Least-cost energy strategies for power system expansion

This paper describes a theoretical framework and practical procedure for identifying least-cost energy strategies for power system expansion. Under such a strategy, the socially optimal decision is defined by a least-cost combination of not only conventional supply-side generating options, but also conservation and renewable resource options — such that the cost of providing an incremental unit of electricity from all resources is the same. In addition, under a least-cost energy strategy, the reliability of electricity supply is determined on an economically optimal basis. Results of an actual case study of the Pacific Northwest region of the USA are presented.     

Transmission network-based energy and environmental assessment of plug-in hybrid electric vehicles

The introduction of plug-in hybrid electric vehicles (PHEVs) is expected to have a significant impact on regional power systems and pollutant emissions. This paper analyzes the effects of various penetrations of PHEVs on the marginal fuel dispatch of coal, natural gas and oil, and on pollutant emissions of CO₂, NO_x, SO₂ in the New York Metropolitan Area for two battery charging scenarios in a typical summer and winter day. A model of the AC transmission network of the Northeast Power Coordinating Council (NPCC) region with 693 generators is used to realistically incorporate network constraints into an economic dispatch model. A data-based transportation model of approximately 1 million commuters in NYMA is used to determine battery charging pattern. Results show that for all penetrations of PHEVs network-constrained economic dispatch of generation is significantly more realistic than unconstrained cases. Coal, natural gas and oil units are on the margin in the winter, and only natural gas and oil units are on the margin in the summer. Hourly changes in emissions from transportation and power production are dominated by vehicular activity with significant overall emissions reductions for CO₂ and NO_x, and a slight increase for SO₂. Nighttime regulated charging produces less overall emissions than unregulated charging from when vehicles arrive home for the summer and vice versa for the winter. As PHEVs are poised to link the power and transportation sectors, data-based models combining network constraints and economic dispatch have been shown to improve understanding and facilitate control of this link.     

中国能源地缘政治的战略定位与对策

中国经济持续高速增长和对国外能源需求的不断增加,对全球能源政治格局产生重要冲击,进而使得构建清晰和有效的中国能源地缘政治战略显得迫切而必要。本文界定了中国能源地缘政治战略的定位和原则,并提出了四大战略任务:(1)建立安全可靠的国内能源供应体系,增强我国能源地缘政治优势,在对外交往合作中处于有利地位;(2)建立多元化利用全球资源的国外能源供应体系;(3)建设海陆并举、贯穿东西南北的油气安全运输体系;(4)建立亚洲能源贸易与国际合作体系,实现能源产品的有序进出口。在此基础上,探讨未来中国能源地缘政治的战略对策。     

Comparative analysis for energy production processes (EPPs): Sustainable energy futures for Turkey

This study presents a comparative analysis of three different energy production process (EPP) scenarios for Turkey. Main goal is to incorporate the prioritization criteria for the assessment of various energy policies for power alternatives, and evaluating these policies against these criteria. The three types of EPPs reviewed in this study are: electricity production from wind farms in the future, existing coal-based thermal power plants and planned nuclear power plants. The analytical hierarchy process (AHP) is utilized to assess the main and sub-factors of EPPs. Main factors such as economic, technical, social and environmental are assigned in first level of the AHP. The importance weights of factors are produced and priority values with realistic numbers are obtained using Fuzzy-AHP Chang’s Model. Priority value for wind energy was determined as two times higher than the others when making the ultimate decision. On aggregate, importance weights of environmental (0.68) and social (0.69) factors make wind power leader. Sub-factors such as public acceptance, waste-emission and environmental impacts cause both nuclear and thermal power to have the lowest priority numbers. Additionally, the CO₂ emissions trade was determined to be a very important criterion associated with both economic and environmental factors according to Kyoto Protocol. This study concludes that Turkey’s existing thermal power stations should gradually be substituted by renewable energy options according to a schedule of Turkish energy policies in future.     

Efficient energy utilization and environmental issues applied to power planning

This document shows the importance of policies for electric energy savings and efficient energy utilization in power planning. The contributions of economic, social, and environmental items were evaluated according to their financial effects in the delay of investments, reduction of production costs and decrement of environmental emissions. The case study is Baja California, México; this system has a unique primary source: geothermal energy. Whether analyzing the planning as usual or planning from the supply side, the forecast for 2005–2025 indicates that 4500 MW additional installed capacity will be required (3-times current capacity), representing an investment that will emit 12.7 Mton per year of CO₂ to the atmosphere and will cost US$2.8 billion. Systemic planning that incorporates polices of energy savings and efficiency allows the reduction of investments and pollutant emissions. For example, a reduction of 20% in the growth trend of the electricity consumption in the industrial customers would save US$10.4 billion over the next 20 years, with a potential reduction of 1.6 Mton/year of CO₂. The increase in geothermal power generation is also attractive, and it can be combined with the reduction of use and energy losses of utilities, which would save US$13.5 billion and prevent the discharge of 8.5 Mton/year of CO₂.     

