Energy efficiency and the cost of GHG abatement: A comparison of bottom-up and hybrid models for the US

A highly influential report by the McKinsey consulting firm suggests that a large potential for profitable energy efficiency exists in the US, and that substantial greenhouse gas emissions reductions can therefore be achieved at a low cost. This result is consistent with other studies conducted using a bottom-up methodology that dates back to the work of Lovins beginning in the 1970s. Research over the past two decades, however, has identified shortcomings with the conventional bottom-up approach, and this has led to the development of new analytical frameworks that are referred to as hybrid energy–economy models. Using the CIMS hybrid model, we conducted simulations for comparison with the McKinsey results. These exercises suggest a more modest potential to reduce greenhouse gas emissions at a given marginal cost, as well as a smaller contribution from energy efficiency relative to other abatement opportunities such as fuel switching and carbon capture and storage. Hybrid models incorporate parameters reflecting risk and quality into their estimates of technology costs, and our analysis suggests that these play a significant role in explaining differences in the results.     

Technical change and the marginal cost of abatement

We address one aspect of the treatment of technical change in the environmental economics literature: how technical change impacts the marginal cost of abatement. We review a selection of papers that employ a variety of representations of technical change, and show that these representations have quite different, and sometimes surprising, effects on the marginal costs of pollution reductions. We argue that these varied representations in fact correspond to a variety of different technology options. We then present results indicating that this representation matters — the impacts of technical change on the marginal cost of abatement can crucially impact policy analysis.     

中国风力发电成本下降和减排碳价分析

根据2009-2016年实证数据构建了中国风电学习曲线模型,并采用逐步回归的方法探究干中学,研究中学和用中学3种机制对投资成本下降的推动作用。结果显示,中国风电最符合干中学单因素模型,学习率为8.87%; 2030年,在风电累计装机量分别达到400 GW,600 GW,800 GW的情况下,单位投资成本较2016年下降10.9%～18.8%,度电成本下降21.3%～27.6%,年均投资分别为186亿美元,335亿美元,476亿美元;当碳价水平高于减排碳价时,风电的装机部署将带来额外社会收益;2017-2030年风电的减排碳价将逐步降低,装机增长越快,减排碳价越低。建议国家制定促进提高碳价水平的政策,加快风电装机部署,更快地实现能源转型和更大社会收益的双赢。     

Financial allocation strategy for the regional pollution abatement cost of reducing sulfur dioxide emissions in the thermal power sector in China

This study explores empirical evidence for two hypotheses through a macro productivity analysis using the nonparametric directional distance function approach applied to the thermal power sector. The first hypothesis is that the marginal abatement cost has significantly declined in recent years mainly due to domestic flue gas desulfurization technology in China, which has become available at a reasonable cost. The second is the existence of a certain budget scale, which, with policy intervention, would have significant outcomes. These hypotheses are successfully addressed through the findings that the marginal abatement cost in 2006 had declined by half since 2003 and that the strategic allocation of 10 billion yuan for SO₂ emissions abatement would result in an additional 550,000 tonnes of SO₂ reductions.     

An assessment of factors impacting Canada's electricity sector's GHG emissions

In this article we develop and then implement a decomposition model of Canada's electricity sector in order to assess multiple factors impacting on trends in greenhouse gas emissions from the sector, with a focus on the impact of climate and energy policy on emissions for the time period spanning from 1990 to 2008. The analysis shows that during these years, the primary factors driving changes in emissions included changes in electricity demand, changes in the generation mix of electricity, and weather, but that government policy and programs had only minor impacts on emissions. Although having relatively lesser impacts compared to the aforementioned factors, the most significant policy related factors included efforts to increase renewables in the generation mix through programs such as renewable portfolio standards and incentives for wind generators.     

