A comparison of the drivers influencing adoption of on-farm anaerobic digestion in Germany and Australia

This review examines the drivers behind the adoption of on-farm anaerobic digestion in Germany where there were more than 4000 plants operating in 2009. In Australia, only one plant is operating, at a piggery in the State of Victoria. Germany’s generous feed-in-tariffs for renewable energy are typically given the credit for promoting investment in on-farm anaerobic digestion. But the particular biophysical and socio-economic character of farming in the country provided the fertile ground for these financial incentives to take root. Energy security has also been a major driver for the promotion of renewable energy in Germany since it imports over 60% of its energy needs. In contrast, Australia is a net energy exporter, exporting about two-thirds of its domestic energy. Although it has considerable potential for application in Australia, anaerobic digestion is unlikely to be widely adopted unless new incentives emerge to strongly encourage investment. Stronger Australian regulation of manures and effluent may serve as an incentive to a limited extent in the future. Yet the experience in Germany suggests that regulation on its own was not sufficient to encourage large numbers of farmers to invest in anaerobic digestion. Even with generous incentives from the German government, increasing construction costs and the rising cost of energy crops can put the financial viability of anaerobic digestion plants at risk. Unless improvements in efficiency are found and implemented, these pressures could lead to unsustainable rises in the cost of the incentive schemes that underpin the development of renewable energy technologies.     

Co-digestion of swine manure and corn stover for bioenergy production in MixAlco™ consolidated bioprocessing

MixAlco™ consolidated bioprocessing (CBP) employs a mixed culture of terrestrial microorganisms to anaerobically ferment waste streams (e.g., animal manure, agriculture residues) into mixed carboxylate salts that can be further chemically converted to commodity chemicals (e.g., acetic acid, acetone) and liquid transportation fuels (e.g., ethanol, mixed alcohols, bio-gasoline). For countercurrent fermentations of 60% swine manure/40% lime-treated corn stover at 55 °C, the highest acid productivity [1.8 g/(L·d)] and highest conversion (73%) in this study occurred at an acid concentration of 25.1 and 17.0 g/L, respectively. The continuum particle distribution model (CPDM) predicted the experimental total acid concentrations and conversions around 11.1% and 17.2%, respectively. The CPDM prediction "map" for MixAlco™ CBP indicates that both high conversions (>79%) and high total acid concentrations (>35 g/L) are possible at industrial scale. The present study shows continuous co-digestion of corn stove and swine manure in the MixAlco™ process has the potential to produce annually 9.3 billion gallons of alcohol fuels (e.g., ethanol and mixed alcohols) in the United States.     

Physiochemical characterization and thermal kinetics of lignin recovered from sustainable agrowaste for bioenergy applications

In this study, lignin, one of the commonly occurring natural polymers, is extracted from banana agro-waste. Lignin is recovered from the spent liquor produced during alkaline pre-treatment of agro-waste and precipitated by acidification. This study focuses on the physio-chemical characterization and thermal degradation behaviour of lignin extracted from agro-waste biomass. The extracted lignin yield accounts for nearly 12% of the biomass composition. Spectral analysis, FTIR and NMR explain purity and carbon skeleton characteristics of herbaceous lignin monomers, majorly G and S units. Morphological analysis by SEM showed hollow spherical structures with large surface area for the extracted lignin. The calorific value of extracted lignin was experimentally found to be 21.4276 MJ/kg, which suggests the possible use of extracted lignin as an alternative to sub-bituminous coal. Thermal studies of lignin showed that lignin degrades in a wide temperature range releasing CO₂, CH₄, H₂O, CO and H₂. The volatile content of extracted lignin is found to be 31.42%, which suggests its possibility for gasification process. The overall outcome supported that recovered lignin from agro-waste is a potential resource for bioenergy.     