Discount rate for technology assessment: An application to the energy sector

When comparing the relative merits of technologies in the energy sector, analysis of a long time span is frequently required. Discounting of costs and benefits is usual in such analysis, and the choice of an appropriate discount rate can be vital. The available empirical evidence suggests that the appropriate real discount rate could vary widely depending on which concept it is based. For Australia, a value reflecting the social time preference rate could be as low as 2%, while one based on the social opportunity cost of capital would be considerably higher, probably 7–10%. A multiperiod linear programming model, MARKAL, suitable for energy technology assessment, was used to analyse the effect on the optimal long-term energy strategy for Australia, of using discount rates over the range 2–10%. The results indicate that capital-intensive technologies such as coal liquefaction and solar water heaters are disadvantaged when using high discount rates. This could result in energy strategies being pursued in which the level of oil imports is much     

Subsidy strategies for energy technologies

The principal types of direct consumer subsidies to encourage the commercialization of unconventional energy sources (solar, conservation, synthetic fuels) are investigated. Although such subsidies can be justified on grounds that the prices to consumers of conventional energy alternatives do not reflect their full social costs, they all have serious drawbacks. Basically those subsidy schemes that are easy to administer encourage inefficient consumer behaviour while subsidies schemes that are efficient raise intractable problems of measurement. Subsidies for unconventional energy provide energy below its full social cost, thus giving the wrong price signals to the consumer. It would be more rational and effective to tax conventional energy up to its full social cost.     

Vietnam's energy sector: A review of current energy policies and strategies

Since the introduction of market-oriented economy in 1986, Vietnam has made noticeable socio-economic progress. In this progress, the energy sector has played a vital role. This role is likely to deepen in the years to come as Vietnam strives to achieve even higher levels in economic progress. Such deepening in the role of energy, this paper argues, will heighten concerns about the security of energy supply, and economic, environmental, social and political consequences. In order to address these issues, Vietnam has over the last decade, developed a suite of energy policies. A deeper review of these policies suggests that they are typified by economic-growth orientation, exclusive focus on a single-sector or single issue, and largely neglect the significance of cross-sectoral and cross-thematic issues arising from the interdependencies between energy, economy, and the polity at large. The existing energy policy settings are, therefore, unlikely to be able to provide a satisfactory redress to the challenges noted above. This paper provides an overview of the current energy policies with a view to identify areas where further policy effort is needed in order to facilitate a sustainable development of the Vietnamese energy sector.     

Techno-economic and environmental assessment of LNG export for hydrogen production

A critical requirement of a widely contemplated hydrogen economy is the development of a low carbon hydrogen supply chain that is cost competitive. This comprehensive techno-economic assessment demonstrates, for the first time, the viability of a complete hydrogen supply chain based on the transport of liquefied natural gas (LNG). This is demonstrated via the established LNG trade route from Australia to Japan against three key performance indicators (KPIs): delivered hydrogen cost, CO₂ emissions intensity (EI) across the entire supply chain, and technology readiness level (TRL). The hydrogen supply chain entails LNG export to Japan where it is used for blue hydrogen production; the by-product CO₂ is then liquefied and repatriated to Australia for sequestration or utilisation. Within this supply chain, various hydrogen production technologies are assessed, including steam methane reforming (SMR), autothermal reforming (ATR) and natural gas pyrolysis (NGP). SMR with carbon capture and storage (CCS) resulted in the lowest total hydrogen supply cost of 19 USD/GJ (2.3 USD/kgH2) which comfortably meets the 2030 Japanese hydrogen cost target of 25 USD/GJ (3 USD/kgH2) and is very close to the 17 USD/GJ 2050 Japanese hydrogen cost target. This technology also obtained the lowest CO₂ emission intensity (EI) of 38 kgCO2/GJ (4.5 kgCO2/kgH2); this was surprisingly lower than ATR with CCS primarily due to the emissions associated with ATR electricity provision for air separation. Future technologies and strategies are detailed so as to further reduce cost and supply chain emissions; these were shown to be able to reduce total CO2 EI to 14 kgCO2/GJ (1.6 kgCO2/kgH2). Hence this analysis indicates that this supply chain can act to significantly reduce CO2 emissions whilst uniquely meeting targeted hydrogen supply costs up to 2050. As such it is proposed here as an eminently viable hydrogen export option deploying both existing technology and capacity, at least until other hydrogen supply chain vectors (such as liquid hydrogen and ammonia) derived from green hydrogen production become competitive across all the KPIs.     

