How does increased corn-ethanol production affect US natural gas prices?

In recent years, there has been a push to increase biofuel production in the United States. The biofuel of choice, so far, has been ethanol produced from corn. The effects of increased corn-ethanol production on the consumer prices of food and energy continue to be studied and debated. This study examines, in particular, the effects of increased corn-ethanol production on US natural gas prices. A structural model of the natural gas market is developed and estimated using two stage least squares. A baseline projection for the period 2007–2018 is determined, and two scenarios are simulated. In the first scenario, current biofuel policies including EISA mandates, tariffs, and tax credits are removed. In the second scenario, we hold ethanol production to the level required only for largely obligatory additive use. The results indicate that the increased level of corn-ethanol production occurring as a result of the current US biofuel policies may lead to natural gas prices that are as much as 0.25% higher, on average, than if no biofuel policies were in place. A similar comparison between the baseline and second scenario indicates natural gas prices could be as much as 0.5% higher, on average, for the same period.     

Optimization of liquid–liquid phase separation characteristics in the Bunsen section of the sulfur–iodine hydrogen production process

In order to optimize the sulfur–iodine thermochemical cycle, a series of experiments were conducted to investigate the separation characteristics of the liquid–liquid phase in the H₂SO₄/HI/I₂/H₂O quaternary solution produced by Bunsen reaction. The effects of the solution composition in the feed and the operating temperature on the separation characteristics were analyzed to determine the preferable operating conditions in the Bunsen section. The increases in both the iodine content and the operating temperature improved the separation characteristics of the liquid–liquid phase when the occurrence of secondary reactions was neglected. The amount of impurities in both phases obviously decreased as the iodine content increased. The effect of the iodine content was more significant relative to that of the operating temperature. The optimal operating conditions were proposed to achieve the concentrations of HI in the HIx phase in excess of the azeotropic composition.     

How does tax system on energy industries affect energy demand,CO2 emissions,and economy in China?

Energy savings and CO₂ emission reduction have become a major issue in recent years. Taxes on energy production sectors may be an effective way to save energy, reduce CO₂ emissions, and improve environmental quality. This paper constructs a dynamic recursive Computable General Equilibrium (CGE) model to analyze the impact of the energy tax on energy, economy, and environment from the perspective of tax rates and tax forms (specific tax and ad valorem tax). The results show that adjusting the tax system and the tax rate has important implications for energy conservation while having minor impacts on the output of other industries. The impact of an increasing energy tax on the energy demand is greater than the impact on sectoral output, indicating that energy efficiency will be increased to some extent. The CO₂ reduction will increase over time when an ad valorem tax is implemented on enterprises. We found that ad valorem tax has greater elasticity of economic output, energy demand, and CO₂ emission reduction. The results support the direction of China's resource tax reform. However, we argue that it is better to increase the tax rate relatively and relax the control on energy prices so that energy efficiency will increase.     

Liquid hydrogen fueled automotive vehicles in Germany—status and development

The activities on liquid hydrogen fueled automotive vehicles in the Federal Republic of Germany are summarized. These activities were started in 1979 when the first European liquid hydrogen fueled automotive vehicle was demonstrated by the DFVLR. Subsequent activities such as the Los Alamos National Laboratory-DFVLR joint car project, as well as the continued DFVLR liquid hydrogen automotive vehicle project, improved engine operation and the fuel conditioning system, and enabled liquid hydrogen storage on board. Based on this, two research activities were started between the DFVLR and two major German automobile manufacturers. In a cooperation between the Bayerische Motorenwerke AG (BMW) and the DFVLR, a BMW 745i limousine was converted to hydrogen operation. A unique property of this vehicle is represented by the digital electronic system (MOTRONIC) using microprocessors in mixture control, spark advance and engine monitoring. This system was adapted for hydrogen and enables convenient dual fuel operation, i.e. either gasoline or hydrogen. Data are reported on testing of the turbocharged 3.5 l 745i engine operated on external mixture formation by timed individual port injection of ambient temperature hydrogen.     

Can increasing gasoline supply in the United States affect ethanol production in Brazil?

The increasing supply of non-conventional oil in the U.S. has changed the dynamics of crude oil market and the flow of oil products in the Atlantic Basin. The Gulf of Mexico (GoM) emerges as an exportation hub of oil products, contributing to a scenario in which gasoline prices tend to decline. Meanwhile, from 2010, the competitiveness of the Brazilian sugarcane ethanol has been ruptured by the country's gasoline price policy that had not followed international price parity. The political conjuncture of the U.S. incites high utilization rates of their refining system in the GoM. In this context the profitability of the ethanol business can be impacted in Brazil, by either the current policy of controlled domestic gasoline prices or a future scenario of declining gasoline international prices. Therefore, this study tests if this gasoline price scenario can compromise even more the competitiveness of the Brazilian ethanol. Particularly, for a scenario of falling prices, ethanol production in Brazil would be under strong pressure of gasoline supply coming from the U.S. This can impact Brazil's ethanol industry, whose development has been justified by climate change policies. In that sense, the paper also discusses the future opportunities and challenges for Brazil's ethanol industry.     

