Decomposition analysis of CO2 emission in long-term climate stabilization scenarios

To achieve the stabilization of greenhouse gas (GHG) concentrations in the atmosphere, the international community will need to intensify its long-term efforts. Many EU countries have released national long-term scenarios toward 2050, and their ambitious targets for CO₂ emission reduction are aiming at a decrease of more than 50% of today's emission. In April 2004, Japan began a research project on its long-term climate policy. This paper discusses the long-term scenarios in other countries and the medium-term scenarios in Japan to support the development of a Japan's long-term climate stabilization scenario. In this study, CO₂ emission is decomposed with an extended Kaya identity (indexes: CO₂ capture and storage, carbon intensity, energy efficiency, energy intensity, economic activity) and a Reduction Balance Table is developed.     

Spanish energy roadmap to 2020: Socioeconomic implications of renewable targets

The European Union has established challenging targets for the share of renewable energies to be achieved by 2020; for Spain, 20% of the final energy consumption must be from renewable sources at such time. The aim of this paper is the analysis of the consequences for the electricity sector (in terms of excess cost of electricity, investment requirements, land occupation, CO₂ emissions and overcapacity of conventional power) of several possibilities to comply with the desired targets. Scenarios are created from different hypotheses for energy demand, biofuel share in final energy in transport, contribution of renewables for heating and cooling, renewable electricity generation (generation mix, deployment rate, learning curves, land availability) and conventional power generation (lifetime of current installations, committed deployment, fossil fuel costs and CO₂ emissions cost). A key input in the estimations presented is the technical potential and the cost of electricity from renewable sources, which have been estimated in previous, detailed studies by the present authors using a methodology based on a GIS (Geographical Information System) and high resolution meteorological data. Depending on the scenario, the attainment of the targets will lead to an increase in the cost of electricity from 19% to 37% with respect to 2007.     

Modelling the impacts of a carbon emission-differentiated vehicle tax system on CO2 emissions intensity from new vehicle purchases in Ireland

The increasing awareness of the effects of climate change on the environment and the economic pressure on oil supply has focused international attention on reducing CO₂ emissions and energy usage across all sectors. In order to meet their Kyoto protocol commitments and in line with European Union policy, the Irish government has introduced a carbon-based tax system for new vehicles purchased from the 1st of July 2008. This new legislation aims to reduce carbon emissions in the transport sector, a sector which is responsible for a significant proportion of both. This paper presents the results of the development, calibration, and application of a car choice model which predicts the changes in CO₂ emissions intensity from new vehicle purchases as a result of the changes in vehicle tax policy and fuel price in Ireland. The model also predicts the impact of such changes on tax revenue for the Irish government and the changes in the split between the number of diesel and petrol vehicles purchased. The investigation found that the introduction of these new carbon-based taxes in Ireland will result in a reduction of 3.6–3.8% in CO₂ emissions intensity and a reduction in annual tax revenue of €191 M.     

Thermodynamics of hydrogen production from urea by steam reforming with and without in situ carbon dioxide sorption

The thermodynamic effects of molar steam to carbon ratio (S:C), of pressure, and of having CaO present on the H₂ yield and enthalpy balance of urea steam reforming were investigated. At a S:C of 3 the presence of CaO increased the H₂ yield from 2.6 mol H₂/mol urea feed at 940 K to 2.9 at 890 K, and decreased the enthalpy of bringing the system to equilibrium. A minimum enthalpy of 180.4 kJ was required to produce 1 mol of H₂ at 880 K. This decreased to 94.0 kJ at 660 K with CaO-based CO₂ sorption and, when including a regeneration step of the CaCO₃ at 1170 K, to 173 kJ at 720 K. The presence of CaO allowed widening the range of viable operation at lower temperature and significantly inhibited carbon formation. The feasibility of producing H₂ from renewable urea in a low carbon future is discussed.     

