Energy intensities and greenhouse gas emission mitigation in global agriculture

Energy efficiency and greenhouse gas emissions are closely linked. This paper reviews agricultural options to reduce energy intensities and their impacts, discusses important accounting issues related to system boundaries, land scarcity, and measurement units and compares agricultural energy intensities and improvement potentials on an international level. Agricultural development in recent decades, while increasing yields, has led to lower average energy efficiencies when comparing the 1960s and the mid 1980s. In the two decades thereafter, energy intensities in developed countries increased, but with little impact on greenhouse gas emissions. Efficiency differences across countries in the year 2000 suggest a maximum improvement potential of 500 million tons of CO₂ annually. If only below average countries would increase their energy efficiency to average levels of the year 2000, the resulting emission reductions would be below 200 million tons of CO₂ annually.

Marginal abatement costs of greenhouse gas emissions: A meta-analysis

In this paper, we carry out a meta-analysis of recent studies into the costs of greenhouse gas mitigation policies that aim at the long-term stabilisation of these gases in the atmosphere. We find the cost estimates of the studies to be sensitive to the stringency of the stabilisation target, the assumed emissions baseline, the way in which the time profile of emissions is determined in the model, the choice of control variable (CO₂ only versus multigas), the number of regions and energy sources in the model and, to a lesser degree, the scientific “forum” in which the study was developed. We find that marginal abatement costs of the stringent long-term targets that are currently considered by the European Commission are still very uncertain but might exceed the costs that have been suggested by recent policy assessments.     

Popularizing household-scale biogas digesters for rural sustainable energy development and greenhouse gas mitigation

Biogas utilization has undergone great development in rural China since the government systematically popularized household-scale biogas digesters for meeting the rural energy needs in the 1970s. In order to comprehensively estimate the significance of biogas utilization on rural energy development and greenhouse gas emission reduction, all types of energy sources, including straw, fuelwood, coal, refined oil, electricity, LPG, natural gas, and coal gas, which were substituted by biogas, were analyzed based on the amount of consumption for the years from 1991 to 2005. It was found that biogas provided 832749.13 TJ of energy for millions of households. By the employment of biogas digesters, reduction of greenhouse gases (GHG) was estimated to be 73157.59 Gg CO₂ equivalents (CO₂-eq), and the emission by the biogas combustion was only 36372.75 Gg CO₂-eq of GHG. Energy substitution and manure management, working in combination, had reduced the GHG emission efficiently. The majority of the emission reduction was achieved by energy substitution that reduced 84243.94 Gg CO₂, 3560.01 Gg CO₂-eq of CH₄ and 260.08 Gg CO₂-eq of N₂O emission. It was also predicted that the total production of biogas would reach to 15.6 billion m³ in the year 2010 and 38.5 billion m³ in the year 2020, respectively. As a result, the GHG emission reductions are expected to reach 28991.04 and 46794.90 Gg CO₂-eq, respectively.     

Oil and natural gas prices and greenhouse gas emission mitigation

The hikes in hydrocarbon prices during the last years have lead to concern about investment choices in the energy system and uncertainty about the costs for mitigation of greenhouse gas emissions. On the one hand, high prices of oil and natural gas increase the use of coal; on the other hand, the cost difference between fossil-based energy and non-carbon energy options decreases. We use the global energy model TIMER to explore the energy system impacts of exogenously forced low, medium and high hydrocarbon price scenarios, with and without climate policy. We find that without climate policy high hydrocarbon prices drive electricity production from natural gas to coal. In the transport sector, high hydrocarbon prices lead to the introduction of alternative fuels, especially biofuels and coal-based hydrogen. This leads to increased emissions of CO₂. With climate policy, high hydrocarbon prices cause a shift in electricity production from a dominant position of natural gas with carbon capture and sequestration (CCS) to coal-with-CCS, nuclear and wind. In the transport sector, the introduction of hydrogen opens up the possibility of CCS, leading to a higher mitigation potential at the same costs. In a more dynamic simulation of carbon price and oil price interaction the effects might be dampened somewhat.     

Greenhouse gas emission mitigation in the Sri Lanka power sector supply side and demand side options

Sri Lanka has had a hydropower dominated electricity generation sector for many years with a gradually decreasing percentage contribution from hydroresources. At the same time, the thermal generation share has been increasing over the years. Therefore, the expected fuel mix in the future in the large scale thermal generation system would be dominated by petroleum products and coal. This will result in a gradual increase in greenhouse gas (GHG) and other environmental emissions in the power sector and, hence, require special attention to possible mitigation measures.