General equilibrium, electricity generation technologies and the cost of carbon abatement: A structural sensitivity analysis

Electricity generation is a major contributor to carbon dioxide emissions, and abatement in this sector is a key determinant of economy-wide regulation costs. The complexity of an integrated representation of economic and electricity systems makes simplifying assumptions appealing, but there is no evidence in the literature on how important the pitfalls may be. The aim of this paper is to provide such evidence, drawing on numerical simulations from a suite of partial and general equilibrium models that share common technological features and are calibrated to the same benchmark data. We report two basic findings. First, general equilibrium inter-sectoral effects of an economy-wide carbon policy are large. It follows that assessing abatement potentials and price changes in the electricity sector with a partial equilibrium Marshallian demand can only provide a crude approximation of the complex demand-side interactions. Second, we provide evidence that widely used top-down representations of electricity technologies produce fuel substitution patterns that are inconsistent with bottom-up cost data. This supports the view that the parametrization of substitution possibilities with highly aggregated production functions is difficult to validate empirically. The overall picture that emerges is one of large quantitative and even qualitative differences, highlighting the role of key structural assumptions in the interpretation of climate policy projections.     

Estimates of GHG emission reduction potential by country,sector, and cost

In this study, emission reduction potentials in greenhouse gases (GHG) are assessed by country, sector, and cost using a GHG emission reduction assessment model with high resolutions with respect to region and technology and high consistency in terms of assumptions, interrelationships, and solution principles. Model analyses show that large potential reductions can be achieved at low cost in developing countries and power sectors. In addition, cost-efficient emission reductions were evaluated for some international emission reduction targets that have been derived on the basis of the principle of common but differentiated responsibilities among developed and developing countries. If (1) emission reduction measures at negative costs and below 50 $/tCO₂ for developed countries, (2) intensity improvement measures for selected sectors at negative costs and below 20 $/tCO₂ for major developing countries, and (3) all emission reduction measures with negative costs for other developing countries in 2020 are adopted, then emission reductions of 8.9, 14.8, and 27.7 GtCO₂ eq./yr compared to the technology-frozen case can be expected in developed countries, major developing countries, and globally, corresponding to a 11% decrease, 40% increase, and 17% increase from 2005 levels, respectively. Large-scale emission reductions can be achieved even if CO₂-intensity targets for major sectors are assumed for major developing countries.     

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.     

The failure of marginal abatement cost curves in optimising a transition to a low carbon energy supply

One of the tools used to optimise actions in reducing the carbon intensity of the economy is to use Marginal Abatement Cost (MAC) curves. Whilst these are known to be imperfect they are widely used to prioritise actions and often in a way that is incorrect. In particular, whilst their use for measures which have positive costs and a net reduction in carbon emissions can correctly rank the measures for effectiveness, use for ranking measures which have a net negative cost, including a wide range of energy efficiency measures, is entirely inappropriate and leads to perverse and incorrect outcomes. As a result, many assessments of low carbon actions are fundamentally flawed in their ranking of effectiveness and action is needed to overcome this and allow an optimum outcome. An alternative approach is suggested here.     

External costs from electricity generation of China up to 2030 in energy and abatement scenarios

This paper presents estimated external costs of electricity generation in China under different scenarios of long-term energy and environmental policies. Long-range Energy Alternatives Planning (LEAP) software is used to develop a simple model of electricity demand and to estimate gross electricity generation in China up to 2030 under these scenarios. Because external costs for unit of electricity from fossil fuel will vary in different government regulation periods, airborne pollutant external costs of SO₂, NO_x, PM₁₀, and CO₂ from fired power plants are then estimated based on emission inventories and environmental cost for unit of pollutants, while external costs of non-fossil power generation are evaluated with external cost for unit of electricity. The developed model is run to study the impact of different energy efficiency and environmental abatement policy initiatives that would reduce total energy requirement and also reduce external costs of electricity generation. It is shown that external costs of electricity generation may reduce 24–55% with three energy policies scenarios and may further reduce by 20.9–26.7% with two environmental policies scenarios. The total reduction of external costs may reach 58.2%.     

