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.     

Growth curves and sustained commissioning modelling of renewable energy: Investigating resource constraints for wind energy

Several recent studies have proposed fast transitions to energy systems based on renewable energy technology. Many of them dismiss potential physical constraints and issues with natural resource supply, and do not consider the growth rates of the individual technologies needed or how the energy systems are to be sustained over longer time frames. A case study is presented modelling potential growth rates of the wind energy required to reach installed capacities proposed in other studies, taking into account the expected service life of wind turbines. A sustained commissioning model is proposed as a theoretical foundation for analysing reasonable growth patterns for technologies that can be sustained in the future. The annual installation and related resource requirements to reach proposed wind capacity are quantified and it is concluded that these factors should be considered when assessing the feasibility, and even the sustainability, of fast energy transitions. Even a sustained commissioning scenario would require significant resource flows, for the transition as well as for sustaining the system, indefinitely. Recent studies that claim there are no potential natural resource barriers or other physical constraints to fast transitions to renewable energy appear inadequate in ruling out these concerns.     

Design and optimum energy management of a hybrid renewable energy system based on efficient various hydrogen production

Utilizing renewable energy resources is one of the convenient ways to reduce greenhouse gas emissions. However, the intermittent nature of these resources has led to stochastic characteristics in the generation and load balancing of the microgrid systems. To handle these issues, an energy management optimization for microgrids operation should be done to urge the minimization of total system costs, emissions, and fuel consumption. An optimization program for decreasing the operational cost of a hybrid microgrid consisting of photovoltaic array, wind unit, electrolyzer, hydrogen storage system, reformer, and fuel cell is presented. Two different methods of producing hydrogen are considered in this study to ensure the effectiveness of the developed methodology. In the microgrid system with high penetration of renewable energy resources, using storage technologies to compensate for the intermittency of these resources is necessary. To evaluate the functioning of the microgrid system, a mathematical model for each source is developed to coordinate the system operation involving energy conversion between hydrogen and electricity. Particle Swarm Optimization Algorithm is utilized to determine the optimum size and operational energy management within the system. It is evident from the results that there is about a 10% reduction in the amount of CH₄ consumption in reformer when the electrolyzer was employed in the system. It is observed that the CH₄ reduction in summer and fall is higher than other seasons (10.6% and 11.5%, respectively). The reason is that the highest RES production occurs in these seasons during a year. It is also worth mentioning that the electrolyzer technology would play a significant role in decreasing the CH₄ consumption in the microgrid system.     

Potential and use of renewable energy sources in Croatia

The current share of renewable energy sources in electricity production in Croatia is very high, around 50%. Nevertheless it is expected that the share of renewables will have to rise and efficient strategies must be examined and adopted. The Croatian government has recognised the important role renewable energy sources could play in Croatian energy and electricity supply. The most important barrier for a wider deployment of renewables in energy production is their cost which is still above those of conventional energy sources. As the energy market is currently undergoing the process of liberalisation, support mechanisms that are compatible with an open market philosophy must be adopted. The characteristics of the Croatian power system, the expected consumption, growth and possible future role of renewables in energy and electricity production is presented. The current legislative framework relevant for renewables is analysed and discussed.     

Macro-level integrated renewable energy production schemes for sustainable development

The production of renewable clean energy is a prime necessity for the sustainable future existence of our planet. However, because of the resource-intensive nature, and other challenges associated with these new generation renewable energy sources, novel industrial frameworks need to be co-developed. Integrated renewable energy production schemes with foundations on resource sharing, carbon neutrality, energy-efficient design, source reduction, green processing plan, anthropogenic use of waste resources for the production green energy along with the production of raw material for allied food and chemical industries is imperative for the sustainable development of this sector especially in an emission-constrained future industrial scenario. To attain these objectives, the scope of hybrid renewable production systems and integrated renewable energy industrial ecology is briefly described. Further, the principles of Integrated Renewable Energy Park (IREP) approach, an example for macro-level energy production, and its benefits and global applications are also explored.     

