Revisiting CO2 mitigation potential and costs in China’s electricity sector

To improve the reliability of sectoral mitigation potential and cost analysis, this paper made an in-depth exploration into China’s electricity sector’s thermal efficiency and inner structure. It is found that unlike what many literatures portray, China is actually among the world’s leaders in coal-fired power plants’ generating efficiencies; besides, although there are still numerous small and inefficient generating units in the current generation fleet, many of them are in fact playing important roles in supporting local economic development, meeting peak load needs, balancing heat and electricity supply and providing job opportunities to the local economy, therefore their existence does not necessarily mean low-cost mitigation potential. Given the efficiency and structural characteristics of China’s electricity sector, it is pointed out that some other mitigation options, such as demand side management, IGCC and renewable energy as well as the break-through of CCS technology may play an even more important role in emission reduction. Considering the significant lock-in effects in electricity sector, it is warned that China, if continues putting majority investment in large and advanced coal-fired generating units, will face another round of chasing-after for the new and advanced renewable generation technologies. Therefore China should put more efforts in renewable generation technologies now.     

Interactions between measures for the support of electricity from renewable energy sources and CO2 mitigation

As Europe wants to move towards a secure, sustainable and competitive energy market, it has taken action, amongst other, to support electricity from renewable energy sources (RES-E) and to mitigate CO₂ emissions. This paper first qualitatively discusses price- and quantity-based measures for RES-E deployment as well as CO₂ mitigation. Next, a simulation model is developed to quantitatively discuss the effects of a tradable green certificate system, a premium mechanism, a tradable CO₂ allowance system and a CO₂ tax on both RES-E deployment and CO₂ mitigation. A three-regional model implementation representing the Benelux, France and Germany is used. In a first step of simulations, all measures are implemented separately. In a second step, combinations of both RES-E supporting and CO₂ mitigating measures are simulated and discussed. Significant indirect effects are demonstrated, especially for RES-E supporting measures on the reduction of CO₂ emissions. Interactions between different measures show that the price level of quantity-based measures can be strongly influenced.     

Challenges for CO2 mitigation in the Lebanese electric-power sector

Similar to other developing countries the electricity sector in Lebanon is monopolized by a vertically integrated public utility, Electricite Du Liban (EDL). EDL's supply is characterized by frequent and lengthy power cuts that have given rise to an alternative, informal, and unregulated backup sector, which serves to satisfy electricity demand during the extended blackout periods. This paper examines the evolvement of the backup sector and its related CO₂ emissions via the use of scenario analysis. The economic and energy policy implications of each scenario are discussed and a number of policy options are presented to ensure that the growth in CO₂ emissions is contained. Results clearly indicate that the backup sector plays a critical role in the success of any greenhouse gas mitigation commitment undertaken by Lebanon. A clear strategy on dealing with this sector needs to be devised simultaneously if not prior to any climate change policy at the national level.     

Achieving 60% CO2 reductions within the UK energy system—Implications for the electricity generation sector

This paper explores how investment in the UK electricity generation sector can contribute to the UK goal of reducing CO₂ emissions with 60% by the year 2050 relative to the 1990 emissions. Considering likely development of the transportation sector and industry over the period, i.e. a continued demand growth and dependency on fossil fuels and electricity, the analysis shows that this implies CO₂ emission reductions of up to 90% by 2050 for the electricity sector. Emphasis is put on limitations imposed by the present system, described by a detailed database of existing power plants, together with meeting targets on renewable electricity generation (RES) including assumptions on gas acting as backup technology for intermittent RES. In particular, it is investigated to what extent new fossil fuelled and nuclear power is required to meet the year 2050 demand as specified by the Royal Commission on Environmental Pollution (RCEP). In addition, the number of sites required for centralized electricity generation (large power plants) is compared with the present number of sites. A simulation model was developed for the analysis. The model applies the UK national targets on RES, taken from Renewable Obligation (RO) for 2010 and 2020 and potentials given by RCEP for 2050, and assumed technical lifetimes of the power plants of the existing system and thus, links this system with targets for the years 2010, 2020 and 2050.     

Abatement costs of CO2 emissions in the Brazilian oil refining sector

This study aims at estimating the abatement costs of CO₂ emissions of the Brazilian oil refining sector. For greenfield refineries that will be built until 2030, mitigation options include the modification of refining schemes and efficiency gains in processing units. For existing refineries and those already under construction, only mitigation options based on efficiency gains in processing units are evaluated. The abatement cost of each mitigation option was determined on the basis of incremental costs compared with a reference scenario. Two discount rates were applied: one adopted by the Brazil’s government official long term plan (8% p.a.), and another typically adopted by the private oil sector (15% p.a.). Findings indicate that refineries face high abatement costs. The cost of changing the processing scheme of greenfield plants reaches US$100/tCO₂ at 15% p.a. discount rate. Even at 8% p.a. discount rate the abatement cost is higher than US$50/tCO₂. The most promising alternative is thermal energy management, whose abatement cost equals US$20/tCO₂ at 8% p.a. discount rate. However, private investors perceive this option at US$80/tCO₂, which is still high. This difference in cost indicates the need for public policies for promoting carbon mitigation measures in Brazilian oil refineries.     

