Robust incentives and the design of a climate change governance regime

In building a governance regime to address climate change, should we prioritize the development of global institutions or national ones? This paper focuses on two neglected characteristics to inform the governance problem: the incentives for investment in low-carbon energy technology and the influence of historical policy volatility. Examining a case study of an important low-carbon energy technology, wind power, this study finds: (1) policy volatility has been substantial, (2) policy changes were uncorrelated across jurisdictions, suggesting that (3) investors could have substantially reduced their exposure to the risk of policy volatility by operating globally. While it also has downsides, a poorly coordinated international policy regime has the advantage of reducing the risk associated with a global policy failure. Beyond this case study, the importance of this positive effect depends on: the probability of policy failures in each country, the correlations among them, and the probability of a global policy failure.     

Drilling contracts and incentives

Shortages of rigs and personnel have encouraged discussion of designing incentive contracts in the drilling sector. However, for the drilling contracts, there are not a large variety of contract types in use. This article describes and analyses incentives for drilling contractors. These are directly represented by the compensation formats utilised in the present and in the consecutive drilling contracts. Indirectly, incentives are also provided by the evaluation criteria that oil companies use for awarding drilling assignments. Changes in contract format pose a number of relevant questions relating to resource management, and the article takes an in-depth look at some of these. Do evaluation criteria for awarding drilling assignments encourage the development of new technology and solutions? How will a stronger focus on drilling efficiency influence reservoir utilisation?     

Understanding energy and exergy efficiencies for improved energy management in power plants

An extensive overview is provided of various energy- and exergy-based efficiencies used in the analysis of power cycles. Vapor and gas power cycles, cogeneration cycles and geothermal power cycles are examined, and consideration is given to different cycle designs. The many approaches that can be used to define efficiencies are provided and their implications discussed. Improvements of the management of energy in power plants that stem from understanding the efficiencies better are described. Examples are given to illustrate the efficiencies and their differences, with the results presented using combined energy and exergy diagrams. It is anticipated that the results will provide a convenient and practical tool for engineers and researchers dealing with the analysis, design, optimization and improvement of power cycles.     

Forecasting uptake of retrofit packages in office building stock under government incentives

As government and industry plan to reduce energy consumption in building stock, there is a need to forecast the uptake of retrofit packages across building stock over time. To address this challenge a diffusion model was set up and applied to office building stock across New South Wales (NSW) in Australia, accommodating a high spatial resolution and temporal capability for projecting uptake of technology packages characterised by multiple variables. Six retrofit packages were set up for the diffusion model, which ranged from inexpensive services and manuals through to mid-priced packages involving energy efficient T5 lighting and solar hot water through to expensive packages such as chilled beams and Solar PV. We evaluated the model using a base case and two policy programs, representing the Green Building Fund and Environmental Upgrade Agreements. These were recent incentive programs funded by the Australian government to accelerate the uptake of retrofit packages, by providing financial support to upfront expenditures and removing barriers to retrofit. By forecasting uptake of each retrofit package to 2032 under each program, we demonstrate how the model can be a valuable resource in tailoring expensive government programs and increasing their effectiveness.     

The effects of economic and policy incentives on carbon mitigation technologies

The ability to estimate the likely effects of potential climate change policies on energy use and greenhouse gas (GHG) emissions requires an improved understanding of the relationship between different policy alternatives and energy-saving and GHG-reducing changes in technology. A particularly important and understudied aspect of this set of issues is the conceptual and empirical modeling of how the various stages of technological change are interrelated, how they unfold over time in response to market forces, and the differential impact of various policies (for example, R&D subsidies, environmental taxes, information programs). We summarize several contributions to this literature and suggest promising areas for continued research on empirical analysis and modeling of induced technological change.     

A simple passivation technique for the edge area of silicon solar cells improves the efficiency

The efficiency of silicon solar cells (SC) can strongly be degraded by localized defects especially at the edge of SC (e.g. scratches) which are introduced during the production of the SC and may cause local shunts. A new optimized chemical etching procedure has been developed which allows a very effective passivation of shunts at the SC edges without reducing the surface area, i.e. without a reduction of the I_sc current. In contrast to other techniques like plasma etching (“coin staking”) or cutting off the edges, this procedure could be implemented cheaply in a large-scale production.The newly developed passivation method always leads to an improvement in the efficiency η of slightly or severely degraded SCs which is typically around 10–30%, but can be as large as 100%, while good SCs are totally unaffected with respect to η but still showing an improvement of the leakage current.     

