A review on hydrogen production using aluminum and aluminum alloys

The hydrogen economy has been identified as an alternative to substitute the non-sustainable fossil fuel based economy. Ongoing research is underway to develop environmentally friendly and economical hydrogen production technologies that are essential for the hydrogen economy. One of the promising ways to produce hydrogen is to use aluminum or its alloys to reduce water or hydrocarbons to hydrogen. This paper gives an overview on these aluminum-based hydrogen production methods, their limitations and challenges for commercialization. Also, a newly developed concept for cogeneration of hydrogen and electrical energy is discussed.     

Transition to renewable energy systems with hydrogen as an energy carrier

Unlike the present energy system based on fossil fuels, an energy system based on renewable energy sources with hydrogen and electricity as energy carriers would be sustainable. However, the renewable energy sources in general have less emergy than the fossil fuels, and their carriers have lower net emergy. Because of that they would not be able to support continuous economic growth, and would eventually result in some kind of a steady-state economy. An early transition to renewable energy sources may prove to be beneficial in the long term, i.e., it may result in a steady state at a higher level than in the case of a transition that starts later. Once the economy starts declining it will not be able to afford transition to a more expensive energy system, and transition would only accelerate the decline. Similarly, if a transition is too fast it may weaken and drain economy too much and may result in a lower steady state. If a transition is too slow, global economy may be weakened by the problems related to utilization of fossil fuels (such as global warming and its consequences) before transition is completed and the result again would be a lower steady state. Therefore, there must be an optimal transition rate; however, its determination would require very complex models and constant monitoring and adjustment of parameters.     

“Green” path from fossil-based to hydrogen economy: An overview of carbon-neutral technologies

While the dominant role of hydrogen in a sustainable energy future is widely accepted, the strategies for the transition from fossil-based to hydrogen economy are still actively debated. This paper emphasizes the role of carbon-neutral technologies and fuels during the transition period. To satisfy the world's growing appetite for energy and keep our planet healthy, at least 10 TW (or terawatt) of carbon-free power has to be produced by mid-century. Three prominent options discussed in the literature include: decarbonization of fossil energy, nuclear energy and renewable energy sources. These options are analyzed in this paper with a special emphasis on the role of hydrogen as a carbon-free energy carrier. In particular, the authors compare various fossil decarbonization strategies and evaluate the potential of nuclear and renewable energy resources to meet the 10 TW target. An overview of state-of-the-art technologies for production of carbon-free energy carriers and transportation fuels, and the assessment of their commercial potential is provided. It is shown that neither of these three options alone could provide 10 TW of carbon-neutral power without major changes in the existing infrastructure, and/or technological breakthroughs in many areas, and/or a considerable environmental risk. The authors propose a scenario for the transition from current fossil-based to hydrogen economy that includes two key elements: (i) changing the fossil decarbonization strategy from one based on CO₂ sequestration to one that involves sequestration and/or utilization of solid carbon, and (ii) producing carbon-neutral synthetic fuels from bio-carbon and hydrogen generated from water using carbon-free sources (nuclear, solar, wind, geothermal). This strategy would allow taking advantage of the existing fuel infrastructure without an adverse environmental impact, and it would secure a smooth carbon-neutral transition from fossil-based to future hydrogen economy.     

The hydrogen economy is complementary and synergetic to the electric economy

There is growing support to electrifying our economy by getting off of fossil fuels by producing renewable energy by wind and solar photovoltaic plants and using batteries to balance production and demand or to store energy onboard vehicles that cannot move along electric lines. Unfortunately, this proposal is pushed forward negating the value of hydrogen as an energy store. As here commented, the hydrogen economy is not competitive, but complementary and synergetic to the electric economy, and both should be promoted together to secure a faster transition towards a CO₂ emission-free economy.     

Biomass energy and the environmental impacts associated with its production and utilization

Biomass is the first-ever fuel used by humankind and is also the fuel which was the mainstay of the global fuel economy till the middle of the 18th century. Then fossil fuels took over because fossil fuels were not only more abundant and denser in their energy content, but also generated less pollution when burnt, in comparison to biomass. In recent years there is a resurgence of interest in biomass energy because biomass is perceived as a carbon-neutral source of energy unlike net carbon-emitting fossil fuels of which copious use has led to global warming and ocean acidification.The paper takes stock of the various sources of biomass and the possible ways in which it can be utilized for generating energy. It then examines the environmental impacts, including impact vis a vis greenhouse gas emissions, of different biomass energy generation–utilization options.     

