Showing papers on "Renewable energy published in 2008"

Second generation biofuels: high-efficiency microalgae for biodiesel production

Abstract: The use of fossil fuels is now widely accepted as unsustainable due to depleting resources and the accumulation of greenhouse gases in the environment that have already exceeded the “dangerously high” threshold of 450 ppm CO2-e. To achieve environmental and economic sustainability, fuel production processes are required that are not only renewable, but also capable of sequestering atmospheric CO2. Currently, nearly all renewable energy sources (e.g. hydroelectric, solar, wind, tidal, geothermal) target the electricity market, while fuels make up a much larger share of the global energy demand (∼66%). Biofuels are therefore rapidly being developed. Second generation microalgal systems have the advantage that they can produce a wide range of feedstocks for the production of biodiesel, bioethanol, biomethane and biohydrogen. Biodiesel is currently produced from oil synthesized by conventional fuel crops that harvest the sun’s energy and store it as chemical energy. This presents a route for renewable and carbon-neutral fuel production. However, current supplies from oil crops and animal fats account for only approximately 0.3% of the current demand for transport fuels. Increasing biofuel production on arable land could have severe consequences for global food supply. In contrast, producing biodiesel from algae is widely regarded as one of the most efficient ways of generating biofuels and also appears to represent the only current renewable source of oil that could meet the global demand for transport fuels. The main advantages of second generation microalgal systems are that they: (1) Have a higher photon conversion efficiency (as evidenced by increased biomass yields per hectare): (2) Can be harvested batch-wise nearly all-year-round, providing a reliable and continuous supply of oil: (3) Can utilize salt and waste water streams, thereby greatly reducing freshwater use: (4) Can couple CO2-neutral fuel production with CO2 sequestration: (5) Produce non-toxic and highly biodegradable biofuels. Current limitations exist mainly in the harvesting process and in the supply of CO2 for high efficiency production. This review provides a brief overview of second generation biodiesel production systems using microalgae.

Energy storage systems—Characteristics and comparisons

Abstract: Electricity generated from renewable sources, which has shown remarkable growth worldwide, can rarely provide immediate response to demand as these sources do not deliver a regular supply easily adjustable to consumption needs. Thus, the growth of this decentralized production means greater network load stability problems and requires energy storage, generally using lead batteries, as a potential solution. However, lead batteries cannot withstand high cycling rates, nor can they store large amounts of energy in a small volume. That is why other types of storage technologies are being developed and implemented. This has led to the emergence of storage as a crucial element in the management of energy from renewable sources, allowing energy to be released into the grid during peak hours when it is more valuable. The work described in this paper highlights the need to store energy in order to strengthen power networks and maintain load levels. There are various types of storage methods, some of which are already in use, while others are still in development. We have taken a look at the main characteristics of the different electricity storage techniques and their field of application (permanent or portable, long- or short-term storage, maximum power required, etc.). These characteristics will serve to make comparisons in order to determine the most appropriate technique for each type of application.

Energy, environment and sustainable development

Abstract: Globally, buildings are responsible for approximately 40% of the total world annual energy consumption. Most of this energy is for the provision of lighting, heating, cooling, and air conditioning. Increasing awareness of the environmental impact of CO2 and NOx emissions and CFCs triggered a renewed interest in environmentally friendly cooling, and heating technologies. Under the 1997 Montreal Protocol, governments agreed to phase out chemicals used as refrigerants that have the potential to destroy stratospheric ozone. It was therefore considered desirable to reduce energy consumption and decrease the rate of depletion of world energy reserves and pollution of the environment. One way of reducing building energy consumption is to design building, which are more economical in their use of energy for heating, lighting, cooling, ventilation and hot water supply. Passive measures, particularly natural or hybrid ventilation rather than air-conditioning, can dramatically reduce primary energy consumption. However, exploitation of renewable energy in buildings and agricultural greenhouses can, also, significantly contribute towards reducing dependency on fossil fuels. Therefore, promoting innovative renewable applications and reinforcing the renewable energy market will contribute to preservation of the ecosystem by reducing emissions at local and global levels. This will also contribute to the amelioration of environmental conditions by replacing conventional fuels with renewable energies that produce no air pollution or greenhouse gases. The provision of good indoor environmental quality while achieving energy and cost-efficient operation of the heating, ventilating and air-conditioning (HVAC) plants in buildings represents a multi-variant problem. The comfort of building occupants is dependent on many environmental parameters including air speed, temperature, relative humidity and quality in addition to lighting and noise. The overall objective is to provide a high level of building performance (BP), which can be defined as indoor environmental quality (IEQ), energy efficiency (EE) and cost efficiency (CE). • Indoor environmental quality is the perceived condition of comfort that building occupants experience due to the physical and psychological conditions to which they are exposed by their surroundings. The main physical parameters affecting IEQ are air speed, temperature, relative humidity and quality. • Energy efficiency is related to the provision of the desired environmental conditions while consuming the minimal quantity of energy. • Cost efficiency is the financial expenditure on energy relative to the level of environmental comfort and productivity that the building occupants attained. The overall cost efficiency can be improved by improving the indoor environmental quality and the energy efficiency of a building. This article discusses the potential for such integrated systems in the stationary and portable power market in response to the critical need for a cleaner energy technology. Anticipated patterns of future energy use and consequent environmental impacts (acid precipitation, ozone depletion and the greenhouse effect or global warming) are comprehensively discussed in this paper. Throughout the theme several issues relating to renewable energies, environment and sustainable development are examined from both current and future perspectives.

