Search

Abstract: This paper presents the results of adding a CCS(Carbon Capture and Storage) plant including an underground CO2 storage to a well described and well documented vision of converting the present Danish fossil based energy system into a future sustainable energy system made by the Danish Society of Engineers. The analyses point in the direction that in such context a CCS investment is not a suitable way to decrease CO2 emissions. Other alternatives are more cost effective and will fit better into the long-term implementation of sustainable energy systems. The reason is that CCS investments involve huge construction costs with the expectation of long lifetimes. Consequently, the CCS has to operate as part of large-scale power or CHP plants with high utilisation hours for the CCS investment to come even close to being feasible. However, seen in the light of transforming to sustainable energy systems, the number of utilisation hours of power and CHP plants will have to decrease substantially due to the energy efficiency measures in combination with the inclusion of renewable energy power inputs from wind and similar resources. Consequently, no power or CHP plants exist in future sustainable energy systems with sufficient utilisation hours to justify a CCS plant. [Copyright &y& Elsevier]

Abstract: In this paper we analyze the role of changes in the fuel mix on emissions reduction and the diversification of risks associated to rising prices of energy. To this purpose we evaluate the average cost and the cost volatility of alternative fuel combinations in the road transport sector by means of the Mean–Variance Portfolio Theory. The results suggest big gains in diversification of risks and emissions reduction associated with shifts away the current fuel mix, which is more than 90% concentrated worldwide in fossil fuels. Those shifts are discussed vis à vis the policy recommendations of the International Energy Agency on fuel use in the transport sector, and both the business as usual and the low carbon scenarios of the European Commission. In particular, shifting toward an efficient system would involve optimizing the use of biofuels (mostly from endogenous feedstock), with second generation biofuels taking the lead in the long-run, and this combined with electricity from clean sources. This scenario would mean reducing cost volatility by more than 50% as well as CO2 emissions by more than 30% in the long-run. [Copyright &y& Elsevier]

Abstract: Petroleum oil refineries account for almost 8% of the total CO2 emissions from industry in the European Union (EU). In this paper, the European petroleum refining industry is investigated and the prospects for future CO2 abatement in relation to associated infrastructure are assessed. A more efficient use of the adjacent infrastructure, e.g., district heating networks, natural gas grids, neighbouring industries, and CO2 transport and storage systems, could provide opportunities for additional CO2 emissions reduction. It is shown that access to infrastructures that can facilitate CO2 abatement varies significantly across countries and between individual refineries. The assessment shows that short-term mitigation options, i.e., fuel substitution and energy efficiency measures, could reduce CO2 emissions by 9–40 MtCO2/year (6–26% of the total refinery emissions). It is further shown that carbon capture and storage offers the greatest potential for more significant emission reductions in the longer term. However, the potential for CO2 capture varies significantly depending on the choice of technology, CO2 source, and scope of implementation (5–80% of the total refinery emissions). [Copyright &y& Elsevier]

Abstract: In current policies, targets for GHG (greenhouse gas) and more specifically CO2 emissions are set on the basis of annual emissions. However, warming effects associated with global average temperature rise depend on accumulation of GHG in the atmosphere. Due to the quantity and longevity of CO2 in the atmosphere there is increasing awareness that taking into account cumulative CO2 emissions in defining targets for restraining the growth of CO2 emissions would be particularly effective. The notion of effectiveness is linked to measuring the degree of achievement of the objectives. Considering CO2 emissions targets set over a few decades, the path of emissions reduction contains relevant information that cannot be captured by a classical measure like the distance to the target. The main contribution of this paper is the definition of an original measure of carbon dioxide reduction effectiveness, which allows comparison of specified CO2 reduction paths expressed in deterministic or probabilistic ways. Appropriate metrics are used to illustrate the proposed measure which in particular captures the importance of early action. The measure is applied to simple what-if scenarios for the EU27 electricity and heat sector to 2050, evaluating the impact of each scenario with respect to a reference case. [Copyright &y& Elsevier]

Abstract: This paper presents the development and use of an optimisation model suitable for analysis of biofuel production scenarios in the EU, with the aim of examining second generation biofuel production. Two policy instruments are considered – targeted biofuel support and a CO2 cost. The results show that over 3% of the total transport fuel demand can be met by second generation biofuels at a cost of approximately 65-73 EUR/MWh. With current energy prices, this demands biofuel support comparable to existing tax exemptions (around 30 EUR/MWh), or a CO2 cost of around 60 EUR/tCO2. Parameters having large effect on biofuel production include feedstock availability, fossil fuel price and capital costs. It is concluded that in order to avoid suboptimal energy systems, heat and electricity applications should also be included when evaluating optimal bioenergy use. It is also concluded that while forceful policies promoting biofuels may lead to a high biofuel share at reasonable costs, this is not a certain path towards maximised CO2 emission mitigation. Policies aiming to promote the use of bioenergy thus need to be carefully designed in order to avoid conflicts between different parts of the EU targets for renewable energy and CO2 emission mitigation. [Copyright &y& Elsevier]