Striving to further harmonization of sustainability criteria for bioenergy in Europe: Recommendations from a stakeholder questionnaire

This questionnaire analyzed the ongoing development of sustainability criteria for solid and liquid bioenergy in the European Union and further actions needed to come to a harmonization of certification systems, based on EU stakeholder views. The questionnaire, online from February to August 2009, received 473 responses collected from 25 EU member countries and 9 non-European countries; 285 could be used for further processing. A large majority of all stakeholders (81%) indicated that a harmonized certification system for biomass and bioenergy is needed, albeit some limitations. Amongst them, there is agreement that (i) a criterion on ‘minimization of GHG emissions’ should be included in a certification system for biomass and bioenergy, (ii) criteria on optimization of energy and on water conservation are considered of high relevance, (iii) the large variety of geographical areas, crops, residues, production processes and end-uses limits development towards a harmonized certification system for sustainable biomass and bioenergy in Europe, (iv) making better use of existing certification systems and standards improves further development of a harmonized European biomass and bioenergy sustainability certification system and (v) it is important to link a European certification system to international declarations and to expand such a system to other world regions.     

An analysis of used lubricant recycling, energy utilization and its environmental benefit in Taiwan

Utilizing used lubricants as energy sources has been currently demonstrated to be one of the best available waste management methods. In this regard, used lubricants for use as energy sources in Taiwan thus became popular in recent years. The objective of this study was to present a comprehensive analysis of used lubricant-to-energy in Taiwan, which includes status of lubricant consumption, and used lubricant generation and its recycling (i.e., collection & treatment) management system. It was found that a major market for utilizing used lubricants in Taiwan (over 90%) was reused as fuel oils or auxiliary fuels in the cogeneration system. Under the regulatory authorization of the Waste Management Act and the Petroleum Administration Act, the central competent authorities encouraged the energy-intensive industries in the waste-to-energy through the excess electricity purchase and subsidiary incentives. Based on the certified volume of collected used lubricant and its energy use proportion in 2009, the total energy potential and the environmental benefit of mitigating CO₂ emissions in place of fuel oils were preliminarily calculated to be around 9.4 × 10² TJ and 7.3 × 10⁷ kg, respectively.     

Estimation of methane and nitrous oxide emission from livestock and poultry in China during 1949–2003

To investigate the greenhouse gases emission from enteric fermentation and manure management of livestock and poultry industry in China, the present study presents a systematic estimation of methane and nitrous oxide emission during 1949–2003, based on the local measurement and IPCC guidelines. As far as greenhouse gases emittion is concerned among livestock swine is found to hold major position followed by goat and sheep, while among poultry chicken has the major place and is followed by duck and geese. Methane emission from enteric fermentation is estimated to have increased from 3.04 Tg in 1949 to 10.13 Tg in 2003, an averaged annual growth rate of 2.2%, and methane emission from manure management has increased from 0.16 Tg in 1949 to 1.06 Tg in 2003, an annual growth rate of 3.5%, while nitrous oxide emission from manure management has increased from 47.76 to 241.2 Gg in 2003, with an annual growth rate of 3.0%. The total greenhouse gas emission has increased from 82.01 Tg CO₂ Eq. in 1949 to 309.76 Tg CO₂ Eq. in 2003, an annual growth rate of 2.4%. The estimation of livestock methane and nitrous oxide emissions in China from 1949 to 2003 is shown to be consistent with a linear growth model, and the reduction of greenhouse gas emission is thus considered an urgent and arduous task for the Chinese livestock industry.     

