On the value of decentralised PV systems for the GCC residential sector

Based on the rich natural potential of the Gulf region, solar energy is expected to play a greater role in the future of the Gulf Corporation Council (GCC) countries. This study examines whether the integration of the photovoltaic (PV) into individual residential buildings in the GCC countries is worth the investment. A prototype residential building is developed and a building integrated photovoltaic (BiPV) system is then designed. The system performance is simulated, and through economic analysis, it is shown that the current BiPV technology is not a cost-effective option for the GCC countries based on the present electricity tariff, PV system cost and system efficiency. The only way such a system would be viable with current technology is if the electricity tariff were to increase substantially. However, if the tariff remains constant for the foreseeable future, BiPV solar energy technology will only be feasible if the total system cost drops drastically. This study shows that BiPV systems offer cost reductions in both energy and economic terms over centralised PV plants, especially if the costs of avoided building construction materials are taken into account. To bring about the benefits of BiPV technology for the GCC residential sector, therefore, the first logical and most practical step is the implementation of a continuous promotion strategy that consists of both subsidies for investments and reasonable tariffs.     

Energy conservation in US buildings: Solving the high potential/low adoption paradox from a behavioural perspective

The US building sector can ‘produce’ 30–50% of its energy needs by more efficient use of energy, ie by conservation. The cost of such energy conservation is usually below that of imported oil or new electric generation capacity. Yet, paradoxically, consumer adoption of this type of ‘energy’ is quite low. This stems from energy analysis traditionally dominated by engineering and economic perspectives, and ignoring a critically relevant behavioural perspective. Unless all three perspectives are integrated, little can be expected in the way of speedy market penetration of energy conservation. In this article the engineering, economic and behavioural perspectives are discussed, and the importance of integration is emphasized. The framework for diffusion of innovations is shown to be useful in an understanding of how demand for energy conservation forms and spreads. Specific recommendations to speed the adoption of energy conservation are outlined.     

Economic effects of energy efficiency improvements in the Finnish building stock

This study estimates the economic effects of investing in energy efficiency in buildings on a national level. First conservation potentials in space heating for two different scenarios with different levels of investment in energy efficiency are quantified. This was done relying on statistical data and future projections of the development of the building stock. Then economic modeling was used to estimate the effects on energy sector and the economy at large. The results show that a rather modest increase resulting in a few percent rise in annual construction and renovation investments can decrease total primary energy consumption 3.8–5.3% by 2020 and 4.7–6.8% by 2050 compared to a baseline scenario. On the short term a slight decrease in the level of GDP and employment is expected. On the medium to long term, however, the effects on both would be positive. Furthermore, a significant drop in harmful emissions and hence external costs is anticipated. Overall, a clear net benefit is expected from improving energy efficiency.     

Energy conservation in Chinese housing

In the People's Republic of China (PR China), even though climatic conditions are severe, energy use in buildings has traditionally been insignificant by Western standards. The recent increases in household energy consumption have left two options: increase household energy use at the expense of industrial and environmental gains, or develop policies to conserve or restrict household energy consumption. This paper explores the problems in introducing low-cost energy conservation practices in Henan Province, PR China. The paper describes both the practical problems encountered in the introduction of new building materials and designs and also the institutional barriers that inhibit the development of an energy conservation delivery system. A major theme of this paper is that conventional Western solutions for energy conservation often come up against significant unexpected barriers in developing nations, rendering these solutions ineffective. For instance, the high cost and/or unavailability of materials in many countries require building redesign solutions that do not utilize insulation, vapour barriers, and modern heating and cooling plants. Similarly, the particular political and economic organization of a country may mean that coordination of a regional or national conservation programme will require an approach quite different from the public or private development programmes in Western developed countries.     

海外勘探项目最小经济储量规模盈亏平衡模型研究

国内利用盈亏平衡原理,建立最小经济储量规模模型应用成熟,而海外油气勘探项目由于财税条款复杂,盈亏平衡法在最小经济储量计算中的应用还是空白。在分析海外项目矿税制、产品分成制合同者收入、投资、税金等特点的基础上,力图建立合同者收入、投资、成本、税金等和储量的数学关系。假定成本回收油全部用来回收成本,较好地处理了产品分成制下合同者的收入问题;引入单位综合税金,解决海外油气项目复杂的税金问题;通过建立最小储量规模和利润油气分成系数之间的迭代计算,较好地处理滑动的分成系数和最小储量规模的关系。在此基础上,依据盈亏平衡、投入产出相等原理,建立海外勘探项目最小经济储量规模盈亏平衡模型,并给出单位综合税金、利润油气分成系数等主要参数的取值原则。利用模型,计算了中国石化某海外天然气勘探项目在不同资金时间价值下的最小油气储量规模,并与现金流法得到的最小储量规模结果进行比较,对盈亏平衡模型进行了讨论。     

Unit sizing and cost analysis of stand-alone hybrid wind/PV/fuel cell power generation systems

An economic evaluation of a hybrid wind/photovoltaic/fuel cell (FC) generation system for a typical home in the Pacific Northwest is performed. In this configuration the combination of a FC stack, an electrolyser, and hydrogen storage tanks is used as the energy storage system. This system is compared to a traditional hybrid energy system with battery storage. A computer program has been developed to size system components in order to match the load of the site in the most cost effective way. A cost of electricity, an overall system cost, and a break-even distance analysis are also calculated for each configuration. The study was performed using a graphical user interface programmed in MATLAB.     

