of major health concern by the World Health Organization, the magnitude of misgivings expands even more as recent studies also demonstrate promising applications of lead halide perovskites in light emitting diodes, lasers, batteries, and photodetectors. Hence, there is no doubt that a discussion should be commenced on how to assess and handle the impact of lead in a new technology of such high potential.

By reflecting on the historical experience gained from anthropogenic lead poisoning that is still shaping our legislatorial systems at present-day, this work investigates and carefully scrutinizes current legislation that governs the exploitation of lead halide perovskites in optoelectronic applications. Analyzing the repetitive pattern of historical lead consumption, focus is extended on creating awareness and caution toward lead halide perovskite commercialization while concurrently pointing out considerations and ambiguity in policies and regulations. Ultimately, this work aims to initialize a discussion on “if” and “how” this burgeoning class of materials can enter the consumer market.

The paper presents a comprehensive overview of electrical and thermal energy storage technologies but will focus on mid-size energy storage technologies for demand charge avoidance in commercial and industrial applications.

Utilities bill customers not only on energy use but peak power use since transmission costs are a function of power and not energy. Energy storage (ES) can deliver value to utility customers by leveling building demand and reducing demand charges. With increasing distributed energy generation and greater building demand variability, utilities have raised demand charges and are even including them in residential electricity bills. This article will present a comprehensive overview of electrical and thermal energy storage technologies but will focus on mid-size energy storage technologies for demand charge avoidance in commercial and industrial applications. Of the ES technologies surveyed, lithium ion batteries deliver the highest value for demand charge reduction especially with systems that have larger power to energy ratios. Current lithium ion ES systems have payback periods below 5 years when deployed in markets with high demand charges.

Material choices can affect both the environmental conditions and the human health impacts of buildings. Decision making can be improved through greater transparency and a broader view of materials impact.

With more architects and engineers recognising the impacts of global climate change, a renewed focus on carbon emissions from buildings is underway. Material choices in the built environment have significant impacts on both the building’s carbon emissions and the health of building occupants. As the operational carbon in buildings falls through improved efficiencies and design, the amount of embodied carbon released from the extraction, manufacturing, and transportation of materials and products is becoming relatively more significant. Through the selection of materials, designers can reduce the overall carbon emissions of buildings while maintaining high standards for occupant health.

During the past decade, solar power has experienced transformative price declines, enabling it to grow to supply 1% of U.S. and world electricity. Addressing grid integration challenges, increasing grid flexibility, and further reducing cost will enable even greater potential for solar as an electricity source.

During the past decade, solar power has experienced transformative price declines, enabling it to become a viable electricity source that is supplying 1% of U.S. and world electricity. Further cost reductions are expected to enable substantially greater solar deployment, and new Department of Energy cost targets for utility-scale photovoltaics (PV) and concentrating solar thermal power are $0.03/kW h and $0.05/kW h by 2030, respectively. However, cost reductions are no longer the only significant challenge for PV—addressing grid integration challenges and increasing grid flexibility are critical as the penetration of PV electricity on the grid increases. The development of low cost energy storage is particularly synergistic with low cost PV, as cost declines in each technology are expected to support greater market opportunities for the other.

Aircraft that take off and land verticallywith rotors or horizontal propellers like drones use more energy than conventional aircraft whose lift is provided by wings. Drones with propellers are less efficient than helicopters with large rotors. The poor energy density of batteries compared to hydrocarbon fuels limits the range and endurance of the electrically powered aircraft. Although the ratio of the mass of payload and fuel (or battery) to the total aircraft mass for the proposed Amazon drone is not that different from the same ratio for a Boeing 747, the range and time in the air is very much less. In principle, a conventional aircraft powered by photovoltaic panels covering a wing with a span of 6 m could match the performance of the proposed Amazon drone.

Amazon has proposed delivering packages by an electrically powered drone capable of vertical take off and landing. By comparison with helicopters, the energy needed to move a 2.5 kg package is estimated to be more than 130 times the energy used in delivering the same package in a small delivery truck. By comparison, a conventional airplane with the same mass could, in principle, be powered by photovoltaic panels, covering the wings, and it would use an energy equivalent to about 3 times the energy used by a small delivery truck. Based on the performance of existing small helicopters, the analysis shows that an electrically powered air taxi would only be able to make journeys of 10 min or less. Vertical take-off and landing add to energy requirements, and drones using a large number of propellers are less efficient than helicopters. The major limitation, not surprisingly, is the poor energy density of batteries compared to liquid hydrocarbon fuels.