Abstract: With the intensification of global warming, the issue of carbon emissions causes more and more attention in recent years. In this paper, China’s 30 provincial-level administrative units are divided into five emission regions according to the annual average value of provincial CO2 emissions per capita during 1990 and 2010. The regional differences in impact factors on CO2 emissions are discussed using STIRPAT (stochastic impacts by regression on population, affluence, and technology) model. The results indicate that although GDP (Gross domestic product) per capita, industrial structure, population, urbanization and technology level have different impacts on CO2 emissions in different emission regions, they are almost always the main factors in all emission regions. In most emission regions, urbanization and GDP per capita has a bigger impact on CO2 emissions than other factors. Improving technology level produces a small reduction in CO2 emissions in most emission regions, but it is still a primary way for CO2 reduction in China. It’s noteworthy that industrial structure isn’t the main factor and improving technology level increases CO2 emissions in high emission region. Different measures should be adopted for CO2 reductions according to local conditions in different regions. [Copyright &y& Elsevier]

Cool roofs are an inexpensive method to save energy and to improve the comfort level in buildings in mild and hot climates. A high scale implementation of cool roofs in Andalusia, in the south of Spain, could potentially save 295,000 kWh per year, considering only residential buildings with flat roofs using electrical heating. At the current energy prices, consumers can save 59 million euros annually in electricity costs and the emission of 136,000 metric tons of CO2 can be directly avoided every year from the production of that electricity. If radiative forcings are considered, Andalucía can potentially offset between 9.44 and 12 Mt of CO2. All the provinces in the rest of Spain are also studied in this paper. The biggest savings are achieved in Gran Canaria (48%), Tenerife (48%), Cádiz (36%), Murcia (33%), Huelva (30%), Málaga (29%), Almería (29%) and Sevilla (28%), where savings are greater than 2 euros per square meter of flat roof for old buildings with dark roofs. For the biggest cities the range of savings obtained are: between 7.4% and 11% in Madrid, between 12% and 18% in Barcelona and between 14% and 20% in Valencia. [Copyright &y& Elsevier]

In this paper, the global CO2 effect of integrating different biomass gasification concepts to meet an increasing demand of hydrogen in an oil refinery is examined and presented in comparison with a conventional steam reformer. The studied refinery is a hydro skimming refinery with a future hydrogen deficit of 16,000 Nm3/h. Three gasification concepts are considered: Entrained Flow (EF), Circulated Fluidised Bed (CFB) and Double Bed (DB). The system analysis is made with respect to global CO2 emissions and primary energy use. The results show that if biomass is considered as an unlimited resource (i.e. sufficient biomass is considered to be available to substitute for all fossil fuels in society), biomass gasification concepts have a potential to reduce CO2 emissions. The EF case shows the largest reduction potential. However, if biomass is considered as a limited resource (i.e. increased use of biomass at the refinery will lead to increased use of fossil fuel elsewhere in society), all concepts show an increase of CO2 emissions. Here, the CFB gasifier shows lowest increase of CO2 emission. The CO2 effect of the different alternatives shows sensitivity to assumptions regarding alternative biomass user. [Copyright &y& Elsevier]

The purpose of this paper is to present a new tool for design of integrated energy systems. The initial choice of the energy system components and the way they should interact is a crucial decision which the outcome of the design heavily relies on. Use of a physical law (instead of engineering judgment) as the basis of the decision making is the main advantage of the proposed approach over conventional approaches for design of community scale energy systems. The methodology has been implemented for design of a district heating system for an existing district in arid region of Iran. The optimum level of interaction between the energy system components has been identified by employing an optimization algorithm seeking to minimize the overall cost of the energy system. Some of the relative merits of the optimum design comparing to the present energy system are 17% increase of the exergy efficiency, 10.8% reduction in the amount of CO2 production per capita and 2% reduction in overall energy related costs. [Copyright &y& Elsevier]

Abstract: The aim of this paper is to provide a critical overview of sensitivity analyses within input-output techniques applied to energy-related CO2 emissions. A classification of those applications is presented and their main advantages and disadvantages are discussed. It is argued that sensitivity analyses within input-output techniques are very relevant to obtain a “map” of hot-spots of the production system, i.e., to identify the transactions between sectors which lead to a large impact on the generation of energy-related CO2 emissions. Possible extensions of this approach are discussed. [Copyright &y& Elsevier]