A management tool for estimating bioenergy production and carbon sequestration in Eucalyptus globulus and Eucalyptus nitens grown as short rotation woody crops in north-west Spain

This study proposes stand level models for estimating biomass yield, total energy and carbon sequestration in Eucalyptus globulus and Eucalyptus nitens plantations, on the basis of measurements made in 131 plots established at the usual range of initial forest densities for southwestern Europe. The timber volume, total aboveground biomass, logging residue biomass, crown biomass, carbon in aboveground biomass and soil organic layer, energy in aboveground biomass, energy in logging residue biomass and usable cellulose yield were represented in the form of isolines (taking mortality into account) and plotted against dominant height. These variables were calculated and compared with previously published data on two silvicultural options for short rotation forestry, one destined for bioenergy production and the other consisting of the standard silviculture regime applied to both species in southern Europe, considering the average site index for each species. Yield levels were higher in E. nitens than in E. globulus for all variables because of faster diameter increment at similar densities. The total yield in terms of biomass was 13.9-14.6 Mg ha⁻¹ y⁻¹ for E. globulus and 20.4-21.5 Mg ha⁻¹ y⁻¹ for E. nitens. Energy in aboveground biomass ranged between 233 and 245 GJ ha⁻¹ y⁻¹ for E. globulus and 345 and 364 GJ ha⁻¹ y⁻¹ for E. nitens, carbon accumulation rate in aboveground biomass and soil organic layer was 6.9-7.2 Mg ha⁻¹ y⁻¹ for E. globulus and 12.7-13.5 Mg ha⁻¹ y⁻¹ for E. nitens, and usable cellulose was 5.7-5.9 Mg ha⁻¹ y⁻¹ for E. globulus and 9.0-10.1 Mg ha⁻¹ y⁻¹ for E. nitens. It was found that 50% increments in the initial density result in only marginal increments in biomass and usable cellulose yields.     

A GIS-based approach for evaluating the potential of biogas production from livestock manure and crops at a regional scale: A case study for the Kujawsko-Pomorskie Voivodeship

In Poland, the promotion of the development of biogas plants was intensified under legal regulations. The potential expansion prompts the need for the assessment of a variety of environmental and geographical constraints as well as technical and economic factors, which ensure socio-economically and ecologically sound biogas development. In this paper, both spatial and non-spatial data were integrated to the GIS model to help determine the optimal sites for installing anaerobic digesters (AD). The focus was placed on animal manure (from cattle and pig populations), and co-substrates such as crop silage. Furthermore, the paper provides insight into the structure of cost and benefits in order to examine what incentive measures suffice to force biogas development and how much biogas feedstock could cost to make investments viable. The techno-economic assessment was carried out for combined heat and power generation and bio-methane injection into the gas grid. The methodology was applied to Kujawsko-Pomorskie Voivodeship.     

Genetic diversity analysis by RAPD markers in candidate plus trees of Pongamia pinnata, a promising source of bioenergy

Pongamia pinnata has received much attention in recent years as a source of seed oil that can provide a substitute for diesel fuel. Very little molecular work has been reported on this species. This paper reports our studies on the diversity amongst the CPTs (candidate plus trees) of P. pinnata previously identified on the basis of morphometric traits, particularly pod and seed traits. For this RAPD (random amplified polymorphic DNA) markers were used to determine the genetic diversity among 10 genotypes of P. pinnata CPTs selected for suitability for energy production. For further investigation, 18 primers generating stable band patterns from 40 tested arbitrary primers were selected. A total of 210 amplification products were obtained of which 10.48% were polymorphic. The genetic similarity index ranged from 0.11 to 0.87. Genetic distance values were used to generate a dendrogram (UPGMA) between the genotypes. The Mantel method used for comparing the similarity matrixes produced correlation coefficients that were statistically significant for the RAPD marker. This genomic analysis allows a cost effective characterization of CPTs of P. pinnata. The present investigation supports in future the development of genetic map in Pongamia which are a highly useful tool in breeding and may provide information on the inheritance of features crucial for increase seed yield, oil content and the resistance to key insects and pests. Thus this study warrants Pongamia producers to realize its full potential and contributes for its sustainable production and improvement.     