Large regions of the United States (and the world) face “situational scarcities” of water that arises from energy extraction and use, agricultural practices, expanding urban populations, and poorly integrated water policies.

Creating “fit-for-purpose” water from suboptimal sources will require new materials and a new understanding of the separation of contaminants from complex aqueous media.

We review here scientific, technological, and societal challenges at the nexus of energy, water, and food. We focus on specific examples of energy and water stress in the southwestern United States and technological routes to new sources of water. Situational scarcities of water are increasing worldwide because of the reliance on uncertain water sources, coupled with expanding populations, expanded agricultural uses of water, and water and energy use policies that have not always been effectively integrated. This review is framed using the outcomes of recent National Science Foundation workshops focusing on the Energy/Water/Food Nexus and from other recent U.S. Department of Energy workshops focused on the Energy/Water nexus. Water-stressed regions, even after extensive conservation measures, may need new supplies of water that come from less than optimal sources. A basic understanding of the separation of water from complex aqueous solutions along with new materials, distributed and publically accepted technologies and unit operations, underpin the future production of “fit-for-purpose” water. Regional test beds are required that are small and provide for simultaneous control of a number of variables, yet large enough to approximate real communities. Solutions to these problems represent opportunities for innovation and creation of economically viable, resilient communities.

We present and analyze three powerful long-term historical trends in the electrification of energy by free-fuel sources. These trends point toward a future in which energy is affordable, abundant, and efficiently deployed; with major economic, geo-political, and environmental benefits to humanity.

We present and analyze three powerful long-term historical trends in energy, particularly electrical energy, as well as the opportunities and challenges associated with these trends. The first trend is from a world containing a diversity of energy currencies to one whose predominant currency is electricity, driven by electricity’s transportability, exchangeability, and steadily decreasing cost. The second trend is from electricity generated from a diversity of sources to electricity generated predominantly by free-fuel sources, driven by their steadily decreasing cost and long-term abundance. These trends necessitate a just-emerging third trend: from a grid in which electricity is transported unidirectionally, traded at near-static prices, and consumed under direct human control; to a grid in which electricity is transported bidirectionally, traded at dynamic prices, and consumed under human-tailored artificial agential control. These trends point toward a future in which energy is not costly, scarce, or inefficiently deployed but instead is affordable, abundant, and efficiently deployed; with major economic, geo-political, and environmental benefits to humanity.

Fusion energy is one of the options to contribute to the energy demand of future generations without adding to global warming. In this paper, we present the status of fusion energy research on the basis of magnetic confinement.

Fusion energy is one of the options to contribute to the energy demand of future generations without contributing to global warming. In this paper, we present the status of fusion energy research on the basis of magnetic confinement. In France, the first fusion reactor ITER is under construction. Its success will be measured on the expectation to deliver 500 MW thermal power—a factor of 10 above the power to maintain the energy producing process. ITER is based on the tokamak concept. In addition, Wendelstein 7-X, an ambitious stellarator, has recently started operation. Both confinement concepts—the tokamak and the stellarator—will be discussed along with general topics regarding fusion technology, operational safety, fusion waste, possible electricity costs, and roadmaps toward a fusion reactor as a power source.

New demand for electric vehicles—are rare earths the bottleneck in the supply chain? Can recycling and substitution make a dent in the demand for REE in the near future? Is it economically feasible for advanced nations to mine for REE but process them elsewhere to allay environmental concerns at home?

Rare earths are critical components to many technologies that drive the modern world. Though rare earths are present in most parts of the world, they are produced mostly in China because of a confluence of several factors. This paper reviews various aspects of rare earths including extraction, geopolitics, and challenges. Rare-earth elements (REEs) not only replace each other in the mineral structure but also occur within different mineral structures in the same deposit. Separation of one REE from another is therefore difficult, environmentally challenging, and expensive. Less than 1% of REEs is recycled due to many challenges of collecting various end products and separating the REE from other metals/contaminants. Recycling investments have primarily focused on applications such as magnets, where economies of scale have allowed it. Substitution for the REE is difficult for most applications, though the automotive and wind energy industries are making good advances with motors and generators. The rare earth market is small and, thus, easily disrupted. Factors that can impact the market are increased production from existing mines, development of mine prospects advanced during price spikes, research and development efforts focused on improving REE recoveries, recycling, substitution, alternate sources of REEs, and governmental policies.