Net energy of cellulosic ethanol from switchgrass

Abstract: Perennial herbaceous plants such as switchgrass (Panicum virgatum L.) are being evaluated as cellulosic bioenergy crops. Two major concerns have been the net energy efficiency and economic feasibility of switchgrass and similar crops. All previous energy analyses have been based on data from research plots (<5 m2) and estimated inputs. We managed switchgrass as a biomass energy crop in field trials of 3–9 ha (1 ha = 10,000 m2) on marginal cropland on 10 farms across a wide precipitation and temperature gradient in the midcontinental U.S. to determine net energy and economic costs based on known farm inputs and harvested yields. In this report, we summarize the agricultural energy input costs, biomass yield, estimated ethanol output, greenhouse gas emissions, and net energy results. Annual biomass yields of established fields averaged 5.2 -11.1 Mg·ha−1 with a resulting average estimated net energy yield (NEY) of 60 GJ·ha−1·y−1. Switchgrass produced 540% more renewable than nonrenewable energy consumed. Switchgrass monocultures managed for high yield produced 93% more biomass yield and an equivalent estimated NEY than previous estimates from human-made prairies that received low agricultural inputs. Estimated average greenhouse gas (GHG) emissions from cellulosic ethanol derived from switchgrass were 94% lower than estimated GHG from gasoline. This is a baseline study that represents the genetic material and agronomic technology available for switchgrass production in 2000 and 2001, when the fields were planted. Improved genetics and agronomics may further enhance energy sustainability and biofuel yield of switchgrass. agriculture bioenergy biomass biomass energy greenhouse gas

Bio-fuels from thermochemical conversion of renewable resources: A review

Abstract: Demand for energy and its resources, is increasing every day due to the rapid outgrowth of population and urbanization. As the major conventional energy resources like coal, petroleum and natural gas are at the verge of getting extinct, biomass can be considered as one of the promising environment friendly renewable energy options. Different thermo-chemical conversion processes that include combustion, gasification, liquefaction, hydrogenation and pyrolysis, have been used to convert the biomass into various energy products. Although pyrolysis is still under developing stage but during current energy scenario, pyrolysis has received special attention as it can convert biomass directly into solid, liquid and gaseous products by thermal decomposition of biomass in absence of oxygen. In this review article, the focus has been made on pyrolysis while other conventional processes have been discussed in brief. For having better insight, various types of pyrolysis processes have been discussed in detail including slow, fast, flash and catalytic pyrolysis processes. Besides biomass resources and constituents, the composition and uses of pyrolysis products have been discussed in detail. This review article aim to focus on various operational parameters, viz. temperature and particle size of biomass and product yields using various types of biomasses.

Renewable Energy Policies and Technological Innovation: Evidence Based on Patent Counts

Abstract: This paper examines the effect of environmental policies on technological innovation in the specific case of renewable energy. The analysis is conducted using patent data on a panel of 25 countries over the period 1978-2003. It is found that public policy plays a significant role in determining patent applications. Different types of policy instruments are effective for different renewable energy sources.