Natural emissions of CO2 from the geosphere and their bearing on the geological storage of carbon dioxide

Carbon dioxide (CO₂) capture and storage has the potential to reduce CO₂ emissions from fossil fuel combustion. Although leakage from monitored CO₂ injection sites has been minimal to non-existent, experience from the natural gas storage industry suggests that, if it becomes a widely deployed technology, leaks may be expected from some storage sites. Natural occurrences of CO₂ in the geosphere, some of which have been exploited, provide insights into the types of emissions that might be expected from anthropogenic CO₂ storage sites. CO₂ emission sites are commonly found in clusters in CO₂-prone geological provinces: the most common natural emissions sites in sedimentary basins consist of carbonated springs and mofettes. These represent at worst only a local hazard. In volcanic and hydrothermal provinces, more energetic emissions may occur due to active supply from degassing magma. These include rare, sudden emissions from fissures and craters that have caused fatalities. It is unlikely that such provinces would be considered for CO₂ storage Major lake overturn events such as occurred at Lake Nyos in 1986 are considered highly unlikely to occur as a result of CO₂ storage, not least because CO₂ levels in lake waters can be monitored and remediated. Natural CO₂ fields indicate that under favourable conditions CO₂ can be retained in the subsurface for millions of years. The main risk from man-made CO₂ storage sites that does not have any close analogy in nature is considered to be a well blowout. A blowout that took place at a natural CO₂ field provides some indication of the likely hazard.     

A sectoral decomposition analysis of Turkish CO2 emissions over 1990–2007

At a time of increased international concern and negotiations for greenhouse gas emission reduction, country studies on the underlying effects of greenhouse gas emission growth gain importance. The case of Turkey is particularly interesting due to rapidly growing emissions, accompanied by a political will and actions to reduce the quick growth. The refined Laspeyres method is used in this study to identify factors that accelerate or reduce the increase in Turkish CO₂ emissions. A year-by-year decomposition over 1990-2007 is carried out at sectoral level based on disaggregated data that is consistent over time and consistent with international standards. Various interesting results on the underlying effects of sectoral emission growth are found. Valuable insights are gained into CO₂ impacts of sectoral policies including energy and emission intensities, fuel switching and activity changes. The results yield important hints for the planning of energy and climate policy.     

Evaluating carbon dioxide emissions in international trade of China

China is the world's largest emitter of carbon dioxide (CO₂). As exports account for about one-third of China's GDP, the CO₂ emissions are related to not only China's own consumption but also external demand. Using the input–output analysis (IOA), we analyze the embodied CO₂ emissions of China's import and export. Our results show that about 3357 million tons CO₂ emissions were embodied in the exports and the emissions avoided by imports (EAI) were 2333 million tons in 2005. The average contribution to embodied emission factors by electricity generation was over 35%. And that by cement production was about 20%. It implies that the production-based emissions of China are more than the consumption-based emissions, which is evidence that carbon leakage occurs under the current climate policies and international trade rules. In addition to the call for a new global framework to allocate emission responsibilities, China should make great efforts to improve its energy efficiency, carry out electricity pricing reforms and increase renewable energy. In particular, to use advanced technology in cement production will be helpful to China's CO₂ abatement.     

A long-term view of fossil-fuelled power generation in Europe

The paper presents a view into the long term future of fossil-fuelled power generation in the European Union, based on a number of alternative scenarios for the development of the coal, natural gas and CO₂ markets, and the penetration of renewable and nuclear technologies. The new fossil fuelled capacity needed and the likely technology mix are estimated using a cost optimisation model based on the screening curve method, taking into consideration the rate of retirement of the current power plant fleet, the capacity already planned or under construction and the role of carbon capture and storage technologies. This analysis shows that measures to increase both non-fossil-fuel-based power generation and the price of CO₂ are necessary to drive the composition of the European power generation capacity so that the European policy goal of reducing greenhouse gas emissions is achieved. Meeting this goal will however require a high capital investment for the creation of an optimal fossil fuel power plant technology mix.     

Determinants of carbon dioxide emissions: Empirical evidence from 69 countries

This study investigates the determinants of carbon dioxide emissions (CO₂) for a global panel consisting of 69 countries using a dynamic panel data model. To make the panel data analysis more homogenous, we also investigate the determinants of CO₂ emissions for a number of sub-panels. These sub-panels are constructed based on the income level of countries. In this way, we end up with three income panels; namely, high income, middle income, and low income panels. The time component of our dataset is 1985–2005 inclusive. Our main findings are that trade openness, per capita GDP, and energy consumption, proxied by per capita electric power consumption and per capita total primary energy consumption, have positive effects on CO₂ emissions. Urbanisation is found to have a negative impact on CO₂ emissions in high income, middle income, and low income panels. For the global panel, only GDP per capita and per capita total primary energy consumption are found to be statistically significant determinants of CO₂ emission, while urbanisation, trade openness, and per capita electric power consumption have negative effects on the CO₂ emissions.     