We raise for debate and discussion what in our opinion is a growing mis-control and mis-protection of U.S. energy research. We outline the origin of this mis-control and mis-protection, and propose two guiding principles to mitigate them and instead nurture research: (1) focus on people, not projects; and (2) culturally insulate research from development, but not science from technology.

Energy research is critical to continuing advances in human productivity and welfare. In this Commentary, we raise for debate and discussion what in our view is a growing mis-control and mis-protection of U.S. energy research. This flawed approach originates in natural human tendencies exacerbated by an historical misunderstanding of research and development, science and technology, and the relationships between them. We outline the origin of the mis-control and mis-protection, and propose two guiding principles to mitigate them and instead nurture research: (i) focus on people, not projects; and (ii) culturally insulate research from development, but not science from technology. Our hope is to introduce these principles into the discourse now, so they can help guide policy changes in U.S. energy research and development that are currently being driven by powerful geopolitical winds.

Summary: Two foundational guiding principles are proposed to mitigate a growing mis-control and mis-protection of U.S. energy research, and instead to nurture it.

We offer a cross section of the numerous challenges and opportunities associated with the integration of large-scale battery storage of renewable energy for the electric grid. These challenges range beyond scientific and technical issues, to policy issues, and even social challenges associated with the transition to a more sustainable energy landscape.

The commissioning on 1 December 2017 of the Tesla-Neoen 100 MW lithium-ion grid support battery at Neoen’s Hornsdale wind farm in South Australia, at the time the world’s largest, has focused the attention of policy makers and energy professionals on the broader prospects for renewable energy storage. An adequate and resilient infrastructure for large-scale grid scale and grid-edge renewable energy storage for electricity production and delivery, either localized or distributed, is a crucial requirement for transitioning to complete reliance on environmentally protective human energy systems. Its realization will require a strong synergy between technological advances in variable renewable energy storage and the governance policies that promote and support them. We examine how existing regulations and governance policies focusing on large-scale batteries have responded to this challenge around the world. We offer suggestions for potential regulatory and governance reform to encourage investment in large-scale battery storage infrastructure for renewable energy, enhance the strengths, and mitigate risks and weaknesses of battery systems, including facilitating the development of alternatives such as hybrid systems and eventually the uptake of hydrogen fuel and storage.

The review article describes the composition, working, and benefits of the electrodynamic screen (EDS) film, a self-cleaning surface technology that can be retrofitted onto solar and thermal energy collectors. The EDS film avoids the use of water and robotic parts that are the common cleaning techniques used in solar/thermal power plants and thus emerges as a viable and scalable solution to the soiling problem faced recurrently by these plants. The article summarizes different experiments conducted to improve the efficiency of the EDS film in terms of reflectivity and performance. Field test results are also included to underscore the success of the EDS film operation.

Dust build-up or soiling on thermal and solar energy collector surfaces is a major problem and its cleaning is a major issue for solar energy conversion. Here, a self-cleaning technology is described as a scalable and viable solution to clear the surfaces. EDS film technology does not require water, manual labor, or moving parts to function, and the power needed to operate EDS is almost negligible and can be derived from the harvesting device itself. The EDS films thereby help mitigate the energy loss caused by soiling in solar and thermal harvesting systems. An EDS film with reflective or transparent electrodes can be retrofitted on concentrated solar power mirrors and on photovoltaic (PV) panels to sustain and aid their unhindered reflection and absorption of incident sunlight, respectively. We report experiments and describe methods used to increase the reflectivity of the electrodes of an EDS film. Results obtained from lab test setups and field test units that define the functionality, reflectivity, and stability of the electrodes on the EDS films are also presented. Field test results that compare and report the performance of PV panel output current over long periods of testing, with and without EDS films are also discussed. Test results from 3-month outdoor testing, which demonstrate recovery back to >95% of the pristine system, after decrease to 80–90% before EDS film activation, are also shown.

The ternary Cu–Sb- and Cu–Bi-chalcogenides presenta rich range of compounds of potential use for large-scale photovoltaics from Earth abundant elements. This paper reviews the state of fundamental knowledge about them, and their technological status with regard to solar cells. Research targets and missing data are highlighted, which may provide opportunities to help realize the goal of sustainable photovoltaics.