Optimal integration of wind farms to isolated wind-Diesel energy system

Wind farms installed on isolated systems are subject to significant restrictions, affecting their expected energy yield and, hence, the feasibility of investments. As wind power penetrations increase in isolated power systems, it is very important to understand how variations in wind plant outputs affect the operation of the isolated system on a day to day basis and what the associated added costs are. In this paper, a wind-Diesel coordination generation scheduling (WCGS) software is developed for appropriate assessment of the added cost to cover the unpredictable wind generator output variations. The developed WCGS software is also a useful tool for the system planner to predict the energy cost and the fuel saving from the expected new wind-Diesel systems. Several technique constraints are applied to determine the optimal proportion of wind generator capacity that can be integrated into the existing system. A simple benefit cost ratio (BCR) is used in this study to evaluate the investment effectiveness of the installation of wind farms for an isolated hybrid system. Numerical experiments are included to understand the wind generator output variations in system operating cost analysis and to assess the impact and economic benefits of the installation of wind farms.     

Economic optimization and sensitivity analysis of photovoltaic system in residential buildings

This paper deals with the problem of optimal size of grid-connected photovoltaic (PV) system for residential application. It is assumed the PV system can input or output liberally the electricity to the utility electricity grid. A simple linear programming model is developed. The objective is to minimize the annual energy cost of a given customer, including PV investment cost, maintenance cost, utility electricity cost, subtracting the revenue from selling the excess electricity. The model reports the optimal PV capacity that customers adopt with their electricity requirements. Using this model, an investigation is conducted of economically optimal PV investment under several conditions for a typical residential building. Additionally, the sensitivity of levelized cost and simple payback period to various economic and technical circumstances has been analyzed.     

基于水库大坝的水能与太阳能融合型并网发电系统研究与应用

针对中国大中型面南的水库电站大坝,向光性比较好,具备安装太阳能光伏发电系统的条件,并使得2种可再生能源融合并网发电模式具有一定的创新性.水库电站的发电系统是已建成的,增加太阳能光伏发电系统并建设融合型并网发电系统,不仅体现了投资成本低发电效益高等特点,同时具有节约国土资源、保护大坝和节能减排等社会效益.在设计和实践过程...     

家用太阳热水器与太阳热水系统的技术经济比较

分析了户用太阳热水器和太阳热水系统工程的经济技术特点,对两者成本构成、项目财务净现值、投入回收期和财务内部收益率等有关指标进行了经济技术比较.分析比较表明,太阳热水系统与家用热水器相比,节省安装占地,与建筑相结合得好,在降低成本,缩短投资回收期,提高经济效益方面有明显的优势.     

On optimal investment strategies for energy conservation

This paper focuses on the problem of optimal time-phasing of investments in energy conservation. We determine the optimal time-phased investment strategy under the assumption that incremental investment can be made at any time without cost penalty. The results of the analysis are compared with the more practical approach of making all conservation investments at one time. We find, for a number of realistic cases, that there are only minor differences (typically 10% or less) between the two strategies in terms of present value. Accordingly, we conclude that a strategy of erring on the side of early investment in energy conservation measures is often justified. The analysis of the optimal time phasing for conservation investments involves the Kuhn-Tucker conditions, and is developed in detail in an appendix to the paper. The final form is quite simple when the amount of energy used annually by a system decreases exponentially with capital investment in conservation.We have found that the exponential form provides a good fit to a number of cases reported in the literature. For the exponential form and for relevant ranges of paramenters, the optimal investment strategy consists of an initial investment in conservation, followed by a constant investment per year up to a cut-off time (t₂) less than the lifetime of the system (T), after which no further investment is justified. The results of an analysis are presented in dimensionless graphical form for convenience of application. The analysis developed is directly relevant and applicable to situations in which an ensemble of conservation opportunities exists. An example would be when an entity (e.g. the Federal Government) is faced with installing conservation measures in a large number of buildings. The methodology developed may then be used to determine the optimal time phasing for each of a series of conservation measures.     

