Household cooking fuel use and its health effects among rural women in southern India-A cross-sectional study

The use of biomass fuel is associated with the deterioration of human health and women are more likely to develop health conditions due to their exposure to indoor air pollution during cooking. This study was conducted to assess the pattern of fuel used for cooking in households as well as to determine the association between the types of fuel used with respect to socio-demographic characteristics and health status of women. A community based cross-sectional survey was conducted between August 2016 and September 2018 in four rural areas and one semi-urban area of Udupi district, Karnataka, India. The study comprised 587 families including 632 women. A pre-tested semi-structured questionnaire was used to collect data on the type of fuel as well as self-reported health conditions. Overall, 72.5% of the families used biomass, where 67.2% families were currently using both biomass and liquefied petroleum gas while only biomass was used in 5.3% of the families for cooking. Among women, being ever exposed to biomass fuel was significantly associated with their age, literacy level, occupation and socio-economic status (p < 0.001). Those who were exposed to biomass fuel showed a significant association with self-reported ophthalmic (AOR = 3.85; 95% CI: 1.79–8.29), respiratory (OR = 5.04; 95% CI: 2.52–10.07), cardiovascular (OR = 6.07; 95% CI: 1.88–19.67), dermatological symptoms /conditions (AOR = 3.67; 95% CI: 1.07–12.55) and history of adverse obstetric outcomes (AOR = 2.45; 95% CI: 1.08–5.57). A positive trend was observed between cumulative exposure to biomass in hour-years and various self-reported health symptoms/conditions (p < 0.001). It was observed that more than two-thirds of women using biomass fuel for cooking were positively associated with self-reported health symptoms. Further longitudinal studies are essential to determine the level of harmful air pollutants in household environment and its association with various health conditions among women in this region.

Household biogas digesters or medium-large-scale biogas plants: a conflicting issue in rural China

There has been a conflicting issue in rural China that whether or not encouraging the development of medium-large-scale biogas plants (MLBPs) to reduce household biogas digesters (HBDs) will be better for China in the long run. In this study, we investigate the difference between HBD users and MLBP users and the factors that affect the biogas use of these two user types on the basis of a survey of 1125 households in four provinces in China. The results indicate that compared to HBD users, MLBP users have a higher ratio (29%) of biogas use, obtain a higher subsidy-to-cost ratio (25%), and present a more positive evaluation of biogas service (3%). For HBD users, installation years and service evaluation are significant predictors of biogas use. For MLBP users, in addition to installation years and service, the subsidy-to-cost ratio affects biogas use negatively, and the biogas price is a key constraint for biogas use. These results provide valuable insights into the future development of biogas energy in rural China and guidance for the development of biogas in similar countries worldwide.

Odour impact from farms with animal husbandry and biogas facilities

Agricultural biogas facilities are usually combined with animal husbandry. Their siting near residential areas can lead to odour complaints by residents. The aim of this study was to identify relevant odour sources, to record odour impact, and to determine the main variables influencing odour impact. Therefore, a combined approach was designed to account for individual odour sources as well as the farms as a whole. On eight farms with cattle husbandry and biogas facilities, two of which kept pigs and poultry, the odour-relevant area sources ranged between 475 and 1810 m². Solid manure from poultry, cattle and horses as well as grass cuttings, vegetable peelings, liquid-silage effluent and fermentation residues figured among the odour-intensive sources, in addition to biogas. Odour-plume inspections were performed at various distances from the farm, and assessors determined their odour perception and -intensities. The odour intensity in the downwind plume axis was explainable in a linear mixed-effects model by distance (p < 0.001), emitting surface area (p = 0.002) and wind speed (p = 0.018). As distance increased, odour intensity decreased by a factor of two per 50 m. Higher odour intensities resulted from larger surface areas in the animal enclosure, substrate storage, or especially odour-relevant sources. A mixture of odours was frequently perceived in the odour plume. If biogas escaped, an increase in odour impact was recognisable (p = 0.021). Biogas leakage should be avoided with a sufficiently large storage capacity, process optimisation, and regular servicing. In summary, animal husbandry and biogas facilities are to be viewed as an entire plant in terms of downwind odour perception. In planning processes for biogas facilities with animal husbandry, great care in the choice of site is called for, as are structural-technical and organisational measures for abatement.

Environmental impact of biogas: A short review of current knowledge

The social acceptance of biogas is often hampered by environmental and health concerns. In this study, the current knowledge about the impact of biogas technology is presented and discussed. The survey reports the emission rate estimates of the main greenhouse gases (GHG), namely CO₂, CH₄ and N₂O, according to several case studies conducted over the world. Direct emissions of gaseous pollutants are then discussed, with a focus on nitrogen oxides (NO_x); evidences of the importance of suitable biomass and digestate storages are also reported. The current knowledge on the environmental impact induced by final use of digestate is critically discussed, considering both soil fertility and nitrogen release into atmosphere and groundwater; several case studies are reported, showing the importance of NH₃ emissions with regards to secondary aerosol formation. The biogas upgrading to biomethane is also included in the study: with this regard, the methane slip in the off-gas can significantly reduce the environmental benefits.

Impact of military on biofuels consumption and GHG emissions: the evidence from G7 countries

It was aimed to test the relation among the greenhouse gases emissions, economic growth, biofuels consumption, and militarization in G7 countries during the 1985-2015 period by Pedroni 1995 and panel Johansen tests and two long-run estimators-dynamic OLS and fully modified OLS. Long-run estimators found that economic growth and militarization have statistically significant positive impact on CO₂ emission of G7 countries. Furthermore, the panel causality tests were applied: Dumitrescu and Hurlin (Econ Model 29(4):1450-1460, 2012) and panel Granger causality. These tests determined the causal relationship between the variables. The results of this paper implied that economic growth and biofuels consumption depend on militarization, and economic growth and militarization are granger causes of the greenhouse gases emissions.

Total environmental impacts of biofuels from corn stover using a hybrid life cycle assessment model combining process life cycle assessment and economic input-output life cycle assessment

Studies on the environmental analysis of biofuels by fast pyrolysis and hydroprocessing (BFPH) have so far focused only on the environmental impacts from direct emissions and have included few indirect emissions. The influence of ignoring some indirect emissions on the environmental performance of BFPH has not been well investigated and hence is not really understood. In addition, in order to avoid shifting environmental problems from one medium to another, a comprehensive assessment of environmental impacts caused by the processes must quantify the environmental emissions to all media (air, water, and land) in relation to each life cycle stage. A well-to-wheels assessment of the total environmental impacts resulting from direct emissions and indirect emissions of a BFPH system with corn stover is conducted using a hybrid life cycle assessment (LCA) model combining the economic input-output LCA and the process LCA. The Tool for the Reduction and Assessment of Chemical and other environmental Impacts (TRACI) has been used to estimate the environmental impacts in terms of acidification, eutrophication, global climate change, ozone depletion, human health criteria, photochemical smog formation, ecotoxicity, human health cancer, and human health noncancer caused by 1 MJ biofuel production. Taking account of all the indirect greenhouse gas (GHG) emissions, the net GHG emissions (81.8 g CO₂ eq/MJ) of the biofuels are still less than those of petroleum-based fuels (94 g CO₂ eq/MJ). Maize production and pyrolysis and hydroprocessing make major contributions to all impact categories except the human health criteria. All impact categories resulting from indirect emissions except eutrophication and smog air make more than 24% contribution to the total environmental impacts. Therefore, the indirect emissions are important and cannot be ignored. Sensitivity analysis has shown that corn stover yield and bio-oil yield affect the total environmental impacts of the biofuels more significantly than the biomass transportation distance and biofuel transportation distance. Integr Environ Assess Manag 2018;14:139-149. © 2017 SETAC.

