Sustainable application of renewable sources in water pumping systems: Optimized energy system configuration

Eighteen years ago, in Portugal, the expenses in a water supply system associated with energy consumption were quite low. However, with the successive crises of energy fuel and the increase of the energy tariff as well as the water demand, the energy consumption is becoming a larger and a more important part of the total budget of water supply pumping systems. Also, new governmental policies, essentially in developed countries, are trying to implement renewable energies. For these reasons, a case-study in Portugal of a water pumping system was analysed to operate connected to solar and wind energy sources.     

Energy system analysis of 100% renewable energy systems—The case of Denmark in years 2030 and 2050

This paper presents the methodology and results of the overall energy system analysis of a 100% renewable energy system. The input for the systems is the result of a project of the Danish Association of Engineers, in which 1600 participants during more than 40 seminars discussed and designed a model for the future energy system of Denmark. The energy system analysis methodology includes hour by hour computer simulations leading to the design of flexible energy systems with the ability to balance the electricity supply and demand. The results are detailed system designs and energy balances for two energy target years: year 2050 with 100% renewable energy from biomass and combinations of wind, wave and solar power; and year 2030 with 50% renewable energy, emphasising the first important steps on the way. The conclusion is that a 100% renewable energy supply based on domestic resources is physically possible, and that the first step towards 2030 is feasible to Danish society. However, Denmark will have to consider to which degree the country shall rely mostly on biomass resources, which will involve the reorganisation of the present use of farming areas, or mostly on wind power, which will involve a large share of hydrogen or similar energy carriers leading to certain inefficiencies in the system design.     

Management of natural gas resources and search for alternative renewable energy resources: A case study of Pakistan

Energy usage in Pakistan has increased rapidly in past few years due to increase in economic growth. Inadequate and inconsistent supply of energy has created pressure on the industrial and commercial sectors of Pakistan and has also affected environment. Demand has already exceeded supply and load shedding has become common phenomenon. Due to excessive consumption of energy resources it would become difficult to meet future energy demands. This necessitates proper management of existing and exploration of new energy resources. Energy resource management is highly dependent on the supply and demand pattern. This paper highlights the future demands, production and supply of energy produced from natural gas based on economic and environmental constraints in Pakistan with special emphasis on management of natural gas. An attempt has been made by proposing a suitable course of action to meet the rising gas demand. A mechanism has been proposed to evaluate Pakistan's future gas demand through quantitative analysis of base, worst and best/chosen option. CO₂ emission for all cases has also been evaluated. The potential, constraints and possible solutions to develop alternative renewable energy resources in the country have also been discussed. This work will be fruitful for the decision makers responsible for energy planning of the country. This work is not only helpful for Pakistan but is equally important to other developing countries to manage their energy resources.     

Energy policy,aid, and the development of renewable energy resources in Small Island Developing States

Small Island Developing States (SIDS) have established ambitious renewable energy targets. The promotion of renewable energy has been motivated by several factors: a desire to lessen dependence on fossil fuels, to attract development assistance in the energy sector, and to strengthen the position of SIDS in climate change negotiations. Here we explore the interplay between the role of aid and energy policy in the development of renewable energy resources in SIDS. We find that the importance of development assistance has implications for the sustainability of renewable energy development, given that funding is not always accompanied by necessary energy policy reforms. We also identify energy efficiency and access to modern energy services as having received insufficient attention in the establishment and structure of renewable energy targets in SIDS, and argue that this is problematic due to the strong economic case for such investments.     

Extended-power pinch analysis (EPoPA) for integration of renewable energy systems with battery/hydrogen storages

An extended-power pinch analysis (EPoPA) is proposed as a means of extending the power pinch analysis (PoPA) for optimal design of renewable energy systems with battery and hydrogen storage (RES-BH). The EPoPA concept is based on the storage of wasted electricity that cannot be stored by the battery bank designed by PoPA. This energy is stored in the form of hydrogen and is discharged in the form of electricity when the external electricity source is needed. EPoPA graphical and numerical tools are introduced to determine the minimum required external electricity source, wasted electricity sources, and appropriate hydrogen storage system capacity of the RES-BH system during first and normal operation years. Furthermore, the integration of the RES-BH system with a diesel generator as a high reliable system is investigated in view point of economic. The optimal sizes of diesel generator and hydrogen storage system components, such as electrolyzer, fuel cell and hydrogen tank are obtained with the minimization of the total annual cost (TAC) of the system. The implementation results of the EPoPA tools on three possible case studies indicate that EPoPA, unlike other process integration methodologies such as PoPA, is able to optimally design RES-BH systems.     