Life cycle assessment of a solar thermal collector: sensitivity analysis, energy and environmental balances

Starting from the results of a life cycle assessment of solar thermal collector for sanitary warm water, an energy balance between the employed energy during the collector life cycle and the energy saved thanks to the collector use has been investigated. A sensitivity analysis for estimating the effects of the chosen methods and data on the outcome of the study was carried out. Uncertainties due to the eco-profile of input materials and the initial assumptions have been analysed.Since the study is concerned with a renewable energy system, attention has been focused on the energy indexes and in particular the “global energy consumption”. Following the principles of Kyoto Protocol, the variations of CO₂ emissions have also been studied.     

Asian energy and environmental policy: Promoting growth while preserving the environment

Asia has experienced spectacular economic growth over the past two decades. However, this economic progress has come at a high cost. It has led to unprecedented environmental consequences. So this region needs to shift the conventional pattern of “develop first and then treat the pollution” to a trajectory of sustainable development. To that end, this paper examines a variety of policy responses, at national, regional and international levels, to deal with growing concerns about the environmental challenges in Asia. In the context of national responses, special attention is paid to the following issues: coordination between the central and local governments, market-based environmental instruments and industrial policies, tougher emissions standards for mobile and stationary sources and fuel quality, policies to promote energy efficiency and the use of clean energy and biofuels, the integration of environmental policies with economic and sectoral policies, and engagement of the private sector through e.g., ecolabelling, green government procurement, corporate ratings and disclosure programs, and drawing the support of financial institutions to promote improved corporate environmental performance. The paper concludes that having the right policy mix, coupled with strengthened cooperation at national, local and regional levels, will ensure continuing economic growth in the region without compromising its limited ecological-carrying capacity and environmental quality.     

Modelling energy systems for developing countries

Developing countries’ energy use is rapidly increasing, which affects global climate change and global and regional energy settings. Energy models are helpful for exploring the future of developing and industrialised countries. However, energy systems of developing countries differ from those of industrialised countries, which has consequences for energy modelling. New requirements need to be met by present-day energy models to adequately explore the future of developing countries’ energy systems. This paper aims to assess if the main characteristics of developing countries are adequately incorporated in present-day energy models. We first discuss these main characteristics, focusing particularly on developing Asia, and then present a model comparison of 12 selected energy models to test their suitability for developing countries. We conclude that many models are biased towards industrialised countries, neglecting main characteristics of developing countries, e.g. the informal economy, supply shortages, poor performance of the power sector, structural economic change, electrification, traditional bio-fuels, urban–rural divide. To more adequately address the energy systems of developing countries, energy models have to be adjusted and new models have to be built. We therefore indicate how to improve energy models for increasing their suitability for developing countries and give advice on modelling techniques and data requirements.     

Sustainability assessment tool for the decision making in selection of energy system—Bosnian case

In this paper the multi-criteria sustainability assessment of various options of the energy power system of the JP Elektroprivreda of Bosnia and Herzegovina is performed. The rehabilitation of a 110 MW Thermal Power Unit is compared with other options, such as: a thermal power unit with a coal-fueled boiler with combustion in fluidized bed; combined cycle gas turbine plants; hydropower plant, power plants based on solar energy (photovoltaic [PV] systems); wind turbines; and biomass power plants. The assessment methodology comprise a system of stochastic models of uncertainty, enabling decision makers to perform the assessment of various systems, as well as to obtain normalization indexes by using non-numeric (ordinal), non-exact (interval) and non-complete information (NNN-information). Through the analysis of multi-criteria assessment of potential options, the decision-makers are able to evaluate options and select the optimal new power plant capacity.     

A review of computer tools for analysing the integration of renewable energy into various energy systems

This paper includes a review of the different computer tools that can be used to analyse the integration of renewable energy. Initially 68 tools were considered, but 37 were included in the final analysis which was carried out in collaboration with the tool developers or recommended points of contact. The results in this paper provide the information necessary to identify a suitable energy tool for analysing the integration of renewable energy into various energy-systems under different objectives. It is evident from this paper that there is no energy tool that addresses all issues related to integrating renewable energy, but instead the ‘ideal’ energy tool is highly dependent on the specific objectives that must be fulfilled. The typical applications for the 37 tools reviewed (from analysing single-building systems to national energy-systems), combined with numerous other factors such as the energy-sectors considered, technologies accounted for, time parameters used, tool availability, and previous studies, will alter the perception of the ‘ideal’ energy tool. In conclusion, this paper provides the information necessary to direct the decision-maker towards a suitable energy tool for an analysis that must be completed.     

