Natural Gas Energy Research Articles

Three Approaches to Low-Duty Turbo Compressor Efficiency Exploitation Evaluation

This paper presents three approaches for isentropic, energy, and exergy evaluations of a low-duty liquid natural gas (LNG) vapor turbo compressor during exploitation on a conventional LNG carrier. The evaluation was conducted on the measured performance parameters under 22 various turbo compressor operating regimes. The turbo compressor performance was evaluated in the temperature span from −69 to −105 °C and during changes in the rpm of the main propulsion turbine and, consequently, the main boiler load. The results show that the highest measured turbo compressor isentropic efficiency is in agreement with the manufacturer specifications, equaling 75.23% at a main propulsion turbine rpm of 53.5. At the highest measured loads and rpm, the turbo compressor energy and exergy efficiencies reach the highest values of 57.81% and 28.51%, respectively. In each observed operating regime, the influence of the ambient temperature change on the turbo compressor exergy efficiency was investigated. At the lowest and the highest measured loads, turbo compressor energy and exergy flow streams are presented in a Sankey diagram. Techniques for cargo temperature maintenance during the ship voyage are presented, as the results show that low suction gas temperatures influence turbo compressor efficiency.

Effects of Energy Consumption on GDP: New Evidence of 24 Countries on Their Natural Resources and Production of Electricity

Because of rapid economic expansion, China, the USA, and India have become the largest energy producers and sources of CO2 emissions in the world. They burned over 45% of global fuels in 2016. Meanwhile, the developing strategies of 24 polluted states to decrease fossil energy consumption without additional economic output. This paper explores the effect of world top polluted countries’ CO2 emission, their GDP and production of electricity by potential indicators and identifies the basic factors that contribute to changes in an environment where petroleum, natural gas, coal, nuclear, biomass, and other renewable energy and hydroelectric sources are examined with GDP per capita. We estimate our data for the period from 1968 to 2017 and use the GLM model. The results show that more production of electricity is causing abnormal CO2 emissions. The Granger causality test shows that there is a unidirectional relationship between energy consumption and economic advancement. Also, there is a short-run bidirectional causality that exists among the energy indicators. We find a unilateral causality between energy consumption and economic growth. Therefore, the consumption of energy might be conductive of 24 (polluted) countries and better economic development; the consumption of energy may be failsafe and guaranteed, while we should limit the resources of countries.

Energy Saving as Key Factor for Increasing Country’s Energy Security

Power engineering is one of the main types of economic activity of the Republic of Belarus. The priority deve-lopment of the country’s energy sector is determined by its key role in ensuring the efficient functioning of the national economy, stable operation of the social infrastructure, and observance of social norms and standards for the population. and importance of energy resources for the development of the economy and society as a whole can hardly be overestimated because of their active influence on the intensity of production and consumption processes. Currently, the main sources of energy are oil, natural gas, coal, oil shale and nuclear energy. Economy of the Republic is very dependent on energy imports. This is a serious test for the country under conditions of constant rise in hydrocarbon prices. Belarus imports more than 90 % of oil, 100 % of natural gas and 25 % of liquefied gas and 100 % of the whole consumed coal. The energy intensity of domestic enterprise products is significantly higher than in industrialized countries. Therefore, improvement of energy efficiency is fundamental for our country. In this regard, a real economic sector depends on the stable operation of energy enterprises, timely modernization of equipment, rational use of fuel and energy resources and effective implementation of energy conservation measures. Most of the energy sector problems can be solved by improving the energy security indicators of the Republic, namely, as a result of the introduction of a range of energy-saving measures, use of secondary energy resources and development of renewable energy sources.

Study of Nature Gas Distributed Energy System development space

Distributed natural gas energy plays an important role in the world low-carbon energy system. The development prospect of global distributed natural gas energy is considerable. And the installed capacity of natural gas distributed energy system (NG-DES) in China is increasing year by year. It’s urgent to clarify the development space of NG-DES for further healthy development. From the perspective of demand supply, China’s natural gas distributed energy development space is affected by social energy demand and other energy development levels. The application scenarios of NG-DES can be divided into commercial complex, industrial park, residential building, Internet data center and other application scenarios. This study summarizes the installed capacity of natural gas distributed energy in different projects under different scenarios, and calculates the new development space of natural gas distributed energy in China in 2020-2025. The results provide a reference for the rational and orderly development of distributed natural gas energy in China.

