Opportunities and challenges for a sustainable energy future.

Access to clean, affordable and reliable energy has been a cornerstone of the world's increasing prosperity and economic growth since the beginning of the industrial revolution. Our use of energy in the twenty-first century must also be sustainable. Solar and water-based energy generation, and engineering of microbes to produce biofuels are a few examples of the alternatives. This Perspective puts these opportunities into a larger context by relating them to a number of aspects in the transportation and electricity generation sectors. It also provides a snapshot of the current energy landscape and discusses several research and development opportunities and pathways that could lead to a prosperous, sustainable and secure energy future for the world.

Energy supplies and future engines for land, sea, and air.

The years 2012 and beyond seem likely to record major changes in energy use and power generation. The Japanese tsunami has resulted in large countries either scaling back or abolishing the future use of nuclear energy. The discovery of what seems like vast amounts of economically deliverable natural gas has many forecasting a rapid switch from coal- to gas-fired generating plants. On the other hand, environmentalists have strong objections to the production of natural gas and of petroleum by hydraulic fracturing from shale, or by extraction of heavy oil. They believe that global warming from the use of fossil fuels is now established beyond question. There has been rapid progress in the development of alternative energy supplies, particularly from on-shore and off-shore wind. Progress toward a viable future energy mix has been slowed by a U.S. energy policy that seems to many to be driven by politics. The author will review the history of power and energy to put all of the above in context and will look at possible future developments. He will propose what he believes to be an idealized energy policy that could result in an optimum system that would be arrived at democratically.

Consumption substitution and change of household indirect energy consumption in China between 1997 and 2012.

With the rapid growth in the Chinese economy in recent decades, household incomes as well as consumption of goods and services have also steadily increased. This has resulted in growing demand for energy consumption across the economy. It has been suggested that consumption upgrades in tandem with substitutions might exert an impact on mitigating this growth. The input-output method was applied in this study to analyze variations in household indirect energy consumption between 1997 and 2012. The impact of consumption substitution on change was also determined using a two-tier structural decomposition analysis, in which the second-tier is a further decomposition based on first-tier results. The results show that the indirect energy use caused by household consumption makes up between 75% and 78% of total household energy demand and that this increased 161.2% over the study period. First-tier decomposition results reveal that this change was mostly caused by household consumption scale and energy intensity effects. Second-tier decomposition results reveal strong evidence for consumption substitution between energy-intensive industries and non-energy-intensive ones and that this can have an impact on reducing household indirect consumption. Household consumption therefore plays a prominent role in total energy consumption. Transforming to non-energy-intensive or services led consumption patterns should therefore be encouraged by the Chinese government in order to achieve conservation goals.

Sedimentary record of polycyclic aromatic hydrocarbons in mud deposits along the southeastern coast of Liaodong Peninsula and its relation to the anthropogenic and natural activities in the Northeast China.

The concentrations of polycyclic aromatic hydrocarbons (PAHs) in two 210Pb-dated sediment cores collected from mud deposits along the southeastern coast of the Liaodong Peninsula were investigated to reconstruct the sedimentary records of PAHs and their relationship with anthropogenic and natural activities. The concentrations of 16 PAHs (∑PAHs) were low and remained stable before the year 1820, reflecting an autarkic agricultural civilization. From 1820 to 1900, with the gradual lifting of prohibition, people migrated into Northeast China, resulting in the release of large amounts of ∑PAHs into the environment. At the beginning of the 1900s, the ∑PAH levels in the two cores displayed increasing trends with significant fluctuations, linked to a period of social turbulence with continuous wars in Northeast China. After 1949, vertical ∑PAH trends in the cores predominantly reflected trends in economic development. Based on the different PAH composition trends (2-3-ring and 4-6-ring PAHs), we consider that historical energy usage in Northeast China can be divided into three stages: biomass fuel use dominated before 1920, biomass and fossil fuels co-existed from 1920 to 1980, and fossil fuels dominated after 1980. In addition, this study also demonstrates that the PAH concentrations (2-3-ring PAHs) in these two sediment cores can be used, to a certain extent, to identify anthropogenic fire events.

Climate impacts on extreme energy consumption of different types of buildings.

