Ex-post economic analysis of photovoltaic power in the Spanish grid: Alternative scenarios

Nowadays, photovoltaic technology as a whole is considered to cause deficit to the Spanish power system, because the bonuses that it receives are higher than the savings generated over the electricity prices thanks to the merit-order-effect. However, the bonuses to generation for new facilities have undergone significant declines over the past five years, along with the drop in the prices of modules. That means that the economic influence of photovoltaic power is highly penalized by the existing feed-in-tariff scheme presented in the years 2007 and 2008, which gave way to the Spanish photovoltaic boom. Based on these facts, the economic profitability to the system of the latest installed photovoltaic plants is analyzed; reaching the conclusion that the facilities registered in and after the second quarter of 2011 have been profitable to the system in the fourth quarter of 2012, and are very close to being profitable for the whole year. Finally, based on the aforementioned conclusions, alternative scenarios for the deployment of photovoltaic power in the Spanish grid are presented, based on a temporary redistribution of the facilities that fostered the boom, to provide a better understanding of the situation. This knowledge may be a valuable tool for less developed countries in terms of photovoltaic energy.     

Biomass production potentials in Central and Eastern Europe under different scenarios

A methodology for the assessment of biomass potentials was developed and applied to Central and Eastern European countries (CEEC). Biomass resources considered are agricultural residues, forestry residues, and wood from surplus forest and biomass from energy crops. Only land that is not needed for food and feed production is considered as available for the production of energy crops. Five scenarios were built to depict the influences of different factors on biomass potentials and costs. Scenarios, with a domination of current level of agricultural production or ecological production systems, show the smallest biomass potentials of 2–5.7 EJ for all CEEC. Highest potentials can reach up to 11.7 EJ (85% from energy crops, 12% from residues and 3% from surplus forest wood) when 44 million ha of agricultural land become available for energy crop production. This potential is, however, only realizable under high input production systems and most advanced production technology, best allocation of crop production over all CEEC and by choosing willow as energy crops. The production of lignocellulosic crops, and willow in particular, best combines high biomass production potentials and low biomass production costs. Production costs for willow biomass range from 1.6 to 8.0 €/GJ HHV in the scenario with the highest agricultural productivity and 1.0–4.5 €/GJ HHV in the scenario reflecting the current status of agricultural production. Generally the highest biomass production costs are experienced when ecological agriculture is prevailing and on land with lower quality. In most CEEC, the production potentials are larger than the current energy use in the more favourable scenarios. Bulk of the biomass potential can be produced at costs lower than 2 €/GJ. High potentials combined with the low cost levels gives CEEC major export opportunities.     

Biochemical production of ethanol and fatty acid ethyl esters from switchgrass: A comparative analysis of environmental and economic performance

As advances in biotechnology have continued at a rapid pace, interest in the biochemical production of so-called “drop-in” fuels has increased as a way to avoid the well-known shortcomings of ethanol as a fuel molecule and to potentially exploit the processing advantages of a water-immiscible fuel to reduce product recovery costs and energy requirements. In the current study, processes to produce either ethanol or a representative fatty acid ethyl ester (FAEE) via the fermentation of sugars liberated from lignocellulosic materials pretreated in acid or alkaline environments are analyzed in terms of economic and environmental metrics. Simplified process models are introduced and employed to estimate fuel production, greenhouse gas emissions, net energy consumption, minimum fuel selling price, and water consumption for both processes. Monte Carlo analyses were carried out to identify key sources of uncertainty and variability, and an analysis of the impact of potential improvements to the FAEE process was performed. We find that the near-term performance of processes to produce FAEE is significantly worse than that of ethanol production processes for all metrics considered, primarily due to poor fermentation yields and higher electricity demands for aerobic fermentation. Even if these issues are addressed in the longer term, the reduced cost and energy requirements of FAEE separation processes will be at least partially offset by inherent limitations in the relevant metabolic pathways that constrain the maximum yield potential of FAEE from biomass-derived sugars.     

