Growing Energy Crops Research Articles

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.

Life cycle assessment of different bioenergy production systems including perennial and annual crops

Energy crops are expected to greatly develop in a very short-term bringing to significant social and environmental benefits. Nevertheless, a significant number of studies report from very positive to negative environmental implications from growing and processing energy crops, thus great uncertainty still remains on this argument. The present study focused on the cradle-to-grave impact assessments of alternative scenarios including annual and perennial energy crops for electricity/heat or first and second generation transport fuels, giving special emphasis to agricultural practices which are frequently surprisingly neglected in Life Cycle Assessment studies despite a not secondary relevance on final outcomes. The results show that cradle-to-farm gate impacts, i.e. including the upstream processes, may account for up to 95% of total impacts, with dominant effects on marine water ecotoxicity. Therefore, by increasing the sustainability of crop management through minimizing agronomic inputs, or with a complementary use of crop resides, can be expected to significantly improve the overall sustainability of bioenergy chains, as well as the competitiveness against fossil counterparts. Once again, perennial crops resulted in substantially higher environmental benefits than annual crops. It is shown that significant amount of emitted CO2 can be avoided through converting arable lands into perennial grasslands. Besides, due to lack of certain data, soil carbon storage was not included in the calculations, while N2O emission was considered as omitted variable bias (1% of N-fertilization). Therefore, especially for perennial grasses, CO2 savings were reasonably higher that those estimated in the present study. For first generation biodiesel, sunflower showed a lower energy-based impacts than rapeseed, while wheat should be preferred over maize for first generation bioethanol given its lower land-based impacts. For second generation biofuels and thermo-chemical energy, switchgrass provided the highest environmental benefits. With regard to bioenergy systems, first generation biodiesel was less impacting than first generation bioethanol; bioelectricity was less impacting than first generation biofuels and second generation bioethanol by thermo-chemical hydrolysis, but highly impacting than Biomass-to-Liquid biodiesel and second generation bioethanol through enzymatic hydrolysis.

Behavior of Heavy Metals in Steam Fluidized Bed Gasification of Contaminated Biomass

Heavy metal phytoextraction by growing energy crops such as flax could be a promising approach for remediation of brownfields with energy benefits. The present paper deals with flax (40 wt %) and hardwood (60 wt %) cogasification with particular focus on the distribution of heavy metals to both solid and gaseous gasification products. The blended fuel was gasified by steam in a fluidized bed gasifier at about 850 °C and steam to biomass ratio of 1.01 kg kg–1. Concentrations of selected heavy metals (Cd, Cu, Ni, Pb, and Zn) were determined in bed ash, cyclone ash, and in downstream producer gas. From the analysis, it follows that under the given experimental conditions the subsequent order of heavy metals volatility can be found: Cd (mostly in producer gas) > Pb > Zn > Cu > Ni. Heavy metals concentrations in the producer gas (nitrogen free, dry gas) were determined in the range of 0.37–4.2 mg m–3.

Are participators in the land retirement program likely to grow energy crops?

Due to the increasing demand for energy, interaction between land use and energy-related crop production has recently become a subject of great attention. Although a considerable body of literature has examined the extent to which the increased demand for biofuel may impact agricultural land use, little evidence has been provided as result of farmer level surveys. Using a unique and national representative survey of all eligible farmers in the land retirement program in Taiwan in 2005, this study examines the interaction between the land retirement program and energy crop production. Results points to a positive association between the enrolled land area and the likelihood of energy crop production. However, the magnitude of the effects is not substantial. This may reflect the fact that the current subsidy to farmers to grow energy crops on their fallow land is not high enough to provide strong incentive.

Morphology and reactivity characteristics of char biomass particles

In this work, 10 different biomasses were selected which included directly grown energy crops, industrial waste material and different wood types. Each biomass was sieved into six different size fractions and pyrolysed in a fixed bed furnace preheated to 1000°C to produce a char residue. Intrinsic reactivity during burnout was measured using a non-isothermal thermogravimetric method. Scanning electron microscopy and oil immersion microscopy were used to characterise the morphology of the products. Char morphology was summarised in terms of degree of deformation, internal particle structure and wall thickness. Intrinsic reactivity corresponded directly with these morphology groupings showing a significant correlation between char morphotypes, char reactivity and the initial biomass material.