Approach and potential of replacing oil and natural gas with coal in China

China’s fossil energy is characterized by an abundance of coal and a relative lack of oil and natural gas. Developing a strategy in which coal can replace oil and natural gas is, therefore, a necessary and practical approach to easing the excessive external dependence on oil and natural gas. Based on the perspective of energy security, this paper proposes a technical framework for defining the substitution of oil and natural gas with coal in China. In this framework, three substitution classifications and 11 industrialized technical routes are reviewed. Then, three scenarios (namely, the cautious scenario, baseline scenario, and positive scenario) are developed to estimate the potential of this strategy for 2020 and 2030. The results indicate that oil and natural gas replaced by coal will reach 67 to 81 Mt and 8.7 to 14.3 Gm3 in 2020 and reach 93 to 138 Mt and 32.3 to 47.3 Gm3 in 2030, respectively. By implementing this strategy, China’s external dependence on oil, natural gas, and primary energy is expected to be curbed at approximately 70%, 40%, and 20% by 2030, respectively. This paper also demonstrates how coal, as a substitute for oil and natural gas, can contribute to carbon and pollution reduction and economic cost savings. It suggests a new direction for the development of the global coal industry and provides a crucial reference for energy transformation in China and other countries with similar energy situations.

Maximizing energy efficiency of islanded micro water-energy nexus using co-optimization of water demand and energy consumption

Water and energy systems are interdependent. However, at national and international levels, energy and water systems have been designed individually. To optimize the use of energy resources and have a more sustainable energy processes, a new formulation is proposed in this paper to optimize the energy consumption of water-energy systems at a community scale. More specifically, single-objective, bi-level, and co-optimization models are developed to minimize the energy consumption of a micro water distribution network concerning three scenarios: (1) standalone operation; (2) integrated with a grid-connected micro energy system with no storage unit; and (3) integrated with an off-grid micro energy system with storage units. In all conditions, a mixed integer nonlinear programming formulation is used to solve the optimization problems. Pump operations with varying statuses, flow rates, and speeds are contemplated to formulate the energy consumption of the micro water, considering a quadratic function for the pump’s energy head changing with flow rate. The micro water network is designed based on a diurnal pattern of water demand for a network including 1 reservoir, 1 water tank, 6 nodes, and 2 pumps. The micro energy system includes a microgrid with a combined heat and power plant (CHP), diesel (DS) generator, natural gas (NG) generator, renewable sources (solar and wind), and energy storage units. Several case studies are carried out to compare the performance of developed optimization models.

PENGARUH PROYEK TRANS ASEAN GAS PIPELINES (TAGP) TERHADAP ARAH KEBIJAKAN LUAR NEGERI INDONESIA DI BIDANG KERJASAMA ENERGI TAHUN 2002-2015

ABSTRACT ASEAN has announced plans to construct a natural gas pipeline network through the Trans-ASEAN Gas Pipeline Infrastructure Project, or TAGP. Furthermore, the advocates of TAGP expect it to promote economic development, earn foreign exchange, mitigate the risks of climate change, and enhance regional energy security. Energy Security is also a system, composed of national policies and international institution, therefore it requires policies and a business climate that promote investment and development and innovation to ensure that adequate supplies and infrastructure will be available, in a timely way, and in the future. Afterwards, Indonesia as a led country in ASEAN which has a natural gas energy resources that are relatively large then considering the direction of Indonesia’s foreign policy to cooperate on the global system through cooperativeenergy governance framework. The direction of Indonesia’s foreign policy has basic optimistic to promote economic growth and embrace the ASEAN region to be more integrated. Keywords: ASEAN, TAGP, Energy Security, Indonesia’s Foreign Policy, Inter-regional Cooperation, Cooperative Energy Governance

Investigating the technical feasibility of various energy carriers for alternative and sustainable overseas energy transport scenarios

The technological barriers against energy transport includes low energy density, intermittent supply and immobility of the energy sources. A potential and sustainable solution to overcome these barriers is to use an effective and efficient energy carrier which can store, transport and distribute energy in a technically feasible manner. Therefore, this study presents five potential energy carriers for overseas energy transport; liquifed natural gas (LNG), dimethyl ether (DME), liquid ammonia, methanol and liquid hydrogen which are used to carry the energy of natural gas in liquefied form from a supplied region to a demanded region. During the supply chain of the energy carriers, the amount of boil-off gas (BOG) for each energy carrier is calculated. A sensitivity analysis affecting BOG rates is implemented under variety of parameters, namely; ambient temperature, storage pressure, land storage time, ocean transportation time, heel percentage and pumping time. This study shows that the daily BOG rates for LNG, DME, ammonia, methanol, and hydrogen are calculated as 0.471%, 0.159%, 0.129%, 0.049%, and 3.438%, respectively. Methanol delivers the greatest mass, DME delivers the greatest energy and hydrogen loses the greatest mass as BOG during the supply chain. The highest BOG generation mainly occurs during ocean transportation phase, implying that ocean transportation time is the most critical parameter among the studied parameters.