Hydrogen perspectives in Italy: Analysis of possible deployment scenarios

The paper analyses Italian hydrogen scenarios to meet climate change, environmental and energy security issues. An Italy-Markal model was used to analyse the national energy–environment up to 2050. About 40 specific hydrogen technologies were considered, reproducing the main chains of production, transport and consumption, with a focus on transport applications. The analysis is based on the Baseline and Alternative scenario results, where hydrogen reaches a significant share. The two scenarios constitute the starting points to analyse the hydrogen potential among the possible energy policy options. The energy demand in the Baseline scenario reaches values around 240 Mtoe at 2030, with an average annual growth of 0.9%. The Alternative scenario reduces consumption down to 220 Mtoe and stabilizes the _CO2${\mathrm{CO}}_2$ emissions. The Alternative scenario expects a rapid increase of hydrogen vehicles in 2030, up to 2.5 million, corresponding to 1 Mtoe of hydrogen consumption. A sensitivity analysis shows that the results are rather robust.     

Energy and economic analysis of rice production under different farm levels in Guilan province of Iran

The study was carried out on energy requirement and energy input–output relationship of rice production in Guilan province of Iran. Data were collected from 105 farmers with face-to-face questionnaire method. The research results revealed rice production consumed a total energy of 39333 MJ ha⁻¹ which fuel energy use was 46% followed by chemical fertilizer (36%), seed (8%) and biocide (6%), respectively. The share of direct, indirect, renewable and non-renewable energies was 49%, 51%, 11% and 89% respectively. The energy use efficiency and energy productivity were found as 1.53, 0.09 kg MJ⁻¹, respectively. The econometric model was developed using Cobb–Douglas type function and results showed that fuel and machinery energy inputs contributed significantly to the yield. The results of sensitivity analysis of the energy inputs showed that the MPP value of fuel was the highest (0.93), followed by machinery (0.23), biocide (0.17) and seed (0.15) energy inputs. Economic analysis indicated that total cost of production was 3156 $ ha⁻¹. Gross and net return were 1642 $ ha⁻¹ and 940 $ ha⁻¹, respectively and the benefit-cost ratio was calculated 1.29. Mainly, large farms (more than 1 ha) had better management and were more successful in energy use and economic performance.     

An economic analysis of the financial viability of switchgrass as a raw material for pulp production in eastern Ontario

This paper examines the economic viability of producing switchgrass (Panicum virgatum) to be used as pulp in fine paper production. Pulp mills in eastern Ontario and western Quebec are considered to be the potential market for switchgrass. The potential size of the market for switchgrass pulp is assessed. Budgets for switchgrass are constructed and various measures of the potential market value of switchgrass are calculated. Based on these preliminary findings, it appears that switchgrass could be an attractive crop for farmers in eastern Ontario and western Quebec. The total land area required to satisfy the potential demand for switchgrass fibre for pulping in eastern Ontario is estimated to be between 22,000 and 48,000 hectares. Further agronomic research to examine the productivity of switchgrass on economically marginal and erosion prone lands is indicated.     

A study on the future of unconventional oil development under different oil price scenarios: A system dynamics approach

Fluctuations in the oil global market has been a critical topic for the world economy so that analyzing and forecasting the conventional oil production rate has been examined by many researchers thoroughly. However, the dynamics of the market has not been studied systematically with regard to the new emerging competitors, namely unconventional oil. In this paper, the future trend of conventional and unconventional oil production and capacity expansion rates are analyzed using system dynamics approach. To do so, a supply-side modeling approach is utilized while main effective loops are modeled mathematically as follows: technological learning and progress, long and short-term profitability of oil capacity expansion and production, and oil proved reserve limitations. The proposed model is used to analyze conventional and unconventional oil production shares, up to 2025, under different oil price scenarios. The results show that conventional oil production rate ranges from 79.995 to 87.044 MB/day, which is 75–80 percent of total oil production rate, while unconventional oil production rate ranges from 19.615 to 28.584 MB/day. Simulation results reveal that unconventional oil can gain a considerable market share in the short run, although conventional oil will remain as the major source for the market in the long run.     

