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1.
In Sweden, wood fuels are traditionally used in the Swedish forest products industry and for heating of single-family houses. More recently they are also become established as an energy source for district heating and electricity production. Energy policy, especially the energy taxation system, has favoured wood fuels and other biofuels, mainly for environmental reasons. There is now an established commercial market for wood fuels in the district heating sector, which amounts to 45 PJ and is growing 20 per cent annually. Price levels have been stable in current prices for a decade, mainly because of good access to wood fuels. Price levels are dominated by production costs on a market that is largely governed by the buyer.It is expected that the use of wood fuels will increase in Sweden in the future, which will push a further development of this sector on the market and bring about technological changes in the area.  相似文献   

2.
《Biomass & bioenergy》2006,30(10):815-825
Wood fuel is a strategic resource for future energy supply and is usually utilised locally. Traditional use of wood fuel and other bioenergy has a share of 10–15% energy supply, used mainly for the household sector. The utilisation for industrial purposes is much smaller but is a strategic resource in the effort to fulfil the Kyoto agreement to replace fossil fuels and to mitigate greenhouse gas emissions. Many industrialised countries already use a significant share of biofuels in their energy supply e.g. Nordic countries while others like some other European Union countries are planning to increase their use. Production and use of biofuels need to be carried out sustainable. Official statistics do not report trade in such detail that international trade in different biomass types can be fully identified. However, FAO and European Forestry Institute are important sources. In some countries, there is a growing interest in the international trade, because the trade can provide biofuels at lower prices, larger quantities and better quality than domestic alternatives. The first signs of an international market price for wood fuel are indicated in Europe. For the future both the use and the trade of wood fuel is expected to increase. Analyses for trade in charcoal, wood chips, fuel wood and wood residues made in this report identify ‘hot’ trade spots in Europe, in south East Asia and in North America.  相似文献   

3.
4.
The growing concern about pollutant emissions and depletion of fossil fuels has been a strong motivator for the development of cleaner and more efficient combustion strategies, such as the gasification of coal, biomass or waste, which have increased the interest in using a new type of fuels, mainly composed of CH4, H2, CO and CO2.These new fuels, commonly called syngas, display a wide range of compositions, which affects their combustion characteristics and, in some cases, are more prone to instabilities or flashback. Since flame properties have been demonstrated to be strongly related to equivalence ratio, a precise measurement of the flame stoichiometry is a key pre-requisite for combustion optimization and prevention of unstable regimes. In particular, chemiluminescence emission from flames has been largely tested for stoichiometry monitoring for methane flames, but its use in syngas flames has been far less studied. Consequently, the main goal of this work is analyzing the effect of fuel composition on the chemiluminescence vs. equivalence ratio curves for different fuel blends, as a first approach for a wide range of syngas compositions. The experimental results revealed that the ratio OH*/CH*, which had been widely demonstrated to be the best option for methane, may not be suitable for monitoring with certain fuels, such as those with a high percent of hydrogen. Alternatively, other signals, in particular the ratio OH*/CO2*, appear as viable stoichiometry indicators in those cases.The analysis was also completed by numerical predictions with CHEMKIN. The comparisons of calculations with different flame models and experimental data reveals differences in the chemiluminescence vs. equivalence ratio curves for the different combustion regimes, depending on the range of the equivalence ratio ranges and fuel compositions. This finding, which confirms previous observations for a much narrower range of fuels, could have important practical consequences for the application of the technique in real combustors.  相似文献   

5.
Fuel cells (FCs) and their hybrid systems can play a key role in reducing carbon dioxide (CO2) emissions. The present paper analyzes the contributions of the FC system to CO2 emission reduction in three application fields.In the mobile application field, the direct methanol FC system has little or no influence on CO2 emission reduction.The benefit of the FC in CO2 emission reduction in the transportation field is directly dependant on the H2 production method. Pre-combustion technology (with carbon capture) represents one of the best mid-term solutions for H2 production. If FC vehicles (FCVs) use the H2 produced by this process, the CO2 emissions in this field could be decreased to 70–80% of the traditional CO2 emissions.In the stationary application field, the FC system can be effectively operated as the distributed generation (DG) in terms of CO2 emission reduction. Among the various types of FC or FC hybrid system used for DG, the solid oxide FC (SOFC) hybrid system with a CO2 capture unit is the best option as it doubled the electricity efficiency compared to the traditional combustion cycle and decreases the CO2 emission to 13.4% of the traditional CO2 emission.However, the FC and carbon capture and sequestration (CCS) technologies need to be fully developed before the FC can contribute to reducing CO2 emissions.  相似文献   

6.
This article analyses the evolution of hard coal trade in West-Europe, known as the Atlantic market, from the 1980s to the end of 2002. It investigates the development of trade pattern, nature of contracts, price setting, supply–demand and the future of trade.  相似文献   

7.
碳科学公司(Carbon Sciences)9月底宣布,正在开发将CO2转化为低碳烃类(C1~C3)的工艺,以便进一步制成高碳烃类燃料,如汽油和喷气燃料.  相似文献   