Scenario analysis on CO2 emissions reduction potential in China''s electricity sector

With the approach of the year 2012, a new round of international negotiations has energized the entire climate change community. With this, analyses on sector-based emissions reduction and mitigation options will provide the necessary information to form the debate. In order to assess the CO₂ emissions reduction potential of China's electricity sector, this research employs three scenarios based on the “long-range energy alternative planning system” (LEAP) model to simulate the different development paths in this sector. The baseline scenario, the current policy scenario, and the new policy scenario seek to gradually increase the extent of industrial restructuring and technical advancement. Results imply that energy consumption and CO₂ emission in China's electricity sector will rise rapidly in all scenarios until 2030—triple or quadruple the 2000 level; however, through structural adjustment in China's electricity sector, and through implementing technical mitigation measures, various degrees of abatement can be achieved. These reductions range from 85 to 350 million tons CO₂ per year—figures that correspond to different degrees of cost and investment. Demand side management and circulating fluidized bed combustion (CFBC) (ranked in order) are employed prior to use to realize emissions reduction, followed by supercritical plants and the renovation of conventional thermal power plants. In the long term, nuclear and hydropower will play the dominant role in contributing to emissions reduction. It is also suggested that a “self-restraint” reduction commitment should be employed to help contribute to the reduction of emission intensity, an avenue that is more practical for China in light of its current development phase. Setting the year 2000 as the base year, the intensity reduction target could possibly range from 4.2% to 19.4%, dependent on the implementation effectiveness of various mitigation options.     

CO2 emission from China's energy sector and strategy for its control

This paper identifies the main features of CO₂ emission from fossil energy combustion in China. Then it estimates China's future energy requirements and projects its CO₂ emission from 2010 to 2020 based on the scenario analysis approach. China's rate of carbon productivity growth is estimated to be 5.4% in the period 2005–2020, while the CO₂ intensity of GDP will reduce by about 50% but CO₂ emission in 2020 will still be about 40% higher than prevailing in 2005 because of rapid growth of GDP. This estimation is based on the assumption that China will implement a sustainable development strategy in consideration of climate change issues. The main objectives of the strategy are to implement an “energy conservation first” strategy, to develop renewable energy and advanced nuclear technology actively, to readjust the country's economic structure, and to formulate and legislate laws and regulations, and to build institutions for energy conservation and development of renewable energy. It concludes that international measures to mitigate CO₂ emission will limit world fossil fuel consumption. China is not placed to replicate the modernization model adopted by developed countries and has to coordinate economic development and carbon dioxide emission control while still in the process of industrialization and modernization. China has to evolve a low carbon industrialization model. This is the key to the success of sustainable development initiatives in China.     

Renewable energy sources in the Mexican electricity sector

This paper analyzes the role of renewable energy sources (RES) in the Mexican electricity sector in the context of the proposed renewable energy bill currently under consideration in the Mexican Congress. This paper was divided into three parts. The first part presents a chronology of institutional background related to the RES. This is followed by an analysis of the coordination and management system of the Mexican electricity sector, which can facilitate the promotion and integration of the RES without significant structural changes. Finally, the pros and cons of the renewable energy bill are analyzed in order to demonstrate the need for greater coherence between the bill and the coordination system of the sector. It is concluded that when inconsistency is eliminated, RES would strongly be promoted in Mexico.     

CO2 emissions,nuclear energy,renewable energy and economic growth in the US

This study explores the causal relationship between carbon dioxide (CO₂) emissions, renewable and nuclear energy consumption and real GDP for the US for the period 1960–2007. Using a modified version of the Granger causality test, we found a unidirectional causality running from nuclear energy consumption to CO₂ emissions without feedback but no causality running from renewable energy to CO₂ emissions. The econometric evidence seems to suggest that nuclear energy consumption can help to mitigate CO₂ emissions, but so far, renewable energy consumption has not reached a level where it can make a significant contribution to emissions reduction.     