Renewable hydrogen production

Abstract: The U.S. Department of Energy and the National Renewable Energy Laboratory are developing technologies to produce hydrogen from renewable, sustainable sources. A cost goal of $2.00–$3.00 kg−1 of hydrogen has been identified as the range at which delivered hydrogen becomes cost competitive with gasoline for passenger vehicles. Electrolysis of water is a standard commercial technology for producing hydrogen. Using wind and solar resources to produce the electricity for the process creates a renewable system. Biomass-to-hydrogen processes, including gasification, pyrolysis, and fermentation, are less well-developed technologies. These processes offer the possibility of producing hydrogen from energy crops and from biomass materials such as forest residue and municipal sewage. Solar energy can be used to produce hydrogen from water and biomass by several conversion pathways. Concentrated solar energy can generate high temperatures at which thermochemical reactions can be used to split water. Photoelectrochemical water splitting and photobiology are long-term options for producing hydrogen from water using solar energy. All these technologies are in the development stage. Copyright © 2007 John Wiley & Sons, Ltd.

Green house gases emissions in the production and use of ethanol from sugarcane in Brazil: the 2005/2006 averages and a prediction for 2020.

Abstract: This work presents the evaluation of energy balance and GHG emissions in the production and use of fuel ethanol from cane in Brazil for 2005/2006 (for a sample of mills processing up to 100 million tons of sugarcane per year), and for a conservative scenario proposed for 2020. Fossil energy ratio was 9.3 for 2005/2006 and may reach 11.6 in 2020 with technologies already commercial. For anhydrous ethanol production the total GHG emission was 436 kg CO 2 eq m −3 ethanol for 2005/2006, decreasing to 345 kg CO 2 eq m −3 in the 2020 scenario. Avoided emissions depend on the final use: for E100 use in Brazil they were (in 2005/2006) 2181 kg CO 2 eq m −3 ethanol, and for E25 they were 2323 kg CO 2 eq m −3 ethanol (anhydrous). Both values would increase about 26% for the conditions assumed for 2020 mostly due to the large increase in sales of electricity surpluses. A sensitivity analysis has been performed (with 2005/2006 values) to investigate the impacts of the huge variation of some important parameters throughout Brazilian mills on the energy and emissions balance. The results have shown the high impact of cane productivity and ethanol yield variation on these balances (and the impacts of average cane transportation distances, level of soil cultivation, and some others) and of bagasse and electricity surpluses on GHG emissions avoidance.

A key review on exergetic analysis and assessment of renewable energy resources for a sustainable future

Abstract: Energy resources and their utilization intimately relate to sustainable development. In attaining sustainable development, increasing the energy efficiencies of processes utilizing sustainable energy resources plays an important role. The utilization of renewable energy offers a wide range of exceptional benefits. There is also a link between exergy and sustainable development. A sustainable energy system may be regarded as a cost-efficient, reliable, and environmentally friendly energy system that effectively utilizes local resources and networks. Exergy analysis has been widely used in the design, simulation and performance evaluation of energy systems. The present study comprehensively reviews exergetic analysis and performance evaluation of a wide range of renewable energy resources (RERs) for the first time to the best of the author's knowledge. In this regard, general relations (i.e., energy, exergy, entropy and exergy balance equations along with exergy efficiency, exergetic improvement potential rate and some thermodynamic parameters, such as fuel depletion ratio, relative irreversibility, productivity lack and exergetic factor) used in the analysis are presented first. Next, exergetically analyzed and evaluated RERs include (a) solar energy systems; (a1) solar collector applications such as solar water heating systems, solar space heating and cooling, solar refrigeration, solar cookers, industrial process heat, solar desalination systems and solar thermal power plants), (a2) photovoltaics (PVs) and (a3) hybrid (PV/thermal) solar collectors, (b) wind energy systems, (c) geothermal energy systems, (c1) direct utilization (district heating, geothermal or ground-source heat pumps, greenhouses and drying) and (c2) indirect utilization (geothermal power plants), (d) biomass, (e) other renewable energy systems, and (f) country based RERs. Studies conducted on these RERs are then compared with the previously ones in tabulated forms, while the Grassmann (or exergy flow) diagrams, which are a very useful representation of exergy flows and losses, for some RERs are given. Finally, the conclusions are presented. It is expected that this comprehensive study will be very beneficial to everyone involved or interested in the exergetic design, simulation, analysis and performance assessment of RERs.

Modeling of hybrid renewable energy systems

Abstract: Hybrid renewable energy systems (HRES) are becoming popular for remote area power generation applications due to advances in renewable energy technologies and subsequent rise in prices of petroleum products. Economic aspects of these technologies are sufficiently promising to include them in developing power generation capacity for developing countries. Research and development efforts in solar, wind, and other renewable energy technologies are required to continue for, improving their performance, establishing techniques for accurately predicting their output and reliably integrating them with other conventional generating sources. The paper describes methodologies to model HRES components, HRES designs and their evaluation. The trends in HRES design show that the hybrid PV/wind energy systems are becoming gaining popular. The issues related to penetration of these energy systems in the present distribution network are highlighted.