Decision support system for exploiting local renewable energy sources: A case study of the Chigu area of southwestern Taiwan

The topic of climate and energy policy has drawn new attention since the Kyoto Protocol has now come into force. It is hoped that strengthened use of renewable energy sources can meet new international environmental requirements and provide self-sufficient domestic energy supplies. The decision support system established in this study integrates potential evaluations, cost analyses, legal incentives, and analysis of returns on investments with the aid of a geographic information system (GIS). This system can provide insights for policymakers into where and the extent of the potentials, for lawmakers into whether the current legal incentives are sufficient to encourage private investment, and for investors into whether investments in exploiting local renewable energy sources are economically feasible. Under the current incentive framework in Taiwan, the amortization periods of investment on renewable energy are generally longer than the period over which the investment is to be recovered. This presents an unfavorable condition for attracting investments to and for developing renewable energy. An increase in remuneration through legal revisions is needed before domestic investment in renewable energy will actively expand.     

Prospects of hydrogen production potential from renewable resources in Algeria

Hydrogen production from renewable energies is a key part in the energy transition to realize a sustainable energy economy for both developed and developing nations. For Algeria, successful energy transition toward a hydrogen economy will require the establishment of its potential. This study was conducted to estimate the potential for producing hydrogen from renewable resources in Algeria. The renewable energies considered are: solar photovoltaic and wind. To accomplish this objective, first, we analyzed renewable resource data both statistically and graphically using Geographical Information System (GIS), a computer-based information system utilized to create and visualize the spatial distribution of the geographic information. Then, the study will evaluate the availability of renewable electricity production potential from these key renewable resources. The potential for the hydrogen production, via the electrolysis process with wind and solar photovoltaic electricity, is described with maps showing it per unit area in each region. Finally, the results of the estimated hydrogen potential from both resources for each region are compared and significant conclusions are drawn.     

Energy conversion efficiency of trout and sea bass production in the Black Sea,Turkey

This study examined the current energy balance, energy conversion efficiency, and farm-level efficiency of trout and sea bass production in the Black Sea of Turkey. Using a structured survey, we collected data from nine monoculture trout farms and five polyculture trout and sea bass farms during the 2005–2006 production season. Energy values were calculated using energy equivalents of the inputs and outputs for the farms. Data envelopment analysis was used to calculate farm-level efficiency. The total energy use per cubic meter was 46.57 MJ for trout production and 87.13 MJ for sea bass production. The main energy inputs were feed and diesel oil for both trout and sea bass production. Indirect energy use was dominant in trout production, while direct energy use was more common in sea bass production. The energy input-to-output ratio of trout production was higher than that of sea bass production. Sea bass production was more economically energy efficient compared to trout production. The allocative and economic energy efficiencies for trout and sea bass production were 0.788 and 0.881, respectively. For both types of farms, the most discriminative variable affecting economic efficiency was operator experience. Increasing focus on product distribution costs could decrease total energy costs by approximately 12%.     

Medium term market perspectives,goal prices and competitiveness of renewable resources in the Italian energy system

Using a multiperiodal LP model (MARKAL) the authors assessed the likely potential of solar thermal and biogas systems under various circumstances. The study covered the period 1980–2005, in five segments of five years. It focused only on the subsystem of the energy end-uses which can be substituted for by solar and biogas technologies. In this paper we show the main results of the study regarding the competitiveness of the single solar and biogas technologies in different scenarios and their sensitivity to incentives and prices, together with the essential technical data regarding demand and supply technologies which produced those results. The analysis performed of the potential penetration of renewable technologies into the Italian energy system shows that their contribution will remain very marginal if the price of conventional energy carriers remains constant in constant money. However, the objective of removing with renewable technologies 1.5 per cent of the total Italian energy consumption appears to be realistic in the short-medium term.     

Costing electricity supply scenarios: A case study of promoting renewable energy technologies on Rodriguez, Mauritius

Small Island Developing States (SIDS) import increasing amounts of fossil fuel to meet their rising energy demand. This places an unnecessary financial burden on their budget, as abundant Renewable Energy Sources (RES) are often available. The introduction of Renewable Energy Technologies (RETs) can harness these resources, providing sufficient electricity as well as maintaining a high degree of independence. However, one of the principle barriers to their application has been the high cost of installing them. This paper argues that the economics of instigating RETs on SIDS are potentially favourable over the application of fossil fuel technologies if the full life-cycle costs are considered. A case study conducted in 2001, modelling three alternative electricity provision scenarios on Rodrigues, Mauritius supports these assumptions. The findings are based on a comparative economic model using Discounted Cash Flow (DCF) analyses, as well as a variety of sensitivity analyses, to predict changing economic environments. This provides crucial guidance for the formulation of energy policy and planning. This work is part of a tripartite research project that connects the economics with renewable resources assessment and a multi criteria analysis investigating the social and environmental consequences to provide a transferable framework assessment of renewable energy supply options on SIDS.     