The assessment of renewable energy planning on CO2 abatement in South Korea

Sources of renewable energies (for example landfill gas, wind, solar energy) are environmentally friendly and electric power generation in South Korea has concentrated on new and renewable energy technologies. The purpose of this paper is to study the economic and environmental influence of renewable energies on existing electricity generation market of South Korea with energy-economic model called ‘Long-range Energy Alternative Planning system’ and the associated ‘Technology and Environmental Database’. Business as usual scenario was based on energy supply planning with existing power plant. And then, the alternative scenarios were considered, namely the base case with existing electricity facilities, the installation plan of different renewable energy facilities, technological improvement and process dispatch rule according to merit order change. In each alternative scenario analysis, alternation trend of existing electricity generation facilities is analyzed and the cost of installed renewable energy plants and CO₂ reduction potential was assessed quantitatively.     

High capacity potassium-promoted hydrotalcite for CO2 capture in H2 production

This paper presents an experimental study for a newly modified K₂CO₃-promoted hydrotalcite material as a novel high capacity sorbent for in-situ CO₂ capture. The sorbent is employed in the sorption enhanced steam reforming process for an efficient H₂ production at low temperature (400–500 ^°C). A new set of adsorption data is reported for CO₂ adsorption over K-hydrotalcite at 400 °C. The equilibrium sorption data obtained from a column apparatus can be adequately described by a Freundlich isotherm. The sorbent shows fast adsorption rates and attains a relatively high sorption capacity of 0.95 mol/kg on the fresh sorbent. CO₂ desorption experiments are conducted to examine the effect of humidity content in the gas purge and the regeneration time on CO₂ desorption rates. A large portion of CO₂ is easily recovered in the first few minutes of a desorption cycle due to a fast desorption step, which is associated with a physi/chemisorption step on the monolayer surface of the fresh sorbent. The complete recovery of CO₂ was then achieved in a slower desorption step associated with a reversible chemisorption in a multi-layer surface of the sorbent. The sorbent shows a loss of 8% of its fresh capacity due to an irreversible chemisorption, however, it preserves a stable working capacity of about 0.89 mol/kg, suggesting a reversible chemisorption process. The sorbent also presents a good cyclic thermal stability in the temperature range of 400–500 °C.     

Solar energy powered Rankine cycle using supercritical CO2

A solar energy powered Rankine cycle using supercritical CO₂ for combined production of electricity and thermal energy is proposed. The proposed system consists of evacuated solar collectors, power generating turbine, high-temperature heat recovery system, low-temperature heat recovery system, and feed pump. The system utilizes evacuated solar collectors to convert CO₂ into high-temperature supercritical state, used to drive a turbine and thereby produce mechanical energy and hence electricity. The system also recovers heat (high-temperature heat and low-temperature heat), which could be used for refrigeration, air conditioning, hot water supply, etc. in domestic or commercial buildings. An experimental prototype has been designed and constructed. The prototype system has been tested under typical summer conditions in Kyoto, Japan; It was found that CO₂ is efficiently converted into high-temperature supercritical state, of while electricity and hot water can be generated. The experimental results show that the solar energy powered Rankine cycle using CO₂ works stably in a trans-critical region. The estimated power generation efficiency is 0.25 and heat recovery efficiency is 0.65. This study shows the potential of the application of the solar-powered Rankine cycle using supercritical CO₂.     

Estimating marginal CO2 emissions rates for national electricity systems

The carbon dioxide (CO₂) emissions reduction afforded by a demand-side intervention in the electricity system is typically assessed by means of an assumed grid emissions rate, which measures the CO₂ intensity of electricity not used as a result of the intervention. This emissions rate is called the “marginal emissions factor” (MEF). Accurate estimation of MEFs is crucial for performance assessment because their application leads to decisions regarding the relative merits of CO₂ reduction strategies. This article contributes to formulating the principles by which MEFs are estimated, highlighting the strengths and weaknesses in existing approaches, and presenting an alternative based on the observed behaviour of power stations. The case of Great Britain is considered, demonstrating an MEF of 0.69 kgCO₂/kW h for 2002–2009, with error bars at +/−10%. This value could reduce to 0.6 kgCO₂/kW h over the next decade under planned changes to the underlying generation mix, and could further reduce to approximately 0.51 kgCO₂/kW h before 2025 if all power stations commissioned pre-1970 are replaced by their modern counterparts. Given that these rates are higher than commonly applied system-average or assumed “long term marginal” emissions rates, it is concluded that maintenance of an improved understanding of MEFs is valuable to better inform policy decisions.     