Reactions for improving efficiencies in thermochemical cycles related to the sulfur dioxide-iodine process

A modification of the sulfur dioxide-iodine cycle which uses magnesium oxide, magnesium sulfite and magnesium iodide is examined with particular emphasis on decreasing the amount of water employed and thereby increasing the efficiency. The key reaction is that of iodine with magnesium oxide and magnesium sulfite hexahydrate with no additional water. This produces 77% of the total possible sulfate as well as magnesium iodide, hydrogen iodide and hydrogen at 523 K. The efficiency of this cycle varies between 58% and 39% depending on the amount of heat that can be recovered. This is the first example of a cycle where there is no large burden due to evaporation.     

A preliminary evaluation of financial incentives for renewable energy technologies in India

The Government of India has been providing various financial incentives including capital subsidy, interest subsidy and depreciation related income tax benefits with the objective of promoting development and dissemination of renewable energy technologies in the country. These financial incentives have, however, changed from time to time in their type, magnitude, scope and even geographical coverage. In some cases, the state governments have also been providing additional incentives. It is therefore, necessary to undertake a detailed evaluation and comparison of different financial incentives provided for dissemination of renewable energy technologies in India (provided in the past as well as the existing incentives) to facilitate a comprehensive grasp of these measures for future planning. An attempt in this direction has been made in this paper. Simple mathematical expressions have been derived to facilitate comparison among some of the commonly provided financial incentives. Results of some exemplifying calculations for three solar energy systems have been presented and briefly discussed. Copyright © 2004 John Wiley & Sons, Ltd.     

Efficiency aspects of electric utility coal operations

Ownership of reserves and production of coal by electric utilities presents special problems for the agencies charged with regulating these utilities. The regulatory bodies have employed various methods to prevent the utilities earning monopoly profits on their downstream coal operations. This paper uses a linear regression model to explore price and productivity differences between utility-owned coal and independent coal mines. Differences between utility-owned coal mines based on the method of regulation are also examined. The results indicate that utility-owned coal mines tend to have lower productivity and higher prices relative to independent mines. It appears that this inefficiency results from the regulation per se rather than the method of regulation to which the utility is subject.     

精益六西格玛方法论证冷水机组节能优化方案

应用精益六西格玛方法,借助Minitab软件,对冷水机组的节能优化方案进行论证。系统收集运行数据,对设备运行负载率、生产供冷负荷进行精确统计,对备选方案的投资回收期进行测算对比,量化论证方案利弊,为企业节能改造项目的优选与实施排序提供数据依据。     

Solar thermal power generation in India: effect of potential incentives on unit cost of electricity

For large-scale dissemination of solar thermal power plants, in countries identified with huge potential, governments are offering various incentives. In an attempt towards studying the effectiveness of various incentives in reducing the levelised cost of electricity (LCOE) delivered by solar thermal power plants in India, this paper presents simple mathematical frameworks that facilitate the determination of the required level of an incentive so as to ensure that the LCOE is within a pre-specified limit. For example, for a 50?MW solar thermal power plant at Barmer (Rajasthan), LCOE of Rs. 9.75 per kWh can be achieved by providing 6.3% viability gap funding or an interest subsidy of 3% or provision of 32% investment tax credits to the equity investor or provision of production tax credits to the equity investor at the rate of Rs. 0.81 per kWh for first 10 years of operation of a plant.     