Drying or anaerobic digestion of fish sludge: Nitrogen fertilisation effects and logistics

Application of fish sludge as fertiliser to agricultural land can contribute to closing nutrient cycles in fish farming. The effect of different treatment technologies on the nitrogen fertilisation effects of fish sludge was studied by a bioassay with barley (Hordeum vulgare), an incubation and a field experiment. Dried fish sludge resulted in relative agronomic efficiency of 50-80% compared with mineral fertiliser. The anaerobic digestate based on fish sludge (20 vol%) and dairy manure did not increase nitrogen uptake in barley. Increasing the ratio of fish sludge in the digestate increased the fertilisation effect, but requires optimisation of the biogas process. A simple logistics analysis conducted for a case hatchery showed that on-site drying and co-digestion of fish sludge in a central biogas plant can be regarded as equal in terms of costs. Norway can become an exporter of fish sludge-based recycling fertilisers if current regulations are modified to facilitate nutrient recycling.

The impact of biogas and fuelwood use on institutional kitchen air quality in Kampala, Uganda

Experts have suggested that microscale biogas systems offer a source of renewable energy that improves indoor air quality, but such impacts have not been directly measured. This study documented cooking behaviors and measured 2.5-μm particulate matter (PM_2.5 ), carbon monoxide (CO), and sulfur dioxide (SO₂ ) concentrations within 14 institutional kitchens in Kampala, Uganda, that prepare meals using biogas (n=5), a mixture of biogas and fuelwood (n=3), and fuelwood (n=6). Small institutions (10-30 people) with biogas kitchens had 99% lower concentrations of PM_2.5 (21 μg/m³ ) than fuelwood kitchens (3100 μg/m³ ). Larger institutions (>100 people) had biogas systems that produced insufficient gas and relied on fuelwood to meet over 90% of their energy needs. PM_2.5 concentrations in these biogas-firewood kitchens were equivalent to concentrations in fuelwood kitchens. Although concentrations of hydrogen sulfide (H₂ S) in biogas were as high as 2000 ppm, 75% of systems had undetectable H₂ S levels (<100 ppm) in the biogas. Kitchens using biogas with high H₂ S had correspondingly higher SO₂ concentrations in the kitchen air. However, even the highest SO₂ concentration in biogas kitchens (150 μg/m³ ) was lower than SO₂ concentration in fuelwood kitchens (390 μg/m³ ). The results suggest that biogas systems can offer air quality improvements if sized properly for energy demands.

Environmental balance of the UK biogas sector: An evaluation by consequential life cycle assessment

Anaerobic digestion (AD) is expanding rapidly in the UK. Previous life cycle assessment (LCA) studies have highlighted the sensitivity of environmental outcomes to feedstock type, fugitive emissions, biomethane use, energy conversion efficiency and digestate management. We combined statistics on current and planned AD deployment with operational data from a survey of biogas plant operators to evaluate the environmental balance of the UK biogas sector for the years 2014 and 2017. Consequential LCA was applied to account for all major environmental credits and burdens incurred, including: (i) substitution of composting, incineration, sewer disposal, field decomposition and animal feeding of wastes; (ii) indirect land use change (ILUC) incurred by the cultivation of crops used for biogas production and to compensate for bakery and brewery wastes diverted from animal feed. In 2014, the UK biogas sector reduced greenhouse gas (GHG) emissions by 551-755Gg CO2e excluding ILUC, or 238-755Gg CO2e including ILUC uncertainty. Fossil energy depletion was reduced by 8.9-10.8PJe, but eutrophication and acidification burdens were increased by 1.8-3.4Gg PO4e and 8.1-14.6Gg SO2e, respectively. Food waste and manure feedstocks dominate GHG abatement, largely through substitution of in-vessel composting and manure storage, whilst food waste and crop feedstocks dominate fossil energy credit, primarily through substitution of natural gas power generation. Biogas expansion is projected to increase environmental credits and loadings by a factor of 2.4 by 2017. If all AD bioelectricity replaced coal generation, or if 90% of biomethane replaced transport diesel or grid natural gas, GHG abatement would increase by 131%, 38% and 20%, respectively. Policies to encourage digestion of food waste and manures could maximize GHG abatement, avoiding the risk of carbon leakage associated with use of crops and wastes otherwise used to feed livestock. Covering digestate stores could largely mitigate net eutrophication and acidification burdens.

Clean fuels for resource-poor settings: A systematic review of barriers and enablers to adoption and sustained use

BACKGROUND

Access to, and sustained adoption of, clean household fuels at scale remains an aspirational goal to achieve sufficient reductions in household air pollution (HAP) in order to impact on the substantial global health burden caused by reliance on solid fuels.

AIM AND OBJECTIVES

To systematically appraise the current evidence base to identify: (i) which factors enable or limit adoption and sustained use of clean fuels (namely liquefied petroleum gas (LPG), biogas, solar cooking and alcohol fuels) in low- and middle-income countries; (ii) lessons learnt concerning equitable scaling-up of programmes of cleaner cooking fuels in relation to poverty, urban-rural settings and gender.

METHODS

A mixed-methods systematic review was conducted using established review methodology and extensive searches of published and grey literature sources. Data extraction and quality appraisal of quantitative, qualitative and case studies meeting inclusion criteria were conducted using standardised methods with reliability checking.

FINDINGS

Forty-four studies from Africa, Asia and Latin America met the inclusion criteria (17 on biogas, 12 on LPG, 9 on solar, 6 on alcohol fuels). A broad range of inter-related enabling and limiting factors were identified for all four types of intervention, operating across seven pre-specified domains (i.e. fuel and technology characteristics, household and setting characteristics, knowledge and perceptions, financial, tax and subsidy aspects, market development, regulation, legislation and standards, and programme and policy mechanisms) and multiple levels (i.e. household, community, national). All domains matter and the majority of factors are common to all clean fuels interventions reviewed although some are fuel and technology-specific. All factors should therefore be taken into account and carefully assessed during planning and implementation of any small- and large-scale initiative aiming at promoting clean fuels for household cooking.

CONCLUSIONS

Despite limitations in quantity and quality of the evidence this systematic review provides a useful starting point for the design, delivery and evaluation of programmes to ensure more effective adoption and use of LPG, biogas, alcohol fuels and solar cooking.

FUNDING

This review was funded by the Department for International Development (DfID) of the United Kingdom. The authors would also like to thank the Evidence for Policy and Practice Information and Co-ordinating Centre (EPPI-Centre) for their technical support.