How does the new-type urbanisation affect CO2 emissions in China? An empirical analysis from the perspective of technological progress

The development of traditional urbanisation has generated environmental problems, so the Chinese Government has proposed a new-type of urbanisation path with uniquely Chinese characteristics. How does this new-type of urbanisation affect CO₂ emissions? Based on panel data from 29 provinces in China (2005 to 2016), we apply an exploratory spatial data analysis model, a spatial econometric model, and a threshold model to analyse the spatial autocorrelation of CO₂ emissions, the direct and indirect effects of new-type urbanisation on CO₂ emissions, and the threshold characteristics produced by technological progress, respectively. The key results are: (1) CO₂ emissions show significant positive autocorrelation in China, and the spatial distribution of CO₂ emissions is HH (High-High) or LL (Low-Low) clustered in most provinces; (2) new-type urbanisation has a paradoxical effect on CO₂ emissions. Energy-saving technology has a rebound effect on CO₂ emissions, but environmental technology inhibits CO₂ emissions; (3) by eliminating the rebound effect of energy-saving technology on CO₂ emissions and promoting environmental technology, new-type urbanisation indirectly inhibits CO₂ emissions; (4) new-type urbanisation exhibits a threshold effect on CO₂ emissions due to the different levels of energy-saving technology and environmental technology. Finally, policy recommendations for CO₂ emissions reduction are proposed from the perspective of new-type urbanisation, energy-saving technology, and environmental technology.     

Bitter sweet: How sustainable is bio-ethanol production in Brazil?

While biofuels have currently been regarded as a good alternative for fossil fuels, there remain many debates on their impacts on human and environment. This paper tried to shed light on bio-ethanol in Brazil as one of the main producers and exporters in the world. The main question was to understand “how sustainable is bio-ethanol production in Brazil?” To answer, the political motives of producing bio-ethanol followed by its ecological and socio-economic impacts were discussed. The paper concluded that although bio-ethanol production in Brazil seems environmentally friendly, it might socio-economically be hazardous.     

“How green are electric vehicles?”

Battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs) are often labeled “green”, implying that they will significantly reduce greenhouse gas (GHG) emissions. But actual GHG reductions will depend on two factors: the number of electric vehicles that can be sold to Americans that are fond of driving large vehicles long distances, and the GHGs emitted by the electrical power plants that charge the EV batteries. This article evaluates the maximum potential of EVs to cut GHG emissions and oil consumption in the U.S. and compares them with the GHG and oil reduction potential of hydrogen-powered fuel cell electric vehicles. Even if all US light duty vehicles (LDVs) (cars and trucks) were replaced by a combination of battery EVs for small vehicles and plug-in hybrids for all other LDVs, then GHGs could at most be reduced by 25% and oil consumption could be reduced by less than 67%. But if all LDVs in the U.S. were replaced by fuel cell electric vehicles powered by hydrogen made from natural gas, then GHGs would be immediately reduced by 44% and oil consumption by nearly 100%.     

Can remote green hydrogen production play a key role in decarbonizing Europe in the future? A cradle-to-gate LCA of hydrogen production in Austria,Belgium, and Iceland

Hydrogen can play a key role in decarbonizing industrial and transportation processes. As the European demand for hydrogen rises, several EU member states have been looking into ways to import remotely-produced hydrogen (H₂) to fulfill their local needs. This cradle-to-gate LCA study assesses the H₂ production in Iceland using local renewable energy sources, including the transport to potential gates in Austria and Belgium and compares it with locally produced H₂ at the European sites. Our results indicate that the Global Warming Potential (GWP) of H₂ production depends primarily on the energy mix, while transportation of H₂ generates a minor impact. Furthermore, in its current state, H₂ production in Iceland through Polymer electrolyte membrane electrolysis (PEM-EC) yields over 13- and 21 times lower GHG emissions compared respectively to Austria and Belgium. Based on these results, we conclude that remotely produced hydrogen can play an important part in decarbonizing European carbon-intensive industries.     

How risky is the introduction of fuel cell electric vehicles in a Mediterranean town?