Overview of hydrogen production technologies from biogas and the applications in fuel cells

Traditionally, H₂ is a large-scale production by the reforming process of light hydrocarbons, mainly natural gas, used by the chemical industry. However, the reforming technologies currently used encounter numerous technical/scientific challenges, which depend on the quality of raw materials, the conversion efficiency and security needs for the integration of H₂ production, purification and use, among others. Biogas is a high-potential versatile raw material for reforming processes, which can be used as an alternative CH₄ source. The production of H₂ from renewable sources, such as biogas, helps to largely reduce greenhouse gas emissions. Within this context, the integration of biogas reforming processes and the activation of fuel cell using H₂ represent an important route for generating clean energy, with added high-energy efficiency. This work expounds a literature review of the biogas reforming technologies, emphasizing the types of fuel cells available, the advantages offered by each route and the main problems faced.     

Potential and cost of electricity generation from human and animal waste in Spain

The energy contents of human and animal waste generated in Spain is estimated, as is the electricity that could be potentially generated from such waste. The waste considered is municipal solid waste, sewage sludge and livestock manure; several energy-recovery options are analyzed for the first one, viz the collection of landfill gas, incineration and anaerobic digestion. To estimate the potential, we use geo-referenced statistical human and animal population data disaggregated to the county level. This level of disaggregation allows the implementation of a cost model for the transformation of the waste into electricity, using a variety of technologies. The model considers the cost of transporting the waste to the transformation plant, and takes into account the economies of scale afforded by larger plants for the combined treatment of the waste in the county. The result is a generation-cost curve, which sorts by increasing costs the generation potential in the whole of the territory. The overall limits, in terms of primary energy and without considering alternative uses for the waste are between 725 and 4438 ktoe/y (depending on the energy-recovery method) for municipal solid waste; 142 ktoe/y for sewage sludge; and 1794 ktoe/y for livestock manure. The cost of the electricity generated depends greatly on the type of residue and the technology used for the transformation. Thus, the most economical option is the incineration of municipal solid waste, with an entry cost of around 4 c€/kWh. The generation entry-costs from livestock manure and sewage sludge are on the other hand in excess of 8 c€/kWh.     

Production of producer gas from sugarcane bagasse and carpentry waste and its sustainable use in a dual fuel CI engine: A performance,emission, and noise investigation

Due to ever increasing use of conventional fuels and improper utilization of renewables, air pollution and GHG (Green House Gas) emissions are the primary areas of concern. Due to this, the world is now shifting interest towards the synthesis and use of alternate fuels; that can replace the conventional fuels. Present work focuses on an experimental investigation, which is carried out on two different biomass materials – sugarcane bagasse and carpentry waste in 1:1 ratio. Biomass samples were used to synthesize producer gas in a downdraft gasifier with a gas flow rate of 5.07 Nm³/h. Producer gas was blended with diesel and fired in a dual fuel CI engine. Engine performance was smooth while it was tested for six load variations for noise characteristics and various performance and emission parameters. A maximum reduction in diesel consumption by 45.7% and NOx emissions by 69.5% was reported with a slight increase (～3.4 dB) in the noise.     

Seasonal constraints in management of alternative sources of energy in rural areas

A plan for the management of alternative sources of energy, namely, wind, solar and biomass, available in a typical village of arid area has been formulated and it is found that the energy potential available in the village from mid February to mid September is much more than the energy requirement of the village; and during the remaining period the energy available is about 78.5 per cent of the energy requirement. Appropriate technologies for the effective and efficient use of these energies are earmarked so as to convert the energy potential available into useful energy.     