Rural energy development in Iran: Non-renewable and renewable resources

Rural areas in Iran are necessarily linked to agriculture with very little diversification. These communities are solely dependent upon the fortunes of one or two primary enterprises. This is an extremely tenuous situation and these communities must diversify to insure economic and social viability. The objectives of this study are to (1) identify problems and difficulties encountered in the social–economic infrastructure as related to rural energy development and (2) present the non-renewable and renewable energy resources and assess the current energy generation and consumption rates. The analysis show that while there are numerous non-renewable and renewable energy resources available, problems such as cultural barriers and lack of appropriate mentality about energy impede the much-needed development in the rural areas of country. To fulfill rural energy needs, renewable energy plants must be developed locally all across the country: hydro and geothermal in the northern and western areas, wind in the eastern and the southern planes, and solar energy in the central desert plateaus. In conclusion, proper distribution of subsidies and adaptation of new efficiency laws are identified as areas for improvements.     

The link between political decision-making and energy options: Assessing future role of renewable energy and energy efficiency in Finland

European Union and Finland are confronted with much the same kind of challenges in energy policy. Because of much higher importance on energy, these issues escalated earlier in Finland including vital political decision-making. Several alternative energy paths to the future can be identified with fairly similar projected costs. The more in-depth analysis in the Finnish case suggests that, e.g., an integrated approach consisting of renewable energy sources and energy efficiency measures would be one competitive alternative to satisfy both increasing energy demand and CO₂ emission reductions already by 2020. The study shows that meeting environmental, energy security and economical targets may not as such be adequate for the future success of an energy option. There is a more profound link between the energy options and the political decision-making, implying a much broader range of criteria than just the 3 Es reflecting thus politicians’ priorities and concerns. For example, in the Finnish case renewable energy sources and energy efficiency did not match optimally the parliamentary majority's preferences when deciding on future electricity direction in 2002. The methodology suggested here can be used to improve the strategic positioning of alternative energy paths.     

The energy situation in OIC countries The possible contribution of renewable energy resources

The paper reviews the socioeconomic situation and energy utilization in Organization of Islamic Conference (OIC) countries which vary considerably. The review indicates that growing energy requirements are associated with economic development and population increase. Renewable energy utilization is indicated as an appropriate alternative for providing a considerable portion of future energy demand in certain energy-consuming sectors. When reviewing the present state of the art of major renewable energy technologies, particular attention is paid to both direct and indirect solar technologies. Possible adaption of renewables into the socioeconomic structures of OIC countries is discussed. The programme of action for renewables in the OIC is stressed, pointing to the priority attached to enhancing the renewable energy contribution.     

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 and renewable energy scenario of Pakistan

This paper presents a review about conventional and renewable energy scenario of the county in quantitative terms of supply, generation and exploitation of available resources. In this energy scenario, the renewable energy share is in the range of a fraction of a percentage compared to total conventional energy supplies, so depicting it as a sector of least significance for government. Main emphasis in this paper has been given on presentation of data about renewable energy (RE) installations in the country, on-going activities, development projects, RE planning and achievements of public sector RE institutions and organizations. At the end some suggestions are given for effective planning and exploitation of RE resources and use of technologies. These suggestions are not only useful for Pakistan but also are equally important for the third world countries to enhance appreciably RE contribution in their total energy supplies of their country.     

Sustainability of energy production and use in Iran

The issue of oil and gas policies in Iran is rather complex. In the present investigation, it is aimed to formulate plans for increasing the capacity of the country's energy production. Analysis of energy consumption pattern over last decades is indicative of inefficient usage. The low energy prices in Iran do not reflect economic costs. Further distortions exist in the tariff structures of most energy sources and in their relative prices. It is recognized that price reform is a key policy element for promotion of energy conservation and fuel substitution with renewable energies. Mitigation policies in the energy sector are crucial to Iran's overall policies. Emission of greenhouse gases can be reduced from 752,156 to 560,791 Gg CO₂ equivalents in 2010 by implementing the policies proposed for the energy sub-sectors. Enhancing energy efficiency, including combined cycle power generation, has proved to be the most economic option for greenhouse gases reduction in energy sector. Iran's energy consumption pattern is unsustainable and consumption oriented.     

