Global bioenergy potentials from agricultural land in 2050: Sensitivity to climate change, diets and yields

There is a growing recognition that the interrelations between agriculture, food, bioenergy, and climate change have to be better understood in order to derive more realistic estimates of future bioenergy potentials. This article estimates global bioenergy potentials in the year 2050, following a "food first" approach. It presents integrated food, livestock, agriculture, and bioenergy scenarios for the year 2050 based on a consistent representation of FAO projections of future agricultural development in a global biomass balance model. The model discerns 11 regions, 10 crop aggregates, 2 livestock aggregates, and 10 food aggregates. It incorporates detailed accounts of land use, global net primary production (NPP) and its human appropriation as well as socioeconomic biomass flow balances for the year 2000 that are modified according to a set of scenario assumptions to derive the biomass potential for 2050. We calculate the amount of biomass required to feed humans and livestock, considering losses between biomass supply and provision of final products. Based on this biomass balance as well as on global land-use data, we evaluate the potential to grow bioenergy crops and estimate the residue potentials from cropland (forestry is outside the scope of this study). We assess the sensitivity of the biomass potential to assumptions on diets, agricultural yields, cropland expansion and climate change. We use the dynamic global vegetation model LPJmL to evaluate possible impacts of changes in temperature, precipitation, and elevated CO(2) on agricultural yields. We find that the gross (primary) bioenergy potential ranges from 64 to 161?EJ?y(-1), depending on climate impact, yields and diet, while the dependency on cropland expansion is weak. We conclude that food requirements for a growing world population, in particular feed required for livestock, strongly influence bioenergy potentials, and that integrated approaches are needed to optimize food and bioenergy supply.     

Utilization of solar–hydrogen energy in the UAE to maintain its share in the world energy market for the 21st century

A preliminary solar–hydrogen energy system for the United Arab Emirates (UAE) has been proposed to bridge the gap between oil and natural gas demand and supply in the 21st century, and to meet the country's share in the energy market. In our study, we quantitatively consider the benefits of such an energy system on the overall energy situation in the UAE. The variables considered include population, energy demand, energy production, income from sales of fossil fuels and hydrogen energy, photovoltaics area, and total land area required for installing such a system. Our study indicated that the UAE would fail to meet its share in the oil market demand by the year 2015, while in the case of natural gas it will be by the year 2042. In order to maintain its share in the world energy market, we propose that hydrogen be gradually introduced to meet the demand. The income generated by hydrogen energy would account for 90% of the nation's total income if such a system were utilized. Our analysis could be greatly influenced by several factors such as future government projects related to fossil fuel production and increasing diversification in the economy of the country.     

Energy resource demands of food production

Historically food has been produced by using solar energy, natural fertilizer and manual labor. However, as populations have increased food products had to be increased proportionately so it has become necessary to use industrial equipment instead of manual labor and artificial fertilizer in place of manure. Thus, in modern agriculture, fuel energy has largely replaced animate energy. This has made the food delivery system one of the most energy intensive industries. It is apparent that this demand for energy will increase because the world population is expected to double by the end of the century and hence will require rapid increases in food production.This paper sets forth the energy supply and demand situation as it concerns food production. Also, considered are externalities such as climate and population. Finally, an agenda for future research in the energy-food sector is presented.     

Electricty generation from woody biomass fuels compared with other renewable energy options

The future New Zealand biomass resource from exotic plantation forest arisings could supply 970 GWh/year by the year 2002. Associated wood processing residues could supply 280 GWh/year. Purpose grown fuelwood plantations could supply 2060 GWh/year with potential to rise to 10,000 GWh/year by 2012.Currently the annual electricity demand is around 30,000 GWh 70% of which is generated by hydro power. Natural gas, a resource with estimated reserves of only approximately 14 years currently supplies 25% of generating capacity. This paper describes how part replacement of gas by biomass could be a feasible proposition for the future.Life cycle cost analyses showed electricity could be generated from arisings for (US)4.8–6 c/kWh; from residues for (US)2.4–4.8 c/kWh; and from plantations for (US)4.8–7.2 c/kWh. For comparison the current retail electricity price is around (US)4–5.5 c/kWh and estimates for wind power generation range from (US)5–10 c/kWh. Future hydropower schemes will generate power between (US)4–9 c/kWh depending on site suitability.     