The incorporation of Fuel Cell Electric Vehicles (FCEVs) in public transport is a fundamental step towards the minimization of the emissions due to transportation globally. In-depth studies are required regarding the potential risk from the storage of hydrogen, the transportation of hydrogen to refuelling stations and the refuelling procedure. Thus, it is a prerequisite to establish a holistic baseline which is related to FCEV safety during operation/maintenance, especially to a country in which the sales of these types of vehicles are significantly low. This paper suggests the employment of operational risk management methodology. Relevant experts and stakeholders requested to fill out an ‘‘Event-Probability Matrix’’ per scenario of likely hazards. This research estimates the interest of the local society about technological hazards and the conviction that hydrogen vehicles could be as safe as conventional vehicles. Additional critical scenarios related to the hydrogen storage are analyzed.     

Carbon emissions in China: How far can new efforts bend the curve?

While China is on track to meet its global climate commitments through 2020, China's post-2020 CO₂ emissions trajectory is highly uncertain, with projections varying widely across studies. Over the past year, the Chinese government has announced new policy directives to deepen economic reform, to protect the environment, and to limit fossil energy use in China. To evaluate how new policy directives could affect energy and climate change outcomes, we simulate two levels of policy effort—a continued effort scenario that extends current policies beyond 2020 and an accelerated effort scenario that reflects newly announced policies—on the evolution of China's energy and economic system over the next several decades. We perform simulations using the China-in-Global Energy Model, C-GEM, a bespoke recursive-dynamic computable general equilibrium model with global coverage and detailed calibration of China's economy and future trends. Importantly, we find that both levels of policy effort would bend down the CO₂ emissions trajectory before 2050 without undermining economic development. Specifically, in the accelerated effort scenario, we find that coal use peaks around 2020, and CO₂ emissions level off around 2030 at 10 bmt, without undermining continued economic growth consistent with China reaching the status of a “well-off society” by 2050.     

How do daily changes in oil prices affect US monthly industrial output?

Detecting asymmetry has become increasingly difficult using single frequency data. This paper goes beyond the prevailing use of aggregate/averaged data in order to provide a more in-depth treatment of the dynamic effects of the price of crude oil on industrial output growth. To do so, we propose an Asymmetric Mixed Data Sampling (AMIDAS) model to examine if there is any concealed evidence of asymmetry arising from daily effects of the price of crude oil on monthly changes in industrial output in the United States (US). We find that this model is able to detect dynamic asymmetric impacts of a high frequency independent variable on a low frequency dependent variable more effectively than when the high frequency variable is aggregated up at the time interval of the low frequency variable. We find that, in comparison with the marginal lagged effects of a rise in the daily price of crude oil, the effects of a fall in the daily price of crude oil are more sluggish as it takes longer for the effects of the oil price drop to die off over time. This finding implies that a fall in the price of crude oil shifts the supply curve rightward less and at a much slower pace than an equivalent price rise shifts it to the left.     

Numerical investigations of catalyst–liquid slurry flow in the photocatalytic reactor for hydrogen production based on algebraic slip model

A new device of photocatalytic reactor with solar concentrator for hydrogen production was introduced in this paper. In order to investigate the effects of the slurry flow and catalyst distributions in the reactor on photocatalysis for hydrogen production, an algebraic slip mixture model (ASM) was used to simulate the dynamics of the catalyst–water slurry flow. A block-structured non-uniform grid was applied to discretize the entire domain and an algebraic multi-grid (AMG) method was used to solve the pressure field. The mean slurry pressure gradients obtained by the model were in agreement with the experimental data in former literature. Based on this verification, catalyst particle distributions, slurry velocity distributions and inter-phase slip velocity distributions in photocatalytic reactor pipe were investigated. The results show that the catalyst tends to distribute near the bottom of the pipe in the reactor, leading to a concentration gradient along the vertical direction of cross section. But due to the effects of turbulence force against the gravity, a heterogeneous suspending state will be achieved in a fully developed flow.     

How close is a hydrogen hypersonic commercial aircraft?

There is a growing interest in hydrogen hypersonic commercial aircraft, which is claimed could permit travel from Sydney to London in less than 1½ hours with reduced environmental and economic costs compared to current subsonic airliners fueled with conventional hydrocarbon jet fuels. As here discussed, this development faces many technical hurdles, from thermal management to materials for extreme environments, from maneuverability to communication, and from sonic boom noise to efficient propulsion over a range of Mach from 0 to 10 and above. The development of this disruptive modality of air travel is constricted by resource availability to tackle these numerous technological challenges. Ultimately, the success will depend on social, political, and economic aspects, from the relevance of mass vs. elite air travel, the developments in the global economy, the synergies with military hypersonic propulsion, and the commitment toward general hydrogen aviation employing hydrogen for subsonic airliners.     