The effect of carbon tax on per capita CO2 emissions

As the most efficient market-based mitigation instrument, carbon tax is highly recommended by economists and international organizations. Countries like Denmark, Finland, Sweden, Netherlands and Norway were the first adopters of carbon tax and as such, research on the impacts and problems of carbon tax implementation in these countries will provide great practical significance as well as caution for countries that are to levy the tax. Different from the existing studies that adopt the model simulation approaches, in this article, we comprehensively estimate the real mitigation effects of the five north European countries by employing the method of difference-in-difference (DID). The results indicate that carbon tax in Finland imposes a significant and negative impact on the growth of its per capita CO₂ emissions. Meanwhile, the effects of carbon tax in Denmark, Sweden and Netherlands are negative but not significant. The mitigation effects of carbon tax are weakened due to the tax exemption policies on certain energy intensive industries in these countries. Notwithstanding, in Norway, as the rapid growth of energy products drives a substantial increase of CO₂ emissions in oil drilling and natural gas exploitation sectors, carbon tax actually has not realized its mitigation effects.     

Chemical recycling of carbon dioxide emissions from a cement plant into dimethyl ether,a case study of an integrated process in France using a Reverse Water Gas Shift (RWGS) step

Recycling of carbon dioxide (CO₂) and hydrogen (H₂) into liquid fuel technology has recently gained wide public interest since it is a potential pathway to increase the liquid fuel supply and to mitigate CO₂ emissions simultaneously.     

A cross-country analysis of aggregate energy and carbon intensities

An update on the study by Ang [Energy Economics 9 (1987) 274–286] shows substantial changes in the relationship between energy consumption and national output across world countries from 1975 to 1997. While the ratio of commercial energy consumption to national output increases across countries as per capita income increases in 1975, the converse is observed in 1997. The cross-country energy elasticity has also dropped from values well above unity to below or close to unity. Using the 1997 data, the relationship between CO₂ emissions and national output across countries is studied and the results show some interesting differences from that between energy consumption and national output.     

Status of thermal power generation in India—Perspectives on capacity,generation and carbon dioxide emissions

India’s reliance on fossil-fuel based electricity generation has aggravated the problem of high carbon dioxide (CO₂) emissions from combustion of fossil fuels, primarily coal, in the country’s energy sector. The objective of this paper is to analyze thermal power generation in India for a four-year period and determine the net generation from thermal power stations and the total and specific CO₂ emissions. The installed generating capacity, net generation and CO₂ emissions figures for the plants have been compared and large generators, large emitters, fuel types and also plant vintage have been identified. Specific emissions and dates of commissioning of plants have been taken into account for assessing whether specific plants need to be modernized. The focus is to find out areas and stations which are contributing more to the total emissions from all thermal power generating stations in the country and identify the overall trends that are emerging.     

A review of carbon dioxide capture and utilization by membrane integrated microalgal cultivation processes

The capture of carbon dioxide (CO₂) from the air for microalgal cultivation has received increasing interest since it allows advantages that do not only reduce the amount of CO₂ already added to the air, but it is also more economical due to the accessibility of air, there are no regeneration requirements and it is a safe method that can help enhance microalgal growth. In order to capture CO₂ from the air, it is necessary to deal with CO₂ emissions from all sources in an atmosphere. Interestingly, the capture unit and microalgal culture can be located at any favorable site. Although a number of photobioreactors have been proposed with a CO₂ distribution system, the consequence of CO₂ losses is still being ignored. Thus, capturing CO₂ from the air via an integrated separation process in a photobioreactor is required for microalgal cultivation. Among the four available separation technologies, the membrane separation process would offer a safe, reliable and low cost method for CO₂ capture. Thus, this method of separation can be considered as a key factor in accelerating the development of a CO₂ enrichment process from the air for microalgal cultivation.     

Carbon abatement potential of solar home systems in India and their cost reduction due to carbon finance

About 78 million rural households in India reportedly lack access to grid electricity. About 67 million of them use kerosene for lighting. Government of India is promoting the use of solar home systems (SHS) as one of the options for meeting lighting requirements in households in remote and less inhabited villages. About 363,399 SHS were reportedly disseminated across the country by December 2007. Apart from meeting the basic lighting need of the households, SHS also help in abating the emissions of green house gases (GHGs) by directly displacing the use of kerosene in households that currently use it for lighting. This study has attempted at estimating the CO₂ mitigation potential of SHS in India by studying the potential for their diffusion and the appropriate baseline. Subsequently, the scope for cost reduction to the user due to carbon finance, if received, is also studied. It is found that carbon finance could reduce the effective burden of SHS to the user by 19% if carbon prices were $10/tCO₂² and no transaction costs were involved in getting the carbon revenues. These benefits are also estimated for scenarios where transaction costs are incurred by the project proponent in getting the carbon benefits.     