Health impacts of anthropogenic biomass burning in the developed world

Climate change policies have stimulated a shift towards renewable energy sources such as biomass. The economic crisis of 2008 has also increased the practice of household biomass burning as it is often cheaper than using oil, gas or electricity for heating. As a result, household biomass combustion is becoming an important source of air pollutants in the European Union.This position paper discusses the contribution of biomass combustion to pollution levels in Europe, and the emerging evidence on the adverse health effects of biomass combustion products.Epidemiological studies in the developed world have documented associations between indoor and outdoor exposure to biomass combustion products and a range of adverse health effects. A conservative estimate of the current contribution of biomass smoke to premature mortality in Europe amounts to at least 40 000 deaths per year.We conclude that emissions from current biomass combustion products negatively affect respiratory and, possibly, cardiovascular health in Europe. Biomass combustion emissions, in contrast to emissions from most other sources of air pollution, are increasing. More needs to be done to further document the health effects of biomass combustion in Europe, and to reduce emissions of harmful biomass combustion products to protect public health.

Life cycle cost optimization of biofuel supply chains under uncertainties based on interval linear programming

The aim of this work was to develop a model for optimizing the life cycle cost of biofuel supply chain under uncertainties. Multiple agriculture zones, multiple transportation modes for the transport of grain and biofuel, multiple biofuel plants, and multiple market centers were considered in this model, and the price of the resources, the yield of grain and the market demands were regarded as interval numbers instead of constants. An interval linear programming was developed, and a method for solving interval linear programming was presented. An illustrative case was studied by the proposed model, and the results showed that the proposed model is feasible for designing biofuel supply chain under uncertainties.

Comparing bioenergy production sites in the Southeastern US regarding ecosystem service supply and demand

Biomass for bioenergy is debated for its potential synergies or tradeoffs with other provisioning and regulating ecosystem services (ESS). This biomass may originate from different production systems and may be purposefully grown or obtained from residues. Increased concerns globally about the sustainable production of biomass for bioenergy has resulted in numerous certification schemes focusing on best management practices, mostly operating at the plot/field scale. In this study, we compare the ESS of two watersheds in the southeastern US. We show the ESS tradeoffs and synergies of plantation forestry, i.e., pine poles, and agricultural production, i.e., wheat straw and corn stover, with the counterfactual natural or semi-natural forest in both watersheds. The plantation forestry showed less distinct tradeoffs than did corn and wheat production, i.e., for carbon storage, P and sediment retention, groundwater recharge, and biodiversity. Using indicators of landscape composition and configuration, we showed that landscape planning can affect the overall ESS supply and can partly determine if locally set environmental thresholds are being met. Indicators on landscape composition, configuration and naturalness explained more than 30% of the variation in ESS supply. Landscape elements such as largely connected forest patches or more complex agricultural patches, e.g., mosaics with shrub and grassland patches, may enhance ESS supply in both of the bioenergy production systems. If tradeoffs between biomass production and other ESS are not addressed by landscape planning, it may be reasonable to include rules in certification schemes that require, e.g., the connectivity of natural or semi-natural forest patches in plantation forestry or semi-natural landscape elements in agricultural production systems. Integrating indicators on landscape configuration and composition into certification schemes is particularly relevant considering that certification schemes are governance tools used to ensure comparable sustainability standards for biomass produced in countries with variable or absent legal frameworks for landscape planning.

Changing the renewable fuel standard to a renewable material standard: bioethylene case study

The narrow scope of the U.S. renewable fuel standard (RFS2) is a missed opportunity to spur a wider range of biomass use. This is especially relevant as RFS2 targets are being missed due to demand-side limitations for ethanol consumption. This paper examines the greenhouse gas (GHG) implications of a more flexible policy based on RFS2, which includes credits for chemical use of bioethanol (to produce bioethylene). A Monte Carlo simulation is employed to estimate the life-cycle GHG emissions of conventional low-density polyethylene (LDPE), made from natural gas derived ethane (mean: 1.8 kg CO2e/kg LDPE). The life-cycle GHG emissions from bioethanol and bio-LDPE are examined for three biomass feedstocks: U.S. corn (mean: 97g CO2e/MJ and 2.6 kg CO2e/kg LDPE), U.S. switchgrass (mean: -18g CO2e/MJ and -2.9 kg CO2e/kg LDPE), and Brazilian sugar cane (mean: 33g CO2e/MJ and -1.3 kg CO2e/kg LDPE); bioproduct and fossil-product emissions are compared. Results suggest that neither corn product (bioethanol or bio-LDPE) can meet regulatory GHG targets, while switchgrass and sugar cane ethanol and bio-LDPE likely do. For U.S. production, bioethanol achieves slightly greater GHG reductions than bio-LDPE. For imported Brazilian products, bio-LDPE achieves greater GHG reductions than bioethanol. An expanded policy that includes bio-LDPE provides added flexibility without compromising GHG targets.

Long-term prospects for the environmental profile of advanced sugar cane ethanol

This work assessed the environmental impacts of the production and use of 1 MJ of hydrous ethanol (E100) in Brazil in prospective scenarios (2020-2030), considering the deployment of technologies currently under development and better agricultural practices. The life cycle assessment technique was employed using the CML method for the life cycle impact assessment and the Monte Carlo method for the uncertainty analysis. Abiotic depletion, global warming, human toxicity, ecotoxicity, photochemical oxidation, acidification, and eutrophication were the environmental impacts categories analyzed. Results indicate that the proposed improvements (especially no-til farming-scenarios s2 and s4) would lead to environmental benefits in prospective scenarios compared to the current ethanol production (scenario s0). Combined first and second generation ethanol production (scenarios s3 and s4) would require less agricultural land but would not perform better than the projected first generation ethanol, although the uncertainties are relatively high. The best use of 1 ha of sugar cane was also assessed, considering the displacement of the conventional products by ethanol and electricity. No-til practices combined with the production of first generation ethanol and electricity (scenario s2) would lead to the largest mitigation effects for global warming and abiotic depletion. For the remaining categories, emissions would not be mitigated with the utilization of the sugar cane products. However, this conclusion is sensitive to the displaced electricity sources.

Effect of operating conditions on yield and quality of biocrude during hydrothermal liquefaction of halophytic microalga Tetraselmis sp

The biomass of halophytic microalga Tetraselmis sp. with 16%w/w solids was converted into biocrude by a hydrothermal liquefaction (HTL) process in a batch reactor at different temperatures (310, 330, 350 and 370°C) and reaction times (5, 15, 30, 45 and 60min). The biocrude yield, elemental composition, energy density and severity parameter obtained at various reaction conditions were used to predict the optimum condition for maximum recovery of biocrude with improved quality. This study clearly indicated that the operating condition for obtaining maximum biocrude yield and ideal quality biocrude for refining were different. A maximum biocrude yield of ∼65wt% ash free dry weight (AFDW) was obtained at 350°C and 5min, with a severity parameter and energy density of 5.21 and ∼35MJ/kg, respectively. The treatment with 45min reaction time recorded ∼62wt% (AFDW) yield of biocrude with and energy density of ∼39MJ/kg and higher severity parameter of 7.53.