Environmental impact assessment of energy crops cultivation in Europe

AbstractThe production of energy crops must be studied and evaluated in terms of environmental impact, in order to integrate them into a sustainable agricultural development. As bioenergy carriers they offer ecological advantages over fossil fuels by contributing to the reduction of greenhouse gases and acidifying emissions. However, there could be ecological shortcomings related to the intensity of agricultural production. There is a risk of polluting water and air, losing soil quality, enhancing erosion, and reducing biodiversity. In the scope of the project Future Crops for Food, Feed, Fiber and Fuel (4F Crops), supported by the European Union, an environmental impact assessment study was developed and applied to the production of potential energy crops in Europe. The following variables were selected as categories: use of water and mineral resources, soil quality and erosion, emission of minerals and pesticides to soil and water, waste generation and utilization, landscape, and biodiversity. In addition, a normalization and weighting procedure was applied, which attempts to aggregate environmental impacts. Results suggest that growing energy crops does not inflict higher impact on the environment compared to potato and wheat farming (regarding the studied categories). Although the different indicators did not yield a common pattern, overall results suggest that woody and lignocellulosic crops have an advantage over annual crop systems, namely regarding erodibility and biodiversity. Some crop management options, such as pesticides and fertilizers inputs, can influence the outcomes. However, site‐specific factors should be accurately assessed to evaluate the adequacy between crop and location. Environmental hotspots in the systems are detected and options for improvement are presented. © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd

Farmers’ attitudes about growing energy crops: A choice experiment approach

The present study adapts the choice experiment (CE) method for an analysis of how Swedish farmers assess the relative value of the characteristics associated with growing energy crops. An additional goal was to find out the willingness of farmers to grow energy crops relative to different levels of income and subsidies based on predictions of acreage of energy crop cultivation. In the first CE, farmers were presented with two energy crops and six of their characteristics and asked to choose the alternative he or she preferred most. In the second CE the respondent was asked how many hectares for each crop he/she would be willing to grow on arable land with an energy crop subsidy and how many hectares he/she would be willing to grow on set-aside land without an energy crop subsidy. The results suggest that among the included characteristics in the first experiment, the visual impact on the landscape and the rotation period of the energy crop appear to have a significant impact on the utility derived from growing an energy crop. An increased utility of a crop increases the arable land used for that crop and the income associated with it. Farm characteristics such as leased land, rented land, share of set-aside land, and type of farming had an insignificant effect on the willingness to grow energy crops. Significant characteristics were age of the farmer, size of the farm, and the geographical area.

Life cycle assessment of biofuels from Jatropha curcas in West Africa: a field study

AbstractIn recent years, liquid biofuels for transport have benefited from significant political support due to their potential role in curbing climate change and reducing our dependence on fossil fuels. They may also participate to rural development by providing new markets for agricultural production. However, the growth of energy crops has raised concerns due to their high consumption of conventional fuels, fertilizers and pesticides, their impacts on ecosystems and their competition for arable land with food crops. Low‐input species such as Jatropha curcas, a perennial, inedible crop well adapted to semiarid regions, has received much interest as a new alternative for biofuel production, minimizing adverse effects on the environment and food supply. Here, we used life‐cycle assessment to quantify the benefits of J. curcas biofuel production in West Africa in terms of greenhouse gas emissions and fossil energy use, compared with fossil diesel fuel and other biofuels. Biodiesel from J. curcas has a much higher performance than current biofuels, relative to oil‐derived diesel fuels. Under West Africa conditions, J. curcas biodiesel allows a 72% saving in greenhouse gas emissions compared with conventional diesel fuel, and its energy yield (the ratio of biodiesel energy output to fossil energy input) is 4.7. J. curcas production studied is eco‐compatible for the impacts under consideration and fits into the context of sustainable development.