Bio-butanol vs. bio-ethanol: A technical and economic assessment for corn and switchgrass fermented by yeast or Clostridium acetobutylicum

Fermentation-derived butanol is a possible alternative to ethanol as a fungible biomass-based liquid transportation fuel. We compare the fermentation-based production of n-butanol vs. ethanol from corn or switchgrass through the liquid fuel yield in terms of the lower heating value (LHV). Industrial scale data on fermentation to n-butanol (ABE fermentation) or ethanol (yeast) establishes a baseline at this time, and puts recent advances in fermentation to butanol in perspective. A dynamic simulation demonstrates the technical, economic and policy implications.The energy yield of n-butanol is about half that of ethanol from corn or switchgrass using current ABE technology. This is a serious disadvantage for n-butanol since feedstock costs are a significant portion of the fuel price. Low yield increases n-butanol's life-cycle greenhouse gas emission for the same amount of LHV compared to ethanol. A given fermenter volume can produce only about one quarter of the LHV as n-butanol per unit time compared to ethanol. This increases capital costs. The sometimes touted advantage of n-butanol being more compatible with existing pipelines is, according to our techno-economic simulations insufficient to alter the conclusion because of the capital costs to connect plants via pipeline.     

Optimal combination of energy crops under different policy scenarios; The case of Northern Greece

Energy crops production is considered as environmentally benign and socially acceptable, offering ecological benefits over fossil fuels through their contribution to the reduction of greenhouse gases and acidifying emissions. Energy crops are subjected to persistent policy support by the EU, despite their limited or even marginally negative impact on the greenhouse effect. The present study endeavors to optimize the agricultural income generated by energy crops in a remote and disadvantageous region, with the assistance of linear programming. The optimization concerns the income created from soybean, sunflower (proxy for energy crop), and corn. Different policy scenarios imposed restrictions on the value of the subsidies as a proxy for EU policy tools, the value of inputs (costs of capital and labor) and different irrigation conditions. The results indicate that the area and the imports per energy crop remain unchanged, independently of the policy scenario enacted. Furthermore, corn cultivation contributes the most to iFncome maximization, whereas the implemented CAP policy plays an incremental role in uptaking an energy crop. A key implication is that alternative forms of motivation should be provided to the farmers beyond the financial ones in order the extensive use of energy crops to be achieved.     

A comparability analysis of global burden sharing GHG reduction scenarios

The distribution of the mitigation burden across countries is a key issue regarding the post-2012 global climate policies. This article explores the economic implications of alternative allocation rules, an assessment made in the run-up to the COP15 in Copenhagen (December 2009). We analyse the comparability of the allocations across countries based on four single indicators: GDP per capita, GHG emissions per GDP, GHG emission trends in the recent past, and population growth. The multi-sectoral computable general equilibrium model of the global economy, GEM-E3, is used for that purpose. Further, the article also compares a perfect carbon market without transaction costs with the case of a gradually developing carbon market, i.e. a carbon market with (gradually diminishing) transaction costs.     

A model for the economic analysis of cogeneration plants with fixed and variable output

A method is presented for an economic sensitivity analysis of a cogeneration plant operating at off-design conditions. The economic parameters are the annual fixed costs, operating costs, fuel costs and the market value of the electrical power and capacity as paid by the local utility. The thermodynamic parameters are the required time-dependent steam energy rate [$\text{q}\text{?}{}_{\mathrm{s}}\text{(θ)}$], the plant power-to-steam energy rate ratio (PSR), and the steam efficiency (η_s). The last two parameters are shown to be functionally related to $\text{q}\text{?}{}_{\mathrm{s}}$ (which may be constant or vary with time). A numerical example is given.     

Facing the uncertainty of CO2 storage capacity in China by developing different storage scenarios

China is very active in the research and development of CO₂ capture and storage technologies (CCS). However, existing estimates for CO₂ storage capacity are very uncertain. This uncertainty is due to limited geological knowledge, a lack of large-scale research on CO₂ injection, and different assessment approaches and parameter settings. Hence storage scenarios represent a method that can be used by policy makers to demonstrate the range of possible storage capacity developments, to help interpret uncertain results and to identify the limitations of existing assessments. In this paper, three storage scenarios are developed for China by evaluating China-wide studies supplemented with more detailed site- and basin-specific assessments. It is estimated that the greatest storage potential can be found in deep saline aquifers. Oil and gas fields may also be used. Coal seams are only included in the highest storage scenario. In total, the scenarios presented demonstrate that China has an effective storage capacity of between 65 and 1551 Gt of CO₂. Furthermore, the authors emphasise a need for action to harmonise storage capacity assessment approaches due to the uncertainties involved in the capacity assessments analysed in this study.     