Biodiesel quality and biochemical changes of microalgae Chlorella pyrenoidosa and Scenedesmus obliquus in response to nitrate levels

Biodiesel quality associated with biochemical components of Chlorella pyrenoidosa and Scenedesmus obliquus under different nitrate levels were investigated. The highest lipid contents of 54.5% for C. pyrenoidosa and 47.7% for S. obliquus were obtained in nitrate absence. Carbohydrate peaked at 0.3gL(-1) with values of 40.7% for C. pyrenoidosa and 42.5% for S. obliquus. Protein content seemed species dependent, which decreased substantially to 11.2% in C. pyrenoidosa and 8.8% in S. obliquus under nitrate absence in present research. Better biodiesel quality (e.g. cetane number >58, iodine value <69) could be obtained from C. pyrenoidosa in nitrate absence and S. obliquus in 0.3gL(-1), where the highest saturated fatty acids (39.5 for C. pyrenoidosa, 31.2 for S. obliquus) and the lowest unsaturated fatty acids (60.5 for C. pyrenoidosa, 68.8 for S. obliquus) were obtained. These results suggest that microalgae grown in the presence of nitrogen may limit biodiesel quality.

Emission of metals from pelletized and uncompressed biomass fuels combustion in rural household stoves in China

Effort of reducing CO₂ emissions in developing countries may require an increasing utilization of biomass fuels. Biomass pellets seem well-suited for residential biomass markets. However, there is limited quantitative information on pollutant emissions from biomass pellets burning, especially those measured in real applications. In this study, biomass pellets and raw biomass fuels were burned in a pellet burner and a conventional stove respectively, in rural households, and metal emissions were determined. Results showed that the emission factors (EFs) ranged 3.20-5.57 (Pb), 5.20-7.58 (Cu), 0.11-0.23 (Cd), 12.67-39.00 (As), 0.59-1.31 mg/kg (Ni) for pellets, and 0.73-1.34 (Pb), 0.92-4.48 (Cu), 0.08-0.14 (Cd), 7.29-13.22 (As), 0.28-0.62 (Ni) mg/kg for raw biomass. For unit energy delivered to cooking vessels, the EFs ranged 0.42-0.77 (Pb), 0.79-1.16 (Cu), 0.01-0.03 (Cd), 1.93-5.09 (As), 0.08-0.19 mg/MJ (Ni) for pellets, and 0.30-0.56 (Pb), 0.41-1.86 (Cu), 0.04-0.06 (Cd), 3.25-5.49 (As), 0.12-0.26 (Ni) mg/MJ for raw biomass. This study found that moisture, volatile matter and modified combustion efficiency were the important factors affecting metal emissions. Comparisons of the mass-based and task-based EFs found that biomass pellets produced higher metal emissions than the same amount of raw biomass. However, metal emissions from pellets were not higher in terms of unit energy delivered.

Life cycle assessment of camelina oil derived biodiesel and jet fuel in the Canadian Prairies

This study evaluated the environmental impact of biodiesel and hydroprocessed renewable jet fuel derived from camelina oil in terms of global warming potential, human health, ecosystem quality, and energy resource consumption. The life cycle inventory is based on production activities in the Canadian Prairies and encompasses activities ranging from agricultural production to oil extraction and fuel conversion. The system expansion method is used in this study to avoid allocation and to credit input energy to co-products associated with the products displaced in the market during camelina oil extraction and fuel processing. This is the preferred allocation method for LCA analysis in the context of most renewable and sustainable energy programs. The results show that greenhouse gas (GHG) emissions from 1 MJ of camelina derived biodiesel ranged from 7.61 to 24.72 g CO2 equivalent and 3.06 to 31.01 kg CO2/MJ equivalent for camelina HRJ fuel. Non-renewable energy consumption for camelina biodiesel ranged from 0.40 to 0.67 MJ/MJ; HRJ fuel ranged from -0.13 to 0.52 MJ/MJ. Camelina oil as a feedstock for fuel production accounted for the highest contribution to overall environmental performance, demonstrating the importance of reducing environmental burdens during the agricultural production process. Attaining higher seed yield would dramatically lower environmental impacts associated with camelina seed, oil, and fuel production. The lower GHG emissions and energy consumption associated with camelina in comparison with other oilseed derived fuel and petroleum fuel make camelina derived fuel from Canadian Prairies environmentally attractive.

Optimization of micro-aeration intensity in acidogenic reactor of a two-phase anaerobic digester treating food waste

Micro-aeration is known to promote the activities of hydrolytic exo-enzymes and used as a strategy to improve the hydrolysis of particulate substrate. The effect of different micro-aeration rates, 0, 129, 258, and 387 L-air/kg TS/d (denoted as LBR-AN, LBR-6h, LBR-3h and LBR-2h, respectively) on the solubilization of food waste was evaluated at 35°C in four leach bed reactors (LBR) coupled with methanogenic upflow anaerobic sludge blanket (UASB) reactor. Results indicate that the intensity of micro-aeration influenced the hydrolysis and methane yield. Adequate micro-aeration intensity in LBR-3h and LBR-2h significantly enhanced the carbohydrate and protein hydrolysis by 21-27% and 38-64% respectively. Due to the accelerated acidogenesis, more than 3-fold of acetic acid and butyric acid were produced in LBR-3h as compared to the anaerobic treatment LBR-AN resulting in the maximum methane yield of 0.27 L CH4/g VS(added) in the UASB. The performance of LBR-6h with inadequate aeration was similar to that of LBR-AN with a comparable hydrolysis degree. Nevertheless, higher aeration intensity in LBR-2h was also unfavorable for methane yield due to significant biomass generation and CO2 respiration of up to 18.5% and 32.8% of the total soluble hydrolysate, respectively. To conclude, appropriate micro-aeration rate can promote the hydrolysis of solid organic waste and methane yield without undesirable carbon loss and an aeration intensity of 258 L-air/kg TS/d is recommended for acidogenic LBR treating food waste.

Enablers and barriers to large-scale uptake of improved solid fuel stoves: a systematic review

BACKGROUND

Globally, 2.8 billion people rely on household solid fuels. Reducing the resulting adverse health, environmental, and development consequences will involve transitioning through a mix of clean fuels and improved solid fuel stoves (IS) of demonstrable effectiveness. To date, achieving uptake of IS has presented significant challenges.

OBJECTIVES

We performed a systematic review of factors that enable or limit large-scale uptake of IS in low- and middle-income countries.

METHODS

We conducted systematic searches through multidisciplinary databases, specialist websites, and consulting experts. The review drew on qualitative, quantitative, and case studies and used standardized methods for screening, data extraction, critical appraisal, and synthesis. We summarized our findings as "factors" relating to one of seven domains-fuel and technology characteristics; household and setting characteristics; knowledge and perceptions; finance, tax, and subsidy aspects; market development; regulation, legislation, and standards; programmatic and policy mechanisms-and also recorded issues that impacted equity.

RESULTS

We identified 31 factors influencing uptake from 57 studies conducted in Asia, Africa, and Latin America. All domains matter. Although factors such as offering technologies that meet household needs and save fuel, user training and support, effective financing, and facilitative government action appear to be critical, none guarantee success: All factors can be influential, depending on context. The nature of available evidence did not permit further prioritization.

CONCLUSIONS

Achieving adoption and sustained use of IS at a large scale requires that all factors, spanning household/community and program/societal levels, be assessed and supported by policy. We propose a planning tool that would aid this process and suggest further research to incorporate an evaluation of effectiveness.

