Comparative assessment of future power generation technologies based on carbon price development

The long-term assessment of new electricity generation was performed for various long-run policy scenarios taking into account two main criteria: private costs and external GHG emission costs. Such policy oriented power generation technologies assessment based on carbon price and private costs of technologies can provide information on the most attractive future electricity generation technologies taking into account climate change mitigation targets and GHG emission reduction commitments for world regions.Analysis of life cycle GHG emissions and private costs of the main future electricity generation technologies performed in this paper indicated that biomass technologies except large scale straw combustion technologies followed by nuclear have the lowest life cycle GHG emission. Biomass IGCC with CO₂ capture has even negative life cycle GHG emissions. The cheapest future electricity generation technologies in terms of private costs in long-term perspective are: nuclear and hard coal technologies followed by large scale biomass combustion and biomass CHPs. The most expensive technologies in terms of private costs are: oil and natural gas technologies. As the electricity generation technologies having the lowest life cycle GHG emissions are not the cheapest one in terms of private costs the ranking of technologies in terms of competitiveness highly depend on the carbon price implied by various policy scenarios integrating specific GHG emission reduction commitments taken by countries and climate change mitigation targets.     

Potential of practical implementation of rice straw-based power generation in Thailand

This paper uses life cycle assessment to evaluate the potential of rice straw power plant implementation in Thailand in terms of GHG emission savings from avoided open burning and from implementing rice straw power production, which can substitute that from natural gas. Annually, 8.5–14.3 Mt rice straw burning contributes 5.0–8.6 MtCO₂-eq which could be converted to 786–1325 MW of power, yielding a total greenhouse gas (GHG) reduction of 7.8–13.2 MtCO₂-eq. Moreover, 1090–1837 Mm³ of natural gas could be substituted annually. A total of 25 provinces in central Thailand have potential to generate electricity with a total capacity of 210–292 MW (plant efficiency 20–27%), resulting in an annual GHG emission savings of 2.3–2.6 MtCO₂-eq, and with a provincial capacity of over 20 MW in 6 provinces, 10–20 MW in 7 provinces, 1–10 MW in 6 provinces and less than 1 MW in 6 provinces.     

Modeling of current and future energyintensity and greenhouse gas emissions ofthe Lebanese industrial sector: assessmentof mitigation options

Greenhouse gas emissions in Lebanon mainly come from energy activities, which are responsible for 85% of all CO₂ emissions. The CO₂ emissions from energy use in manufacturing industries and construction represent 24% of the total emissions of the energy sector. Lebanese manufacturers' accounted for 39.15 million gigajoules of fuel consumption for heat and power generation in 1994, including both fuel used directly and fuel burned remotely to generate electricity used in the sector. In addition to being processed by combustion, CO₂ is generated in calcining of carbonates in the manufacture of cement, iron and glass. Electricity, the most expensive form of energy, represented 25.87% of all fuel used for heat and power. Residual fuel oil and diesel, which are used mainly in direct combustion processes, represent 26.85 and 26.55% of all energy use by industry, respectively. Scenarios for future energy use and CO₂ emissions are developed for the industrial sector in Lebanon. The development of the baseline scenario relied on available data on major plants' outputs, and on reported amounts of fuels used by the industrial sector as a whole. Energy use in industry and the corresponding greenhouse gas (GHG) emissions for Lebanon are projected in baseline scenarios that reflect technologies, activities and practices that are likely to evolve from the base year 1994 to year 2040. Mitigation work targets a 15% of CO₂ emissions from the baseline scenario by year 2005 and a 20–30% reduction of CO₂ emissions by year 2040. The mitigation options selected for analysis are screened on the basis of GHG emissions and expert judgement on the viability of their wide-scale implementation and economic benefits. Using macroeconomic assessment and energy price assumptions, the final estimates of potential GHG emissions and reduction costs of various mitigation scenarios are calculated. The results show that the use of efficient electric motors, efficient boilers and furnaces with fuel switching from fuel oil to natural gas has the largest impact on GHG emissions at a levelized annual cost that ranges from −20 to −5 US$/tonne of CO₂ reduced. The negative costs are indicative of direct savings obtained in energy cost for those mitigation options.     