低碳经济背景下的新能源开发和利用

环境污染和能源短缺的现实压力使新能源的开发利用成为低碳经济背景下更为紧迫的选择,全世界开始重新关注新能源。但至今还没有一种新能源能够取代现在普遍使用的化石能源,而只能作为常规能源有限的补充。太阳能光伏发电和风力发电的利用过程无疑是低碳的;但其开发制造过程却要耗散大量的资源,需要大量化石燃料作支撑,应该说是高碳的,新能源低碳、无污染、零排放等说法是不全面、不客观的。新能源开发和设备制造过程对化石燃料的依赖、高成本和二氧化碳等污染物的排放之间是有正相关性的。目前新能源的开发利用并不经济,风力发电成本是火电的2～3倍,太阳能光伏发电成本是火电的5～10倍。生物能源被视为唯一可以大规模替代汽油和柴油的可再生能源,应重视发展纤维素乙醇,其制造技术的突破是可以预期的,相关问题的解决也相对容易。新能源发展规划要结合国情,趋利避害,不能一哄而起,企业竞争的关键是技术创新和成本的不断降低。要全面看待新能源开发利用的优势和存在的问题,加强研发、稳步推进,避免重复浪费,对不同种类新能源的发展规划要做出科学合理的选择。另外,要特别注意对常规能源的节约,无论今后能源结构如何变化发展,节能都应当是一个永恒的主题。     

The transition towards renewable energies: Physical limits and temporal conditions

The perspectives of the depletion of fossil energy resources, together with the consequences of climate change, have provoked the development of numerous national and pluri-national energy policies. However, there have been few overall studies on the evolution of these resources. This paper uses a dynamic model to study the exhaustion patterns of world fossil and nuclear fuels and their possible replacement by renewable energy sources. The results show that peak oil will be the first restriction and it will not be easily overcome. Electric vehicles can produce some interesting savings, but they are insufficient to avoid the decline in oil. Biofuels are even more limited, due to the enormous extensions of fertile land they require and their low productivity. This shows that overcoming the decline in oil will need much more ambitious policies than the mere substitution of technology. If the “oil–economy” relationship does not change substantially, world economic growth may be seriously limited or even negative. In contrast, the production of electrical energy is not such a worrying problem in the short and middle-term.     

International overview of hydrogen and fuel cell research

Increasing environmental problems, limited fossil resources and the geopolitical dependence on crude oil are enormous challenges for our societies. According to energy experts from all over the world, fuel cell and hydrogen energy technologies will play an important role in the portfolio for a future energy economy. This is particularly true for the transport sector which is marked today by an extreme dependency on oil. Hydrogen needs to be produced cost-effectively and with zero or near-zero CO₂ emissions. Fuel cells, with their high electrical efficiencies and clean exhaust energy conversion, have the potential to produce excellent solutions to the ecological and economic problems provided that their development is pursued in a determined way and that their market launch is prepared.     

Emerging technologies by hydrogen: A review

The majority of energy being used is obtained from fossil fuels, which are not renewable resources and require a longer time to recharge or return to its original capacity. Energy from fossil fuels is cheaper but it faces some challenges compared to renewable energy resources. Thus, one of the most potential candidates to fulfil the energy requirements are renewable resources and the most environmentally friendly fuel is Hydrogen. Hydrogen is a clean and efficient energy carrier and a hydrogen-based economy is now widely regarded as a potential solution for the future of energy security and sustainability. Hydrogen energy became the most significant energy as the current demand gradually starts to increase. It is an important key solution to tackle the global temperature rise. The key important factor of hydrogen production is the hydrogen economy. Hydrogen production technologies are commercially available, while some of these technologies are still under development. Therefore, the global interest in minimising the effects of greenhouse gases as well as other pollutant gases also increases. In order to investigate hydrogen implementation as a fuel or energy carrier, easily obtained broad-spectrum knowledge on a variety of processes is involved as well as their advantages, disadvantages, and potential adjustments in making a process that is fit for future development. Aside from directly using the hydrogen produced from these processes in fuel cells, streams rich with hydrogen can also be utilised in producing ethanol, methanol, gasoline as well as various chemicals of high value. This paper provided a brief summary on the current and developing technologies of hydrogen that are noteworthy.     

The Bourner lecture: Power sources and the new energy economy

This paper focuses on the critical role of power sources in the future energy economy. It highlights the disruptive nature of the new energy technologies that will come into play, addressing the problems of greenhouse emissions and reduced availability of fossil fuel reserves. The importance of power sources such as fuel cells and batteries is discussed and their inter-relationship with the hydrogen economy explored. Overall it is clear that improved methods of energy storage are of critical importance and these must be optimised both in terms of cost and energy density. There are important challenges to be addressed; however, very positive outcomes can be anticipated.     