The impact of a growing bioethanol industry on food production in Brazil

The Brazilian production of major food commodities increased fivefold between 1961 and 2008. In the same time, the area cropped with sugar cane increased with high growth rates, currently covering 3% of the area dedicated to agricultural production in Brazil. In order to assess a possible competition between biofuel and food production, the development of agricultural productivity and area expansion in the past was analysed. Furthermore, the future situation of land resources for agricultural production was illustrated. The findings of this study indicated that area resources of more than 20 million hectare would be available for agricultural production in the upcoming years. A current constraint of food production throughout land dedicated to biofuels was not found. Three scenarios were investigated, simulating possibilities of future changes in Brazilian agriculture. The results demonstrated that primary food production could be enhanced by 1.5 times while bioethanol production was enhanced simultaneously by 1.8 times over the years 2007/2008 and 2020. The generated bioethanol volumes would meet 38% of the total energy demand in Brazilian transport sector, applied to the year 2007. The second scenario evaluated an agricultural development with a higher focus on biofuels. It was projected that the production of bioethanol could be increased by 3.0 times to 76.7 million m³ of bioethanol, while increasing at the same time primary food production with the factor 1.4 aligned to the projected population growth. This bioethanol volume represents 67% of the total energy demand in Brazilian transport sector in the year 2007. A third scenario demonstrated that food production could be increased even with no area expansion higher than the projected population growth, due to a continued increase of productivity. At the same time bioethanol production would rise to 32 million m³ without occupying more area.     

Management of natural gas resources and search for alternative renewable energy resources: A case study of Pakistan

Energy usage in Pakistan has increased rapidly in past few years due to increase in economic growth. Inadequate and inconsistent supply of energy has created pressure on the industrial and commercial sectors of Pakistan and has also affected environment. Demand has already exceeded supply and load shedding has become common phenomenon. Due to excessive consumption of energy resources it would become difficult to meet future energy demands. This necessitates proper management of existing and exploration of new energy resources. Energy resource management is highly dependent on the supply and demand pattern. This paper highlights the future demands, production and supply of energy produced from natural gas based on economic and environmental constraints in Pakistan with special emphasis on management of natural gas. An attempt has been made by proposing a suitable course of action to meet the rising gas demand. A mechanism has been proposed to evaluate Pakistan's future gas demand through quantitative analysis of base, worst and best/chosen option. CO₂ emission for all cases has also been evaluated. The potential, constraints and possible solutions to develop alternative renewable energy resources in the country have also been discussed. This work will be fruitful for the decision makers responsible for energy planning of the country. This work is not only helpful for Pakistan but is equally important to other developing countries to manage their energy resources.     

Energy crops for biofuel production: Analysis of the potential in Tuscany

The possibility of using biomass as a source of energy in reducing green-house gas emissions is a matter of great interest. In particular, biomasse from agriculture represent one of the largest and most diversified sources to be exploited and more specifically, ethanol and diesel deriving from biomass have the potential to be a sustainable means of replacing fossil fuels for transportation. Nevertheless, the cultivation of dedicated energy crops does meet with some criticism (competitiveness with food crop cultivation, water requirements, use of fertilizers, etc.) and the economical and environmental advantages of this activity depend on accurate evaluations of the total efficiency of the production system. This paper illustrates the production potential of two energy crops, sunflower (Helianthus annuus) and maize (Zea mais), cultivated with different water and fertilization supplies in the region of Tuscany, in central Italy. A 50-year climatic series of 19 weather stations scattered around Tuscany was used to run the crop model CropSyst for obtaining crop biomass predictions. The effect of climate change and variability was analyzed and the potential production of bioenergy was investigated in terms of pure vegetable oil (sunflower) and bioethanol (maize). The results demonstrated that despite a reduction in crop yields and an increase of their variability due to climate change, the cultivation of maize in the regional set-aside areas would be capable of supplying approximately 50% of the energy requirements in terms of biofuel for transportation obtained, while the cultivation of a sunflower crops would supply less than 10%.     