The family of ternary Cu–Sb- and Cu–Bi-chalcogenides and their solid solutions present a rich selection of potential candidates for Earth-abundant low toxicity photovoltaic (PV) absorber materials. Moreover, they have some novel features imparted by the ns2 lone pair of electrons on the Sb and Bi ions. This review evaluates them as electronic materials, including experimental and theoretical evaluations of their phases, thermodynamic stability, point defects, conductivity, optical data, and PV performances. Formation of the materials in bulk, thin film, and nanoforms and the properties of the materials are critically assessed with relevance to their suitability for PV devices. There is special emphasis on CuSbS2 and CuSbSe2 which form the mainstay of the device literature and provide the most insights into the present-day limitation of the device efficiencies to 3 or 4%. Missing features of the literature are highlighted and clear statements recommending potential research pathways are made, which may help advance the technological performance from its present stuck position.

Concerted efforts by stakeholders could overcome the hurdles and enable a viable recycling system for automotive LIBs by the time many of them go out of service.

Lithium-ion batteries (LIBs) were commercialized in the early 1990s and gained popularity first in consumer electronics, then more recently for electric vehicle (EV) propulsion, because of their high energy and power density and long cycle life. Their rapid adoption brings with it the challenge of end-of-life waste management. There are strong arguments for LIB recycling from environmental sustainability, economic, and political perspectives. Recycling reduces material going into landfills and avoids the impacts of virgin material production. LIBs contain high-value materials like cobalt and nickel, so recycling can reduce material and disposal costs, leading to reduced EV costs. Battery recycling can also reduce material demand and dependence on foreign resources, such as cobalt from Democratic Republic of the Congo, where much production relies on armed aggression and child labor.

Several companies are finding ways to commercialize recycling of the increasingly diverse LIB waste stream. Although Pb-acid battery recycling has been successfully implemented, there are many reasons why recycling of LIBs is not yet a universally well-established practice. Some of these are technical constraints, and others involve economic barriers, logistic issues, and regulatory gaps. This paper first builds a case as to why LIBs should be recycled, next compares recycling processes, and then addresses the different factors affecting LIB recycling to direct future work towards overcoming the barriers so that recycling can become standard practice.

This article offers a conceptual understanding and easily applicable guidelines for sustainable urban infrastructure design by focusing on the demand for and supply of the services provided by seven urban infrastructure systems.

For more than 10,000 years, cities have evolved continuously, often shaped by the challenges they had to face. Similarly, we can imagine that cities will have to evolve again in the future to address their current challenges. Specifically, urban infrastructure will need to adapt and use less energy and fewer resources while becoming more resilient. In this article, starting with a definition of sustainability, two urban infrastructure sustainability principles (SP) are introduced: (i) controlling the demand and (ii) increasing the supply within reason, which are then applied to seven urban infrastructure systems: water, electricity, district heating and cooling and natural gas, telecommunications, transport, solid waste, and buildings. From these principles, a four-step urban infrastructure design (UID) process is compiled that can be applied to any infrastructure project: (i) controlling the demand to reduce the need for new infrastructure, (ii) integrating a needed service within the current infrastructure, (iii) making new infrastructure multifunctional to provide for other infrastructure systems, and (iv) designing for specific interdependencies and decentralizing infrastructure if possible. Overall, by first recognizing that urban infrastructure systems are inherently integrated and interdependent, this article offers several strategies and guidelines to help design sustainable urban infrastructure systems.

We explore the status of state-of-the-art upconverter materials in the context of improving solar cell performance. We focus on semiconductor upconversion nanostructures that can harvest two separate bands of the solar spectrum and offer a promising path to rational engineering of improved performance and thus improved overall solar energy harvesting.

Photon upconversion is a process in which two low-energy photons are sequentially absorbed and one high-energy photon is emitted. Photon upconversion in both inorganic and organic material platforms has been used to improve solar cell efficiency. Lanthanide-doped salts (inorganic) and triplet–triplet annihilation molecules (organic) have achieved 33% and 60% internal upconversion quantum efficiency, respectively, leading to current density increases of 17 mA/cm2 and 0.86 mA/cm2. However, their performance is limited by their narrow absorption bandwidth (AB) and limited tunability, especially at low photon fluxes. Recently, colloidal semiconductor nanostructures have emerged as a promising material platform for upconversion. The optical absorption in these low-dimensional heterostructures involves both quantum-confined and continuum band states, enabling a much larger AB. Moreover, the techniques of semiconductor heterostructure engineering can be used to optimize performance and to tailor absorption and emission wavelengths. We review the performance and potential impact on solar energy harvesting of upconversion materials, focusing on semiconductor upconverters. We discuss computational models that suggest that semiconductor upconverter nanostructures could have outstanding performance for photovoltaic. We then discuss the current state of the art in semiconductor upconversion morphologies and compositions and provide an outlook on the ways in which nanostructures can be tailored to improve performance for applications.