EROI of different fuels and the implications for society

All forms of economic production and exchange involve the use of energy directly and in the transformation of materials. Until recently, cheap and seemingly limitless fossil energy has allowed most of society to ignore the importance of contributions to the economic process from the biophysical world as well as the potential limits to growth. This paper centers on assessing the energy costs of modern day society and its relation to GDP. Our most important focus is the characteristics of our major energy sources including each fuel's energy return on investment (EROI). The EROI of our most important fuels is declining and most renewable and non-conventional energy alternatives have substantially lower EROI values than traditional conventional fossil fuels. At the societal level, declining EROI means that an increasing proportion of energy output and economic activity must be diverted to attaining the energy needed to run an economy, leaving less discretionary funds available for “non-essential” purchases which often drive growth. The declining EROI of traditional fossil fuel energy sources and the effect of that on the world economy are likely to result in a myriad of consequences, most of which will not be perceived as good.     

Global challenges in energy

Environmental and security concerns are stimulating global interest in hydrogen power, renewable energy, and advanced transportation technologies, but no significant movement away from oil and a carbon-based world economy is expected soon. Over the longer-term, however, a transition from fossil fuels to a non-carbon-based economy will likely occur, affecting the type of environment future generations may encounter. Key challenges will face the world's energy industry over the next few decades to ensure a smooth transition—challenges which will require government and industry solutions beginning as early as today. This paper identifies four critical challenges in energy and the choices which will have to be made on how best to confront growing pollution caused by fossil fuels and how to facilitate an eventual revolutionary-like transition to a non-carbon-based global economy.     

Improving energy consumption structure: A comprehensive assessment of fossil energy subsidies reform in China

Fossil energy subsidies reform would be an effective way to improve the energy consumption structure; however, the reform needs to be assessed comprehensively beforehand as it would exert uncertain impacts on economy, society and environment. In this paper, we use price-gap approach to estimate the fossil energy subsidies of China, then establish CGE model that contains pollutant emissions accounts and CO₂ emissions account to stimulate the fossil energy subsidies reform under different scenarios, and the environmental economic analysis concept is introduced to monetize the pollutant reduction benefits. Furthermore, we analyze the possibility and scope of improving the energy consumption structure from the perspective of technical and economic analysis. Analytical results show that the energy consumption structure could be improved by different extent by removing coal or oil subsidies, while the economic and social indexes will be influenced distinctively. Meanwhile, the effects of cutting coal subsidies are more feasible than that of cutting oil subsidies overall. It is recommended to implement fossil energy subsidies gradually, cut the coal first and then cut oil subsidies successively.     

Positioning of major energy sources in Korea and its implications

Energy is an integral component of today's economy, and Korea is no exception. Due to controversies around fossil fuel and nuclear energy, Korea had major discussions on its energy portfolio. In particular, for effective policy, it is essential to identify the public's perception of different energy sources. This research analyzed 458 valid responses from survey data and compared 5 aspects (“safety,” “environment friendliness,” “economic fea [Colour figure can be viewed at wileyonlinelibrary.com ]sibility,” “job creation,” and “contribution to economic development”) of 4 energy sources (new and renewable, hydropower, nuclear, and fossil fuel). The results suggest that new and renewable energy is perceived by the Korean public as the best energy source in 4 aspects, while fossil fuel is the worst in all aspects. Furthermore, the Korean public perceives safety and environment friendliness as closely coupled attributes because citizens are more aware of the environment and concerned about their own safety, which is a typical attribute of developed nations. The implications for the government and the businesses involved in each energy source are given in the conclusion.     

宁夏风力发电前景分析

能源是人类赖以生存的物质基础,是国民经济的基本支撑。中国的能源供应主要依靠煤炭、石油和天然气等化石能源,尤其是宁夏的能源供应主要依靠煤炭,但是化石能源资源的有限性及其开发利用过程对生态环境造成的巨大影响,严重制约经济社会的可持续发展。叙述了宁夏风能资源的现状,分析了风力发电的前景。     

Current scenario of biodiesel development in India: prospects and challenges

For a developing nation like India, the current energy portfolio is dominated by fossil fuels such as oil, coal, and petroleum products. Due to the rapid depletion and limited available resources, the price of fossil fuel increases. Also, fossil fuel induces climate change, environmental pollution, and rising global temperature. There is urgent need to shift from conventional energy to renewable energy source for sustainable and economic growth and to enhance a country’s energy security. Biofuel offers an attractive source of energy for the substitution of fossil fuels, and looking at the huge demand for diesel in all sectors of the economy, the biodiesel is being viewed as the best substitute for diesel. The other advantage for biofuel promotion in India is climate change mitigation through reduced greenhouse gas (GHG) emission. This article provides the current status of biodiesel development in India and discusses the role played by the centre and state government in promoting second-generation feedstock (nonedible seeds) and third-generation feedstock (algae) for biodiesel production.     