Effects of operating conditions and fuel properties on emission performance and combustion efficiency of a swirling fluidized-bed combustor fired with a biomass fuel

This work reports an experimental study on firing 80 kg/h rice husk in a swirling fluidized-bed combustor (SFBC) using an annular air distributor as the swirl generator. Two NO_x emission control techniques were investigated in this work: (1) air staging of the combustion process, and (2) firing rice husk as moisturized fuel. In the first test series for the air-staged combustion, CO, NO and C_xH_y emissions and combustion efficiency were determined for burning “as-received” rice husk at fixed excess air of 40%, while secondary-to-primary air ratio (SA/PA) was ranged from 0.26 to 0.75. The effects of SA/PA on CO and NO emissions from the combustor were found to be quite weak, whereas C_xH_y emissions exhibited an apparent influence of air staging. In the second test series, rice husks with the fuel-moisture content of 8.4% to 35% were fired at excess air varied from 20% to 80%, while the flow rate of secondary air was fixed. Radial and axial temperature and gas concentration (O₂, CO, NO) profiles in the reactor, as well as CO and NO emissions, are discussed for the selected operating conditions. The temperature and gas concentration profiles for variable fuel quality exhibited significant effects of both fuel-moisture and excess air. As revealed by experimental results, the emission of NO from this SFBC can be substantially reduced through moisturizing rice husk, while CO is effectively mitigated by injection of secondary air into the bed splash zone, resulting in a rather low emission of CO and high (over 99%) combustion efficiency of the combustor for the ranges of operating conditions and fuel properties.     

Rice straw as a renewable energy source in India, Thailand, and the Philippines: Overall potential and limitations for energy contribution and greenhouse gas mitigation

Rice is a widely grown crop in the South and South-East Asia that leaves substantial quantity of straw in the field. The aim of this paper is to assess the quantity of rice straw produced, estimate Greenhouse Gas (GHG) emissions based on its current uses, and assess its possible energy potential and related GHG emissions mitigation potential. Updated statistics on rough rice production are used in this study in combination with the literature values on Straw-to-Grain Ratio (SGR) to quantify the amount of rice straw produced in the three countries of focus. It is estimated that 97.19, 21.86, and 10.68 Mt of rice straw residue are produced in India, Thailand, and the Philippines, respectively.In India, 23% of rice straw residue produced is surplus and is either left in the field as uncollected or to a large extent open-field burnt. About 48% of this residue produced is subjected to open-field burning in Thailand, and in the Philippines it is 95%. The GHG emissions contribution through open-field burning of rice straw in India, Thailand, and the Philippines are 0.05%, 0.18%, and 0.56%, and the mitigated GHG emissions when generated electricity is used would be 0.75%, 1.81%, and 4.31%, respectively, when compared to the total country GHG emissions.     

Life cycle assessment of electricity generation using fast pyrolysis bio-oil

Biomass is expected to become an important energy source in U.S. electricity generation under state-lead renewable portfolio standards. This paper investigated the greenhouse gas (GHG) emissions for energy generated from forest resources through pyrolysis-based processing. The GHG emissions of producing pyrolysis bio-oil (pyrolysis oil) from different forest resources were first investigated; logging residues collected from natural regeneration mixed hardwood stands, hybrid poplar cultivated and harvested from abandoned agricultural lands, short rotation forestry (SRF) willow plantations and waste wood available at the site of the pyrolysis plant. Effects of biomass transportation were investigated through a range of distances to a central pyrolysis facility through road transport by semi-truck. Pyrolysis oil is assumed to be converted to electrical power through co-combustion in conventional fossil fuels power plants, gas turbine combined cycle (GTCC) and diesel generators. Life cycle GHG emissions were compared with power generated using fossil fuels and power generated using biomass direct combustion in a conventional Rankine power plant. Life cycle GHG savings of 77%–99% were estimated for power generation from pyrolysis oil combustion relative to fossil fuels combustion, depending on the biomass feedstock and combustion technologies used. Several scenario analyses were conducted to determine effects of pyrolysis oil transportation distance, N-fertilizer inputs to energy crop plantations, and assumed electricity mixes for pyrolysis oil production.     