8.
Suvi Salmela  Vilja Varho   《Energy Policy》2006,34(18):3669-3683
“Green” electricity, i.e. electricity produced from environmentally less harmful sources and marketed as such, has been available to Finnish households since 1998, but the demand for it has remained low. In this paper we discuss the barriers identified by consumers to purchasing green electricity and contrast these with the interpretation energy sector actors give to consumer passivity. The empirical material consists of thematic interviews. Energy policy actors often assume that consumers’ passivity signifies their lack of interest or low environmental consciousness. This results partly from the failure to differentiate between the roles of consumer and citizen. The interpretation the energy sector actors give to consumer passivity and the role they assign to consumers affect the direction of green electricity policy. We argue that consumers need more information on both the environmental impact of different electricity products and in particular about the electricity supply and electricity contracts in a liberalised electricity market if they are to become active in the market.  相似文献   

9.
This paper presents a structural model of the market for kerojet fuel in the United States. Upon empirical estimation, it demonstrates that more kerojet output is forthcoming as the price of kerojet increases relative to the price of other refined petroleum products. Imports of kerojet into the United States increase as the domestic price of kerojet increases relative to the world price. Finally, the quantity of kerojet demanded falls in a small, but perceptible, way as its price increases.  相似文献   

10.
This study investigated capillary-trapped CO2 depending on the consideration of hysteresis effect in relative permeability for various water-alternation-gas (WAG) operating conditions to ascertain the oil production process. From the simulation results of CO2 WAG flooding method, the trapped CO2 led to prevent water-flow, in which CO2 acts as a gas blocker near the well. It caused the injection pressure increase during water injection period. As the trapped CO2 in pores increased, the reservoir pressure was also increased and maintained above minimum miscibility pressure (MMP). Ultimately, it was concluded that the reservoir was kept under miscible conditions throughout WAG process, reducing residual oil and increasing oil recovery.  相似文献   

11.
木质燃料发热量的研究   总被引:6,自引:0,他引:6  
介绍了木质燃料发热量的实验结果,对计算木质燃料发热量的经验公式进行了修正,并分析了木质燃料中水分对发热量的影响。  相似文献   

12.
It is found that carbon monoxide (CO) poisoning could be mitigated by increasing only cathode backpressure for a proton exchange membrane fuel cell (PEMFC) with ultra-thin membranes (≤25 μm). This mitigation can be explained by a heterogeneous oxidation of CO on a Pt-Ru/C anode by the permeated O2 which is known as “internal air bleed” in his paper. A steady-state model which accounts for this internal air bleed has been developed to model the Pt-Ru/C anode polarization data when 50 ppm CO in H2 is used as anode feed gas. The modeling results show that the mitigation of CO poisoning by the internal air bleed even exists at ambient conditions for a PEMFC with an ultra-thin membrane. Therefore, the effect of internal air bleed must be considered for modeling fuel cell performance or anode polarization data if an ultra-thin membrane and a low level of CO concentration are used for a Pt-Ru/C anode. An empirical relationship between the amount of internal air bleed used for the mitigation of CO poisoning and the fraction of free Pt sites is provided to facilitate the inclusion of an internal air bleed term in the modeling of anode polarization and the fuel cell performance.  相似文献   

13.
EU bioenergy policies and oil price hikes have resulted in a significant increase of installed pellet boilers for residential heating. Hence, European demand for wood pellets has been growing faster and more steadily than supply leading to rising market prices in recent years. This article presents an econometric analysis of demand and supply of wood pellets in the residential heating sector in Austria, one of the most dynamic markets for residential pellets. Annual and monthly time series data between 2000 and 2014 are used in a two-stage least-squares (2SLS) regression to estimate supply and demand elasticities of wood pellets. In all model specifications, pellets demand is found to be inelastic (from −0.66 to −0.76) and pellets supply unit-elastic (from 1.03 to 1.18). Thus, consumers are highly exposed to price changes resulting from supply shocks. Policies which support investments in pellet boilers will shift the demand of wood pellets and likely leading to higher prices for consumers.  相似文献   

14.
Algeria is one of the most important CO2 emitters among developing countries and the third among African countries. It pledged to curb carbon emissions by at least 7% by 2030. However, complying with this target may be a difficult task without compromising economic growth. The aim of this paper is to analyze the relationship between CO2 emissions and economic growth in Algeria, taking into account energy use, electricity consumption, exports and imports. The validity of the EKC hypothesis, throughout the period from 1970 to 2010, is tested by using the Autoregressive Distributed Lag model extended to introduce the break points. Results confirm the EKC for Algeria. Nevertheless, the turning point is reached for a very high GDP per capita value, indicating that economic growth in Algeria will continue to increase emissions. Results also indicate that an increase in energy use and electricity consumption increase CO2 emissions, and that exports and imports affect them negatively and positively, respectively. Therefore, it is necessary to promote renewable energies and energy efficiency policies. Regulatory reforms are needed to facilitate foreign investments with which to carry out these policies. Likewise, it may be appropriate to decrease subsides in energy prices to encourage energy efficiency.  相似文献   