The reduction and control technology of tar during biomass gasification/pyrolysis: An overview

Abstract: Biomass is an important primary energy source as well as renewable energy source. As the most promising biomass utilization method, gasification/pyrolysis produces not only useful fuel gases, char and chemicals, but also some byproducts like fly ash, NOx, SO2 and tar. Tar in the product gases will condense at low temperature, and lead to clogged or blockage in fuel lines, filters and engines. Moreover, too much tar in product gases will reduce the utilization efficiency of biomass. Therefore, the reduction or decomposition of tar in biomass derived fuel gases is one of the biggest obstacles in its utilization for power generation. In this paper, we review the literatures pertaining to tar reduction or destruction methods during biomass gasification/pyrolysis. On the basis of their characteristics, the current tar reduction or destruction methods can be broadly divided into five main groups: mechanism methods, self-modification, thermal cracking, catalyst cracking and plasma methods.

A Review of Recent Literature to Search for an Efficient Catalytic Process for the Conversion of Syngas to Ethanol

Abstract: Alternatives to petroleum-derived fuels and chemicals are being sought in an effort to improve air quality and increase energy security through development of novel technologies for the production of synthetic fuels and chemicals using renewable energy sources such as biomass. In this context, ethanol is being considered as a potential alternative synthetic fuel to be used in automobiles or as a potential source of hydrogen for fuel cells as it can be produced from biomass. Renewable ethanol can also serve as a feedstock for the synthesis of a variety of industrial chemicals and polymers. Currently, ethanol is produced primarily by fermentation of biomass-derived sugars, especially those containing six carbons, whereas 5-carbon sugars and lignin, which are also present in the biomass, remain unusable. Gasification of biomass to syngas (CO + H2), followed by catalytic conversion of syngas, could produce ethanol in large quantities. However, the catalytic conversion of syngas to ethanol remains challenging,...

Structural health monitoring for a wind turbine system: a review of damage detection methods

Abstract: Renewable energy sources have gained much attention due to the recent energy crisis and the urge to get clean energy. Among the main options being studied, wind energy is a strong contender because of its reliability due to the maturity of the technology, good infrastructure and relative cost competitiveness. In order to harvest wind energy more efficiently, the size of wind turbines has become physically larger, making maintenance and repair works difficult. In order to improve safety considerations, to minimize down time, to lower the frequency of sudden breakdowns and associated huge maintenance and logistic costs and to provide reliable power generation, the wind turbines must be monitored from time to time to ensure that they are in good condition. Among all the monitoring systems, the structural health monitoring (SHM) system is of primary importance because it is the structure that provides the integrity of the system. SHM systems and the related non-destructive test and evaluation methods are discussed in this review. As many of the methods function on local damage, the types of damage that occur commonly in relation to wind turbines, as well as the damage hot spots, are also included in this review.

Biomass energy: the scale of the potential resource.