Exploring changes of building energy consumption and its relationships with climate can provide basis for energy-saving and carbon emission reduction. Heating and cooling energy consumption of different types of buildings during 1981-2010 in Tianjin city, was simulated by using TRNSYS software. Daily or hourly extreme energy consumption was determined by percentile methods, and the climate impact on extreme energy consumption was analyzed. The results showed that days of extreme heating consumption showed apparent decrease during the recent 30 years for residential and large venue buildings, whereas days of extreme cooling consumption increased in large venue building. No significant variations were found for the days of extreme energy consumption for commercial building, although a decreasing trend in extreme heating energy consumption. Daily extreme energy consumption for large venue building had no relationship with climate parameters, whereas extreme energy consumption for commercial and residential buildings was related to various climate parameters. Further multiple regression analysis suggested heating energy consumption for commercial building was affected by maximum temperature, dry bulb temperature, solar radiation and minimum temperature, which together can explain 71.5 % of the variation of the daily extreme heating energy consumption. The daily extreme cooling energy consumption for commercial building was only related to the wet bulb temperature (R2= 0.382). The daily extreme heating energy consumption for residential building was affected by 4 climate parameters, but the dry bulb temperature had the main impact. The impacts of climate on hourly extreme heating energy consumption has a 1-3 hour delay in all three types of buildings, but no delay was found in the impacts of climate on hourly extreme cooling energy consumption for the selected buildings.

'Frankie the Frog': the total transformation of a river basin as 'totalitarian' technology (Spain, 1946-1961).

After the Spanish Civil War (1936-1939), Francisco Franco's emphasis on dam building became so intense that it is still today associated with his dictatorial rule. Rather than being purely a personal obsession, however, this intensive period of reservoir construction was the result of the influential political role played by engineers from the early years of the regime. During the years 1946-1961 some of these engineers undertook the 'total transformation' of the Noguera Ribagorzana river basin in the Catalonian Pyrenees. But this explicitly 'totalitarian' project encountered important limitations posed both by competing state agencies and by the basin's geology. Analysing the efforts of these engineers allows for new understandings of the Francoist regime and of the place of science, technology, and the landscape within it.

Ethanol's energy return on investment: a survey of the literature 1990-present.

Various authors have reported conflicting values for the energy return on investment (rE) of ethanol manufacture. Energy policy analysts predisposed to or against ethanol frequently cite selections from these studies to supporttheir positions. This literature review takes an objective look at the disagreement by normalizing and comparing the data sets from ten such studies. Six of the reviewed studies treat starch ethanol from corn, and four treat cellulosic ethanol. Each normalized data set is also submitted to a uniform calculation of rEdefined as the total product energy divided by nonrenewable energy input to its manufacture. Defined this way rE > 1 indicates that the ethanol product has nominally captured at least some renewable energy, and rE > 0.76 indicates that it consumes less nonrenewable energy in its manufacture than gasoline. The reviewed corn ethanol studies imply 0.84 < or = rE < or = 1.65; three of the cellulosic ethanol studies imply 4.40 < or = rE < or = 6.61. The fourth cellulosic ethanol study reports rE= 0.69 and may reasonably be considered an outlier.

Breve história da ciência moderna: v.4: a belle-époque da ciência (séc. XIX) / Brief history of modern science: v.4: the belle-époque of science (nineteenth century)

O quarto volume da série 'Breve História da Ciência Moderna' trata de um período de grande euforia em relação às conquistas da ciência, sobretudo às ligadas à tecnologia. No século XIX, a eletricidade passou a iluminar as cidades e a acelerar as comunicações; surgiram os motores a explosão que iriam dar origem aos automóveis. O século se defrontou ainda com a teoria da evolução das espécies por seleção natural – que revolucionou não apenas a ciência, mas também o olhar do homem sobre si mesmo. Essa explosão de temas gerou uma onda de otimismo em relação ao futuro. O progresso era inevitável. Os homens e mulheres do século XIX viviam a belle-époque da ciência. Dividida em cinco volumes, esta série trata do conhecimento científico que se desenvolveu num curto período de tempo da história da humanidade – da Idade Média até hoje. Enfatizando o diálogo entre diferentes campos do conhecimento, os autores constroem um painel útil para quem deseja encontrar a porta de entrada dos principais problemas que formam o universo da ciência.