Biomass for energy, food and materials in an industrial society of 10 billion people

In this paper we analyse the requirements of bioproductive land in a future industrial society of 10 billion people, with an average per capita economic standard comparable to that of the industrialized countries of today. Despite significantly more efficient technology, lowering demand for both energy and material per service delivered, requirement for food and material alone will call for a heavily increased demand for bioproductive land for use in agriculture and forestry. Large areas of short rotation energy plantations may be biophysically possible, but will clearly compete for available bioproductive land with agriculture and silviculture, as well as with preservation of the world's biodiversity. Therefore, the notion that there exists large areas of surplus or degraded land, which, without coming in conflict with food production and preservation of biodiversity, can be used for large energy plantations has not fully taken into account possible increased demand for bioproductive land from global industrialization and the raising of the global average economic standard.     

上海天然气市场和液化天然气的现状与展望

2009年,上海能源供应体系自从引入液化天然气以来,进口液化天然气对全市天然气供应总量和来源多元化做出了重要贡献。2013年,液化天然气消费在全市天然气消费总量中占比达50%,在天然气供应体系中发挥了越来越重要的作用。近年来,上海天然气市场发生了深刻变化,天然气需求增长放缓,与2013年之前十多年的两位数增长形成了鲜明对比。为了更好地理解市场的基本面,首先回顾了上海天然气消费的历史趋势,随后分析了影响需求增长的驱动因素和约束条件,以判断未来天然气需求的趋势和液化天然气在市场中扮演的角色,认为天然气需求增长的潜力主要在民用及商业领域。结合分析可能的供应选择,其结论是未来液化天然气将继续作为上海天然气供应体系的主力气源,同时提供市场急需的灵活性以保障高峰时段的用气需求。     

Potential of solar electricity generation in the European Union member states and candidate countries

During the years 2001–2005, a European solar radiation database was developed using a solar radiation model and climatic data integrated within the Photovoltaic Geographic Information System (PVGIS). The database, with a resolution of 1 km × 1 km, consists of monthly and yearly averages of global irradiation and related climatic parameters, representing the period 1981–1990. The database has been used to analyse regional and national differences of solar energy resource and to assess the photovoltaic (PV) potential in the 25 European Union member states and 5 candidate countries. The calculation of electricity generation potential by contemporary PV technology is a basic step in analysing scenarios for the future energy supply and for a rational implementation of legal and financial frameworks to support the developing industrial production of PV. Three aspects are explored within this paper: (1) the expected average annual electricity generation of a ‘standard’ 1 kW_p grid-connected PV system; (2) the theoretical potential of PV electricity generation; (3) determination of required installed capacity for each country to supply 1% of the national electricity consumption from PV. The analysis shows that PV can already provide a significant contribution to a mixed renewable energy portfolio in the present and future European Union.     