Emissions from multiple-spouted and spout-fluid fluidized beds using rice husks as fuel

This paper presents the experimental results of the emissions of CO and CO₂ using rice husks as fuel on different configurations of spout-sluidized beds namely, multiple-spouted and spout-fluid fluidized bed. The emission of pollutants from the multiple-spouted bed and spout-fluid bed was investigated with rice husk fuel. The operating parameters considered were the different levels of excess air, different primary-to-secondary air ratios at each level of excess air and method of feeding. It was found that emission of CO from the multiple-spouted bed seemed to be lower with under-bed feeding of the rice husk fuel compared to over-bed feeding. However, the emission of CO₂ did not change significantly for both methods of feeding. Changes in excess air levels influenced the emissions of CO and CO₂ from the multiple-spouted bed within the excess air range investigated. It was found that emission of CO was less at 10% excess air with over-bed feeding; emission of CO in the case of under-bed feeding was lowest at 20% excess air level. It was found that the method of feeding had not significantly influenced the emission of CO and CO₂ in the spout-fluid bed. The combustion efficiency however, in general, was slightly higher in the case of under-bed feeding compared to over-bed feeding. Emission of CO was less in the spout-fluid bed compared with the emission of CO in the multiple-spouted bed. The result can be likely attributed to the higher combustion efficiency attained by the spout-fluid bed compared with that of multiple-spouted bed.     

Development of a scalable infrastructure model for planning electricity generation and CO2 mitigation strategies under mandated reduction of GHG emission

In a power-generation system, power plants as major CO₂ sources may be widely separated, so they must be connected into a comprehensive network to manage both electricity and CO₂ simultaneously and efficiently. In this study, a scalable infrastructure model is developed for planning electricity generation and CO₂ mitigation (EGCM) strategies under the mandated reduction of GHG emission. The EGCM infrastructure model is applied to case studies of Korean energy and CO₂ scenarios in 2020; these cases consider combinations of prices of carbon credit and total electricity demand fulfilled by combustion power plants. The results highlight the importance of systematic planning for a scalable infrastructure by examining the sensitivity of the EGCM infrastructure. The results will be useful both to help decision makers establish a power-generation plan, and to identify appropriate strategies to respond to climate change.     

Particulate matter and gaseous emission rate from combustion of Thai lignite and agricultural residues in a fixed-bed combustor

This research has been conducted in order to obtain a database of emission rate of particulate matter and gases (CO, NO, and SO₂) from combustion of lignite and agricultural residues, such as rice husk. The experimental investigation was performed in a fixed-bed combustor. Thirteen stages–electrical low-pressure impactor was used to collect particles ranging in sizes from 40 nm to 10 μm. The results show that emission rate of total mass of particulate matter from combustion of rice husk is lower than that of lignite combustion but the total number of particles emitted is higher. This implies lower particle density from agricultural residue combustion. For co-firing lignite and rice husk, particulate matter emission is found to be higher than combustion of either lignite or rice husk and an increase in rice husk mass fraction in fuel mixture leads to an increase in particulate matter emission. From these quantitative data, it could be mentioned that the fuel characteristics influenced directly on particulate emission. For gaseous emission factors, CO and NO_x concentration decrease as SA/TA ratio increases. Meanwhile, SO₂ emission tends to increase. Both NO_x and SO₂ emissions are reduced as increased rice husk mass fraction in fuel mixture.     

Development forecast of renewable energy power generation in China and its influence on the GHG control strategy of the country

CO₂ emissions of the electricity supply sector in China account for about half of the total volume in the country. Thus, reducing CO₂ emissions in China’s electricity supply sector will contribute significantly to the efforts of greenhouse gas (GHG) control in the country and the rest of the world. This paper introduces the development status of renewable energy and other main CO₂ mitigation options in power generation in China and makes a preliminary prediction of the development of renewable energy in the country for future decades. Besides, based on the situation in China, the paper undertakes a comprehensive analysis of CO₂ mitigation costs, mitigation potential, and fossil energy conversation capacity of renewable energy and other mitigation options, through which the influence of renewable energy on the mitigation strategy of China is analyzed.     