Decomposition analysis of CO2 emissions from passenger cars: The cases of Greece and Denmark

The paper presents a decomposition analysis of the changes in carbon dioxide (CO₂) emissions from passenger cars in Denmark and Greece, for the period 1990–2005. A time series analysis has been applied based on the logarithmic mean Divisia index I (LMDI I) methodology, which belongs to the wider family of index decomposition approaches. The particularity in road transport that justifies a profound analysis is its remarkably rapid growth during the last decades, followed by a respective increase in emissions. Denmark and Greece have been selected based on the challenging differences of specific socio-economic characteristics of these two small EU countries, as well as on the availability of detailed data used in the frame of the analysis. In both countries, passenger cars are responsible for half of the emissions from road transport as well as for their upward trend, which provokes the implementation of a decomposition analysis focusing exactly on this segment of road transport. The factors examined in the present decomposition analysis are related to vehicles ownership, fuel mix, annual mileage, engine capacity and technology of cars. The comparison of the results discloses the differences in the transportation profiles of the two countries and reveals how they affect the trend of CO₂ emissions.     

On the baseline evolution of automobile fuel economy in Europe

‘Business as usual’ scenarios in long-term energy forecasts are crucial for scenario-based policy analyses. This article focuses on fuel economy of passenger cars and light trucks, a long-disputed issue with serious implications for worldwide energy use and CO₂ emissions. The current status in Europe is explained and future developments are analysed with the aid of historical data of the last three decades from the United States and Europe. As a result of this analysis, fuel economy values are proposed for use as assumptions in baseline energy/transport scenarios in the 15 ‘old’ European Union Member States. Proposed values are given for new gasoline and diesel cars and for the years 2010, 2020 and 2030. The increasing discrepancy between vehicle fuel consumption measured under test conditions and that in the real world is also considered. One main conclusion is that the European Commission's voluntary agreement with the automobile industry should not be assumed to fully achieve its target under baseline conditions, nor should it be regarded as a major stimulus for autonomous vehicle efficiency improvements after 2010. A second conclusion is that three very recent studies enjoying authority across the EU tend to be overly optimistic as regards the technical progress for conventional and alternative vehicle propulsion technologies under ‘business as usual’ conditions.     

The social return on investment in the energy efficiency of buildings in Germany

The German government has developed a variety of policy instruments intended to reduce national CO₂ emissions. These instruments include a programme administered by KfW bank, which aims at improving the energy efficiency of buildings. It provides attractive credit conditions or subsidies to finance refurbishment measures which improve the energy efficiency of buildings significantly.     

High pressure anode operation of direct methanol fuel cells for carbon dioxide management

Experiments with independent pressurization of the direct methanol fuel cell anode and cathode allow for the observation of DMFC operation with carbon dioxide gas formation suppressed. Results indicate that the limiting current density is strongly related to the applied pressure, and, therefore, to the presence of CO₂ in the liquid phase. An additional experiment where CO₂ is allowed to accumulate in recycled anode fuel solution over a period of time and is then stripped from solution using nitrogen gas indicates that the presence of CO₂ in anode fuel solution at any pressure contributes to significant decreases in power and current density. Because CO₂ bubbles are ubiquitous in direct methanol fuel cells, this finding is key to the optimization of these systems.     

Electricity sector reforms in four Latin-American countries and their impact on carbon dioxide emissions and renewable energy

This paper analyzes carbon dioxide (CO₂) emissions related to energy consumption for electricity generation in four Latin-American countries in the context of the liberalization process. From 1990 to 2006, power plants based on renewable energy sources decreased its share in power installed capacity, and the carbon index defined as CO₂ emission by unit of energy for electricity production stayed almost constant for all countries with the exception of Colombia, where the index reduced due to increase in hydroelectricity generation in the last years. The paper also presents a new set of policies to promote renewable energy sources that have been developed in the four countries. The paper concludes that restructuring did not bring about environmental benefits related to a decrease in CO₂ emissions because this depend on the existence of committed policies, and dedicated institutional and regulatory frameworks.