Growth in global energy demand and contribution of alternative supply systems

Growth in global energy demand since the end of World War II has been nearly constant at a rate of 5.3% each year. When energy demand is projected into the future, the basic question is how long such an exponentially growing global energy use can continue, and a more accurate analysis than projecting exponential growth indefinitely into the future is certainly desirable.In this analysis, nine political/geographical segments are used and it is shown that the less developed countries will grow much more rapidly than the industrialized countries. Analyses of individual nations- or at least small sub-divisions of the nine segments—based on factors such as population growth, availability of resources, capability of food production, potential for formation of capital, and prospects for political stability are necessary in order to achieve reasonable accuracy in projections.Such concepts of growth suggest very strongly that fifty years from now the global energy demand will be approximately 31 TW, with over half the total coming from the developing world. This will present unusual opportunities for employing alternative energy supply systems. In rapidly growing situations, market penetration of new technologies is easier, but, in any event, the magnitude of the effort required is enormous if alternative supply systems are to make major contributions to the total.As a target, the 17 TW demand in AD2025 from the developing world might be met by the following supply system: TW Solar Heating (water and air) 1.5 Biomass (firewood, charcoal, alcohol) 3.5 Wind 0.8 Hydro and Geothermal 2.2 Fission 0.5 Fossil fuels (oil, gas, coal) 8.5 Total 17.0To place these in perspective and to indicate the size of the task involved, note that the total world energy demand in 1975 was only 7.3 TW. The target calls for alternative supply systems in the developing world alone to exceed the present world total within 50 yr. Contributions from hydro and geothermal sources (in the developing world) approach the present total energy demand in North America—one-third of the world's total. Biomass as a supply system is targeted for 1.5 times the present N. American total. While this is a formidable target, I believe that if economic growth throughout the world is to continue and if the gap between the rich and poor countries is to shrink, it is, in fact, a modest social goal.     

Feasibility of edible oil vs. non-edible oil vs. waste edible oil as biodiesel feedstock

Biodiesel has high potential as a new and renewable energy source in the future, as a substitution fuel for petroleum-derived diesel and can be used in existing diesel engine without modification. Currently, more than 95% of the world biodiesel is produced from edible oil which is easily available on large scale from the agricultural industry. However, continuous and large-scale production of biodiesel from edible oil without proper planning may cause negative impact to the world, such as depletion of food supply leading to economic imbalance. A possible solution to overcome this problem is to use non-edible oil or waste edible oil (WEO). In this context, the next question that comes in mind would be if the use of non-edible oil overcomes the short-comings of using edible oil. Apart from that, if WEO were to be used, is it sufficient to meet the demand of biodiesel. All these issues will be addressed in this paper by discussing the advantages and disadvantages of using edible oil vs. non-edible vs. WEO as feedstock for biodiesel production. The discussion will cover various aspects ranging from oil composition, oil yield, economics, cultivation requirements, land availability and also the resources availability. Finally, a proposed solution will be presented.     

Large-scale fuelwood production on agricultural fields in mesoscale river catchments – GIS-based determination of potentials in the Dahme river catchment (Brandenburg,NE Germany)

Woody biomass (dendromass) today already has an important role in bioenergy production and will even increase in the future as a renewable resource for energetic as well as for material use. In eastern Germany, an increasing demand for dendromass in renewable energy production is unlikely to be covered by sustainable forest wood production. Hence, a deficit for the federal state of Brandenburg of 4.02 million tonnes per year is predicted. Besides imports, one option of increasing dendromass supply in Brandenburg is short rotation coppice (SRC) on arable land. The potential of SRC on arable land is determined by the economic competitiveness of SRC compared to conventional annual crops. This factor is strongly influenced by the water supply, expressed as the transpiration water supply (TWS) in the growing season, and the soil quality.First evaluations of SRC potentials in Brandenburg identify large areas of arable land where SRC seems to be able to compete with annual crops.Potential areas in the Dahme river catchment, located in the south of Berlin, were identified at a regional scale through a GIS-based approach. The results indicate that lowland river catchments like the Dahme basin have great potentials for fuelwood production. Especially the large amount of arable land with accessible groundwater resources offers water for transpiration in a region where average annual precipitation and water storage capacity of soils is relatively low (550 mm and 100–150 mm m⁻¹ resp.) and thus too small to meet the demands of optimal SRC growth. In total, 340,000 tonnes fuelwood could be produced annually in the Dahme river catchment, if all potential sites were transformed into SRC. This accounts for 8.5% of the deficit produced on just 1.8% of the federal state of Brandenburg's total agricultural area by 2030 and meet the heating energy demand of approximately 130,000 people. The results show that the applied method is an effective way to identify biomass potentials in mesoscale river basins and demonstrates the relevance of the Dahme catchment for a sustainable energy supply in the future.     