Mathematical and computational approaches for design of biomass gasification for hydrogen production: A review

The ever growing environmental concern caused by excessive use of fossil fuels in energy and transportation systems triggered considerable investigations on alternative energy sources such as biomass. Furthermore, the availability and security of fossil fuels to meet future global energy need are also subjected to uncertainty. For these reasons, the world's current focus is shifted towards hydrogen-based future economy. Gasification is a proven technology to produce satisfactory yield of hydrogen. Many studies have been performed to increase the production yield. Due to the extensive range of investigations, mathematical and computational approaches have been applied to conduct these studies. Thus, this paper aims to update and broaden the review coverage by incorporating works done to materialize the investigations on the potential of producing hydrogen from biomass via gasification encompassing mathematical modeling, simulation, optimization, process heat integration and cogeneration. Each of these subjects is reviewed and analyzed which helped to identify their respective strength and areas which require further research effort.     

Prospect of biodiesel in Pakistan

Developing countries like Pakistan need continuous supply of cheap energy. It is common fear in today’s world that fossil fuels will be depleted soon. The cost of energy is increasing continuously and is expected to be at its peak by 2050. Many technologically advanced countries are successfully using renewable energy sources for their energy needs, however, they still believe in the importance of fossil fuel. In renewable energy field, Pakistan is using hydropower for energy needs successfully, whereas project regarding solar and wind energy is in progress. Biomass, a renewable energy source, is gaining interest in many researchers because it produces similar type of fuel extracted from crude oil. Energy from biomasses only depends upon the availability of cheap raw material.Biodiesel, which is produced by the reaction of vegetable oil and alcohol, can be used with same or with better performance in diesel engine. It is a clean fuel that causes less environment pollution as compared to petro diesel. High cost and non-continuous supply of vegetable oil is the main hurdle for its general acceptance. Many advanced countries have developed strategy for continuous supply of cheap price energy crops (source of biomass). Biodiesel is the only possible reciprocal to petro diesel or otherwise diesel engine will be useless after the depletion of crude oil.In this study, biodiesel as an energy source has been discussed; this is indigenous diesel engine fuel and is beneficial for our environment, economy, and more importantly will increase the income of our farmers.     

Reforming fossil fuel prices in India: Dilemma of a developing economy

Over the period between 1990–1 and 2012–3, fossil fuel use on farms has risen and its indirect use in farming, particularly for non-energy purposes, is also growing. Consequently, both energy intensity and fossil fuel intensity are rising for Indian agriculture. But, these are declining for the aggregate Indian economy. Thus, revision of fossil fuel prices acquires greater significance for Indian agriculture than for rest of the economy. There are significant differences across crops. The crop-level analysis is supplemented by an alternative approach that utilizes a three-sector input–output (I–O) model for the Indian economy representing farming, fossil fuels, and rest of economy. Fossil fuels sector is assessed to portray, in general, strong forward linkages. The increase in total cost of farming, for a given change in fossil fuel prices, is estimated as a multiple of increase in direct input cost of fossil fuels in farming. From the three-sector aggregated economy this multiple was estimated at 3.99 for 1998–9. But it grew to 6.7 in 2007–8. The findings have stronger ramifications than commonly recognized, for inflation and cost of implementing the policy on food security.     

Technical efficiency of economic systems of EU-15 countries based on energy consumption

In the present study, Data Envelopment Analysis is used to determine the Technical Efficiency index of EU-15 countries from 1980 to 2008, using cross-country comparison. Technical Efficiency index represents the capacity of an economy to produce a higher level of Gross Domestic Product for a given level of total energy input. The level of the Technical Efficiency index is determined from the energy mix (fossil fuels, non-fossil fuels, nuclear energy) of each country and depends on the maximization level of the production of the Gross Domestic Product of the economic system, without waste of energy resources. The current study is applied in the case of the EU15 countries. Its scope is to highlight the differentiations of country classifications before and after the integration of nuclear energy in the energy mix of each country. The main result is that the integration of nuclear energy as an additional input in the energy mixture affects negatively the Technical Efficiency of countries. Also, when an economy achieves a decrease of the energy consumption produced from fossil fuels, and a better exploitation of renewable energy sources, clearly improves its capacity to produce more output with the given levels of inputs.