This paper analyses both the supply side and demand side (DSM) options available in the Sri Lanka power sector in mitigating emissions in the sector considering the technical feasibility and potential of such options. Further, the paper examines the carbon abatement costs associated with such supply side and DSM interventions using an integrated resource planning model, which is not used in Sri Lanka at present. The sensitivities of the final generation costs and emissions to different input parameters, such as discount rates, fuel prices and capital costs, are also presented in the paper. It is concluded that while some DSM measures are economically attractive as mitigation measures, all the supply side options have a relatively high cost of mitigation, particularly in the context of GHG emission mitigation. Further it is observed that when compared with the projected price of carbon under different global carbon trading scenarios, these supply side options cannot provide economically beneficial CO₂ mitigation in countries like Sri Lanka.     

Planning regional energy system in association with greenhouse gas mitigation under uncertainty

Greenhouse gas (GHG) concentrations are expected to continue to rise due to the ever-increasing use of fossil fuels and ever-boosting demand for energy. This leads to inevitable conflict between satisfying increasing energy demand and reducing GHG emissions. In this study, an integrated fuzzy-stochastic optimization model (IFOM) is developed for planning energy systems in association with GHG mitigation. Multiple uncertainties presented as probability distributions, fuzzy-intervals and their combinations are allowed to be incorporated within the framework of IFOM. The developed method is then applied to a case study of long-term planning of a regional energy system, where integer programming (IP) technique is introduced into the IFOM to facilitate dynamic analysis for capacity-expansion planning of energy-production facilities within a multistage context to satisfy increasing energy demand. Solutions related fuzzy and probability information are obtained and can be used for generating decision alternatives. The results can not only provide optimal energy resource/service allocation and capacity-expansion plans, but also help decision-makers identify desired policies for GHG mitigation with a cost-effective manner.     

The impact of fuel cell vehicle deployment on road transport greenhouse gas emissions: The China case

Considerable attention has been paid to energy security and climate problems caused by road vehicle fleets. Fuel cell vehicles provide a new solution for reducing energy consumption and greenhouse gas emissions, especially those from heavy-duty trucks. Although cost may become the key issue in fuel cell vehicle development, with technological improvements and cleaner pathways for hydrogen production, fuel cell vehicles will exhibit great potential of cost reduction. In accordance with the industrial plan in China, this study introduces five scenarios to evaluate the impact of fuel cell vehicles on the road vehicle fleet greenhouse gas emissions in China. Under the most optimistic scenario, greenhouse gas emissions generated by the whole fleet will decrease by 13.9% compared with the emissions in a scenario with no fuel cell vehicles, and heavy-duty truck greenhouse gas emissions will decrease by nearly one-fifth. Greenhouse gas emissions intensity of hydrogen production will play an essential role when fuel cell vehicles' fuel cycle greenhouse gas emissions are calculated; therefore, hydrogen production pathways will be critical in the future.     

Potentials and costs of carbon dioxide mitigation in the world's buildings

Buildings are responsible for over a third of global energy-related carbon dioxide (CO₂) emissions. A significant share of these emissions can be avoided cost effectively through improved energy efficiency, while providing the same or higher level of energy services. How large is this emission reduction potential globally and how much will it cost for society to unlock it? This paper provides answers to these questions, presenting the results of bottom-up research conducted for the Intergovernmental Panel on Climate Change (IPCC), based on the assessment of 80 country- or regional-level mitigation studies throughout the world. First, the paper analyses the findings of these studies in a common framework. Then, it aggregates their results into a global estimate of CO₂ mitigation potential. The paper concludes that by 2020 it is possible to cut cost effectively approximately 29% of buildings-related global CO₂ emissions, the largest among all sectors reported by the IPCC, representing a 3.2 GtCO₂eq. reduction. Developing countries house the largest cost-effective potential with up to 52% of building-level emissions, whereas transition economies and industrialised countries have cost-effective potentials of up to 37% and 25%, respectively. Energy-efficient lighting was identified as the most attractive measure worldwide, in terms of both reduction potential and cost effectiveness. If this potential is realised, the building-related CO₂ emissions would stay constant over 2004–2030. These stabilisation levels (if achieved by all other sectors) would cancel about 3°C temperature increase over the projected period of time.     