Assessing of energy policies based on Turkish agriculture:: current status and some implications

In this study, the current energy status of Turkey and the effects of national energy policies on Turkish agricultural support policies are discussed for both current and future requirements. Turkey is an energy-importing country producing 30 mtoe (million tons of oil equivalent) energy but consuming 80 mtoe. The energy import ratio of Turkey is 65–70% and the majority of this import is based on petroleum and natural gas. Furthermore, while world energy demand increases by 1.8% annually, Turkey’s energy demand increases by about 8%. Although energy consumption in agriculture is much lower than the other sectors in Turkey, energy use as both input and output of agricultural sector is a very important issue due to its large agricultural potential and rural area. Total agricultural land area is 27.8 million hectares and about 66.5% of this area is devoted for cereal production. On the other hand, Turkey has over 4 million agricultural farm holdings of which 70–75% is engaged in cereal production. Machinery expenses, mainly diesel, constitute 30–50% of total variable expenses in cereal production costs. It is observed that energy policies pursued in agriculture have been directly affected by diesel prices in Turkey. Therefore, support policy tools for using diesel and electricity in agriculture are being pursued by the Turkish government.     

Analysing uncertainties of supply and demand in the future use of hydrogen as an energy vector

The future use of hydrogen as an energy supply vector and as a feedstock for the chemical industry depends on many variables in the future energy market, which at this time are uncertain. In evaluating the potential of hydrogen in the future it is necessary to take into account the uncertainties in supply and demand of energy, including competitive primary energy sources, competitive energy vectors and all possible end-uses. The current work centres on the construction of a probabilistic activity (RPD) network expressing the role of hydrogen in energy production and utilization. The potential benefit of hydrogen depends on the values assigned to future energy market sizes, the ability of primary energy production routes to meet demand and the availability and cost of competitive energy vectors. There are consequently considerable uncertainties in the values to be assigned to the input quantities in the network. An analytical technique (AUQ), developed at Fulmer, is being used to examine the sensitivity of the outcome to uncertainties in input quantities in order to highlight which input quantities critically affect the potential role of hydrogen. The work presented here includes an outline of the model and the analysis technique, along with basic considerations of the input quantities to the model (demand, supply and constraints). Some examples are given of probabilistic estimates of input quantities.     

Variation in energy consumption in production of wheat–maize with varying altitudes in hilly regions of Himachal Pradesh, India

Availability and consumption pattern of energy and constraints in its proper supply and management for crop production was studied in wheat–maize cropping system in selected hilly rural villages located at different altitudes of Himachal Pradesh in Western Himalayas. The information was collected from 90 farmers drawn from nine villages, three each from three selected altitudes using two-stage random sampling. The average values of energy consumption for wheat crop in low and high hills were, respectively, 41.68 and 110.8 MJ/ha and those for maize crop were, respectively, 43.43 and 81.33 MJ/ha. The productivity of wheat crop ranged from 1077 to 1840.9 kg/ha and for maize crop from 1108 to 1573 kg/ha, in low and high hills, respectively. The major constraints in the proper use of energy in crop production were the uncertain supply of different inputs due to difficult and undulating terrain, poor land holdings and non-availability of suitable technologies. The introduction of small powered equipment, precise use of seed and fertilizer and proper management of irrigation water were recommended for efficient energy use and better crop productivity.     

Exploration of the land potential for the production of biomass for energy in the Netherlands

The energy potential for energy crops and biomass residues in the Netherlands is assessed. The analysis explores the possible use of land for biomass production in the future. Various government memorandums and analyses of the expected future land use in various sectors have served as the basis for the assessment of the supply of and the demand for land in the future. In this study the potential supply of agricultural land is based on expected productivity increments in agriculture and assumptions with respect to the future demand for agricultural products. Various future claims for infrastructure, forestry, urban areas and nature are subtracted from the expected supply. The net projected supply of land ranges from zero to 52 000 ha in 2000 to 110 000-250 000 ha in 2015. The supply of agricultural land depends however on a number of supra-national factors, such as the European agricultural policy, world market developments and the agricultural production in the countries in Eastern Europe. Uncertainties remain, therefore, and the projected supply of agricultural land should be considered as a possible scenario based on current trends. If the calculated land potential is used for energy crops like miscanthus and short rotation coppice, this land could contribute 0-10 PJ in 2000 and 27-59 PJ in 2015. Secondary biomass yields, such as those from forestry, agricultural residues, wood from prunings, etc., could contribute a further 34 PJ in 2000, decreasing to approximately 28 PJ in 2015. Taken together these potentials could satisfy 1-1.5% of the energy requirements of the Netherlands in 2000 and 1.5-2.5% in 2015, provided that energy farming is an economically feasible activity for farmers.     