Investigation of biomass gasification hydrogen and electricity co-production with carbon dioxide capture and storage

Biomass is one of the renewable energy resources which can be used instead of fossil fuels to diminish environment pollution and emission of greenhouse gases. Hydrogen as a biomass is considered as an alternative fuel which can be derived from a variety of domestically available primary sources. In this paper, a hydrogen and electricity co-generation plant with rice husk is proposed. Rice husk with water vapor and oxygen produces syngas in gasifier. In this design, electricity is generated by using two Rankine cycles. The Results show that the net electric efficiency and hydrogen production efficiency are 1.5% and 40.0%, respectively. Hydrogen production is 1.316 kg/s in case which carbon dioxide is gathered and stored. The electricity generation is 5.923 MW_e. The main propose of implementing Rankine cycle is to eliminate hydrogen combustion for generating electricity and to reduce NO_x production. Furthermore, three kinds of membranes are studied in this paper.     

Embedded energy and total greenhouse gas emissions in final consumptions within Thailand

In order to quantify the total Greenhouse Gas (GHG) emissions from different commodities, the contribution of emissions in all subprocess chains has to be considered. In embedded energy analysis, the higher order production processes are usually truncated due to a lack of data. To fill the truncated subprocesses up to infinite process chains, energy intensities and GHG emission factors of various final consumptions in the economy evaluated by the Input–Output Analysis (IOA) must be applied. The direct GHG emissions in final consumptions in Thailand are evaluated by imitating the approach in the energy sector of the revised 1996 Intergovernmental Panel on Climate Change (IPCC) guidelines for national GHG inventories. The indirect energy and indirect emissions are evaluated by using the 1998 Input–Output (I–O) table. Results are presented of emissions in the main process, indirect processes, and on each subprocess chain order. The trend of energy intensity and emission factors of all final consumptions for 1995, 1998, 2001 and 2006 are also presented. Results show that the highest energy intensive sector is the electricity sector where fossil fuel is primarily used, but the highest total GHG emitter is the cement industry where the major sources of the emissions are industrial processes and the combustion of fossil fuels. Implication of the emission factors on electricity generating technologies shows that various cleaner electricity generating technologies, including renewable energy technology, could help in global GHG mitigation.     

Renewable energy technologies for the Indian power sector: mitigation potential and operational strategies

The future economic development trajectory for India is likely to result in rapid and accelerated growth in energy demand, with attendant shortages and problems. Due to the predominance of fossil fuels in the generation mix, there are large negative environmental externalities caused by electricity generation. The power sector alone has a 40 percent contribution to the total carbon emissions. In this context, it is imperative to develop and promote alternative energy sources that can lead to sustainability of the energy–environment system. There are opportunities for renewable energy technologies under the new climate change regime as they meet the two basic conditions to be eligible for assistance under UNFCCC mechanisms: they contribute to global sustainability through GHG mitigation; and, they conform to national priorities by leading to the development of local capacities and infrastructure. This increases the importance of electricity generation from renewables. Considerable experience and capabilities exist in the country on renewable electricity technologies. But a number of techno–economic, market-related, and institutional barriers impede technology development and penetration. Although at present the contribution of renewable electricity is small, the capabilities promise the flexibility for responding to emerging economic, socio–environmental and sustainable development needs. This paper discusses the renewable and carbon market linkages and assesses mitigation potential of power sector renewable energy technologies under global environmental intervention scenarios for GHG emissions reduction. An overall energy system framework is used for assessing the future role of renewable energy in the power sector under baseline and different mitigation scenarios over a time frame of 35 years, between 2000 to 2035. The methodology uses an integrated bottom-up modelling framework. Looking into past performance trends and likely future developments, analysis results are compared with officially set targets for renewable energy. The paper also assesses the CDM investment potential for power sector renewables. It outlines specific policy interventions for overcoming the barriers and enhancing deployment of renewables for the future.     