A multi-criteria evaluation of policy instruments for climate change mitigation in the power generation sector of Trinidad and Tobago

Even as small island developing states (SIDS) like Trinidad and Tobago (T&T) increase industrialization and grapple with the challenges of increased pollution, few studies provide guidance to policy makers of such countries on appropriate policy measures and instruments that can be implemented to mitigate greenhouse gas emissions. Here we apply a multi-criteria evaluation methodology to ascertain preferences for policy measures and instruments in the power generation sector. Four broad policy measures and twelve policy instruments are assessed on criteria of environmental performance, feasibility of implementation and political acceptability. This method proves useful in T&T, since typical to many SIDS, the intensive data required by other policy assessment methods is unavailable. Results indicate little difference in preference among the four policy measures thereby indicating that a multi-pronged approach on several policy fronts is required. The most preferred policy instruments to operationalize measures included provision of subsidies for energy saving technologies, creating an industry wide carbon trading scheme and implementing a feed-in tariff to increase the use of renewable energy sources. This study therefore provides specific insights for policy makers in Trinidad and Tobago while also providing power generation sector specific guidance to other rapidly industrializing small island developing states.     

Estimating the potential CO2 mitigation from agricultural energy efficiency in the United States

Energy efficiency in agriculture is an underanalyzed aspect of a potential climate change mitigation strategy. According to the Fourth Assessment Report, experts report only medium agreement and medium evidence that energy efficiency can provide substantial reductions (Smith et al. 2007). This paper estimates the CO₂ mitigation potential achievable through improvements in energy efficiency in the US agriculture sector. The data are presented in three formats: the cost data or break-even points of each technology, a marginal abatement supply curve expressed in terms of reduction in energy use by fuel category, and a marginal abatement supply curve expressed in terms of CO₂ emission reductions by fuel category. The largest sources of energy use in the sector were identified as motors used in irrigation systems or other pumping operations; farm machinery such as tractors used in daily farm operations; and space conditioning, such as HVAC systems for livestock and crop-drying systems.

Industrial energy efficiency and climate change mitigation

Industry contributes directly and indirectly (through consumed electricity) about 37% of the global greenhouse gas emissions, of which over 80% is from energy use. Total energy-related emissions, which were 9.9 GtCO₂ in 2004, have grown by 65% since 1971. Even so, industry has almost continuously improved its energy efficiency over the past decades. In the near future, energy efficiency is potentially the most important and cost-effective means for mitigating greenhouse gas emissions from industry. This paper discusses the potential contribution of industrial energy-efficiency technologies and policies to reduce energy use and greenhouse gas emissions to 2030.

Weekly greenhouse gas emissions of municipalities: Methods and comparisons

Local authorities need timely information on their greenhouse gas (GHG) emissions and their causes, comparison with other municipalities and tools for dissemination of information to the citizens. This paper presents a weekly GHG emission calculation system, CO₂-report, which provides such data for citizens and local decision-makers in a timely manner, in contrast to the official emissions statistics, which are available on an annual basis 1–2 years afterwards. In this paper, we present the methodology and three main outputs of CO₂-report: (1) weekly GHG emissions; (2) advance annual emissions; and (3) final annual emissions for 2009 with comparison of 64 municipalities in Finland. We explain the reasons for the large variability of annual emissions, from 5 to 13 t CO₂-eq/capita, discuss the accuracy of advance and final emission estimates at local level, and show the weekly variability of emissions for three example municipalities with different emission profiles.     

Valuing the greenhouse gas emissions from nuclear power: A critical survey

This article screens 103 lifecycle studies of greenhouse gas-equivalent emissions for nuclear power plants to identify a subset of the most current, original, and transparent studies.     

New power generation technology options under the greenhouse gases mitigation scenario in China

Climate change has become a global issue. Almost all countries, including China, are now considering adopting policies and measures to reduce greenhouse gas (GHG) emissions. The power generation sector, as a key source of GHG emissions, will also have significant potential for GHG mitigation. One of the key options is to use new energy technologies with higher energy efficiencies and lower carbon emissions. In this article, we use an energy technology model, MESSAGE-China, to analyze the trend of key new power generation technologies and their contributions to GHG mitigation in China. We expect that the traditional renewable technologies, high-efficiency coal power generation and nuclear power will contribute substantially to GHG mitigation in the short term, and that solar power, biomass energy and carbon capture and storage (CCS) will become more important in the middle and long term. In the meantime, in order to fully bring the role of technology progress into play, China needs to enhance the transfer and absorption of international advanced technologies and independently strengthen her ability in research, demonstration and application of new power generation technologies.     