An energy management approach for renewable energy integration with power generation and water desalination

The share of the renewable energy sources (RES) in the global electricity market is substantially increasing as a result of the commitment of many countries to increase the contribution of the RES to their energy mix. However, the integration of RES in the electricity grid increases the complexity of the grid management due to the variability and the intermittent nature of these energy sources. Energy storage solutions such as batteries offer either short-term storage that is not sufficient or longer period storage that is significantly expensive. This paper introduces an energy management approach which can be applied in the case of power and desalinated water generation. The approach is based on mathematical optimization model which accounts for random variations in demands and energy supply. The approach allows using desalination plants as a deferrable load to mitigate for the variability of the renewable energy supply and water and/or electricity demands. A mathematical linear programming model is developed to show the applicability of this idea and its effectiveness in reducing the impact of the uncertainty in the environment. The model is solved for the real world case of Saudi Arabia. The optimal solution accounts for random variations in the renewable energy supply and water and/or electricity demands while minimizing the total costs for generating water and power.     

Analysis and techno-economic assessment of renewable hydrogen production and blending into natural gas for better sustainability

In this study, comprehensive thermodynamic analysis and techno-economic assessment studies of the renewable hydrogen production and its blending with natural gas in the existing pipelines are performed. Solar and wind energy-based on-grid and off-grid power systems are designed and compared in energy, exergy, and cost. Solar PV panels and wind turbines are particularly considered for electricity and hydrogen production for residential applications in an environmentally benign way. Fuel cell units are included to supply continuous electricity in the off-grid system. Here, the heat required for a community consisting of 100 houses is provided by hydrogen and natural gas mixture as a more environmentally benign fuel. The costs of capital, fuel, operation, and maintenance are calculated and evaluated in detail. The total net present costs are calculated as $6.95 million and $2.47 million for the off-grid and on-grid power systems, respectively. For the off-grid system, energy and exergy efficiencies are calculated as 32.64% and 40.73%, respectively. Finally, the energy and exergy efficiencies of the on-grid system are determined as 26.58% and 35.25%, respectively.     

Reviewing optimisation criteria for energy systems analyses of renewable energy integration

The utilisation of fluctuating renewable energy sources is increasing world-wide; however, so is the concern about how to integrate these resources into the energy systems. The design of optimal energy resource mixes in climate change mitigation actions is a challenge faced in many places. This optimisation may be implemented according to economic objectives or with a focus on techno-operational aims and within these two main groupings, several different criteria may potentially be applied to the design process.In this article, a series of optimisation criteria are reviewed and subsequently applied to an energy system model of Western Denmark in an analysis of how to use heat pumps for the integration of wind power.The analyses demonstrate that the fact whether the system in question is modelled as operated in island mode or not has a large impact on the definition of the optimal wind power level. If energy savings and CO₂ emission reductions beyond the system boundary are not included in the analysis, then it is either not feasible to expand wind power to a high degree or it is conversely more feasible to install relocation technologies that can utilise any excess production. The analyses also demonstrate that different optimisation criteria render different optimal designs.     

Bio-methanization of energy crops through mono-digestion for continuous production of renewable biogas

The aim of this laboratory-scale study was to investigate the long-term anaerobic fermentation of an extremely sour substrate, an energy crop, for continuous production of methane (CH₄) as a source of renewable energy. The sugar beet silage was used as the mono-substrate, which had a low pH of around 3.3–3.4, without the addition of manure. The mesophilic biogas digester was operated in a hydraulic retention time (HRT) range between 15 and 9.5 days, and an organic loading rate (OLR) range of between 6.33 and 10 g VS l⁻¹ d⁻¹. The highest specific gas production rate (spec. GPR) and CH₄ content were 0.67 l g VS⁻¹ d⁻¹ and 74%, respectively, obtained at an HRT of 9.5 days and OLR of 6.35 g VS l⁻¹ d⁻¹. The digester worked within the neutral pH range as well. Since this substrate lacked the availability of macro and micro nutrients, and the buffering capacity as well, external supplementation was definitely required to provide a stable and efficient operation, as provided using NH₄Cl and KHCO₃ in this case. The findings of this ongoing long-term fermentation of an extremely acidic biomass substrate without manure addition have reflected crucial information about how to appropriately maintain the operational and particularly the environmental parameters in an agricultural biogas plant.     