The role of nuclear energy in long-term climate scenarios: An analysis with the World-TIMES model

There is a revival in the nuclear debate observed in the literature. Several analyses have shown that nuclear technologies may represent very attractive options for greenhouse gas (GHG) emission reductions, especially in countries with high growth projections for energy demand. Our objective is to analyze the role of nuclear energy in long-term climate scenarios using the World-TIMES (The Integrated MARKAL-EFOM System) bottom-up model. World-TIMES is a global model that optimizes the energy system of 15 regions over a 100-year horizon (2000–2100).     

电站锅炉脱硫方法的技术经济分析

叙述了电站锅炉各类脱硫方法的脱硫原理、技术特点、适用范围及运行成本核算等。目前,关于脱硫方法成本核算方面的文章较多,但相互之间缺乏可比性,究其原因,主要是由于计算时所包括的项目不尽相同所致。以中国计算运行成本（包括材料消耗、动力消耗、维修与管理、人工、折旧、在修、偿还投资贷款等）的规定为计算基础,将中国正在运行的或即将投产的较大的脱硫工程进行了运行成本的计算与相互比较。除了比较运行成本外,还进行了     

A mathematical analysis of full fuel cycle energy use

Given concerns about the environmental impacts of fossil fuel use, there is a keen interest in developing a broad range of new energy sources and technologies. This in turn creates a need for metrics that can reliably quantify the costs, benefits, and potential trade-offs of different alternatives. In this paper, we present a definition of a full fuel-cycle metric that is flexibile enough to describe a wide variety of energy production chains, and has sufficient mathematical rigor to allow meaningful comparisons between them. The term FFC (full fuel cycle) refers to the complete fuel production chain including extraction, processing, conveyance to the retail distribution center and delivery to final consumers. For ease of use in applications, the metric is defined as an FFC multiplier which, when applied to the point-of-use energy consumption, gives an estimate of the FFC energy use. We also show that the FFC multiplier can be used to provide precise and intuitively reasonable definitions of other energy production metrics such as EROI (energy return on energy invested). The multiplier is a non-linear function of a set of energy–intensity parameters that depend only on directly observable physical data.     

Large-scale bioenergy production from soybeans and switchgrass in Argentina: Part A: Potential and economic feasibility for national and international markets

This study focuses on the economic feasibility for large-scale biomass production from soybeans or switchgrass from a region in Argentina. This is determined, firstly, by estimating whether the potential supply of biomass, when food and feed demand are met, is sufficient under different scenarios to 2030. On a national level, switchgrass has a biomass potential of 99 × 10⁶ (1.9 EJ) to 243 × 10⁶ tdm (4.5 EJ)/year depending on the scenario. Soybean (crude vegetable oil content) production for bioenergy has a potential of 7.1 × 10⁶ (0.25 EJ) to 13.8 × 10⁶ tdm (0.5 EJ)/year depending on the scenario. The most suitable region (La Pampa province) to cultivate energy crop production is selected based on a defined set of criteria (available land for biomass production, available potential for both crops, proximity of logistics and limited risk of land use competition). The available potential for bioenergy in La Pampa ranges from 1.2 × 10⁵ to 1.8 × 10⁵ tdm/year for soybean production (based on vegetable oil content) and from 6.3 × 10⁶ to 18.2 × 10⁶ tdm/year for switchgrass production, depending on the scenario. Bioenergy chains for large-scale biomass production for export or for local use are further defined to analyse the economic performance. In this study, switchgrass is converted to pellets for power generation in the Netherlands or for local heating in Argentina. Soybeans are used for biodiesel production for export or for local use. Switchgrass cultivation costs range from 33–91 US$/tdm (1€ = 1.47 US$ based on 19 February 2008). Pellet production costs are 58–143 US$/tdm for local use and 150–296 US$/tdm until delivery at the harbour of Rotterdam. Total conversion costs for electricity in the Netherlands from switchgrass pellets range from 0.06–0.08 US$/kWh. Heating costs in Argentina from switchgrass pellets range from 0.02–0.04 US$/kWh. Soybean cultivation costs range from 182–501 US$/tdm depending on the scenario. Biodiesel production costs are 0.3–1.2 US$/l for local use and 0.5–1.7 US$/l after export to the Netherlands. Key parameters for the economic performance of the bioenergy chains in La Pampa province are transport costs, cultivation costs, pre-processing and conversion costs and costs for fossil fuels and agricultural commodities.     