Cadmium tolerance and accumulation in eight potential energy crops

The production of energy crops that can be used for biodiesel production is a sustainable approach for the removal of metal pollutants by phytoremediation. This study investigated the cadmium (Cd) accumulation and tolerance of eight potential energy crops. After growth for 28 days in substrates containing 0, 50, 100 or 200 mg Cd·kg − 1 , seedlings were evaluated for growth parameters, chlorophyll content, chlorophyll fluorescence parameters and Cd accumulation. All eight crops were moderately tolerant to Cd toxicity, with four [i.e., hemp ( Cannabis sativa), flax ( Linum usitatissimum), castor ( Ricinus communis) and peanut ( Arachis hypogaea)] being more tolerant than the others. Three of these crops (hemp, flax and peanut) had higher Cd accumulation capacities. The roots of peanut and hemp had high bioconcentration factors (BCF > 1000), while flax shoots accumulated a higher concentration of Cd (> 100 mg/kg). These results demonstrate that it is possible to grow energy crops on Cd-contaminated soil. Hemp, flax and peanut are excellent candidates for phytoremediation.

Establishing perennial grass energy crops in the UK: A review of current propagation options for Miscanthus

A key UK government strategy is to expand the supply of home grown biomass and facilitate the development and competitiveness of a sustainable supply chain, while promoting low-carbon technology. Analysis of the potential supply chain suggests that this can, in part, be achieved by growing energy crops. Meeting expectations is, however, reliant on developing an economically viable biomass sector which incorporates efficient, sustainable and regional supply chains to increase biomass use. This review aims to present the knowledge by which plant propagules, for the biomass supply chain, can be produced at minimum cost. It specifically addresses the potential of biomass production from the perennial grass Miscanthus. This review is part of a project to identify the causes for the apparent limitations in the establishment of UK perennial energy crops. The work reported here focuses on the knowledge available regarding the potential routes by which Miscanthus material could be mass produced. The review concludes that high density plantings must be established to maximise yields. Vegetative clonal plant propagation is required to deliver uniform crops of selected germplasm. Commercial seed production in the UK is not possible and potentially undesirable for selected germplasm. Rhizome production and division is slow, but currently does not limit increases in production because the UK industry uptake is currently small. Uptake of new germplasm will be dependent on the use of rapid and cost effective plant propagation systems, particularly vegetative systems. The germplasm collection established provides an opportunity for genotypes to be propagated by a range of techniques to determine ease of propagation in terms of cost and multiplication rates. At present the establishment rate of Miscanthus is slow and this appears limited by economics; evidence suggests that the cost of plant propagules is one factor that constrains widespread planting. New techniques are required that simultaneously reduce unit costs of propagules and increase the speed of their availability to aid this developing industry.

County-Level Analysis of Crop Residues Availability for Fuel Ethanol Production in Ohio

Increasing demand of corn for ethanol production places significant pressure on the availability of corn for food and animal feed. Other feedstocks such as crop residues, energy crops, wood waste, and forest residues are being considered for cellulosic ethanol production in the near future. The availability of crop residues for cellulosic ethanol production in Ohio was analyzed in this study. Results showed that two clusters of counties, each with a collection radius of less than 80 km (50 miles), had the capability to provide feedstock for two ethanol plants with feedstock demand of 5,000 dry tons per day each. These two plants would be located in the northwestern region of Ohio to produce a total of 927 million L (245 million gal) of ethanol per year. Other counties that have low biomass availability could grow energy crops such as switchgrass and provide mixed feedstocks for a cellulosic ethanol plant.

Bioenergy production: are the objects realistic??