Abstract: China has been the second CO2 emitter in the world, while the transportation sector accounts for a major share of CO2 emissions. Analysis of transportation sector CO2 emissions is help to decrease CO2 emissions. Thus the purpose of this paper is to investigate the potential factors influencing the change of transport sector CO2 emissions in China. First, the transport sector CO2 emissions over the period 1985–2009 is calculated based on the presented method. Then the presented LMDI (logarithmic mean Divisia index) method is used to find the nature of the factors those influence the changes in transport sector CO2 emissions. We find that: (1) Transport sector CO2 emissions has increased from 79.67 Mt in 1985 to 887.34 Mt in 2009, following an annual growth rate of 10.56%. Highways transport is the biggest CO2 emitter. (2) The per capita economic activity effect and transportation modal shifting effect are found to be primarily responsible for driving transport sector CO2 emissions growth over the study period. (3) The transportation intensity effect and transportation services share effect are found to be the main drivers of the reduction of CO2 emissions in China. However, the emission coefficient effect plays a very minor role over the study period. [Copyright &y& Elsevier]

Abstract: This paper applies the co-integration technique and causality test to examine the dynamic relationships between pollutant emissions, energy use, and real output during the period between 1990 and 2007 for Russia. The empirical results show that in the long-run equilibrium, emissions appear to be energy use elastic and output inelastic. This elasticity suggests high energy use responsiveness to changes in emissions. The output exhibits a negative significant impact on emissions and does not support EKC hypothesis. These indicate that both economic growth and energy conservation policies can reduce emissions and no negative impact on economic development. The causality results indicate that there is a bidirectional strong Granger-causality running between output, energy use and emissions, and whenever a shock occurs in the system, each variable makes a short-run adjustment to restore the long-run equilibrium. The average speed of adjustment is as low as just over 0.26 years. Hence, in order to reduce emissions, the best environmental policy is to increase infrastructure investment to improve energy efficiency, and to step up energy conservation policies to reduce any unnecessary waste of energy. That is, energy conservation is expected to improve energy efficiency, thereby promoting economic growth. [Copyright &y& Elsevier]

Abstract: Based on the need to reduce CO2 emissions and minimize energy dependency, the EU Member States have set ambitious energy policies goals and have developed respective, specific regulations, in order to improve the energy performance of the building sector. Thus, specific measures regarding the buildings’ envelope, the use of efficient HVAC technologies and the integration of renewable energy systems are being constantly studied and promoted. The effective combination of these three main aspects will consequently result in maximum energy efficiency. Germany has played a key role in this development, with intensive work focusing in the improvement of the energy behaviour of the residential building stock. In this paper, the use of radiative heating systems placing special emphasis on infrared is being studied as part of the energy renovation of residential buildings from the 1970’s. This is done by applying an integrated assessment model to evaluate specific interventions regarding the improvement of the energy behaviour of the buildings’ envelope and the use of radiative heating systems, based on a thorough Life Cycle Analysis according to criteria of energy, economic and environmental performance, as well as thermal comfort. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: In the context of the present worldwide concern and desperate search for policies to curtail carbon dioxide emission, the paper aims to determine the roles of major driving forces in aggravating emission and examine the possibility of emission cut without compromising economic growth. Variance analysis method, in the line of management accounting, is used to decompose the changes in emission of 156 sample countries over the period 1993–2007. The major findings suggest that in aggregate, rising per capita GDP has been about seven times more responsible than that of population in accentuating emission; decline in energy intensity has been instrumental in offsetting nearly half of their potential effects, while inter-fuel substitution and change in emission intensities have meager roles. However, wide disparities in structural composition of energy intensity and emission intensity of fuels among countries over the period, point towards the crucial role of proper energy management in lowering emission concomitant with high economic growth. Management accounting control, particularly variance analysis, at the national level can be an effective tool in identifying the weaknesses and exploring the areas where emission reduction can be possible. [ABSTRACT FROM AUTHOR]