Euphorbia tirucalli L.-comprehensive characterization of a drought tolerant plant with a potential as biofuel source

Of late, decrease in mineral oil supplies has stimulated research on use of biomass as an alternative energy source. Climate change has brought problems such as increased drought and erratic rains. This, together with a rise in land degeneration problems with concomitant loss in soil fertility has inspired the scientific world to look for alternative bio-energy species. Euphorbia tirucalli L., a tree with C3/CAM metabolism in leaves/stem, can be cultivated on marginal, arid land and could be a good alternative source of biofuel. We analyzed a broad variety of E. tirucalli plants collected from different countries for their genetic diversity using AFLP. Physiological responses to induced drought stress were determined in a number of genotypes by monitoring growth parameters and influence on photosynthesis. For future breeding of economically interesting genotypes, rubber content and biogas production were quantified. Cluster analysis shows that the studied genotypes are divided into two groups, African and mostly non-African genotypes. Different genotypes respond significantly different to various levels of water. Malate measurement indicates that there is induction of CAM in leaves following drought stress. Rubber content varies strongly between genotypes. An investigation of the biogas production capacities of six E. tirucalli genotypes reveals biogas yields higher than from rapeseed but lower than maize silage.

Bioenergy as a biodiversity management tool and the potential of a mixed species feedstock for bioenergy production in Wales

A cutting management regime maintains high levels of biodiversity in semi-natural habitats across Europe. We utilise three years of annual yield data from Welsh semi-natural areas to calculate the mean feedstock production from cutting management to be 1.05×10(6) t DM annum(-1). Using formulae based upon Fischer Tropsch (FT) fuel process models, we predict that 2.12×10(5) t of FT fuel annum(-1) could be produced. That represents 38% of the Welsh transport sector's green house gas (GHG) reduction target for 2020. Alternatively, predictive formulae reveal that methane yields from anaerobic digestion of the feedstock could reduce GHG emissions by 11% of the domestic sector's reduction target for 2020. Electricity generation from methane is also explored. The results presented encourage further investigation into the contribution of this resource to sustainable domestic energy supply. Furthermore, the proposed system would potentially protect a broad range of ecosystem services and maintain biodiversity.

Life cycle assessment of biodiesel production in China

This study aims to evaluate energy, economic, and environmental performances of seven categories of biodiesel feedstocks by using the mixed-unit input-output life cycle assessment method. Various feedstocks have different environmental performances, indicating potential environmental problem-shift. Jatropha seed, castor seed, waste cooking oil, and waste extraction oil are preferred feedstocks for biodiesel production in the short term. Positive net energy yields and positive net economic benefits of biodiesel from these four feedstocks are 2.3-52.0% of their life cycle energy demands and 74.1-448.4% of their economic costs, respectively. Algae are preferred in the long term mainly due to their less arable land demands. Special attention should be paid to potential environmental problems accompanying feedstock choice: freshwater use, ecotoxicity potentials, photochemical oxidation potential, acidification potential and eutrophication potential. Moreover, key processes are identified by sensitivity analysis to direct future technology improvements. Finally, supporting measures are proposed to optimize China's biodiesel development.

Biomass fuel use for cooking in Sri Lanka: analysis of data from national demographic health surveys

BACKGROUND

Biomass cooking fuel is the main source of indoor air pollution in the majority of households in the developing world. Sri Lanka is an island of about 20 million population with urban, rural, and estate population of 14.6%, 80.0%, and 5.4%, respectively. This study describes biomass fuel use for cooking in Sri Lanka.

METHODS

We analyzed data from two national Demographic Health Surveys (2000 and 2007) to identify the use and determinants of cooking fuels in Sri Lankan households. The results are based on a sample of 8,169 households in 2000 and 19,862 households in 2007.

RESULTS

Wood was the principal cooking fuel used in 78.3% and 78.5% of households in 2000 and 2007, respectively. In 2007, 96.3% of estate sector households used firewood as compared to 84.2% in the rural and 34.6% in the urban sectors. Similar trends were noted in 2000 as well.

CONCLUSIONS

The shift from firewood to cleaner fuels in Sri Lanka is negligible from 2000 to 2007. Improving the quality of life of the population does not necessarily predict a shift towards the use of cleaner cooking fuels in Sri Lanka.

Energy, water and fish: biodiversity impacts of energy-sector water demand in the United States depend on efficiency and policy measures

Rising energy consumption in coming decades, combined with a changing energy mix, have the potential to increase the impact of energy sector water use on freshwater biodiversity. We forecast changes in future water use based on various energy scenarios and examine implications for freshwater ecosystems. Annual water withdrawn/manipulated would increase by 18-24%, going from 1,993,000-2,628,000 Mm(3) in 2010 to 2,359,000-3,271,000 Mm(3) in 2035 under the Reference Case of the Energy Information Administration (EIA). Water consumption would more rapidly increase by 26% due to increased biofuel production, going from 16,700-46,400 Mm(3) consumption in 2010 to 21,000-58,400 Mm(3) consumption in 2035. Regionally, water use in the Southwest and Southeast may increase, with anticipated decreases in water use in some areas of the Midwest and Northeast. Policies that promote energy efficiency or conservation in the electric sector would reduce water withdrawn/manipulated by 27-36 m(3)GJ(-1) (0.1-0.5 m(3)GJ(-1) consumption), while such policies in the liquid fuel sector would reduce withdrawal/manipulation by 0.4-0.7 m(3)GJ(-1) (0.2-0.3 m(3)GJ(-1) consumption). The greatest energy sector withdrawal/manipulation are for hydropower and thermoelectric cooling, although potential new EPA rules that would require recirculating cooling for thermoelectric plants would reduce withdrawal/manipulation by 441,000 Mm(3) (20,300 Mm(3) consumption). The greatest consumptive energy sector use is evaporation from hydroelectric reservoirs, followed by irrigation water for biofuel feedstocks and water used for electricity generation from coal. Historical water use by the energy sector is related to patterns of fish species endangerment, where water resource regions with a greater fraction of available surface water withdrawn by hydropower or consumed by the energy sector correlated with higher probabilities of imperilment. Since future increases in energy-sector surface water use will occur in areas of high fish endemism (e.g., Southeast), additional management and policy actions will be needed to minimize further species imperilment.

Economic approach to assess the forest carbon implications of biomass energy

There is widespread concern that biomass energy policy that promotes forests as a supply source will cause net carbon emissions. Most of the analyses that have been done to date, however, are biological, ignoring the effects of market adaptations through substitution, net imports, and timber investments. This paper uses a dynamic model of forest and land use management to estimate the impact of United States energy policies that emphasize the utilization of forest biomass on global timber production and carbon stocks over the next 50 years. We show that when market factors are included in the analysis, expanded demand for biomass energy increases timber prices and harvests, but reduces net global carbon emissions because higher wood prices lead to new investments in forest stocks. Estimates are sensitive to assumptions about whether harvest residues and new forestland can be used for biomass energy and the demand for biomass. Restricting biomass energy to being sourced only from roundwood on existing forestland can transform the policy from a net sink to a net source of emissions. These results illustrate the importance of capturing market adjustments and a large geographic scope when measuring the carbon implications of biomass energy policies.