Currently we do not have the possibility to define our energy reserves, since we do not know the magnitude of extant material resources. The known petroleum (crude) supply will be sufficient for about 100 years at the longest, and according to the latest estimates in 2008 we will reach and even exceed the maximum level of oil extraction, and after this it is going to decrease.Hungary has good givens to go upon the way of sustainable energy economy according to experts, however a coherent government policy that lasts for not just one period is essential, and a sound economic- and agricultural policy is needed as well. According to the FVM’s under-secretary in Hungary more than 1 million hectares can be disposable for energy crop production. This would mean that 20 percent of the fields would be taken away from food production and on these fields energy crops would be grown. But we also have to take into consideration that the increase in energy plant production could happen at the expense of food production. If we would like to ensure the food for Hungary’s population from national sources we have to make calculations in determining energy need. In my research I set out the objective to determine the level of that specific turnover and marginal cost which supports the profitability of grain cultivation. With these indicators it is possible to analyze the economy and competitiveness of growing energy crops in the region of the North Plain. The alternatives of using cereals and rational land use should be also considered. A developing bio-fuel program can be a solution for the deduction of excess grain that is typical in Hungary for several years in the cereals sector. The pressure on the national market caused by excess grain can be ceased or moderated, and therefore the storage problems would decrease as well.

Quantification of employment from biomass power plants

One of the attractions of developing bioenergy systems is the potential for job creation and economic development of rural economies. This paper seeks to quantify the expected employment impacts of individual bioenergy developments. The assessment includes agricultural labour growing energy crops for SRC and miscanthus options, transport and processing of the feedstock, staffing at the thermal conversion plant, employment within the equipment supply chain and the induced employment impact. Power only bioenergy systems are shown to typically create 1.27 man years of employment per GWh electricity produced, regardless of technology or scale of implementation. CHP systems can create more than 2 man years of employment per GWh electricity produced, although most of this enhanced economic impact can be attributed to the fact that a comparative analysis per unit of electricity produced ignores the heat output of the system.

Organisation of Petroleum Importing Countries Must Support Ethanol as a Fuel through Research and Vegetarianism

The author had earlier proposed formation of Organisation of Petroleum Importing Countries(OPIC) to combat OPEC and control oil prices. Ethanol is being projected as a solution to all oil related problems. Many argue that ethanol can replace all transportation related fuel requirements. There is some element of truth in this. However agricultural productivity would need to increase 5-10 times for this to happen. It is argued that this will happen in next 20-30 years. Hence ethanol as replacement for oil is doubtful. One way to enable ethanol is to free land by shifting to vegetarianism, so that precious land used to feed livestock can be used to grow energy crops. OPIC needs to support research to increase productivity of energy crops and a strongly advocate vegetarianism so that land is made available for growing energy crops.

A Life Cycle Analysis of Hydrogen Production for Buildings and Vehicles

AbstractAspects of the hydrogen economy are addressed by quantifying impacts and costs associated with a hydrogen-based energy infrastructure. It is recommended that hydrogen (H2) is produced from Solar Thermochemical (STC) Cycles and Wind Electrolysis, with the possible use of Steam Methane Reforming (SMR) to aid in the creation of a hydrogen infrastructure. Despite high impact assessment results from SimaPro, the external costs associated with Biomass gasification are shown to be comparable with those for Wind Electrolysis. Thus, biomass-produced hydrogen could also be a viable alternative, especially in areas ideally suited to the growth of energy crops. Finally, the most influential life cycle stages are the Construction of the FCV and Hydrogen Production (except for the environmentally benign wind electrolysis). For the Wind/Electrolysis case, the majority of impacts come from plant construction.

Soil Carbon Sequestration Impacts on Global Climate Change and Food Security

The carbon sink capacity of the world's agricultural and degraded soils is 50 to 66% of the historic carbon loss of 42 to 78 gigatons of carbon. The rate of soil organic carbon sequestration with adoption of recommended technologies depends on soil texture and structure, rainfall, temperature, farming system, and soil management. Strategies to increase the soil carbon pool include soil restoration and woodland regeneration, no-till farming, cover crops, nutrient management, manuring and sludge application, improved grazing, water conservation and harvesting, efficient irrigation, agroforestry practices, and growing energy crops on spare lands. An increase of 1 ton of soil carbon pool of degraded cropland soils may increase crop yield by 20 to 40 kilograms per hectare (kg/ha) for wheat, 10 to 20 kg/ha for maize, and 0.5 to 1 kg/ha for cowpeas. As well as enhancing food security, carbon sequestration has the potential to offset fossil fuel emissions by 0.4 to 1.2 gigatons of carbon per year, or 5 to 15% of the global fossil-fuel emissions.