Abstract: This paper examines the impacts of CO2 emission reduction on future technology selection and energy use in Bangladesh power sector up to 2035 considering the base year 2005. It also examines the implications of CO2 emission reduction targets on energy security of the country. The analysis is based on a long-term energy system model of Bangladesh using the MARKAL framework. The results show that the introduction of the CO2 emission reduction targets directly affect the shift of technologies from high carbon content fossil-based to low carbon content fossil-based as well as clean, renewable energy-based technologies compared to the base scenario. With the CO2 emission reduction target of 10–30%, the cumulative net energy imports during 2005–2035 would be reduced in the range of over 1400PJ to 4898PJ compared to the base scenario emission level. The total primary energy requirement would be reduced in the range of 5.5–15.2% in the CO2 emission reduction targets and the primary energy supply system would be diversified compared to the base scenario. [ABSTRACT FROM AUTHOR]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: In this paper, three main steps allowing the definition of the sustainability of a wind power plant (WPP) are described in detail. The first step is to choose a site with a good wind potential. In this respect, two approaches have been introduced: traditional wind statistical estimations based on the identification of the Weibull probability density function on specific sites; and an innovative Kriging approach based on artificial neural networks to reconstruct the profile of the mean wind speed of the territory. In the second step, given technical details, the energetic sustainability of a WPP installation is assessed according to a model computing the wind energy production per year, as well as the details of its efficiency. Finally, as third step, a cost/benefit evaluation on the overall reduction in CO2 emissions with respect to traditional fossil fuel energy plants is reported. From a wind speed characterisation viewpoint, the case study is referred to the overall Moroccan territory. From a WPP model viewpoint, the case study is referred to the installation of a specific WPP, which would allow the production of more than 2GWh per year in the south Atlantic coast and of nearly 1GWh per year in the Mediterranean coast in the neighbourhood of Tangier. [ABSTRACT FROM AUTHOR]

Abstract: The paper highlights the energy dilemma in China’s modernization process. It explores the technological and policy options for the transition to a sustainable energy system in China with Tsinghua University’s Low Carbon Energy Model (LCEM). China has already taken intensive efforts to promote research, development, demonstration and commercialization of sustainable energy technologies over the past five year. The policy actions cover binding energy conservation and environmental pollution control targets, economic incentives for sustainable energy, and public R&D supports. In order to achieve the sustainable energy system transformation eventually, however, China needs to take further actions such as strengthening R&D of radically innovative sustainable energy technologies and systems such as poly-generation, enhancing the domestic manufacturing capacity of sustainable energy technologies and systems, creating stronger economic incentives for research, development, demonstration and commercialization of sustainable energy technologies, and playing a leading role in international technology collaborations. [ABSTRACT FROM AUTHOR]

A number of large-scale sequestration strategies have been considered to help mitigate rising levels of atmospheric carbon dioxide (CO2). Here, we use an ocean general circulation model (OGCM) to evaluate the efficiency of one such strategy currently receiving much attention, the direct injection of liquid CO2 into selected regions of the abyssal ocean. We find that currents typically transport the injected plumes quite far before they are able to return to the surface and release CO2 through air–sea gas exchange. When injected at sufficient depth (well within or below the main thermocline), most of the injected CO2 outgasses in high latitudes (mainly in the Southern Ocean) where vertical exchange is most favored. Virtually all OGCMs that have performed similar simulations confirm these global patterns, but regional differences are significant, leading efficiency estimates to vary widely among models even when identical protocols are followed. In this paper, we make a first attempt at reconciling some of these differences by performing a sensitivity analysis in one OGCM, the Princeton Modular Ocean Model. Using techniques we have developed to maintain both the modeled density structure and the absolute magnitude of the overturning circulation while varying important mixing parameters, we estimate the sensitivity of sequestration efficiency to the magnitude of vertical exchange within the low-latitude pycnocline. Combining these model results with available tracer data permits us to narrow the range of model behavior, which in turn places important constraints on sequestration efficiency. [Copyright &y& Elsevier]

This paper deals with the seasonal energy and environmental characterization of a commercial micro gas turbine fueled with hydrogen enriched natural gas blends, to implement a Power-to-Gas option. When the renewable electricity excess occurs in a hybrid system, that energy can be converted into hydrogen to increase micro-turbine environmental performance. The experimental approach consists of testing on field that device at rated and partial load over the hot and cold seasons. The energy and environmental performance, along with the method to properly allocate the pollutants emissions for such applications, have been presented when the hydrogen fraction ranges in 0% vol. - 10% vol, by means of a 2% vol. step. From the main findings it emerges that both heat recovery and electrical efficiency undergo a slight increase even if the machine is strongly affected by the environmental derating. However, the larger beneficial effects occurred over the summertime, since the hydrogen mixtures can partially offset the outdoor environmental conditions change. Indeed, beyond the hydrogen fraction of 6% vol. and beyond 15 kW of electric output, the enrichment increases the rotational speed providing a leaner combustion. In so doing, the CO emissions are equal to zero, while the NO x are almost constant. • Experimental analysis on Micro Gas Turbine fueled with hydrogen and Natural Gas. • Micro Gas Turbine seasonal energy and environmental characterization. • Electric and heat recovery efficiency evaluation in rated and partial loads. • Pollutants emissions assessment and carbon dioxide reduction. • The most effective method to allocate emissions hailing from Micro Gas Turbine. [ABSTRACT FROM AUTHOR]