Improvement of solar cell efficiencies by impurity transitions

Transitions via impurities, in addition to transitions from the valence band to the conduction band, increase the generation rate of electron–hole pairs. By the presence of impurities, however, the recombination rate is also increased. In this study, the recombination process is assumed to be entirely radiative. The probability for photon absorption in generation and for photon emission in recombination depend on the occupation probability of the impurity states. The variation of the occupation resulting in a variation of the optical properties along a current–voltage characteristic is taken into account. With a single impurity state a maximal efficiency of 46% for the AM0 spectrum is found for a band gap of 2.3 eV and an impurity level at 0.88 eV. No improvement is found for band gaps less than 1.2 eV. For two different impurity levels, transitions between these levels must be excluded, otherwise the lower level is mostly occupied and the higher level is mostly empty leading to poor optical absorption for some of the possible impurity transitions.     

A strategy for optimizing efficiencies of solar thermochemical fuel production based on nonstoichiometric oxides

Thermochemical cycling (TC) is a promising means of harvesting solar energy. Two-step TC with a redox active metal oxide (e.g., ceria, a benchmark material) serving as a reaction intermediate for dissociating steam or carbon dioxide, has attracted much attention recently. However, further improving the energy conversion efficiency of this process remains a major challenge. In this work, we propose an innovative modification to the heat recovery approach as a means of enhancing efficiency. Specifically, a variable amount of oxidant (e.g., steam) is injected to actively assist the cooling of thermally reduced metal oxide, achieving both in-situ heat recovery and potentially faster cooling rates than conventional approaches. Our analysis, based on a thermochemical heat engine model, shows that the solar-to-fuel efficiency using ceria under typical solar TC operating conditions could be significantly improved (the efficiency of the new strategy can reach 24.36% without further gas or solid heat recovery when the reduction temperature is 1600 °C) whilst temperature swing be reduced simultaneously compared with conventional methods. Exergy efficiency is also analyzed for thermochemical splitting of water and CO₂. This new strategy contributes significantly to the simplification of solar reactor design and to potential enhancement in both fuel productivity and energy conversion efficiency on a temporal basis.     

Parametric analysis and assessment of a coal gasification plant for hydrogen production

The purpose of this paper is to conduct a parametric study to show the best steam to carbon ratio that produces the maximum system performance of an integrated gasifier for hydrogen production. The study focuses on the energy and exergetic efficiency of the system and hydrogen production. The work is completed using computer simulation models in Engineering Equation Solver software package. This software is used for its extensive thermodynamic properties library. An equilibrium based model is used to determine the performance of the system. The data is presented in graphs which show the chemical composition in molar fractions of the syngas, the overall energy and exergy efficiency of the system, and the hydrogen production rates. A study of these parameters is conducted by varying the steam to carbon ratio entering the gasifier and the ambient temperature. It is observed that the higher the steam to carbon ratio that is achieved the more hydrogen and more power the plant is able to produce. Because of this, the exergy and energy efficiency of the system increases as the steam to carbon ratio increases as well. It is also observed that the system favors a lower ambient temperature for maximum exergy efficiency and hydrogen production.     

Contribution of silicon substrates to the efficiencies of silicon thin layer solar cells

Although silicon solar cells based on layers less than 50 μm thick have become very popular, little attention has been paid to the role of the underlying silicon substrate. This treatment uses the device simulation program PC-1D and the ray tracing program SUNRAYS to examine the role of the substrate in contributing to the current and efficiency of textured and non-textured thin layer solar cells. For the case of a heavily doped silicon substrate, substrate contributions can be significant for cells with sufficiently thin base layers. For example, for the case of a silicon thin layer cell with a base layer thickness of 20 μm and a substrate doping of 6 × 10¹⁸ cm⁻³, the substrate contributes no more than 4% of the total short-circuit current. However, decreasing the base width to 5 μm results in an increase in this substrate contribution to 20%. Light trapping tends to alleviate the substrate contribution by increasing the effective path length in the base. Examination of the current components under forward bias reveals that for a thin layer cell with a high quality base and good front surface passivation, back diffusion of electrons into the substrate limits cell performance.     