An economic analysis of using crop residues for energy in China

This study examines the economics of using crop residues to replace coal burning for energy in China in order to mitigate carbon emissions. About 60 per cent of the available crop residues are now used by rural households in China to replace coal so that the residues are already making a major contribution to controlling China's potential carbon emissions. Using the crop residues more efficiently in village or centralized facilities, shifting to crops with more residues, or growing energy crops can all further reduce carbon emissions. However, accounting for the costs of collecting, transporting, drying and storing crop residues and the foregone crop revenue, the study estimates that the marginal cost to remove more carbon emissions with crop residues will be high.

Perspectives on biomass energy tree plantations and changes in habitat for biological organisms

Large-scale deployment of biomass energy plantations has the potential to affect biodiversity (positively or negatively) through altered habitat quality, pesticide use, soil erosion, water quality or other factors. In this paper, effects on biodiversity through habitat change are discussed. Effects will depend in part on the land-use type that the plantation replaces. Studies on hybrid poplar plantations in the north-central United States suggest that replacement of agricultural croplands with energy tree plantations would have little if any negative effect on overall avian and mammalian abundance and diversity. Most birds and mammals occupying plantations are widespread, regionally abundant species with ample habitat. Within-plantation heterogeneity, an important determinant of animal use, could be incorporated into plantation design to enhance biodiversity. However, it is not clear whether this approach is compatible with cultural techniques used to grow energy crops. Varying the size or shape of plantations may be a strategy for manipulating animal use of plantations. In addition to habitat replacement per se, effects on biological organisms could occur through altered landscape-level patterns. These include 1) effects on organisms in adjacent habitats (via competition, predation, or nest parasitism) resulting from changes in abundance of some species on plantations; 2) possible fragmentation of open or shrubby habitats; 3) altered interactions among local populations as a result of the unique boundaries created by plantation establishment. Further research is needed on these and other issues to provide a basis for guiding the development of biomass energy plantations in an environmentally sound manner.

Biological systems for uptake of carbon dioxide

Photosynthetic processes provide environmentally sustainable mechanisms for removal of CO 2. Biological systems produce biomass which can act as a reservoir of carbon or as a direct substitute for fossil fuels. Three alternative strategies are examined and compared: Sequestration of carbon by reforestation; growing energy crops to offset the use of fossil fuels; and the use of photobiology and photobiochemistry. This report concludes that it is more efficient to use land to grow biomass for energy, offsetting fossil fuel use, than to simply sequester CO 2 in forests. Biological systems are among the most promising alternatives for reducing atmospheric CO 2 levels in combination with improved energy efficiencies. A comparative study is shown for 16 European countries, the USA and Japan.

Energy from agriculture—The most economic method of large scale solar energy conversion

The economics of terrestrial growth of vegetation for its energy content is far more favorable than other more technically sophisticated methods of large-scale solar energy conversion—mirrors, photovoltaics, etc. This paper summarizes our view of what might be attainable in biomass production, hoping, thereby, to stimulate interest in the concept. The types of vegetation best suited for an intensive energy plantation, as well as vegetation selection criteria, will be discussed. The type and availability of land for growing energy crops on a conceptual terrestrial plantation, as well as the logistics and economics, are discussed. An energy budget for plant-material production and harvesting for the conceptual plantation is developed. A technoeconomic comparison of firing the crops directly for electric power generation with conversion to clean fuel gas (methane or low-BTu gas) either at the farm site or at selected markets is made.