Life cycle GHG assessment of fossil fuel power plants with carbon capture and storage

The evaluation of life cycle greenhouse gas emissions from power generation with carbon capture and storage (CCS) is a critical factor in energy and policy analysis. The current paper examines life cycle emissions from three types of fossil-fuel-based power plants, namely supercritical pulverized coal (super-PC), natural gas combined cycle (NGCC) and integrated gasification combined cycle (IGCC), with and without CCS. Results show that, for a 90% CO₂ capture efficiency, life cycle GHG emissions are reduced by 75–84% depending on what technology is used. With GHG emissions less than 170 g/kWh, IGCC technology is found to be favorable to NGCC with CCS. Sensitivity analysis reveals that, for coal power plants, varying the CO₂ capture efficiency and the coal transport distance has a more pronounced effect on life cycle GHG emissions than changing the length of CO₂ transport pipeline. Finally, it is concluded from the current study that while the global warming potential is reduced when MEA-based CO₂ capture is employed, the increase in other air pollutants such as NO_x and NH₃ leads to higher eutrophication and acidification potentials.     

我国建筑行业温室气体减排机会分析

我国建筑行业温室气体排放总量大且增长快,建筑建造和运行阶段是建筑行业减排的重点环节。本文分析了建筑行业二氧化碳排放的影响因素,从技术进步、能源结构优化、建设模式转变三方面识别了我国建筑行业的十大减排机会,并对每个减排机会进行了具体分析,为建筑行业碳减排提出了建议。     

Evaluating the effectiveness of urban energy conservation and GHG mitigation measures: The case of Xiamen city,China

To assess the effectiveness of urban energy conservation and GHG mitigation measures, a detailed Long-range Energy Alternatives Planning (LEAP) model is developed and applied to analyze the future trends of energy demand and GHG emissions in Xiamen city. Two scenarios have been designed to describe the future energy strategies in relation to the development of Xiamen city. The ‘Business as Usual’ scenario assumes that the government will do nothing to influence the long-term trends of urban energy demand. An ‘Integrated’ scenario, on the other hand, is generated to assess the cumulative impact of a series of available reduction measures: clean energy substitution, industrial energy conservation, combined heat and power generation, energy conservation in building, motor vehicle control, and new and renewable energy development and utilization. The reduction potentials in energy consumption and GHG emissions are estimated for a time span of 2007–2020 under these different scenarios. The calculation results in Xiamen show that the clean energy substitution measure is the most effective in terms of energy saving and GHG emissions mitigation, while the industrial sector has the largest abatement potential.     

Contributing to local policy making on GHG emission reduction through inventorying and attribution: A case study of Shenyang,China

Cities consumed 84% of commercial energy in China, which indicates cities should be the main areas for GHG emissions reduction. Our case study of Shenyang in this paper shows how a clear inventory analysis on GHG emissions at city level can help to identify the major industries and societal sectors for reduction efforts so as to facilitate low-carbon policy-making. The results showed total carbon emission in 2007 was 57 Mt CO₂ equivalents (CO₂e), of which 41 Mt CO₂e was in-boundary emissions and 16 Mt CO₂e was out-of-boundary emissions. The energy sector was dominant in the emission inventory, accounting for 93.1% of total emissions. Within energy sector, emissions from energy production industry, manufacturing and construction industry accounted for 88.4% of this sector. Our analysis showed that comparing with geographical boundary, setting system boundary based on single process standard could provide better information to decision makers for carbon emission reduction. After attributing electricity and heating consumption to final users, the resident and commercial sector became the largest emitter, accounting for 28.5% of total emissions. Spatial analysis of emissions showed that industrial districts such as Shenbei and Tiexi had the large potential to reduce their carbon emissions. Implications of results are finally discussed.     