论饭店固体废弃物管理

饭店废弃物管理是饭店环境管理的重要内容,管理的目的不仅是保护环境,同时能为饭带来效益并促进管理,文章对饭店的废弃物状况进行了分析,并提出了初步的管理方案。     

高校能源管理的现状分析及对策探讨

随着规模的迅速扩大,高校能源消费支出也有所增长,其中不合理消费占了一定的比重。在节能减排工作面临较为复杂、严峻的形势下,高校作为人口密度较大的能耗组织,应强化能源管理、提高能源利用效率。     

Overview of energy storage systems for storing electricity from renewable energy sources in Saudi Arabia

Renewable power (photovoltaic, solar thermal or wind) is inherently intermittent and fluctuating. If renewable power has to become a major source of base-load dispatchable power, electricity storage systems of multi-MW capacity and multi-hours duration are indispensable. An overview of the advanced energy storage systems to store electrical energy generated by renewable energy sources is presented along with climatic conditions and supply demand situation of power in Saudi Arabia. Based on the review, battery features needed for the storage of electricity generated from renewable energy sources are: low cost, high efficiency, long cycle life, mature technology, withstand high ambient temperatures, large power and energy capacities and environmentally benign. Although there are various commercially available electrical energy storage systems (EESS), no single storage system meets all the requirements for an ideal EESS. Each EESS has a suitable application range.     

An analysis of power generation from municipal solid waste (MSW) incineration plants in Taiwan

Heavily (about 99%) depending on imported energy, Taiwan, a country in the subtropics, has limited natural resources. In this regard, biomass energy from (MSW) municipal solid waste incineration plants thus became attractive during the 1990s. The objective of this paper is to present a comprehensive analysis of MSW-to-energy in Taiwan. This paper gave a concise summary of current status of domestic energy consumption &; power generation, MSW generation &; MSW incineration treatment, and electricity generation from MSW incineration plants since 2000. Based on the electricity generation in 2008 (i.e., 2967 GWh), the environmental benefit of mitigating CO₂ emissions and the economic benefit of selling electricity were preliminarily calculated to be around 1.9 × 10⁶ tons and US$ 1.5 × 10⁸, respectively. However, since the heat content of incinerated MSW and the methodologies were used on the recommendation of the (IPCC) Intergovernmental Panel on Climate Change, the net emissions of CO₂ equivalent from methane (CH₄) &; nitrous oxide (N₂O) have been estimated to be at around 76,000 and 88,000 tons/year compared to coal and oil, respectively.     

Charcoal from biomass residues of a Cryptomeria plantation and analysis of its carbon fixation benefit in Taiwan

Charcoal production as an age-old industry not only supplies fuel in developing countries, in recent decades, it has also become a means of supplying new multifunctional materials for environmental improvement and agricultural applications in developed countries. These include air dehumidification and deodorization, water purification, and soil improvement due to charcoal's excellent adsorption capacity. Paradoxically, charcoal production might also help curb greenhouse gas emissions. In this study, we made charcoal from discarded branches and tops of wood from a Cryptomeria plantation after thinning using a still-operational earthen kiln. Woody biomass was used as the carbonization fuel. The effect of carbonization on carbon fixation was calculated and its benefits evaluated. The results showed that the recovered fixed carbon reached 33.2%, i.e., one-third of the biomass residual carbon was conserved as charcoal which if left on the forest ground would decompose and turn into carbon dioxide, and based on a net profit of US$1.13 kg⁻¹ for charcoal, an annual net profit of US$14,665 could be realized. Charcoaling thus appears to be a feasible alternative to promote reutilization of woody resides which would not only reduce greenhouse gas emissions, but also provide potential benefits to regional economies in developing countries.     

Energy policy implications of waste management in various sectors of the economy—An analysis based on physical systems theory

This paper aims to bring into focus the impact of waste management in different sectors of the economy on some important policy issues related to energy. In a multi-sector economy, the total energy demand consists of the direct energy demand of human population, the intermediate demand of other sectors and the energy wastes which cannot be recycled and have to be rejected to nature. These sectorial interlinkages in the economy, due to their cascading effects, are very important for studying the real impact of waste generation or waste recycling on the energy demand and prices. A generalized multi-sector economy model which combines the concepts of input-output economics with waste management (input-output-waste model) has been developed based on physical systems theory. The results of sensitivity analysis of this model are presented in this paper, which suggest the need to have a serious look into waste management practices in all sectors of the economy from an energy policy point of view.