15.
In this paper we analyze the short-term spot price behavior of carbon dioxide (CO2) emission allowances of the new EU-wide CO2 emissions trading system (EU ETS). After reviewing the stylized facts of this new class of assets we investigate several approaches for modeling the returns of emission allowances. Due to different phases of price and volatility behavior in the returns, we suggest the use of Markov switching and AR–GARCH models for stochastic modeling. We examine the approaches by conducting an in-sample and out-of-sample forecasting analysis and by comparing the results to alternative approaches. Our findings strongly support the adequacy of the models capturing characteristics like skewness, excess kurtosis and in particular different phases of volatility behavior in the returns.  相似文献   

16.
The present paper analyzes the CO2 emissions from mobile communications and portable wireless electronic devices in the Korea environment. The quantitative and qualitative contributions to CO2 emission reduction of the substitution of renewable energy for traditional electricity as the power supply in these devices are also investigated.Firstly, the national CO2 emission coefficient is temporarily estimated as 0.504 tCO2/MWh, which can be regarded as the basis for calculating CO2 emissions in mobile devices. The total annual CO2 emissions from mobile devices is calculated as approximately 1.4 million tons, comprising 0.3 million tCO2 for portable wireless electronic devices and 1.1 million tCO2 for electric equipment required for mobile communication service.If renewable energy sources are substituted for traditional electricity sources in the supply for mobile devices, solar cell and wind turbine systems can reduce CO2 emissions by about 87% and 97%, respectively. However, the use of fuel cell systems will only slightly reduce the CO2 emissions. However, the use of the direct methanol fuel cell system can release 8% more CO2 emissions than that emitted by using traditional electricity sources.  相似文献   

17.
Considerable potential exists in the UK for utilising woody biomass, grown under short rotation forestry management systems, to produce electricity or heat. There are benefits to using biomass in generating heat and power the main environmental benefit being from substituting for fossil fuel combustion and consequent carbon emissions. Woody biomass production in short rotation forestry involves growing single stemmed trees rather than coppice over rotations of between 10 and 15 years. Eucalypts are particularly suited to such biomass production as they exhibit relatively high wood density, have suitable chemical characteristics, exhibit low moisture content and can be easily harvested all year around using conventional machinery if single-stemmed growth form is maintained.The UK has a climate that is not well suited to the majority of eucalypts. However, there is a small number of eucalypt species that can withstand the stresses caused by frozen ground and desiccating winds or sub-zero temperatures that can occur. These species are from more southern latitudes and high altitude areas of Australia. However, even the most cold resistant species can be damaged by UK winter climate extremes and therefore careful matching of species to site environmental constraints is critical. Informed decision making is made problematic by the small area and limited distribution of current planting, although it is clear that particularly cold areas and for most species, sites with poor drainage should be generally avoided. This article provides a discussion of the potential of, and constraints to, using eucalypts for biomass in the UK and provides a tentative list of recommended species, their potential growth rates and their advantages and disadvantages.  相似文献   

18.
This study examines the prospect that a consumer-driven market could eventually replace the myriad regulations and demand quotas in the US ethanol and gasoline fuel market. Given efficient households that minimize the cost of operating automobiles, recent vehicle technology that improves blended fuel substitution, and typical market conditions of the last five years, blended fuels with 20% ethanol concentration could occupy a volume of 82.2 billion gallons in a 138.3 billion gallon gasoline market. The consumer welfare gain associated with blended fuel is $15.9 billion annually for US consumers, or about $1000 over the life of a vehicle.The ethanol demand associated with a voluntary blended fuel market is 16.4 BGY, slightly more than the conventional component of the Renewable Fuels Standard. It is time to replace the corn RFS with a free market. But an active competition policy in the fuel marketing system may also be required. Intervention for the impending Biomass Ethanol Industry, such as a subsidy or an exemption a carbon tax, may also be in order.  相似文献   

19.
Samples of solid cottonwood in the form of discs have been heated at 250°C in both air and nitrogen, up to 12 h, and in air at 150°C up to 30 days. The preheated samples were then further heated in air at 5°C/min to unpiloted ignition. Despite major chemical changes during the various preheating treatments, the ignition temperatures were not significantly affected, except for a slight decrease (11 °C) after 5 days at 150°C in air.  相似文献   

20.
To investigate how fuel economy is valued in the Indian car market, we compute the cost to Indian consumers of purchasing a more fuel-efficient vehicle and compare it to the benefit of lower fuel costs over the life of the vehicle. We estimate hedonic price functions for four market segments (petrol hatchbacks, diesel hatchbacks, petrol sedans, and diesel sedans) to compute 95% confidence intervals for the marginal cost to the consumer for an increase in fuel economy. We find that the associated present value of fuel savings falls within the 95% confidence interval for most specifications, in all market segments, for the years 2002 through 2006. Thus, we fail to consistently reject the hypothesis that consumers appropriately value fuel economy.  相似文献   

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