H2 processes with CO2 mitigation: Thermo-economic modeling and process integration

Within the challenge of greenhouse gas reduction, hydrogen is regarded as a promising decarbonized energy vector. The hydrogen production by natural gas reforming and lignocellulosic biomass gasification are systematically analyzed by developing thermo-economic models. Taking into account thermodynamic, economic and environmental factors, process options with CO₂ mitigation are compared and optimized by combining flowsheeting with process integration, economic analysis and life cycle assessment in a multi-objective optimization framework. The systems performance is improved by introducing process integration maximizing the heat recovery and valorizing the waste heat. Energy efficiencies up to 80% and production costs of 12.5–42 $/GJH₂${\text{GJ}}_{{\text{H}}_2}$ are computed for natural gas H₂ processes compared to 60% and 29–61 $/GJH₂${\text{GJ}}_{{\text{H}}_2}$ for biomass processes. Compared to processes without CO₂ mitigation, the CO₂ avoidance costs are in the range of 14–306 $/tCO_2,avoided${\text{t}}_{{\text{CO}}_2,\text{avoided}}$. The study shows that the thermo-chemical H₂ production has to be analyzed as a polygeneration unit producing hydrogen, captured CO₂, heat and electricity.     

Towards the hydrogen era using near-zero CO2 emissions energy systems

In this paper, the integration of a solid oxide fuel cell operating at a very high temperature (900–1000 °C, 55–60% efficiency) in a near-zero emission power cycle is presented. A more efficient and powerful hybrid near-zero emission CO₂/O₂ cycle is obtained with a CO₂ release as small as 6 g CO₂/kW h_e. Based on a trade-off analysis, the net efficiency is around 47–48%, similar to a current one-pressure level natural gas fired combined cycle, and the power output (940 kW_e) is increased by 66% compared to the so-called E-MATIANT cycle but currently at a much higher cost than those of other known zero-emission power cycles.     

Decomposition analysis and mitigation strategies of CO2 emissions from energy consumption in South Korea

Energy-related CO₂ emissions in South Korea have increased substantially, outpacing those of Organisation for Economic Co-operation and Development (OECD) countries since 1990. To mitigate CO₂ emissions in South Korea, we need to understand the main contributing factors to rising CO₂ levels as part of the effort toward developing targeted policies. This paper aims to analyze the specific trends and influencing factors that have caused changes in emissions patterns in South Korea over a 15-year period. To this end, we employed the Log Mean Divisia index method with five energy consumption sectors and seven sub-sectors in terms of fuel mix (FM), energy intensity (EI), structural change (SC) and economic growth (EG). The results showed that EG was a dominant explanation for the increase in CO₂ emissions in all of the sectors. The results also demonstrated that FM causes CO₂ reduction across the array of sectors with the exception of the energy supply sector. CO₂ reduction as a function of SC was also observed in manufacturing, services and residential sectors. Furthermore, EI was an important driver of CO₂ reduction in most sectors except for several manufacturing sub-sectors. Based on these findings, it appears that South Korea should implement climate change policies that consider the specific influential factors associated with increasing CO₂ emissions in each sector.     

CO2 emissions,electricity consumption and output in ASEAN

This study examines the causal relationship between carbon dioxide emissions, electricity consumption and economic growth within a panel vector error correction model for five ASEAN countries over the period 1980–2006. The long-run estimates indicate that there is a statistically significant positive association between electricity consumption and emissions and a non-linear relationship between emissions and real output, consistent with the environmental Kuznets curve. The long-run estimates, however, do not indicate the direction of causality between the variables. The results from the Granger causality tests suggest that in the long-run there is unidirectional Granger causality running from electricity consumption and emissions to economic growth. The results also point to unidirectional Granger causality running from emissions to electricity consumption in the short-run.     

Technologies and costs of SO2-emissions reduction for the energy sector

The emissions limits, which are currently harder to meet than a few years ago, foster energy sector entrepreneurs to consider the possibilities of economically efficient emissions-reductions at their power plants. Within this paper the main methods of sulphur dioxide reduction will be described. The second problem considered in this paper is related to the economic aspect of emissions reduction. The choice of the method is often based on the comparison of costs associated with the appropriate methods. Therefore, for the technologies described, the average reduction costs will be presented and the most efficient way will be highlighted.     

Energy saving and CO2 mitigation through restructuring Jordan's transportation sector: The diesel passenger cars scenario

The transportation sector is responsible for 37% of the total final energy consumption in Jordan, with passenger cars taking a share of 57% in this sector. Improvement of the energy efficiency of the transportation sector can help in alleviating socio-economic pressures resulting from the inflating fuel bill and in lowering the relatively high CO₂ emission intensity. Current legislations mandate that all passenger cars operating in Jordan are to be powered with spark ignition engines using gasoline fuel. This paper examines potential benefits that can be achieved through the introduction of diesel cars to the passenger cars market in Jordan. Three scenarios are suggested for implementation and investigated with a forecasting model on the basis of local and global trends over the period 2007–2027. It is demonstrated that introducing diesel passenger cars can slow down the growth of energy consumption in the transportation sector resulting in significant savings in the national fuel bill. It is also shown that this is an effective and feasible option for cutting down CO₂ emissions.