Ceria as a catalyst for hydrogen iodide decomposition in sulfur–iodine cycle for hydrogen production

In this work, ceria (CeO₂) prepared with different methods and at various calcination temperatures have been tested to evaluate their effect on hydrogen iodide (HI) decomposition in sulfur–iodine (SI) cycle at various temperatures. The CeO₂ catalysts' strongly enhance the HI decomposition by comparison with blank test, especially gel CeO₂ 300. TG–FTIR, BET, XRD, TEM and TPR were performed for catalysts' characterization. The results show that the CeO₂ catalyst synthesized by citric-aided sol–gel method and calcined at low temperature (<500 °C) shows more lattice defects, smaller crystallites, larger surface area and better reducibility. Oxygen can promote the significantly rapid surface reaction, but simultaneously consume hydrogen species (H) contained in HI. Lattice defects, especially the reduced surface sites, i.e., Ce³⁺ and oxygen vacancy, play the dominant role in surface reactions of HI decomposition. A new reaction mechanism for HI catalytic decomposition over CeO₂ catalyst is proposed.     

How does manufacturing agglomeration affect green economic efficiency?

It is the theme of today to develop green economy and improve green economic efficiency (GEE). Adopting the panel data of 287 cities in China between 2003 and 2016, this research investigates the nonlinear impact and its action path of Manufacturing Agglomeration (MA) on GEE theoretically and empirically via adopting dynamic spatial panel Durbin model and mediating effect model. The results suggest the existence of a significant positive “U-shaped” relationship between MA and GEE, no matter in the short-term or long-term. However, for traditional economic efficiency, in the short-term, MA first inhibits it and then promotes it; while in the long-term, there is no significant positive “U-shaped” relationship between the two. In addition, industrial structure upgrading plays an important mediating role between MA and GEE, which accounts for 31.992%. Therefore, this paper believes that in order to improve green economic efficiency, it is necessary to dynamically adjust regional related policies, eliminate the congestion effect caused by manufacturing agglomeration, and achieve high-quality development of manufacturing agglomeration through industrial structure transformation and upgrading.     

New methods for new systems – How to find the techno-economically optimal hydrogen conversion system

In this paper, the method of multi-pole system analysis (MPSA) is presented, which contributes to the task of multicriterial, model-based system analysis and is applied to an innovative wind-energy converter which uses converted energy to electrolytically split water into hydrogen and oxygen. First, the method MPSA is presented in its most general form without a specific application. For illustration, MPSA is applied to the wind-energy converter in the second part and thereby the system is described simultaneously technically as well as economically. Using methods of robust optimization, the optimal system is identified. Since the optimal system design has been derived on the basis of models, methods of sensitivity analysis are applied to assess the model quality and reveal potential for model improvements. We demonstrate that MPSA enables the consideration of energetic and economic aspects simultaneously in the system design and hence supports the establishment of hydrogen energy conversion systems.     

How can we improve biomethane production per unit of feedstock in biogas plants?

Biogas production is one of the number of tools that may be used to alleviate the problems of global warming, energy security and waste management. Biogas plants can be difficult to sustain from a financial perspective. The facilities must be financially optimized through use of substrates with high biogas potential, low water content and low retention requirement. This research carried out in laboratory scale batch digesters assessed the biogas potential of energy crops (maize and grass silage) and solid manure fractions from manure separation units. The ultimate methane productivity in terms of volatile solids (VS) was determined as 330, 161, 230, 236, 361 L/kg VS from raw pig slurry, filter pressed manure fiber (FPMF), chemically precipitated manure fiber (CPMF), maize silage and grass silage respectively. Methane productivity based on mass (L/kg substrate) was significantly higher in FPMF (55 L/kg substrate), maize silage (68 L/kg substrate) and grass silage (45–124 L/kg substrate (depending on dry solids of feedstock)) as in comparison to raw pig slurry (10 L/kg substrate). The use of these materials as co-substrates with raw pig slurry will increase significantly the biomethane yield per unit feedstock in the biogas plant.     

Is liquid hydrogen a solution for mitigating air pollution by airports?

This paper investigates the potential of LH₂ (Liquid Hydrogen) as an alternative fuel for achieving more sustainable long-term development of large airports in terms of mitigating their air pollution. For such purpose, a methodology for quantifying the potential of LH₂ is developed. It consists of two models: the first model enables the estimation of the fuel demand and the specification of the fuel production and storage capacity needed to satisfy that demand at a given airport under given conditions; the other model enables assessment of the effects of introducing LH₂ on mitigating air pollution at that airport.