A full model for simulation of electrochemical cells including complex behavior

This communication presents a model of electrochemical cells developed in order to simulate their electrical, chemical and thermal behavior showing the differences when thermal effects are or not considered in the charge–discharge process. The work presented here has been applied to the particular case of the Pb,PbSO₄|H₂SO₄ (aq)|PbO₂,Pb cell, which forms the basis of the lead-acid batteries so widely used in the automotive industry and as traction batteries in electric or hybrid vehicles.     

Conservation of energy estimated by second law analysis of a power-consuming process

A refrigeration system removing heat from a cold storage is analyzed to determine exergetic losses of the thermodynamic cycle and the power needed for the flows of the refrigerant and the media transferring heat at a specified temperature. How much the overall power consumption of the system can be decreased by lowering the condensing temperature, by either increasing the external heat transfer at the condenser or by lowering the inlet temperature of the heat exchanging media, is investigated. The latter depends on the relative humidity of the air. The performance of air, water and evaporative-cooled condensers are evaluated as a function of relative humidity of the ambient air. It is shown that the evaporative condenser operates at the lowest condensing temperature and, therefore, the least power consumption of the total system is achieved. Wetting the condenser with water requires only 1% of the overall power consumption but reduces the consumption by 30% as compared with the air-cooled condenser. Precooling the air by a water spray before it enters an air-cooled condenser is of benefit only at relative humidities of 65% or less. At other state conditions of the air, a higher power consumption will result. Lowering the temperature of the surroundings lowers P_rev and the second law efficiency must be properly defined so that, for cases of lowest power consumption, highest values of the efficiency will be obtained. Means for the design of least power-consuming air-conditioners are briefly stated, as well as the advantages of evaporative condensers for fog-free operation.     

Technical and economic analysis of biogas production in Ireland utilising three different crop rotations

The Biofuels Directive sets reference values for the quantity of biofuels and other renewable fuels to be placed on the transport market. Biogas from agricultural crops can be used to meet this directive. This paper investigates biogas production for three crop rotations: wheat, barley and sugar beet; wheat, wheat and sugar beet; wheat only. A technical and economic analysis for each crop rotation was carried out. It was found that wheat produces significantly more biogas than either barley or sugar beet, when examined on a weight basis. However sugar beet produces more biogas and subsequently more energy when examined on an area basis. When producing biofuels, land is the limiting factor to the quantity of energy that may be produced. Thus if optimising land then a crop rotation of wheat, wheat and sugar beet should be utilised, as this scenario produced the greatest quantity of energy. This scenario has a production cost of €0.90/m_N³, therefore, this scenario is competitive with petrol when the price of petrol is at least €1.09/l (VAT is charged at 21%). If optimising the production costs then a crop rotation of wheat only should be utilised when the cost of grain is less than €132/ton. This scenario has the least production cost at €0.83/m_N³, therefore, this scenario is competitive with petrol when the price of petrol is at least €1.00/l. But as this scenario produces the least quantity of biogas, it also produces the least quantity of energy. In comparing with other works by the authors it is shown that a biomethane system produces more energy from the same crops at a cheaper cost than an ethanol system.     

Assessing the operation and different refuelling cost scenarios of a fuel cell electric bicycle under low-pressure hydrogen storage

The transition to low- or zero-emission vehicles in the transportation sector is a challenging task toward meeting the greenhouse gas emission targets set by the majority of countries. One way of achieving this goal is to utilise hydrogen gas via fuel cell electric vehicles. This paper investigates the operation, driving range and refuelling process of a fuel cell electric bicycle. The methodology applied includes an estimation of the bike's range under different routes and riders, the riders' opinions and a financial evaluation of the hydrogen fuel cost compared to other urban vehicle alternatives. The results showed a minimum median range-to-energy consumption ratio of 20.5 km/kWh, while the maximum hydrogen cost was found to reach 0.025 €/km when refuelling the hydrogen bicycle in an autonomous hydrogen station. The outcome of this study indicates that the introduction of light-duty hydrogen vehicles in urban transportation may adequately meet the average daily driving distance of city residents.