The water footprint of sweeteners and bio-ethanol

An increasing demand for food together with a growing demand for energy crops result in an increasing demand for and competition over water. Sugar cane, sugar beet and maize are not only essential food crops, but also important feedstock for bio-ethanol. Crop growth requires water, a scarce resource. This study aims to assess the green, blue and grey water footprint (WF) of sweeteners and bio-ethanol from sugar cane, sugar beet and maize in the main producing countries. The WFs of sweeteners and bio-ethanol are mainly determined by the crop type that is used as a source and by agricultural practise and agro-climatic conditions; process water footprints are relatively small. The weighted global average WF of sugar cane is 209 m(3)/tonne; for sugar beet this is 133 m(3)/tonne and for maize 1222 m(3)/tonne. Large regional differences in WFs indicate that WFs of crops for sweeteners and bio-ethanol can be improved. It is more favourable to use maize as a feedstock for sweeteners or bio-ethanol than sugar beet or sugar cane. The WF of sugar cane contributes to water stress in the Indus and Ganges basins. In the Ukraine, the large grey WF of sugar beet contributes to water pollution. In some western European countries, blue WFs of sugar beet and maize need a large amount of available blue water for agriculture. The allocation of the limited global water resources to bio-energy on a large scale will be at the cost of water allocation to food and nature.

Carbon consequences and agricultural implications of growing biofuel crops on marginal agricultural lands in China

Using marginal agricultural lands to grow energy crops for biofuel feedstocks is a promising option to meet the biofuel needs in populous China without causing further food shortages or environmental problems. Here we quantify the effects of growing switchgrass and Miscanthus on Chinese marginal agricultural lands on biomass production and carbon emissions with a global-scale biogeochemical model. We find that the national net primary production (NPP) of these two biofuel crops are 622 and 1546 g C m(-2) yr(-1), respectively, whereas the NPP of food crops is about 600 g C m(-2) yr(-1) in China. The net carbon sink over the 47 Mha of marginal agricultural lands across China is 2.1 Tg C yr(-1) for switchgrass and 5.0 Tg C yr(-1) for Miscanthus. Soil organic carbon is estimated to be 10 kg C m(-2) in both biofuel ecosystems, which is equal to the soil carbon levels of grasslands in China. In order to reach the goal of 12.5 billion liters of bioethanol in 2020 using crop biomass as biofuel feedstocks, 7.9-8.0 Mha corn grain, 4.3-6.1 Mha switchgrass, or 1.4-2.0 Mha Miscanthus will be needed. Miscanthus has tremendous potential to meet future biofuel needs, and to benefit CO(2) mitigation in China.

Comparison of PM emissions from a commercial jet engine burning conventional, biomass, and Fischer-Tropsch fuels

Rising fuel costs, an increasing desire to enhance security of energy supply, and potential environmental benefits have driven research into alternative renewable fuels for commercial aviation applications. This paper reports the results of the first measurements of particulate matter (PM) emissions from a CFM56-7B commercial jet engine burning conventional and alternative biomass- and, Fischer-Tropsch (F-T)-based fuels. PM emissions reductions are observed with all fuels and blends when compared to the emissions from a reference conventional fuel, Jet A1, and are attributed to fuel properties associated with the fuels and blends studied. Although the alternative fuel candidates studied in this campaign offer the potential for large PM emissions reductions, with the exception of the 50% blend of F-T fuel, they do not meet current standards for aviation fuel and thus cannot be considered as certified replacement fuels. Over the ICAO Landing Takeoff Cycle, which is intended to simulate aircraft engine operations that affect local air quality, the overall PM number-based emissions for the 50% blend of F-T fuel were reduced by 34 ± 7%, and the mass-based emissions were reduced by 39 ± 7%.

Effects on aquatic and human health due to large scale bioenergy crop expansion

In this study, the environmental impacts of large scale bioenergy crops were evaluated using the Soil and Water Assessment Tool (SWAT). Daily pesticide concentration data for a study area consisting of four large watersheds located in Michigan (totaling 53,358 km²) was estimated over a six year period (2000-2005). Model outputs for atrazine, bromoxynil, glyphosate, metolachlor, pendimethalin, sethoxydim, triflualin, and 2,4-D model output were used to predict the possible long-term implications that large-scale bioenergy crop expansion may have on the bluegill (Lepomis macrochirus) and humans. Threshold toxicity levels were obtained for the bluegill and for human consumption for all pesticides being evaluated through an extensive literature review. Model output was compared to each toxicity level for the suggested exposure time (96-hour for bluegill and 24-hour for humans). The results suggest that traditional intensive row crops such as canola, corn and sorghum may negatively impact aquatic life, and in most cases affect the safe drinking water availability. The continuous corn rotation, the most representative rotation for current agricultural practices for a starch-based ethanol economy, delivers the highest concentrations of glyphosate to the stream. In addition, continuous canola contributed to a concentration of 1.11 ppm of trifluralin, a highly toxic herbicide, which is 8.7 times the 96-hour ecotoxicity of bluegills and 21 times the safe drinking water level. Also during the period of study, continuous corn resulted in the impairment of 541,152 km of stream. However, there is promise with second-generation lignocellulosic bioenergy crops such as switchgrass, which resulted in a 171,667 km reduction in total stream length that exceeds the human threshold criteria, as compared to the base scenario. Results of this study may be useful in determining the suitability of bioenergy crop rotations and aid in decision making regarding the adaptation of large-scale bioenergy cropping systems.

Energy-water nexus for mass cultivation of algae

Microalgae are currently considered a potential feedstock for the production of biofuels. This work addresses the energy needed to manage the water used in the mass cultivation of saline, eukaryotic algae grown in open pond systems. Estimates of both direct and upstream energy requirements for obtaining, containing, and circulating water within algae cultivation systems are developed. Potential productivities are calculated for each of the 48 states within the continental U.S. based on theoretical photosynthetic efficiencies, growing season, and total available land area. Energy output in the form of algal biodiesel and the total energy content of algal biomass are compared to energy inputs required for water management. The analysis indicates that, for current technologies, energy required for water management alone is approximately seven times greater than energy output in the form of biodiesel and more than double that contained within the entire algal biomass. While this analysis addresses only currently identified species grown in an open-pond system, the water management requirements of any algae system will be substantial; therefore, it is critical that an energy assessment of water management requirements be performed for any cultivation technology and algal type in order to fully understand the energy balance of algae-derived biofuels.

Life cycle water consumption and withdrawal requirements of ethanol from corn grain and residues

We assessed the water requirements of ethanol from corn grain and crop residue. Estimates are explicit in terms of sources-green (GW) and blue (BW) water, consumptive and nonconsumptive requirements across the lifecycle, including evapotranspiration, application and conveyance losses, biorefinery uses, and water use of energy inputs, and displaced requirements or credits due to coproducts. Ethanol consumes 50-146 L/vehicle kilometer traveled (VKT) of BW and 1-60 L/VKT of GW for irrigated corn and 0.6 L/VKT of BW and 70-137 L/VKT of GW for rain-fed corn after coproduct credits. Extending the system boundary to consider application and conveyance losses and the water requirements of embodied energy increases the total BW withdrawal from 23% to 38% and BW + GW consumption from 5% to 16%. We estimate that, in 2009, 15-19% of irrigation water is used to produce the corn required for ethanol in Kansas and Nebraska without coproduct credits and 8-10% after credits. Harvesting and converting the cob to ethanol reduces both the BW and GW intensities by 13%. It is worth noting that the use of GW is not without impacts, and the water quantity and water quality impacts at the local/seasonal scale can be significant for both fossil fuel and biofuel.