A superstructure model of an isolated power supply system using renewable energy: Development and application to Jeju Island,Korea

In this study, we aim to develop a superstructure-based optimization model using mixed integer linear programming (MILP) to determine the optimal combination and sizing for a hybrid renewable energy system to be used in an isolated area. The developed model has a three-layered energy structure to reflect the current reality in which energy production and consumption sites are generally separate. A variety of economic factors, including distance between facilities and an installation area, are considered for a more accurate estimation of the total annualized cost. Two types of optimization models, i.e., with and without a battery, are proposed to evaluate the economic and technical effects of a storage device to resolve operation issues caused by intermittent resources. An application case study on Jeju Island, Korea, confirms that the proposed model is suitable for decision making at the planning stage of a renewable energy system.     

Multi-objective optimization model for sustainable Indonesian electricity system: Analysis of economic,environment, and adequacy of energy sources

This paper presents a multi-objective optimization model for a long-term generation mix in Indonesia. The objective of this work is to assess the economic, environment, and adequacy of local energy sources. The model includes two competing objective functions to seek the lowest cost of generation and the lowest CO₂ emissions while considering technology diffusion. The scenarios include the use of fossil reserves with or without the constraints of the reserve to production ratio and exports. The results indicate that Indonesia should develop all renewable energy and requires imported coal and natural gas. If all fossil resources were upgraded to reserves, electricity demand in 2050 could be met by domestic energy sources. The maximum share of renewable energy that can be achieved in 2050 is 33% with and 80% without technology diffusion. The least cost optimization produces lower generation costs than the least CO₂ emissions, as well as the combined scenario. Total CO₂ emissions in 2050 are five to six times as large as current emissions. The least CO₂ emissions scenario can reduce almost half of the CO₂ emissions of the least cost scenario by 2050. The proposed multi-objective optimization model leads some optimal solutions for a more sustainable electricity system.     

Perspective and potential of CO2: A focus on potentials for renewable energy conversion in the Mediterranean basin

Figures commonly quoted on the soon shortage of generating energy from fossil sources which may give the impression that it will be possible to switch to renewable energies conversion as foundations for the future of industrial instances in the Mediterranean basin. In this study, CO₂ energy potential and perspectives in the Mediterranean basin have been investigated in terms of efficiency, feasibility, geographical patterns and savings. Two conjoint mathematical protocols have been carried out in order to yield a simplified extracted scheme for prototype CO₂ trapping/storage plants.     

Local challenges in the promotion of renewable energy sources: The case of Crete

Crete, the largest Greek island, attracts about 20% of the total Greek tourist activity and hosts more than 50% of all renewable energy projects situated in the Hellenic island territories. In this article, we probe the comparatively successful promotion of renewable energy applications among Cretan municipalities by identification of key components and drivers of local dynamics which facilitate the development of such innovative and collective projects. We then refer to a theoretical economic grid highlighting the strength of local factors (i.e. social and institutional forces) in co-ordination mechanisms. We conclude that for the case of Crete, both internal factors (such as local acceptance) and external elements (such as macrostructure) play a core role in successful implementation of renewable energy, and from this we propose a number of facilitating conditions which could help promote renewable energy production on other islands.     

A model for investigation of optimal hydrogen pathway,and evaluation of environmental impacts of hydrogen supply system

In order to achieve a hydrogen economy, developing widespread hydrogen supply systems are vitally important. A large number of technological options exist and are still in development for hydrogen production, storage, distribution…, which cause various pathways for supplying hydrogen. Besides the technical factors, there are other effective parameters such as cost, operability, reliability, environmental impacts, safety and social implications that should be considered when assessing the different pathways as optimal and viable long-term alternatives. To aid this decision-making process, we have developed a generic optimization-based model for the long-range energy planning and design of future hydrogen supply systems. By applying Linear Dynamic Programming techniques, the model is capable of identifying optimal investment strategies and integrated supply system configurations from the many alternatives. Also, the environmental impacts of hydrogen supply system can be evaluated through scenario analysis. The features and capabilities of the model are illustrated through application to Iran as a case study.     