Economic Structure Transformation and Low-Carbon Development in Energy-Rich Cities: The Case of the Contiguous Area of Shanxi and Shaanxi Provinces, and Inner Mongolia Autonomous Region of China

Energy-rich cities tend to rely on resource-based industries for economic growth, which leads to a great challenge for its low-carbon and sustainable economic development. The contiguous area of Shanxi and Shaanxi Provinces, and the Inner Mongolia Autonomous Region (SSIM) is one of the most important national energy bases in China. Its development pattern, dominated by the coal industry, has led to increasingly prominent structural problems along with difficult low-carbon transition. Taking energy-rich cities in the contiguous area of SSIM as examples, this study analyzes the main drivers of CO2 emissions and explores the role of economic structure transformation in carbon emission reduction during 2002–2012 based on structural decomposition analysis (SDA). The results show that CO2 emissions increase significantly with the coal industry expansion in energy-rich cities. Economic growth and structure are the main drivers of CO2 emission increments. An energy structure dominated by coal and improper product allocation structure can also cause CO2 emission increases. Energy consumption intensity is the main factor curbing CO2 emission growth in energy-rich cities. The decline of agriculture and services contributes to carbon emission reduction, while the expansion of mining and primary energy processing industries has far greater effects on CO2 emission growth. Finally, we propose that energy-rich cities must make more efforts to transform energy-driven economic growth patterns, cultivate new pillar industries by developing high-end manufacturing, improve energy efficiency through more investment in key technologies and the market-oriented reform of energy pricing and develop natural gas and renewable energy to accelerate low-carbon transition.

US New Energy Policy in the New Century

In the 21st century, the US government has passed a series of laws and regulations on energy, strengthening the domestic supply of energy and reducing its dependence on international energy supply. The US government uses legal instruments and fiscal and taxation levers to promote energy conservation. It vigorously develops renewable energy, researches on substitute energy, and invests on clean energy such as natural gas and nuclear energy, to create a diversified energy landscape. It has a profound impact on global new energy and its industries, international energy supply, and the world’s environmental protection industry.

Water management in hydraulic fracturing technology

Shale gas is a clean and efficient unconventional natural gas energy, which has gradually become a new hotspot in global oil and gas exploration and development. Hydraulic fracturing technology is one of the core technologies in shale gas production, which consumes a lot of water resources and produces a lot of polluted flowback fluid. How to effectively deal with the treatment of flowback fluid is a crucial issue. By analyzing the characteristics of fracturing flowback fluid, this paper lists the treatment technologies of fracturing flowback fluid, which can relieve the worries of shale gas exploitation and wide application.

Thermal design and performance evaluation of a shell-and-tube heat exchanger using LNG cold energy in LNG fuelled ship

This study focuses on integrating the cold energy of liquid natural gas (LNG) fuelled ships with the ORC and the thermal design of the heat exchanger in the organic Rankine cycle (ORC) system. An ORC system is constructed to utilise the cold energy of the LNG and the jacket cooling water of the main engine as a low and high-temperature heat source, respectively, to exploit the large amount of energy consumed in the process of raising the temperature of the LNG to a constant value to allow its use as a fuel. Five kinds of working fluids are applied to analyse the performance of the cycle according to the change in the condensation temperature. The results of the cycle performance analysis indicate that the R123 and R227ea have the highest and lowest thermal efficiency of about 17–23% and about 15–21%, respectively. The R123 and R134a exhibit the highest and lowest exergy efficiency of about 25–31% and about 23–29%, respectively. The condensation temperature at which the maximum output is obtained is about 223 [K]. In addition, since the efficiency of the ORC system can be improved through the optimal design of the heat exchanger, the thermal design of the heat exchanger, which is a primary part of the ORC system, is performed. As the working fluid, three kinds of organic fluids, which are the most widely used among the five considered types, are selected to simulate the evaporator, condenser, and preheater. The simulation result shows that the condenser and preheater have the largest and smallest heat transfer surface area of 73 m2 and 34 m2 for R134a, respectively. For the condenser, it is found that the R134a and R152a have the largest and smallest heat transfer surface areas of 73 m2 and 59 m2, respectively. In contrast, in the case of the evaporator, the R245fa and R134a have the largest and smallest heat transfer surface areas of 42 m2 and 36 m2, respectively.