Towards real energy economics: Energy policy driven by life-cycle carbon emission

Alternative energy technologies (AETs) have emerged as a solution to the challenge of simultaneously meeting rising electricity demand while reducing carbon emissions. However, as all AETs are responsible for some greenhouse gas (GHG) emissions during their construction, carbon emission “Ponzi Schemes” are currently possible, wherein an AET industry expands so quickly that the GHG emissions prevented by a given technology are negated to fabricate the next wave of AET deployment. In an era where there are physical constraints to the GHG emissions the climate can sustain in the short term this may be unacceptable. To provide quantitative solutions to this problem, this paper introduces the concept of dynamic carbon life-cycle analyses, which generate carbon-neutral growth rates. These conceptual tools become increasingly important as the world transitions to a low-carbon economy by reducing fossil fuel combustion. In choosing this method of evaluation it was possible to focus uniquely on reducing carbon emissions to the recommended levels by outlining the most carbon-effective approach to climate change mitigation. The results of using dynamic life-cycle analysis provide policy makers with standardized information that will drive the optimization of electricity generation for effective climate change mitigation.     

Estimating GHG emission mitigation supply curves of large-scale biomass use on a country level

This study evaluates the possible influences of a large-scale introduction of biomass material and energy systems and their market volumes on land, material and energy market prices and their feedback to greenhouse gas (GHG) emission mitigation costs. GHG emission mitigation supply curves for large-scale biomass use were compiled using a methodology that combines a bottom-up analysis of biomass applications, biomass cost supply curves and market prices of land, biomaterials and bioenergy carriers. These market prices depend on the scale of biomass use and the market volume of materials and energy carriers and were estimated using own-price elasticities of demand. The methodology was demonstrated for a case study of Poland in the year 2015 applying different scenarios on economic development and trade in Europe. For the key technologies considered, i.e. medium density fibreboard, poly lactic acid, electricity and methanol production, GHG emission mitigation costs increase strongly with the scale of biomass production. Large-scale introduction of biomass use decreases the GHG emission reduction potential at costs below 50 €/Mg CO_2eq with about 13–70% depending on the scenario. Biomaterial production accounts for only a small part of this GHG emission reduction potential due to relatively small material markets and the subsequent strong decrease of biomaterial market prices at large scale of production. GHG emission mitigation costs depend strongly on biomass supply curves, own-price elasticity of land and market volumes of bioenergy carriers. The analysis shows that these influences should be taken into account for developing biomass implementations strategies.     

Future energy consumption and greenhouse gas emissions in Jordanian industries

Most, i.e. 85%, of greenhouse gas (GHG) emissions in Jordan emanate as a result of fossil fuel combustion. The industrial sector consumed 23.3% of the total national fuel consumption for heat and electric-power generation in 1999. The CO₂ emissions from energy use in manufacturing processes represent 12.1% of the total national CO₂ emissions. Carbon dioxide is also released as a result of the calcining of carbonates during the manufacture of cement and iron. Electricity, which is the most expensive form of energy, in 1999 represented 45% of total fuel used for heat and power nationally. Heavy fuel oil and diesel oil represented 46% and 7%, respectively, of all energy used by industry. Scenarios for future energy-demands and the emissions of gaseous pollutants, including GHGs, have been predicted for the industrial sector. For these, the development of a baseline scenario relied on historical data concerning consumption, major industries’ outputs, as well as upon pertinent published governmental policies and plans. Possible mitigation options that could lead to a reduction in GHG emissions are assessed, with the aim of achieving a 10% reduction by 2010, compared with the baseline scenario. Many viable CO₂ emission mitigation measures have been identified for the industrial sector, and some of these can be considered as attractive opportunities due to the low financial investments required and short pay back periods. These mitigation options have been selected on the basis of low GHG emission rates and expert judgement as to their viability for wide-scale implementation and economic benefits. The predictions show that the use of more efficient lighting and motors, advanced energy systems and more effective boilers and furnaces will result in a significant reduction in the rates of GHG emissions at an initial cost of between 30 and 90 US$ t⁻¹ of CO₂ release avoided. However, most of these measures have a negative cost per ton of CO₂ reduced, indicating short pay-back periods for the capital investments needed.     