Rice straw as a renewable energy source in India, Thailand, and the Philippines: Overall potential and limitations for energy contribution and greenhouse gas mitigation

Rice is a widely grown crop in the South and South-East Asia that leaves substantial quantity of straw in the field. The aim of this paper is to assess the quantity of rice straw produced, estimate Greenhouse Gas (GHG) emissions based on its current uses, and assess its possible energy potential and related GHG emissions mitigation potential. Updated statistics on rough rice production are used in this study in combination with the literature values on Straw-to-Grain Ratio (SGR) to quantify the amount of rice straw produced in the three countries of focus. It is estimated that 97.19, 21.86, and 10.68 Mt of rice straw residue are produced in India, Thailand, and the Philippines, respectively.In India, 23% of rice straw residue produced is surplus and is either left in the field as uncollected or to a large extent open-field burnt. About 48% of this residue produced is subjected to open-field burning in Thailand, and in the Philippines it is 95%. The GHG emissions contribution through open-field burning of rice straw in India, Thailand, and the Philippines are 0.05%, 0.18%, and 0.56%, and the mitigated GHG emissions when generated electricity is used would be 0.75%, 1.81%, and 4.31%, respectively, when compared to the total country GHG emissions.     

Use of material flow accounting for assessment of energy savings: A case of biomass in Slovakia and the Czech Republic

Anthropogenic material and energy flows are considered to be the major cause of many environmental problems humans face today. In order to measure material and energy flows, and to mitigate related problems, the technique of material flow and energy flow analysis has been conceived. The aim of this article is to use material and energy flow accounting approaches to quantify the amount of biomass that is available, but that so far has not been used for energy purposes in Slovakia and the Czech Republic and to calculate how much consumed fossil fuels and corresponding CO₂ emissions can be saved by utilising this biomass. Based on the findings presented, 3544 kt/yr of the total unused biomass in Slovakia could replace 53 PJ/yr of energy from fossil fuels and 6294 kt/yr of the total unused biomass in the Czech Republic could replace 91 PJ/yr of energy. Such replacement could contribute to a decrease in total CO₂ emissions by 9.2% in Slovakia and by 5.4% in the Czech Republic and thus contribute to an environmental improvement with respect to climate change.     

Resource and environment efficiency analysis of provinces in China: A DEA approach based on Shannon’s entropy

Data envelopment analysis (DEA) has been widely used in energy efficiency and environment efficiency analysis in recent years. Based on the existing environment DEA technology, this paper presents several DEA models for estimating the aggregated efficiency of resource and environment. These models can evaluate DMUs’ energy efficiencies and environment efficiencies simultaneously. However, efficiency ranking results obtained from these models are not the same, and each model can provide some valuable information of DMUs’ efficiencies, which we could not ignore. Under this situation, it may be hard for us to choose a specific model in practice. To address this kind of performance evaluation problem, the current paper extends Shannon-DEA procedure to establish a comprehensive efficiency measure for appraising DMUs’ resource and environment efficiencies. In the proposed approach, the measure for evaluating a model's importance degree is provided, and the targets setting approach of inputs/outputs for DMU managers to improve DMUs’ energy and environmental efficiencies is also discussed. We illustrate the proposed approach using real data set of 30 provinces in China.     

Household energy needs of a village in the Rayalaseema area of Andhra Pradesh, India

Energy shortages in rural areas have several far-reaching ill-consequences. The scarcity of fuelwood forces people to use animal dung and crop residue as fuel, reducing the soil fertility and productivity. Progressive deforestation adversely affects the environment. Women and children in villages walk long distances and spend more time in searching for fuel. For effective energy planning, it is necessary to understand the energy-use patterns of different categories of farmers in village ecosystems and the influence of income and family size on it. This paper reports such a study conducted in a village in the State of Andhra Pradesh in India where dryland agriculture is pursued. The household energy-use patterns observed in the village clearly show that most energy is utilized for basic survival tasks such as cooking, cleaning, fetching fuel, water and other necessities of life. Commercial energy, which accounts for 6.5% of the total energy consumption of households, is used exclusively for lighting. A number of measures have been suggested for enhancing the efficiency of energy use in rural household systems, which include the design and installation of a fuel-efficient improved chulha, with dampers, baffle and a grate in the combustion chamber, installation of family size biogas plants, planting of hardwood trees on field bunds, energy plantation on marginal and waste lands, utilization of solar photovoltaics for power generation, installation of windmills for lifting water, and briquetting and pelletization of groundnut shell, and farm and forest residues. A well-knit and coordinated infrastructure has to be developed for successful implementation of the above measures. Local skill and participation, especially of artisans and women, should be encouraged and should be supplemented by appropriate training and monitoring. An energy utilization system based on local resources can improve productivity and standards in all spheres of rural living.