Tradeoffs between energy use and ventilation rates in U.S. Retail stores

This study conducted experimental measurements of ventilation rates and associated pollutant concentrations in two retail stores for one-week intervals. Pollutants monitored were formaldehyde and total volatile organic compounds. Based on the pollutant measurements and mass–balance modeling, different ventilation rate reduction scenarios were proposed, and for these scenarios the differences in energy consumption were estimated. This investigation focused on (a) the tradeoff between energy savings and ventilation rates that do not compromise indoor air quality, and (b) the tradeoff between energy savings and resets of indoor air temperature that do not compromise thermal comfort in winter heating conditions. Two energy simulation models for retail stores were built, calibrated, and validated with actual utility bills. Energy simulation results indicated that by lowering the ventilation rates from the measured values to the lowest acceptable values would reduce natural gas energy use by estimated 6% to 19%. Also, this study found that the electrical cooling energy consumption was not significantly sensitive to variable ventilation rates as the internal heat sources are significant. Results of optimization between heating indoor set-point temperature and different ventilation rate scenarios indicated that the lowest acceptable ventilation rate with the set point temperature of 19.4 °C is the best scenario.

Modeling and advanced exergy analysis of integrated reverse osmosis desalination with geothermal energy

Abstract In this research, the integrated carbon dioxide power cycle with a geothermal energy source to supply the required reverse osmosis desalination power for freshwater production is defined. It is also a carbon dioxide power cycle, coupled with thermal energy recovery of infrared energy of liquid natural gas (LNG) to generate more power. A sodium hypochlorite generator is considered to prevent the brine water discharging. The brine water portion of the desalination outlet was the input to this generator. The cycling power is consumed by the desalination system and sodium hypochlorite generator. After modeling, the advanced exergy analyses are studied. By exergy analysis, it is observed that in this model the condenser has the highest exergy destruction rate, equal to 952 kW. Additionally, the unavoidable part of the exergy destruction of carbon dioxide turbine constitutes 88% of its exergy destruction that is equal to 301 kW. So this component is the best option to improve exergy destruction.

Characteristic of Energy Fractions and Emissions under Natural Gas/Diesel Dual-Fuel Heavy-Duty Engine in Terms of the Combustion Parameters

In this research, it was investigated the energy fraction and emission characteristics of natural gas/diesel dual-fuel combustion in terms of the combustion index such as combustion duration and mass fraction burned 50% (MFB50) of a 6-L heavy-duty compression ignition (CI) engine. The reactivity gradient was varied by changing the diesel injection timing and natural gas energy fraction from 60 to 90%. Engine speed was fixed at 1,200 rpm, and the total input energy from the two fuels was maintained at 11,880 J/cycle for all six cylinders. Diesel injection timing was varied from top dead center (TDC) to 40° before TDC (BTDC) (at intervals of 10°). First, the combustion parameters were analyzed in terms of differences in reactivity gradients. The main combustion parameters considered included ignition delay, combustion duration, and MFB 50. For all cases, the indicated thermal efficiency (ITE) was analyzed with respect to the energy fractions of combustion loss, heat transfer loss, and exhaust loss, to determine the main influences on combustion duration and the MFB 50. Engine-out emission was introduced as an operating parameter associated with ITE and the various losses. These values were compared to those of neat diesel combustion conditions.

PET bottles recycling in China: An LCA coupled with LCC case study of blanket production made of waste PET bottles

A large number of polyethylene terephthalate (PET) bottles are discarded daily after usage. Thus, plastic bottle recycling has elicited considerable attention in recent years. In this context, this study aims to quantify the environmental and economic impacts of blanket production from 100% recycled waste plastic bottles in China through a life cycle assessment coupled with life cycle costing method. In addition, the environmental impact of replacing coal with natural gas and solar energy was evaluated. Results show that impact categories of global warming and fossil depletion have significant influence on the overall environment. Carbon dioxide, water, iron, coal and chromium (VI) to water are the main contributors to the overall environmental burden. The internal and external costs are $6433/metric ton and $370/metric ton, respectively. Analysis results indicate that the optimization of organic chemicals, recycled polyester filament and steam production processes can reduce environmental and economic burdens substantially. Energy substitutions with natural gas and the use of solar photovoltaic in steam production and electricity generation are effective measures for decreasing environmental impacts. Finally, suggestions based on research results and the current status of waste plastic bottle recycling in China are proposed.