The coming sustainable energy transition: History,strategies, and outlook

Facing global climate change and scarce petroleum supplies, the world must switch to sustainable energy systems. While historical transitions between major energy sources have occurred, most of these shifts lasted over a century or longer and were stimulated by resource scarcity, high labor costs, and technological innovations. The energy transition of the 21st century will need to be more rapid. Unfortunately, little is known about how to accelerate energy transitions. This article reviews past transitions and factors behind them, along with their time frames. Three modern case studies are discussed: Brazil, which shifted from an oil-based transportation system to one based on sugarcane-ethanol (success); France, which shifted from oil-fired electric power to nuclear power (success); and the United States, which attempted to shift from foreign oil to a mix of domestic energy resources (failure). Lessons from these attempts to govern energy transitions are discussed. Several policy instruments to accelerate a transition are identified, though even under ideal circumstances a global energy supply transition will be very slow. Given the need to simultaneously implement programs in countries with different political economies, a greater focus on energy efficiency, promotion of Smart Grids, and possibly a new treaty should yield more timely results.     

Sustainable urban energy: Development of a mesoscale assessment model for solar reflective roof technologies

Buildings and other engineered structures that form cities are responsible for a significant portion of the global and local impacts of climate change. Consequently, the incorporation of building design strategies and materials such as the use of reflective roof materials, or ‘cool’ roofs, are being widely investigated. However, although their benefits for individual buildings have been studied, as yet there is little understanding of the potential benefits of urban scale implementation of such systems. Here we report the development of a new methodology for assessing the potential capacity and benefits of installing reflective roofs in an urbanized area. The new methodology combines remote sensing image data with a building energy computer simulation to quantify the current rooftop reflectivity and predict the potential benefits of albedo improvement. In addition to the direct electricity savings, cool roof systems reduce peak electrical demand in the month of August when the peak demand is at its highest in the case study area. Environmental benefits associated with lowering greenhouse-gas emissions are also substantial. The new methodology allows the calculation of payback periods to assist planners to evaluate the potential economic benefits of the widespread installation of cool roof systems.     

On the complexity of radiation models for PV energy production calculation

Several authors have analysed the changes of the probability density function of the solar radiation with different time resolutions. Some others have approached to study the significance of these changes when produced energy calculations are attempted. We have undertaken different transformations to four Spanish databases in order to clarify the interrelationship between radiation models and produced energy estimations. Our contribution is straightforward: the complexity of a solar radiation model needed for yearly energy calculations, is very low. Twelve values of monthly mean of solar radiation are enough to estimate energy with errors below 3%. Time resolutions better than hourly samples do not improve significantly the result of energy estimations.     

Thermodynamic assessment of geothermal energy use in hydrogen production

In this study, geothermal-based hydrogen production methods, and their technologies and application possibilities are discussed in detail. A high-temperature electrolysis (HTE) process coupled with and powered by a geothermal source is considered for a case study, and its thermodynamic analysis through energy and exergy is conducted for performance evaluation purposes. In this regard, overall energy and exergy efficiencies of the geothermal-based hydrogen production process for this HTE are found to be 87% and 86%, respectively.     

Renewable energy strategies for sustainable development

This paper discusses the perspective of renewable energy (wind, solar, wave and biomass) in the making of strategies for a sustainable development. Such strategies typically involve three major technological changes: energy savings on the demand side, efficiency improvements in the energy production, and replacement of fossil fuels by various sources of renewable energy. Consequently, large-scale renewable energy implementation plans must include strategies for integrating renewable sources in coherent energy systems influenced by energy savings and efficiency measures. Based on the case of Denmark, this paper discusses the problems and perspectives of converting present energy systems into a 100% renewable energy system. The conclusion is that such development is possible. The necessary renewable energy sources are present, and if further technological improvements of the energy system are achieved the renewable energy system can be created. Especially technologies of converting the transportation sector and the introduction of flexible energy system technologies are crucial.     

Potential energy savings in the production route for plastics

The gross energy requirement (GER) for the major petrochemical products (ethylene, propylene, butadiene and benzene) and the major bulk polymers (low density polyethylene, polypropylene, polystyrene and polyvinylchloride) is determined. The GER-values for LDPE, PP, PS and PVC are 69.8, 61.6, 81.5 and 55.7 GJ/ton, respectively. The potential energy saving in the process chain for each product is assessed on the basis of commercially available technologies. The profitable potential, savings (i.e. with a payback period shorter than 3 yr) is about 8% of the GER-figure. The technical potential for savings varies from 12% for ethylene to 25% for PVC. In addition, the potential savings are investigated for the industrial sectors involved, namely oil refining (15% of total primary energy demand), inorganic chemicals (6%) and petrochemicals (9%).