考虑多弹性资源调峰成本的可再生能源开发协同优化模型

中国制定了2030年和2060年的碳排放目标.可再生能源,主要是风能和光伏发电,被认为是未来的发电方式.新能源发展的主要制约因素是电力系统资源监管灵活性有限,导致消费能力不足.因此需要考虑调峰灵活的资源成本以及区域可再生能源的合理协调开发和运行优化.本研究考虑了电力系统综合成本,综合分析电力系统各种弹性调节资源潜力及其...     

Potential of renewable hydrogen production for energy supply in Hong Kong

Hong Kong is highly vulnerable to energy and economic security due to the heavy dependence on imported fossil fuels. The combustion of fossil fuels also causes serious environmental pollution. Therefore, it is important to explore the opportunities for clean renewable energy for long-term energy supply. Hong Kong has the potential to develop clean renewable hydrogen energy to improve the environmental performance. This paper reviews the recent development of hydrogen production technologies, followed by an overview of the renewable energy sources and a discussion about potential applications for renewable hydrogen production in Hong Kong. The results show that although renewable energy resources cannot entirely satisfy the energy demand in Hong Kong, solar energy, wind power, and biomass are available renewable sources for significant hydrogen production. A system consisting of wind turbines and photovoltaic (PV) panels coupled with electrolyzers is a promising design to produce hydrogen. Biomass, especially organic waste, offers an economical, environmental-friendly way for renewable hydrogen production. The achievable hydrogen energy output would be as much as 40% of the total energy consumption in transportation.     

Sustainability assessment of renewable energy projects for off-grid rural electrification: The Pangan-an Island case in the Philippines

Renewable energy systems (RESs) have been promoted for rural electrification as an answer to the growing energy needs of communities while simultaneously satisfying environmental and resource scarcity problems. These off-grid systems however have several challenges in the perspective of sustainability due to the technically and financially weak recipients and users of the projects. There is still, however, less detailed understanding how the technical and economic aspects of the projects can properly match the social aspects to promote sustainability. This paper aimed to further understand the challenges and social impacts of rural electrification projects using RES through a case study of a centralized off-grid solar plant in the Philippines. The study used multiple correspondence analysis (MCA) to identify essential user attributes which explain the users’ electricity consumption behaviors. The community cooperative had difficulties maintaining the facility in the long term due to financial and capacity related challenges. A holistic approach dealing with the technical, economic and social aspects in developing RES projects promote sustainability.     

Assessing complementarity of wind and solar resources for energy production in Italy. A Monte Carlo approach

Wind and solar energy are expected to play a major role in the current decade to help Europe reaching the renewable energy penetration targets fixed by Directive 2009/28/EC. However, it is difficult to predict the actual production profiles of wind and solar energy as they depend heavily on variable meteorological features of solar radiation and wind speed. In an ideal system, wind and solar electricity are both injected in a fast reacting grid instantaneously matching supply and demand. In such a system wind and solar electricity production profiles should complement each other as much as possible in order to minimise the need of storage and additional capacity. In the present paper the complementarity of wind and solar resources is assessed for a test year in Italy.To achieve this goal we employ data at high spatial and temporal resolution data for both solar radiation and wind speed in Italy obtained from running two state of the art models (PVGIS and MINNI). Hourly profiles for solar and wind energy produced are compared in each 4 × 4 km² grid cell in Italy for 2005, and hourly, daily and monthly correlation coefficients are computed in order to assess the local complementarity of the two resources. A Monte Carlo approach is also developed to estimate how large-scale wind and solar energy productions could be potentially involved to complement each other in a scenario with up to 100 production sites across Italy. The results show how local complementarity can be very interesting with monthly correlation coefficients reaching values lower than −0.8 in several areas. Large-scale complementarity is also relevant with nation-wide monthly correlation coefficients showing values between −0.65 and −0.6. These model results indicate that in this sample year of 2005, wind and solar energy potential production have shown complementary time behaviour complementary, favourably supporting their integration in the energy system.     

The role of energy efficiency and renewable energies in the future world energy market

The world population is rising rapidly, notably in the developing countries. Historical trends suggest that increased annual energy use per capita is a good surrogate for the standard of living factors which promote a decrease in population growth rate. If these trends continue, the stabilization of the world's population will require the increased use of all sources of energy as cheap oil and gas are depleted. The improved efficiency of energy use and renewable energy sources will be essential to stabilizing population, while providing a decent standard all over the world.