Techno-economic analysis of fuel cell auxiliary power units as alternative to idling

This paper presents a techno-economic analysis of fuel-cell-based auxiliary power units (APUs), with emphasis on applications in the trucking industry and the military. The APU system is intended to reduce the need for discretionary idling of diesel engines or gas turbines. The analysis considers the options for on-board fuel processing of diesel and compares the two leading fuel cell contenders for automotive APU applications: proton exchange membrane fuel cell and solid oxide fuel cell. As options for on-board diesel reforming, partial oxidation and auto-thermal reforming are considered. Finally, using estimated and projected efficiency data, fuel consumption patterns, capital investment, and operating costs of fuel-cell APUs, an economic evaluation of diesel-based APUs is presented, with emphasis on break-even periods as a function of fuel cost, investment cost, idling time, and idling efficiency. The analysis shows that within the range of parameters studied, there are many conditions where deployment of an SOFC-based APU is economically viable. Our analysis indicates that at an APU system cost of $ 100 kW⁻¹, the economic break-even period is within 1 year for almost the entire range of conditions. At $ 500 kW⁻¹ investment cost, a 2-year break-even period is possible except for the lowest end of the fuel consumption range considered. However, if the APU investment cost is $ 3000 kW⁻¹, break-even would only be possible at the highest fuel consumption scenarios. For Abram tanks, even at typical land delivered fuel costs, a 2-year break-even period is possible for APU investment costs as high as $ 1100 kW⁻¹.     

Effects of cross-border power trade between Laos and Thailand: Energy security and environmental implications

This paper analyzed the effects of hydropower development in Laos and power trade between Laos and Thailand on economy wide, energy resource mix, power generation capacity mix, energy system cost, environment, as well as, energy security. A MARKAL-based model for an integrated energy system of Laos and Thailand was developed to assess the effects of energy resource development and trade to meet the national energy demands of the two countries. Two national MARKAL-based energy system models of Laos and Thailand were formulated for the study. The results show that 80% exploitation of water resource in Laos would induce power trade between the countries. The integrated energy system cost is found to decrease marginally but it would mitigate the CO₂ emission by 2% when compared with the base case. Thailand is expected to gain benefit from the increased level of power imported from Laos in terms of the lower energy system cost, better environmental quality and, greater diversification of energy sources. As compared to the base case, Laos would become the net energy exporter, earn significant export revenue, and improve the increase in revenue of energy export per increase in total energy system cost from the maximum exploitation of hydropower resource.     

Promotion of energy conservation in developing countries through the combination of ESCO and CDM: A case study of introducing distributed energy resources into Chinese urban areas

The implementation of an energy service company (ESCO) project in developing countries may result not only in reduced energy cost but also in considerable environmental benefits, including the reduction of CO₂ emissions, which can be assessed in an economic manner under the Clean Development Mechanism (CDM) scheme. In this way, the economic and environmental benefits of energy conservation activities can be enjoyed by both the investor and the end-user, which can reduce the investment risk and realize a rational profit allocation. This study presents a numerical analysis of the introduction of distributed energy resources (DER) into a Chinese urban area. An optimization model is developed to determine the energy system combination under the constraints on the electrical and thermal balances and equipment availability. According to the simulation results, the introduction of DER systems possesses considerable potential to reduce CO₂ emissions, especially when considering that the economic profit of the CO₂ credit will increase the incentive to adopt DER systems to an even greater extent. Furthermore, by sharing the energy cost savings with the investors under an ESCO framework, the investment risk can be further reduced, and the conditions required for the project to qualify for CDM can be relaxed.     

Fundamental aspects of energy conservation policy

The formulation of a governmental energy conservation policy requires that the issues involved be fundamentally analyzed. Information transfer, more intensive use of data, and good housekeeping can all contribute to reduced energy use. Our major choice, however, is between producing the present mix of materials, commodities, and services more efficiently or decreasing demand for them. The first option is referred to as the “technical fix”, the second one as “change of lifestyle”. If the first option fails, changes in life-style might become mandatory.This paper deals with the technical fix approach. Higher capital investment can lead to a decrease in direct use of energy. Both the cost and the energy involved in these investments are analyzed along a conservation path, and a limited number of constants is used to describe the changes along this path. These constants can also be used to feed technological information into macroeconomic analysis.The time scales involved pose the major problem to achieving conservation by means of a technological fix. An increase in the price of energy will lead to higher capital investments in accordance with the economic lifecycles in the different sectors. For applications with a short life-time, such as in the transport sector, energy conservation will mainly take place through the construction of new equipment. In sectors with long lifetime investments (e.g. buildings), retrofitting will be important.Including the indirect energy requirements in the conservation study leads to some important conclusions. It can be demonstrated that the thermodynamic limit is not the ultimate limit for conservation. An energy minimum is obtained, which corresponds to a use of energy higher than the thermodynamic limit. It is also impossible to reduce or eliminate some components of the present energy supply system and at the same time to introduce a new decentralized supply system.A crucial aspect of the technological fix approach is that within the present rules, capital investments for saving direct energy can only be made after the increase in energy price has taken place or when it can be firmly anticipated on a short term. At this point, however, the time needed for making these capital investments is lacking and adverse economic consequences can be expected.It is therefore the major task of governmental policy to induce conservation before it is economically acceptable or possible. This requires some form of government interaction. The theory developed in this paper provides a method by which to rank the options according to the energy saved per dollar of public funds invested. This measures the difference between the objectives of the private sector and those of society.The longer this policy is postponed, the larger is the risk that conservation will have to be achieved in an emergency program. In that situation the indirect energy necessary for the capital construction might jeopardize the short-term goals.     