Climate impact of biofuels in shipping: global model studies of the aerosol indirect effect

Aerosol emissions from international shipping are recognized to have a large impact on the Earth's radiation budget, directly by scattering and absorbing solar radiation and indirectly by altering cloud properties. New regulations have recently been approved by the International Maritime Organization (IMO) aiming at progressive reductions of the maximum sulfur content allowed in marine fuels from current 4.5% by mass down to 0.5% in 2020, with more restrictive limits already applied in some coastal regions. In this context, we use a global bottom-up algorithm to calculate geographically resolved emission inventories of gaseous (NO(x), CO, SO(2)) and aerosol (black carbon, organic matter, sulfate) species for different kinds of low-sulfur fuels in shipping. We apply these inventories to study the resulting changes in radiative forcing, attributed to particles from shipping, with the global aerosol-climate model EMAC-MADE. The emission factors for the different fuels are based on measurements at a test bed of a large diesel engine. We consider both fossil fuel (marine gas oil) and biofuels (palm and soy bean oil) as a substitute for heavy fuel oil in the current (2006) fleet and compare their climate impact to that resulting from heavy fuel oil use. Our simulations suggest that ship-induced surface level concentrations of sulfate aerosol are strongly reduced, up to about 40-60% in the high-traffic regions. This clearly has positive consequences for pollution reduction in the vicinity of major harbors. Additionally, such reductions in the aerosol loading lead to a decrease of a factor of 3-4 in the indirect global aerosol effect induced by emissions from international shipping.

Biodiesel production in a semiarid environment: a life cycle assessment approach

While the use of biodiesel appears to be a promising alternative to petroleum fuel, the replacement of fossil fuel by biofuel may not bring about the intended climate cooling because of the increased soil N2O emissions due to N-fertilizer applications. Using a life cycle assessment approach, we assessed the influence of soil nitrous oxide (N2O) emissions on the life cycle global warming potential of the production and combustion of biodiesel from canola oil produced in a semiarid climate. Utilizing locally measured soil N2O emissions, rather than the Intergovernmental Panel on Climate Change (IPCC) default values, decreased greenhouse gas (GHG) emissions from the production and combustion of 1 GJ biodiesel from 63 to 37 carbon dioxide equivalents (CO2-e)/GJ. GHG were 1.1 to 2.1 times lower than those from petroleum or petroleum-based diesel depending on which soil N2O emission factors were included in the analysis. The advantages of utilizing biodiesel rapidly declined when blended with petroleum diesel. Mitigation strategies that decrease emissions from the production and application of N fertilizers may further decrease the life cycle GHG emissions in the production and combustion of biodiesel.

Analysis of federal and state policies and environmental issues for bioethanol production facilities

The purpose of this work was to investigate incentives and barriers to fuel ethanol production from biomass in the U.S. during the past decade (2000-2010). In particular, we examine the results of policies and economic conditions during this period by way of cellulosic ethanol activity in four selected states with the potential to produce different types of feedstocks (i.e., sugar, starch, and cellulosic crops) for ethanol production (Florida, California, Hawaii, and Iowa). Two of the four states, Iowa and California, currently have commercial ethanol production facilities in operation using corn feedstocks. While several companies have proposed commercial scale facilities in Florida and Hawaii, none are operating to date. Federal and state policies and incentives, potential for feedstock production and conversion to ethanol and associated potential environmental impacts, and environmental regulatory conditions among the states were investigated. Additionally, an analysis of proposed and operational ethanol production facilities provided evidence that a combination of these policies and incentives along with the ability to address environmental issues and regulatory environment and positive economic conditions all impact ethanol production. The 2000-2010 decade saw the rise of the promise of cellulosic ethanol. Federal and state policies were enacted to increase ethanol production. Since the initial push for development, expansion of cellulosic ethanol production has not happened as quickly as predicted. Government and private funding supported the development of ethanol production facilities, which peaked and then declined by the end of the decade. Although there are technical issues that remain to be solved to more efficiently convert cellulosic material to ethanol while reducing environmental impacts, the largest barriers to increasing ethanol production appear to be related to government policies, economics, and logistical issues. The numerous federal and state policies do not effectively give investors confidence to commit to the construction and long-term operation of facilities under current economic conditions. Additional changes in policy and breakthroughs in technology and logistics will be required to address these hurdles to increases in ethanol production in the U.S. in the next decade.

Biochemical suitability of crop residues for cellulosic ethanol: disincentives to nitrogen fertilization in corn agriculture

Concerns about energy security and climate change have increased biofuel demand, particularly ethanol produced from cellulosic feedstocks (e.g., food crop residues). A central challenge to cropping for cellulosic ethanol is the potential environmental damage from increased fertilizer use. Previous analyses have assumed that cropping for carbohydrate in residue will require the same amount of fertilizer as cropping for grain. Using (13)C nuclear magnetic resonance, we show that increases in biomass in response to fertilization are not uniform across biochemical classes (carbohydrate, protein, lipid, lignin) or tissues (leaf and stem, grain, reproductive support). Although corn grain responds vigorously and nonlinearly, corn residue shows only modest increases in carbohydrate yields in response to high levels of fertilization (25% increase with 202 kg N ha(-1)). Lignin yields in the residue increased almost twice as much as carbohydrate yields in response to nitrogen, implying that residue feedstock quality declines as more fertilizer is applied. Fertilization also increases the decomposability of corn residue, implying that soil carbon sequestration becomes less efficient with increased fertilizer. Our results suggest that even when corn is grown for grain, benefits of fertilization decline rapidly after the ecosystem's N demands are met. Heavy application of fertilizer yields minimal grain benefits and almost no benefits in residue carbohydrates, while degrading the cellulosic ethanol feedstock quality and soil carbon sequestration capacity.

Protein extraction from biomass in a bioethanol refinery--possible dietary applications: Use as animal feed and potential extension to human consumption

The economy of the production of lignocellulosic ethanol could be supported by the simultaneous use of different components of the biomass other than sugars. Among these, protein is present at high concentration in leaves and is a candidate for different possible utilizations. Among dietary applications, plant protein may be used as animal feed and possibly extended to human consumption, in close similarity to leaf protein concentrates already proposed in the past. This would be especially beneficial for developing countries. For this aim, protein quality plays a crucial role: separating only the noble fraction of protein in biomass and preserving its nutritional value, while simultaneously obtaining good yields and limiting drawbacks on other steps of the production chain is particularly challenging from a technical viewpoint. In this review, we compare the possible extraction of protein from dry biomass with the more commonly studied situation in which freshly harvested material is used, with special focus on dietary implications.

Land availability for biofuel production

Marginal agricultural land is estimated for biofuel production in Africa, China, Europe, India, South America, and the continental United States, which have major agricultural production capacities. These countries/regions can have 320-702 million hectares of land available if only abandoned and degraded cropland and mixed crop and vegetation land, which are usually of low quality, are accounted. If grassland, savanna, and shrubland with marginal productivity are considered for planting low-input high-diversity (LIHD) mixtures of native perennials as energy crops, the total land availability can increase from 1107-1411 million hectares, depending on if the pasture land is discounted. Planting the second generation of biofuel feedstocks on abandoned and degraded cropland and LIHD perennials on grassland with marginal productivity may fulfill 26-55% of the current world liquid fuel consumption, without affecting the use of land with regular productivity for conventional crops and without affecting the current pasture land. Under the various land use scenarios, Africa may have more than one-third, and Africa and Brazil, together, may have more than half of the total land available for biofuel production. These estimations are based on physical conditions such as soil productivity, land slope, and climate.