Land use change to bioenergy: A meta-analysis of soil carbon and GHG emissions

A systematic review and meta-analysis were used to assess the current state of knowledge and quantify the effects of land use change (LUC) to second generation (2G), non-food bioenergy crops on soil organic carbon (SOC) and greenhouse gas (GHG) emissions of relevance to temperate zone agriculture. Following analysis from 138 original studies, transitions from arable to short rotation coppice (SRC, poplar or willow) or perennial grasses (mostly Miscanthus or switchgrass) resulted in increased SOC (+5.0 ± 7.8% and +25.7 ± 6.7% respectively). Transitions from grassland to SRC were broadly neutral (+3.7 ± 14.6%), whilst grassland to perennial grass transitions and forest to SRC both showed a decrease in SOC (−10.9 ± 4.3% and −11.4 ± 23.4% respectively). There were insufficient paired data to conduct a strict meta-analysis for GHG emissions but summary figures of general trends in GHGs from 188 original studies revealed increased and decreased soil CO₂ emissions following transition from forests and arable to perennial grasses. We demonstrate that significant knowledge gaps exist surrounding the effects of land use change to bioenergy on greenhouse gas balance, particularly for CH₄. There is also large uncertainty in quantifying transitions from grasslands and transitions to short rotation forestry. A striking finding of this review is the lack of empirical studies that are available to validate modelled data. Given that models are extensively use in the development of bioenergy LCA and sustainability criteria, this is an area where further long-term data sets are required.     

太阳能热水器节能减排效果显著

我国太阳能热水器近几年来得到快速发展。2006年全国总产量达1800万m~2(相当于12600MW_(th)),总保有量为9000万m~2(相当于63000MW_(th)),分别占世界总量的75%和60%以上,居世界之首位(见表1、表2)。2007年产品的增长率仍保持在27～30%,而     

Power generation scenarios for Nigeria: An environmental and cost assessment

Exploratory scenarios for the power sector in Nigeria are analysed in this paper using possible pathways within the Nigerian context and then compared against the Government's power expansion plan in the short to medium term. They include two fossil-fuel (FF and CCGT) and two sustainable-development-driven scenarios (SD1 and SD2). The results from the FF scenarios indicate this is the preferred outcome if the aim is to expand electricity access at the lowest capital costs. However, the annual costs and environmental impacts increase significantly as a consequence. The SD1 scenario, characterised by increased penetration of renewables, leads to a reduction of a wide range of environmental impacts while increasing the annual costs slightly. The SD2 scenario, also with an increased share of renewables, is preferred if the aim is to reduce GHG emissions; however, this comes at an increased annual cost. Both the SD1 and SD2 scenarios also show significant increases in the capital investment compared to the Government's plans. These results can be used to help inform future policy in the Nigerian electricity sector by showing explicitly the range of possible trade-offs between environmental impacts and economic costs both in the short and long terms.     

Spatiotemporal evolution and driving factors for GHG emissions of aluminum industry in China

China’s aluminum (Al) production has released a huge amount of greenhouse gas (GHG) emissions. As one of the biggest country of primary Al production, China must mitigate its overall GHG emission from its Al industry so that the national carbon neutrality target can be achieved. Under such a background, the study described in this paper conducts a dynamic material flow analysis to reveal the spatiotemporal evolution features of Al flows in China from 2000 to 2020. Decomposition analysis is also performed to uncover the driving factors of GHG emission generated from the Al industry. The major findings include the fact that China’s primary Al production center has transferred to the western region; the primary Al smelting and carbon anode consumption are the most carbon-intensive processes in the Al life cycle; the accumulative GHG emission from electricity accounts for 78.14% of the total GHG emission generated from the Al industry; China’s current Al recycling ratio is low although the corresponding GHG emission can be reduced by 93.73% if all the primary Al can be replaced by secondary Al; and the total GHG emission can be reduced by 88.58% if major primary Al manufacturing firms are transferred from Inner Mongolia to Yunnan. Based upon these findings and considering regional disparity, several policy implications are proposed, including promotion of secondary Al production, support of clean electricity penetration, and relocation of the Al industry.