采暖居住建筑节能改造收益分析

面对我国华北地区既有采暖居住建筑节能改造资金的匮乏 ,提出既有建筑的节能改造经济性分析不仅要计算冬季供暖节能收益 ,而且还要包括夏季空调节能收益 ,同时还应计入冷热源建设等潜在经济收益 ,这对缩短既有建筑节能改造初投资回收期、推动我国建筑节能的发展具有积极意义。     

Bounds test approach to cointegration and causality between nuclear energy consumption and economic growth in India

This paper attempts to examine the dynamic relationship between economic growth, nuclear energy consumption, labor and capital for India for the period 1969–2006. Applying the bounds test approach to cointegration developed by Pesaran et al. (2001) we find that there was a short- and a long-run relationship between nuclear energy consumption and economic growth. Using four long-run estimators we also found that nuclear energy consumption has a positive and a statistically significant impact on India's economic growth. Further, applying the Toda and Yamamoto (1995) approach to Granger causality and the variance decomposition approach developed by Pesaran and Shin (1998), we found a positive and a significant uni-directional causality running from nuclear energy consumption to economic growth without feedback. This implies that economic growth in India is dependent on nuclear energy consumption where a decrease in nuclear energy consumption may lead to a decrease in real income. For a fast growing energy-dependent economy this may have far-reaching implications for economic growth. India's economic growth can be frustrated if energy conservation measures are undertaken without due regard to the negative impact they have on economic growth.     

Method for a component-based economic optimisation in design of whole building renovation versus demolishing and rebuilding

AimThis paper presents a two-fold evaluation method determining whether to renovate an existing building or to demolish it and thereafter erect a new building.ScopeThe method determines a combination of energy saving measures that have been optimised in regards to the future cost for energy. Subsequently, the method evaluates the cost of undertaking the retrofit measures as compared to the cost of demolishing the existing building and thereafter erecting a new one. Several economically beneficial combinations of energy saving measures can be determined. All of them are a trade-off between investing in retrofit measures and buying renewable energy. The overall cost of the renovation considers the market value of the property, the investment in the renovation, the operational and maintenance costs. A multi-family building is used as an example to clearly illustrate the application of the method from macroeconomic and private financial perspectives.ConclusionThe example shows that the investment cost and future market value of the building are the dominant factors in deciding whether to renovate an existing building or to demolish it and thereafter erect a new building. Additionally, it is concluded in the example that multi-family buildings erected in the period 1850–1930 should be renovated.     

非节能住宅节能改造方案研究

基于矿区老式居民住宅楼冬季供暖单耗的考察、测试数据,遵循封闭式门窗抑制楼内热量向外扩散和外墙敷设保温层降低墙体热值传导系数的原理,制定出了铁法矿区老式住宅楼供暖节能改造总体方案。至2009年10月仅完成了该方案中的封闭式门窗增设工程,投资1 323万元,实现节省热值45.33 GJ/h,已供扩展挂网增收1 600万元。预计2011年10月全部完成节能改造总体方案,将完成总投资13 737万元,节省热值达99.32 GJ/h,供扩展挂网增收总额9 486万元,年增收取暖费2 134.35万元,经济效益和社会效益都十分明显。     

Effect of wall orientation on the optimum insulation thickness by using a dynamic method

A comprehensive economic analysis has been performed to inter-relate the optimum thickness of insulation materials for various wall orientations. The yearly cooling and heating transmission loads of building walls were determined by use of implicit finite-difference method with regarding steady periodic conditions under the climatic conditions of Elaz??, Turkey. The economic model including the cost of insulation material and the present value of energy consumption cost over lifetime of 10 years of the building was used to find out the optimum insulation thickness, energy savings and payback periods for all wall orientations. Considered insulation materials in the analysis were extruded polystyrene and polyurethane. As a result, the optimum insulation thickness of extruded polystyrene was found to be 5.5 cm for south oriented wall and 6 cm for north, east and west oriented walls. Additionally, the lowest value of the optimum insulation thickness and energy savings were obtained for the south oriented wall while payback period was almost same for all orientations.