Long-term implications of alternative light-duty vehicle technologies for global greenhouse gas emissions and primary energy demands

This study assesses global light-duty vehicle (LDV) transport in the upcoming century, and the implications of vehicle technology advancement and fuel-switching on greenhouse gas emissions and primary energy demands. Five different vehicle technology scenarios are analyzed with and without a CO₂ emissions mitigation policy using the GCAM integrated assessment model: a reference internal combustion engine vehicle scenario, an advanced internal combustion engine vehicle scenario, and three alternative fuel vehicle scenarios in which all LDVs are switched to natural gas, electricity, or hydrogen by 2050. The emissions mitigation policy is a global CO₂ emissions price pathway that achieves 450 ppmv CO₂ at the end of the century with reference vehicle technologies. The scenarios demonstrate considerable emissions mitigation potential from LDV technology; with and without emissions pricing, global CO₂ concentrations in 2095 are reduced about 10 ppmv by advanced ICEV technologies and natural gas vehicles, and 25 ppmv by electric or hydrogen vehicles. All technological advances in vehicles are important for reducing the oil demands of LDV transport and their corresponding CO₂ emissions. Among advanced and alternative vehicle technologies, electricity- and hydrogen-powered vehicles are especially valuable for reducing whole-system emissions and total primary energy.     

Greenhouse gases (GHG) emissions reduction in a power system predominantly based on lignite

In this paper the GHG mitigation potential of a power system with prevailing use of lignite is assessed through the example of the Macedonian power system. The analysis is conducted using the WASP model in order to develop three different scenarios (business as usual - BAU and two mitigation scenarios) for the power system expansion over the period 2008-2025. In the first mitigation scenario two gas power plants with combined cycle are planned to replace some of the lignite-based capacities. The second mitigation scenario, besides the gas power plants, assumes electricity consumption reduction related to the large industrial consumers and an increased share of new renewable energy sources. Detailed calculations of the GHG emissions are made for all scenarios. The comparison of emissions in 2025 and in 2008 shows that the increase of 78% in the case of predominantly lignite BAU scenario is reduced to 41% by the first mitigation scenario, and to 14% by the second mitigation scenario. The mitigation costs appeared to be less then 10 $/t CO₂-eq for the first mitigation scenario, and even negative for the second one.     

Energy policy tools for agricultural residues utilization for heat and power generation: A case study of sugarcane trash in Thailand

Cane trash could viably substitute fossil fuels in heat and power generation projects to avoid air pollution from open burning and reduce greenhouse gas (GHG) emission. It is competitive with bituminous and other agro-industrial biomass. Using cane trash for heat generation project could provide a higher reliability and return on investment than power generation project. The heat generation project could be viable (Financial Internal Rate of Return, FIRR = 36–81%) without feedstock subsidy. With current investment and support conditions, the capacity of 5 MW option of power generation project is the most viable (FIRR = 13.6–15.3%); but 30 MW, 1 MW and 10 MW options require feedstock subsidy 450–1100 Baht/t-cane trash to strengthen financial viability. Furthermore, the revenue from carbon credit sales could compensate the revenue from current energy price adder and increases 0.5–1.0% FIRR of power generation project. Using cane trash for 1 MW power generation could reduce GHG emission 637–861 t CO₂eq and avoid air pollutant emissions of 3.35 kg nitrogen oxides (NO_x), 0.41 kg sulfur oxides (SO_x) and 2.05 kg volatile organic compounds (VOC). Also, 1 t steam generation from cane trash could avoid pollutant emissions of 0.6 kg NO_x, 0.07 kg SO_x, and 0.37 kg VOC. The potential of cane trash to cause fouling/slagging as well as erosion are not significantly different from other biomass, but chlorinated organic compounds and NO_x could be higher than bituminous and current biomass feedstock at sugar mill (bagasse and rice husk).