Abstract: Increased production of biomass for energy has the potential to offset substantial use of fossil fuels, but it also has the potential to threaten conservation areas, pollute water resources and decrease food security. The net effect of biomass energy agriculture on climate could be eithercoolingor warming, depending on the crop,the technology for converting biomass into useable energy, and the difference in carbon stocks and reflectance of solar radiation between the biomass crop and the preexisting vegetation. The area with the greatest potential for yielding biomass energy that reduces net warming andavoidscompetitionwithfoodproduction islandthat was previously used for agriculture or pasture but that has been abandoned and not converted to forest or urban areas. At the global scale, potential above-ground plant growth on these abandoned lands has an energy content representing � 5% of world primary energy consumption in 2006. The global potential for biomass energy production is large in absolute terms, but it is notenoughtoreplacemore thana fewpercentof current fossil fuel usage. Increasing biomass energy production beyond this level would probably reduce food security and exacerbate forcing of climate change. Biomass energy in context Biomass energy sources are among the most promising, most hyped and most heavily subsidized renewable energy sources. They have real potential to heighten energy security in regions without abundant fossil fuel reserves, to increase supplies of liquid transportation fuels and to decrease net emissions of carbon into the atmosphere per unit of energy delivered. However, increased exploitation of biomass energy also risks sacrificing natural areas to managed monocultures, contaminating waterways with agricultural pollutants, threatening food supplies or farm lifestyles through competition for land and increasing net emissions of carbon to the atmosphere, as a consequence of increased deforestation or energy-demanding manufacturing technologies. The opportunities are real, but the concerns are also justified. As investments in biomass energy increase, there needs to be an active, continuing discussion on strategies for balancing the pros and cons of biomass energy. The future of biomass energy in the global energy system is dependent on the complex interplay of four major factors. The first is conversion technology and the prospects for using new plant and microbe varieties as well as novel biomass-to-fuel conversion processes for increasing the yield of usable energy from each unit of available land or water. The second is the intrinsic productive capacity of the land and ocean ecosystems that can be used for biomass energy production. The third is alternative uses for the land and water resources that are candidate sites for biomass energy production. The fourth is offsite implications of biomass energy technologies for invasive species [1] and for levels of air and water pollution. These factors must be effectively integrated to maximize the benefits and minimize the ecosystem and societal costs of biomass energy production. In particular, constraints owing to ecosystem characteristics, competition from alternative land uses and offsite impacts can lead to practical or desirable levels of biomass energy production that are much smaller than theoretical potential levels. A clear picture of these constraints can be an important asset in encouraging rational development of the biomass energy industry. In this article we briefly review all four of these factors, with an emphasis on their integration. We first discuss the main types of biomass energy production systems, their relative efficiencies, and their environmental impacts. Next, we consider the role of existing vegetation in the distinction between energy and climate security, arguing that biomass energy production on current forest or crop lands is unlikely to result in significant climate benefits relative to fossil fuel use. Finally, we assess the potential total production of biomass on land other than forests or croplands.

Small-Signal Stability Analysis of an Autonomous Hybrid Renewable Energy Power Generation/Energy Storage System Part I: Time-Domain Simulations

Abstract: Small-signal stability analyzed results of an autonomous hybrid renewable energy power generation/energy storage system connected to isolated loads using time-domain simulations is presented in this paper. The companion paper presents frequency-domain analyzed results of the same hybrid system. The proposed renewable energy power generation subsystems include three wind turbine generators (WTGs), a diesel engine generator, two fuel cells (FCs), and a photovoltaic system (PV) while the energy storage subsystems consist of a battery energy storage system and a flywheel energy storage system. An aqua electrolyzer absorbs a part of generated energy from PV or WTGs to generate available hydrogen for FCs. A time-domain approach based on three mathematical models for three studied cases under various operating points and disturbance conditions is performed. It can be concluded from the simulation results that the proposed hybrid power generation/energy storage system feeding isolated loads can be properly operated to achieve system power-frequency balance condition.

Opportunities for renewable bioenergy using microorganisms

Abstract: Global warming can be slowed, and perhaps reversed, only when society replaces fossil fuels with renewable, carbon-neutral alternatives. The best option is bioenergy: the sun's energy is captured in biomass and converted to energy forms useful to modern society. To make a dent in global warming, bioenergy must be generated at a very high rate, since the world today uses approximately 10 TW of fossil-fuel energy. And, it must do so without inflicting serious damage on the environment or disrupting our food supply. While most bioenergy options fail on both counts, several microorganism-based options have the potential to produce large amounts of renewable energy without disruptions. In one approach, microbial communities convert the energy value of various biomass residuals to socially useful energy. Biomass residuals come from agricultural, animal, and a variety of industrial operations, as well as from human wastes. Microorganisms can convert almost all of the energy in these wastes to methane, hydrogen, and electricity. In a second approach, photosynthetic microorganisms convert sunlight into biodiesel. Certain algae (eukaryotes) or cyanobacteria (prokaryotes) have high lipid contents. Under proper conditions, these photosynthetic microorganisms can produce lipids for biodiesel with yields per unit area 100 times or more than possible with any plant system. In addition, the non-lipid biomass can be converted to methane, hydrogen, or electricity. Photosynthetic microorganisms do not require arable land, an advantage because our arable land must be used to produce food. Algae or cyanobacteria may be the best option to produce bioenergy at rates high enough to replace a substantial fraction of our society's use of fossil fuels.

Life cycle assessment of greenhouse gas emissions from plug-in hybrid vehicles: implications for policy.