Strategic Research on the Urban Natural Gas Energy System Under the Path to Ecological Civilization: Fuyang City Case Study

To help meet the strategic development needs of urban energy systems today and reduce carbon emissions, natural gas can play a pivotal transition role, especially in a country such as China which has relied very heavily on coal for decades. Though making significant towards the maximum possible use of clean, renewable forms of energy, such as hydro, thermal, solar and wind power, it will be a long time yet before China can completely abandon the use of fossil fuels. . In this paper, using Fuyang City in Anhui Province as a case study, a four-dimensional differential equation model, based on the consumption, price, economic growth, and “ecological civilization construction” of natural gas energy, is developed which incorporates concepts and calculations of natural gas energy intensity, “natural gas ecological civilization intensity”, and “economic ecological civilization intensity”. It is the first attempt ever made to quantify the construction of urban ecological civilization and discuss the evolutionary relationship among the internal variables of the system . Regression analysis, data fitting, neural network, and other methods are used to confirm the parameters of the system model. Through Matlab simulation of each variable and using an evolution map, a quantitative understanding of the role of natural gas is generated. The research findings reveal that paying attention to the environmental aspects of energy consumption is beneficial to economic growth. The paper concludes that, at present, the best ways for China to reduce its carbon emissions are to implement a market price and peak–valley prices for natural gas, improve the tiered price mechanism, appropriately reduce the economic growth rate, continue to adjust the industrial structure away from heavy industry and scientifically manage the natural gas energy system. These reforms are of great practical significance in working towards a sustainable development path for the city.

Analysis and Design of Interruptible Gas Contract in China under Energy Market Reform

Under the background of economic development, energy security and environmental demands, the development of clean and low-carbon energy has promoted natural gas and non-fossil energy to become the main direction of world energy development. China’s natural gas consumer market has wide seasonal peaks and valleys. Because China’s natural gas peak shaving practices have some problems, we concluded that interruptible gas management has become a viable short-term emergency peak shaving method for natural gas systems in the transition period. In this paper, we take Shaanxi Province as an example. From the perspective of option pricing, this paper explains the method of using interruptible gas management to deal with the short-term supply and demand imbalance of natural gas. Therefore, we propose an interruptible gas contract trading mode, discuss the content of the interruptible gas contract and the relevant market organization form, and try to use the Black–Scholes model to calculate the option price of the interruptible gas contract. Finally, based on the price of interruptible gas and the option price of the interruptible gas contract to meet the maximum capacity shortage constraint, a provincial natural gas pipeline network company’s optimal purchase model for the interruptible gas was established, and the model was solved using the dynamic queuing method. The results show that the interruptible gas contract can not only reduce the market risk of the provincial natural gas pipeline network company and maintain the stable operation of the gas pipeline, but also reduce the cost of the interruptible users and make up for gas shortage losses.

Cooperation of EU with Russia in the Field of Energy: A Review

Natural gas is of immense importance in the energy relationship between the European Union (EU) and Russian Federation. Over the past half century, the Soviet Union initially and the Russian Federation since the early 90 s’ have been vital suppliers of natural gas to the EU member states. Since 2000, the two parties’ trade relations in the field of natural gas and other energy commodities trading can be characterized as turbulent. The purpose of this review study is to present the main aspects of the cooperation of the EU member states with Russia in the field of energy. Aspects of the EU-Russia dialogue, as well as of the Roadmap for the Energy Cooperation between the EU and Russia, are also discussed. Through a literature review of some prominent studies on EU-Russia energy relations, the main challenges of the EU-Russia gas cooperation are identified. This study aspires to provide further insight to energy security aspects of the European Region.

Economic Efficiency Analysis of Micro Energy Grid Considering Time-of-Use Gas Pricing

The application of time-of-use (TOU) pricing in the electricity market has significant value, which can improve economic efficiency and promote effective management of resources. However, this pricing mechanism has not been applied and promoted in the gas market in China. In this paper, we propose a bi-level transaction model considering TOU gas pricing for analyzing the economic efficiency of micro energy grid (MEG) operation based on Game Theory. The multiple energies trading is conducted between the natural gas company (NGC), the MEG and energy users (EUs), which forms a hierarchical Stackelberg game model. We first analyze utilities and strategies of aforementioned participants, and derive the Stackelberg equilibrium (SE) analytically as a balanced solution that captures the equilibrium strategies of participants. Then, a mixed integer nonlinear programming is formulated to determine the optimal TOU gas prices delivering maximum NGC profit, the optimal energy sales prices corresponding to the MEG' SE utility, and the optimal load pattern for EUs. Finally, numerical experiments are conducted in two scenarios, which reveal that the TOU pricing can well balance the gas supply and demand, and has significant potential for improving the economic efficiency of the MEG.