Current performance of Mg battery cathode is reviewed. Perspective for research in this field is provided and discussed.

Mg battery has recently gathered more and more interest as a high energy density replacement of current Li-ion battery. Significant progress has been made in developing sustainable anode and novel electrolyte. However, the success of Mg battery still high demands the search of cathode material with high energy density, good rate capability, and nice cyclability. This current review focuses on the development of Mg battery cathode in the past 15 years. A detailed review about the performance and limitations of reported cathode material is provided. A perspective for this area is discussed with insights for future research direction. Three important areas that must be explored in this field in near future are suggested: the investigation of high capacity cathode, the study of hybrid ion battery, and deeper understanding about the magnesiation chemistry of the cathode.

The desire of the international community to balance global economic growth against concerns of accelerated CO 2 emissions has brought solar technologies into the forefront for meeting increasing energy demands. This manuscript discusses the historical and potential future roles for small-to-medium scale solar thermal technologies in addressing the challenge of leveling energy access standards across countries with widely variable economic resources and consumer needs.

Access to modern energy services, such as heating for water, pumping for agricultural irrigation or potable water sources, and an on-demand 24/7 electrical grid, is central to provision of high quality social services, economic growth, and improved quality of life; however, over 1 billion people remain unelectrified globally. Enabling the projected growth in energy demands without relying on fossil fuels requires consideration of the viability of renewable energy technologies to serve these markets; this manuscript provides a discussion of the role of solar thermal energy systems in this capacity. A survey of systems under 1 MW capacity reported in the literature (academic and commercial) was conducted, with projects aggregated by service type (heat, cooling, electricity, or multi-) in the database provided as an appendix to this manuscript. In general, many hardware configurations have been explored, with economics driven substantially by supply chain pricing, and no clear winner has emerged. Process heat applications demonstrate economic competitiveness over a wide range of commercial applications; however, early explorations into power generation—or co/tri-generation configurations—provide indications that such technologies, while not expected to reach grid-parity tariffs, may in fact provide the most economical pathway to energy delivery in the currently most underserved communities.

This article aims to shed light on the factors that frame the competitiveness and signal the viability of photovoltaic (PV), solar to electrical energy conversion: retail electricity prices, the levelized cost of electricity (LCOE), subsidies, as well as the energy return on investment (EROI). To that end a review of the ‘true cost’ of electricity generation, including the environmental impacts is necessary. We argue that renewables are part of the solution to updating and shoring up the aging grid. In addition, public engagement in changing the culture of energy use and provision is enabled with PV ownership and job creation, which stimulates the economy.

The accumulation of incremental additions of renewable energy systems in European markets is now revealing that the fundamental structure of the energy market is inadequate to meet 21st century requirements. In Europe, where renewables provide ∼20% of the electricity supply, PV installations have stalled despite goals to increase the amount of renewable energy. This article aims to shed light on the factors that frame the competitiveness and that signal the viability of PV: retail electricity prices, the energy market and subsidies, the LCOE, as well as a critical examination of the EROI. While a starting point, an incremental approach is not sufficient to address the systemic changes required to decarbonize the electricity supply in line with the recent (2015) Paris Agreement. The ‘true cost’ of electricity generation, including the environmental impacts, must be kept in sight. In terms of grid investments, renewables can play a crucial role in updating the aging grid infrastructure and making it more resilient. Public engagement in changing the culture of energy use and provision is enabled with PV ownership. Furthermore, a broad base of the economy is stimulated, not only because fossil fuel imports are avoided, keeping investment and creating value within the region, but also through significantly higher job creation with renewables than with incumbent technologies.

The premise of this Viewpoint article is that the sustainability of the electricity supply is very often addressed in narrow frames of reference, which sets up incremental decision-making. To more fairly compare the economic, social, and environmental aspects of renewables, such as photovoltaics, to fossil fuels, a broader view is required which needs to take into account the impacts of the fossil fuel supply chain.

February 2016 was the warmest February since record keeping began in 1880, and was the warmest month in recorded history (in terms of its deviation from average). May 2016, the warmest May on record, was the 13th consecutive record-breaking month. The Paris Agreement signed in December 2015 has solidified agreement that the world must address climate change, and has resounded the warning that inaction on climate change carries potentially catastrophic risk for the global economy. Electricity generated from renewable energy sources is often compared to fossil fuel energy in terms of economics. Recently there have also been increased calls to incorporate the external costs of electricity generation into the price of electricity. Fossil fuels are largely responsible for global warming (as 85% of the CO2 emissions come from fossil fuel combustion). This Viewpoint article looks at fuel supply chains for oil & gas, coal, and nuclear in terms of their economics, environmental and social consequences. This reflection upon the historical and present fossil fuel supply chain gives a perspective useful in avoiding limited frames of reference when addressing the consequences of the business-as-usual operation of fossil fuel supply chains.

This paper reviews existing literature to assess the consensus of the scientific and engineering communities concerning the potential for the United States’ light-duty transportation sector to meet a goal of 80% reduction in vehicle emissions and examine what it will take to meet this target.

Climate change is a problem that must be solved. The primary cause of this problem is burning of fossil fuels to generate energy. A dramatic reduction in carbon emissions must happen soon, and a significant fraction of this reduction must come from the transportation sector. This paper reviews existing literature to assess the consensus of the scientific and engineering communities concerning the potential for the United States' light-duty transportation sector to meet a goal of 80% reduction in vehicle emissions and examine what it will take to meet this target. It is unlikely that reducing energy consumption in just vehicles with gasoline-based internal combustion drivetrains will be sufficient to meet GHG emission-reduction targets. This paper explores what additional benefits are possible through the adoption of alternative energy sources, looking at three possible on-vehicle energy carriers: carbon-based fuels, hydrogen, and batteries.