Abstract: Plug-in hybrid electric vehicles (PHEVs), which use electricity from the grid to power a portion of travel, could play a role in reducing greenhouse gas (GHG) emissions from the transport sector. However, meaningful GHG emissions reductions with PHEVs are conditional on low-carbon electricity sources. We assess life cycle GHG emissions from PHEVs and find that they reduce GHG emissions by 32% compared to conventional vehicles, but have small reductions compared to traditional hybrids. Batteries are an important component of PHEVs, and GHGs associated with lithium-ion battery materials and production account for 2–5% of life cycle emissions from PHEVs. We consider cellulosic ethanol use and various carbon intensities of electricity. The reduced liquid fuel requirements of PHEVs could leverage limited cellulosic ethanol resources. Electricity generation infrastructure is long-lived, and technology decisions within the next decade about electricity supplies in the power sector will affect the potential for l...

Energy issues in desalination processes.

Abstract: Water, energy, and environmental issues are closely related. New water techniques consume energy, and innovative renewable energy techniques using biofuels and biodiesel consume an incredible amount of water. Different desalination techniques that consume different energy levels from different sources are in use today. Some people, environmentalists, decision makers, and even scientists, mainly in nonscientific publications, consider energy consumption in desalination to be too high and are seeking new ways of reducing it, which often involves increasing capital investment. Efforts should be directed at reducing not only energy consumption but also total water cost. A competent grasp of thermodynamics and heat and mass transfer theory, as well as a proper understanding of current desalination processes, is essential for ensuring beneficial improvements in desalination processes. Thermodynamics sets the absolute minimum limit of the work energy required to separate water from a salt solution. Unavoidable i...

Biodiesel production from various feedstocks and their effects on the fuel properties.

Abstract: Biodiesel, which is a new, renewable and biological origin alternative diesel fuel, has been receiving more attention all over the world due to the energy needs and environmental consciousness Biodiesel is usually produced from food-grade vegetable oils using transesterification process Using food-grade vegetable oils is not economically feasible since they are more expensive than diesel fuel Therefore, it is said that the main obstacle for commercialization of biodiesel is its high cost Waste cooking oils, restaurant greases, soapstocks and animal fats are potential feedstocks for biodiesel production to lower the cost of biodiesel However, to produce fuel-grade biodiesel, the characteristics of feedstock are very important during the initial research and production stage since the fuel properties mainly depend on the feedstock properties This review paper presents both biodiesel productions from various feedstocks and their effects on the fuel properties

Utilization of oil palm as a source of renewable energy in Malaysia

Abstract: Malaysia is currently the world's largest producer and exporter of palm oil. Malaysia produces about 47% of the world's supply of palm oil. Malaysia also accounts the highest percentage of global vegetable oils and fats trade in year 2005. Besides producing oils and fats, at present there is a continuous increasing interest concerning oil palm renewable energy. One of the major attentions is bio-diesel from palm oil. Bio-diesel implementation in Malaysia is important because of environmental protection and energy supply security reasons. This palm oil bio-diesel is biodegradable, non-toxic, and has significantly fewer emissions than petroleum-based diesel (petro-diesel) when burned. In addition to this oil, palm is also a well-known plant for its other sources of renewable energy, for example huge quantities of biomass by-products are developed to produce value added products such as methane gas, bio-plastic, organic acids, bio-compost, ply-wood, activated carbon, and animal feedstock. Even waste effluent; palm oil mill effluent (POME) has been converted to produce energy. Oil palm has created many opportunities and social benefits for the locals. In the above perspective, the objective of the present work is to give a concise and up-to-date picture of the present status of oil palm industry enhancing sustainable and renewable energy. This work also aims to identify the prospects of Malaysian oil palm industry towards utilization of oil palm as a source of renewable energy.

Comparison of environmental and economic aspects of various hydrogen production methods

Abstract: A wide variety of processes are available for hydrogen production from gaseous or liquid fuels They differ according to the nature of the primary fuel used (ammonia, methanol, ethanol, gaseous or liquid hydrocarbons, water) and to the chemical reactions involved (decomposition, steam reforming, partial oxidation, electrolysis, gasification) As recent technology progress makes hydrogen a realistic long-term energy option with little or no pollution, developments of new methods for its production and improvement of conventional technology are important This paper analyzes the recent development of hydrogen production technologies followed by an overview of conventional and renewable energy sources and a discussion about enviro-economic aspects for hydrogen production methods The results show that although renewable energy resources cannot entirely satisfy the energy demand but electrolysis associated with solar energy, wind power, hydropower and biomass are available renewable sources for significant hydrogen production