A thermoeconomic analysis of biomass energy for trigeneration

The principal objective of this study is to formulate a calculation process, based on the second law of exergy, for evaluating the thermoeconomic potential of a steam-turbine plant for trigeneration. The plant employs biomass, namely, waste wood as its energy source. Four different plant configurations are presented and assessed. ‘Their cost effectiveness is evaluated with varying economic and operating parameters’, because only the fuel price and electricity price are varied. In case 1, high pressure superheated steam generated is supplied to meet the demand for process heat as well as chilled water production in an absorption chiller. In cases 2 and 3, steam is extracted at appropriate stages of the turbine and supplied to meet the demand for process heat and chilled water production in an absorption chiller. Steam generated in case 2 produces sufficient power to meet internal demands while case 3 generates excess electricity for sale back to the utility. In case 4, low pressure saturated steam is generated to meet the demand for process heat and electricity is bought from the utilities, including those used to power an electric vapour-compression chiller. For all cases, it was found that exergy destruction is most extensive in the furnace, amounting to nearly 60%. Exergy destruction in the steam drum is the next most extensive ranging from 11% to 16%. It was also observed that the overall production cost decreases with steam pressure and increases with steam temperature.     

Energy crop production costs in the EU

The objective of this study was to calculate indicative ranges of production costs and assess the main sources of cost for a number of energy crops, both annual and perennial, on a regional level in Europe. The production costs were calculated in terms of the economic compensation required by the farmer in order to grow the crop, and therefore include not only the cost of cultivation, but also the costs of land and risk, which are often omitted in production cost calculations. The cost of land was calculated as the opportunity cost based on the production of cereals. Thus, higher food prices lead to higher land costs, which in turn lead to higher energy crop production costs. The analysis was performed for three cases with different assumptions concerning yields and production cost reductions resulting from scale (total cultivation area in the region), and learning effects. The calculated energy crop production costs were found to be consistently lowest for short-rotation coppice (SRC) crops and highest for annual straw crops. The production costs of SRC crops were calculated to be about 4–5 € GJ⁻¹ under present conditions and 3–4 € GJ⁻¹ under improved future conditions. The production costs for perennial grasses were calculated to be about 6–7 € GJ⁻¹ and 5–6 € GJ⁻¹ under present and improved future conditions, respectively. The production costs for annual straw crops were estimated to be 6–8 € GJ⁻¹ under present conditions with small potential for cost reductions in the future.     

The role of biomass in California's hydrogen economy

This paper presents the results of a model of hydrogen production from waste biomass in California. We develop a profit-maximizing model of a biomass hydrogen industry from field to vehicle tank. This model is used to estimate the economic potential for hydrogen production from two waste biomass resources in Northern California—wheat straw and rice straw—taking into account the on the ground geographic dimensions of both biomass supply and hydrogen demand. The systems analysis approach allows for explicit consideration of the interactions between feedstock collection, hydrogen production, and hydrogen distribution in finding the optimal system design. This case study approach provides insight into both the real-world potential and the real-world cost of producing hydrogen from waste biomass. Additional context is provided through the estimation of California's total waste biomass hydrogen potential. We find that enough biomass is available from waste sources to provide up to 40% of the current California passenger car fuel demand as hydrogen. Optimized supply chains result in delivered hydrogen costing between $3/kg and $5.50/kg with one-tenth of the well-to-wheels greenhouse gas emissions of conventional gasoline-fueled vehicles.