A global coal production forecast with multi-Hubbert cycle analysis

Based on economic and policy considerations that appear to be unconstrained by geophysics, the Intergovernmental Panel on Climate Change (IPCC) generated forty carbon production and emissions scenarios. In this paper, we develop a base-case scenario for global coal production based on the physical multi-cycle Hubbert analysis of historical production data. Areas with large resources but little production history, such as Alaska and the Russian Far East, are treated as sensitivities on top of this base-case, producing an additional 125 Gt of coal. The value of this approach is that it provides a reality check on the magnitude of carbon emissions in a business-as-usual (BAU) scenario. The resulting base-case is significantly below 36 of the 40 carbon emission scenarios from the IPCC. The global peak of coal production from existing coalfields is predicted to occur close to the year 2011. The peak coal production rate is 160 EJ/y, and the peak carbon emissions from coal burning are 4.0 Gt C (15 Gt CO₂) per year. After 2011, the production rates of coal and CO₂ decline, reaching 1990 levels by the year 2037, and reaching 50% of the peak value in the year 2047. It is unlikely that future mines will reverse the trend predicted in this BAU scenario.     

Monitoring of energy exergy efficiencies and exergoeconomic parameters of geothermal district heating systems (GDHSs)

In this work, the monitoring energy and exergy efficiency results of the last heating seasons of operation of the geothermal district heating systems (GDHSs) and their technical availability analysis and monitoring exergoeconomic parameters are presented. The case studies cover the actual system data taken from the systems in Afyon and Salihli GDHSs, Turkey. General energy, exergy, technical availability, and exergoeconomic analysis of the GDHSs are introduced. Furthermore, the average technical availability, real availability, capacity factor and energy and exergy efficiencies value of GDHSs have been analyzed.     

Comparison between the conventional and recirculation modes in desiccant cooling cycles and deriving critical efficiencies of components

Desiccant evaporative systems are heat driven at moderate temperature and are usually coupled with solar collectors or with waste heat. The performance of desiccant systems is very sensitive to outside conditions and to the efficiency of the system components. In this paper the impact of these factors on the performance of two configurations of desiccant systems is investigated through simulation. First, a model of a desiccant air handling unit is briefly presented and validated experimentally. Then different efficiency combinations are studied and the critical efficiencies are derived. Finally, a comparison of the conventional and the recirculation configurations is made, based on outside conditions.     

Trend in efficiency and capacity of fossil power generation in the EU

The purpose of this study is to determine past and future energy efficiency of fossil power generation in EU-27. It is found that the average efficiency for gas-fired power generation increased sharply from 34% in 1990 to 50% in 2005 and is expected to increase to 54% by 2015 (based on lower heating value). For coal-fired power generation the efficiency increased from 34% in 1990 to 38% in 2005 and is expected to increase to 40% by 2015 (LHV). The improvements are largely determined by the introduction of new generating capacity. The amount of natural gas-based generating capacity has strongly increased in the last 15 years. The share of gas-fired power generation in total fossil power generation in the EU increased from 11% in 1990 to 34% in 2005 and is expected to increase to 46% by 2015. The average CO₂-intensity for fossil-fired power generation in the EU decreased from 920 g CO₂/kWh in 1990 to 720 g/kWh in 2005, mainly due to a shift from coal to natural gas. For the period 2005–2015 another decrease is expected from 720 to 630 g/kWh. Total greenhouse gas emissions from fossil power generation are however expected to increase by 10% in 2020.     

Potential benefits from improved energy efficiency of key electrical products: The case of India

The economy of the world's second most populous country continues to grow rapidly, bringing prosperity to a growing middle class while further straining an energy infrastructure already stretched beyond capacity. At the same time, efficiency policy initiatives have gained a foothold in India, and promise to grow in number over the coming years. This paper considers the maximum cost-effective potential of efficiency improvement for key energy-consuming products in the Indian context. The products considered are: household refrigerators, window air conditioners, motors and distribution transformers. Together, these products account for about 27% of delivered electricity consumption in India. The analysis estimates the minimum Life-Cycle Cost option for each product class, according to use patterns and prevailing customer marginal rates in each sector. This option represents an efficiency improvement ranging between 12% and 60%, depending on product class. If this level of efficiency was achieved starting in 2010, we estimate that total electricity consumption in India could be reduced by 4.7% by 2020, saving over 74 million tons of oil equivalent and over 246 million tons of carbon dioxide emissions. Net present financial savings of this efficiency improvement totals 8.1 billion dollars.