Catálogo de publicaciones - revistas

<jats:p>Europe wants clean power. North Africa has lots of sun. Can Desertec move solar electricity across the Mediterranean Sea?</jats:p>

<jats:p>After early optimism, alcohol brewed from farm and forest waste is struggling to fulfill its promise as the next great biofuel.</jats:p>

<jats:p>The world's “energy problem” is in fact a slew of technological and sociological challenges involving the use of the land, water, and air we share.</jats:p>

<jats:p>Renewables like wind turbines are spreading fast, but can they survive complaints that they mar neighborhoods and threaten wildlife?</jats:p>

<jats:p>Other forms of renewable energy are facing siting problems similar to those facing wind power, including fears of triggering earthquakes, marring historic buildings, threatening wildlife, and polluting aquifers.</jats:p>

<jats:p>In 2008, the world produced approximately 87 gigaliters of liquid biofuels, which is roughly equal to the volume of liquid fuel consumed by Germany that year. Essentially, all of this biofuel was produced from crops developed for food production, raising concerns about the net energy and greenhouse gas effects and potential competition between use of land for production of fuels, food, animal feed, fiber, and ecosystem services. The pending implementation of improved technologies to more effectively convert the nonedible parts of plants (lignocellulose) to liquid fuels opens diverse options to use biofuel feedstocks that reach beyond current crops and the land currently used for food and feed. However, there has been relatively little discussion of what types of plants may be useful as bioenergy crops.</jats:p>

<jats:p>Rapid growth in demand for lignocellulosic bioenergy will require major changes in supply chain infrastructure. Even with densification and preprocessing, transport volumes by mid-century are likely to exceed the combined capacity of current agricultural and energy supply chains, including grain, petroleum, and coal. Efficient supply chains can be achieved through decentralized conversion processes that facilitate local sourcing, satellite preprocessing and densification for long-distance transport, and business models that reward biomass growers both nearby and afar. Integrated systems that are cost-effective and energy-efficient will require new ways of thinking about agriculture, energy infrastructure, and rural economic development. Implementing these integrated systems will require innovation and investment in novel technologies, efficient value chains, and socioeconomic and policy frameworks; all are needed to support an expanded biofuels infrastructure that can meet the challenges of scale.</jats:p>

<jats:p>Microalgae are considered one of the most promising feedstocks for biofuels. The productivity of these photosynthetic microorganisms in converting carbon dioxide into carbon-rich lipids, only a step or two away from biodiesel, greatly exceeds that of agricultural oleaginous crops, without competing for arable land. Worldwide, research and demonstration programs are being carried out to develop the technology needed to expand algal lipid production from a craft to a major industrial process. Although microalgae are not yet produced at large scale for bulk applications, recent advances—particularly in the methods of systems biology, genetic engineering, and biorefining—present opportunities to develop this process in a sustainable and economical way within the next 10 to 15 years.</jats:p>

<jats:p>Concerns about climate change, security of supply, and depleting fossil fuel reserves have spurred a revival of interest in nuclear power generation in Europe and North America, while other regions continue or initiate an expansion. We suggest that the first stage of this process will include replacing or extending the life of existing nuclear power plants, with continued incremental improvements in efficiency and reliability. After 2030, a large-scale second period of construction would allow nuclear energy to contribute substantially to the decarbonization of electricity generation. For nuclear energy to be sustainable, new large-scale fuel cycles will be required that may include fuel reprocessing. Here, we explore the opportunities and constraints in both time periods and suggests ways in which measures taken today might, at modest cost, provide more options in the decades to come. Careful long-term planning, along with parallel efforts aimed at containing waste products and avoiding diversion of material into weapons production, can ensure that nuclear power generation remains a carbon-neutral option.</jats:p>

<jats:p>An unusually well-preserved 45-meter-diameter crater provides ground truth for small-scale meteorite impacts on Earth.</jats:p>