Policy implications of uncertainty in modeled life-cycle greenhouse gas emissions of biofuels

Biofuels have received legislative support recently in California's Low-Carbon Fuel Standard and the Federal Energy Independence and Security Act. Both present new fuel types, but neither provides methodological guidelines for dealing with the inherent uncertainty in evaluating their potential life-cycle greenhouse gas emissions. Emissions reductions are based on point estimates only. This work demonstrates the use of Monte Carlo simulation to estimate life-cycle emissions distributions from ethanol and butanol from corn or switchgrass. Life-cycle emissions distributions for each feedstock and fuel pairing modeled span an order of magnitude or more. Using a streamlined life-cycle assessment, corn ethanol emissions range from 50 to 250 g CO(2)e/MJ, for example, and each feedstock-fuel pathway studied shows some probability of greater emissions than a distribution for gasoline. Potential GHG emissions reductions from displacing fossil fuels with biofuels are difficult to forecast given this high degree of uncertainty in life-cycle emissions. This uncertainty is driven by the importance and uncertainty of indirect land use change emissions. Incorporating uncertainty in the decision making process can illuminate the risks of policy failure (e.g., increased emissions), and a calculated risk of failure due to uncertainty can be used to inform more appropriate reduction targets in future biofuel policies.

Nitrogen dioxide and household fuel use in the Pakistan

More than half the world's population use biomass fuels as a household energy source and, hence, face significant exposure to a number of air pollutants. In Pakistan about 90% of rural households and 22% of urban households use biomass fuels. In order to assess the levels of NO(2) in the residential micro-environment, two sampling campaigns were carried out at different times of the year (summer and winter) at an urban and two rural sites during 2005 and 2007. Rural site I used biomass fuels while natural gas was utilized at rural site II and the urban site. In winter NO(2) concentrations at all three sites were higher in the kitchens than living rooms and outdoors. ANOVA showed that, although, there was a significant difference among NO(2) concentrations in the kitchens, living rooms and courtyards, at all the three sites, there was no significant different between kitchens using biomass fuels and natural gas. During the summer NO(2) levels fell sharply at both rural sites (from 256 μg/m(3) and 242 μg/m(3) to 51 μg/m(3) and 81 μg/m(3)). However at the urban site the mean levels were slightly higher in summer (234 μg/m(3)) than in winter (218 μg/m(3)). The considerable seasonal variation at the rural sites was due to a shift of indoor kitchens to open outdoor kitchens at rural site I and more ventilation at rural site II during summer. There was no significant difference between kitchens using biomass (site I) or natural gas (site II), however the kitchens at rural site II and urban site showed a significant difference. Overall fuel selection showed no significant effect on NO(2) levels. However the NO(2) concentrations may pose a significant threat to the health of people, especially women and children.

Land-use and alternative bioenergy pathways for waste biomass

Rapid escalation in biofuels consumption may lead to a trade regime that favors exports of food-based biofuels from tropical developing countries to developed countries. There is growing interest in mitigating the land-use impacts of these potential biofuels exports by converting biorefinery waste streams into cellulosic ethanol, potentially reducing the amount of land needed to meet production goals. This increased land-use efficiency for ethanol production may lower the land-use greenhouse gas emissions of ethanol but would come at the expense of converting the wastes into bioelectricity which may offset fossil fuel-based electricity and could provide a vital source of domestic electricity in developing countries. Here we compare these alternative uses of wastes with respect to environmental and energy security outcomes considering a range of electricity production efficiencies, ethanol yields, land-use scenarios, and energy offset assumptions. For a given amount of waste biomass, we found that using bioelectricity production to offset natural gas achieves 58% greater greenhouse gas reductions than using cellulosic ethanol to offset gasoline but similar emissions when cellulosic ethanol is used to offset the need for more sugar cane ethanol. If bioelectricity offsets low-carbon energy sources such as nuclear power then the liquid fuels pathway is preferred. Exports of cellulosic ethanol may have a small impact on the energy security of importing nations while bioelectricity production may have relatively large impacts on the energy security in developing countries.

Nitrogen fertiliser production based on biogas - energy input, environmental impact and land use

The aim of the present paper was to investigate the land use, environmental impact and fossil energy use when using biogas instead of natural gas in the production of nitrogen fertilisers. The biogas was assumed to be produced from anaerobic digestion of ley grass and maize. The calculations showed that 1 ha of agricultural land in south-west Sweden can produce 1.7 metric ton of nitrogen in the form of ammonium nitrate per year from ley grass, or 3.6 ton from maize. The impact on global warming, from cradle to gate, was calculated to be lower when producing nitrogen fertiliser from biomass compared with natural gas. Eutrophication and acidification potential was higher in the biomass scenarios. The greatest advantage of the biomass systems however lies in the potential to reduce agriculture's dependency on fossil fuels. In the biomass scenarios, only 2-4 MJ of primary fossil energy was required, while 35 MJ/kgN was required when utilising natural gas.

Fuel-mix, fuel efficiency, and transport demand affect prospects for biofuels in northern Europe

Rising greenhouse gas (GHG) emissions in the road transport sector represents a difficult mitigation challenge due to a multitude of intricate factors, namely the dependency on liquid energy carriers and infrastructure lock-in. For this reason, low-carbon renewable energy carriers, particularly second generation biofuels, are often seen as a prominent candidate for realizing reduced emissions and lowered oil dependency over the medium- and long-term horizons. However, the overarching question is whether advanced biofuels can be an environmentally effective mitigation strategy in the face of increasing consumption and resource constraints. Here we develop both biofuel production and road transport consumption scenarios for northern Europe-a region with a vast surplus of forest bioenergy resources-to assess the potential role that forest-based biofuels may play over the medium- and long-term time horizons using an environmentally extended, multiregion input-output model. Through scenarios, we explore how evolving vehicle technologies and consumption patterns will affect the mitigation opportunities afforded by any future supply of forest biofuels. We find that in a scenario involving ambitious biofuel targets, the size of the GHG mitigation wedge attributed to the market supply of biofuels is severely reduced under business-as-usual growth in consumption in the road transport sector. Our results indicate that climate policies targeting the road transport sector which give high emphases to reducing demand (volume), accelerating the deployment of more fuel-efficient vehicles, and promoting altered consumption patterns (structure) can be significantly more effective than those with single emphasis on expanded biofuel supply.

Unlocking the resource potential of organic waste: a South African perspective

In many countries, especially on the Asian continent, waste is considered a valuable renewable energy resource. At present 40% of waste generated in South Africa comprises organic material which, when digested supplies biogas. The biogas produced can either be used as it is, or it can be delivered as electricity using gas turbines. The electricity generated can be added to the national grid. In light of the increased demand for energy in South Africa, alternative sources of energy are required. When taking the examples of the Asian countries, where anaerobic digestion of waste is applied in rural areas to produce energy for cooking and lighting, it can be hypothesized that this technology could be transferred especially to the rural areas of South Africa. Small-scale anaerobic digestion is presently being implemented by a private company in Ivory Park, South Africa, illustrating that anaerobic digestion in South Africa may be a means of unlocking the energy potential of organic waste. This paper evaluates the requirements for an enabling governance environment to unlock the full potential of organic waste as renewable energy resource.