The potential for greenhouse gases mitigation in household sector of Iran: cases of price reform/efficiency improvement and scenario for 2000–2010

Iran's demographic profile is sharply youth oriented and this upcoming generation's needs for employment and housing, coupled with low-energy efficiency vectors and consumption patterns, has created a constant rise in energy demand and greenhouse gas (GHGs) emissions in the residential sector. Improved energy efficiency as a national policy lynchpin for demand reduction and GHGs mitigation, has become commonplace. OPEC countries however, Iran included, suffer an obvious lack of consumer incentive because of low fuel prices. This study evaluates the twin impacts of price reform and efficiency programs on energy carriers’ consumption and GHGs mitigation in the Iranian housing sector. For this purpose, the demand functions for energy carriers, has been developed by econometrics process models.     

Benchmarking energy use and greenhouse gas emissions in Singapore’s hotel industry

Hotel buildings are reported in many countries as one of the most energy intensive building sectors. Besides the pressure posed on energy supply, they also have adverse impact on the environment through greenhouse gas emissions, wastewater discharge and so on. This study was intended to shed some light on the energy and environment related issues in hotel industry. Energy consumption data and relevant information collected from hotels were subjected to rigorous statistical analysis. A regression-based benchmarking model was established, which takes into account, the difference in functional and operational features when hotels are compared with regard to their energy performance. In addition, CO₂ emissions from the surveyed hotels were estimated based on a standard procedure for corporate GHG emission accounting. It was found that a hotel’s carbon intensity ranking is rather sensitive to the normalizing denominator chosen. Therefore, carbon intensity estimated for the hotels must not be interpreted arbitrarily, and industry specific normalizing denominator should be sought in future studies.     

Mitigating greenhouse gas emissions from China's cities: Case study of Suzhou

Knowledge of the factors driving greenhouse gas (GHG) emissions from cities is crucial to mitigating China's anthropogenic emissions. In this paper, the main drivers increasing GHG emissions from the Chinese city of Suzhou between 2005 and 2010 were identified and quantitatively analyzed using the Kaya identity and the log-mean Divisia index method. We found that economy and population were the major drivers of GHG emissions in Suzhou, having contributed 162.20% and 109.04%, respectively, to the increase in emissions. A decline in carbon intensity, which was caused by the declining energy intensity and an adjustment to the mixture of power and industrial structures, was the major determinant and accounted for a reduction of 171.24% in GHG emissions. Slowing and maintaining healthy growth rates of economy and population could be the primary and most effective means if Suzhou tries to curb the total emissions over the short term. It may be more realistic for Suzhou to control emissions by optimizing the economic structure for low-carbon industrial development because of the city's relative high energy requirements and low potential to mitigate GHGs by adjusting the energy mixture.     

Sectoral trends in global energy use and greenhouse gas emissions

Integrated assessment models have been used to project both baseline and mitigation greenhouse gas emissions scenarios. Results of these scenarios are typically presented for a number of world regions and end-use sectors, such as industry, transport, and buildings. Analysts interested in particular technologies and policies, however, require more detailed information to understand specific mitigation options in relation to business-as-usual trends. This paper presents sectoral trend for two of the scenarios produced by the Intergovernmental Panel on Climate Change's Special Report on Emissions Scenarios. Global and regional historical trends in energy use and carbon dioxide emissions over the past 30 years are examined and contrasted with projections over the next 30 years. Macro-activity indicators are analyzed as well as trends in sectoral energy and carbon demand. This paper also describes a methodology to calculate primary energy and carbon dioxide emissions at the sector level, accounting for the full energy and emissions due to sectoral activities.     

Reductions in greenhouse gas emissions and cost by shipping at lower speeds

CO₂ emissions from maritime transport represent a significant part of total global greenhouse gas (GHG) emissions. According to the International Maritime Organization (Second IMO GHG study, 2009), maritime transport emitted 1046 million tons (all tons are metric) of CO₂ in 2007, representing 3.3% of the world's total CO₂ emissions. The International Maritime Organization (IMO) is currently debating both technical and market-based measures for reducing greenhouse gas emissions from shipping. This paper presents investigations on the effects of speed reductions on the direct emissions and costs of maritime transport, for which the selection of ship classes was made to facilitate an aggregated representation of the world fleet. The results show that there is a substantial potential for reducing CO₂ emissions in shipping. Emissions can be reduced by 19% with a negative abatement cost (cost minimization) and by 28% at a zero abatement cost. Since these emission reductions are based purely on lower speeds, they can in part be performed now.