scholarly journals A Coupled Thermo-Hydro-Mechanical Model of Jointed Hard Rock for Compressed Air Energy Storage

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Xiaoying Zhuang ◽  
Runqiu Huang ◽  
Chao Liang ◽  
Timon Rabczuk

Renewable energy resources such as wind and solar are intermittent, which causes instability when being connected to utility grid of electricity. Compressed air energy storage (CAES) provides an economic and technical viable solution to this problem by utilizing subsurface rock cavern to store the electricity generated by renewable energy in the form of compressed air. Though CAES has been used for over three decades, it is only restricted to salt rock or aquifers for air tightness reason. In this paper, the technical feasibility of utilizing hard rock for CAES is investigated by using a coupled thermo-hydro-mechanical (THM) modelling of nonisothermal gas flow. Governing equations are derived from the rules of energy balance, mass balance, and static equilibrium. Cyclic volumetric mass source and heat source models are applied to simulate the gas injection and production. Evaluation is carried out for intact rock and rock with discrete crack, respectively. In both cases, the heat and pressure losses using air mass control and supplementary air injection are compared.

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Hehua Zhu ◽  
Xingyu Chen ◽  
Yongchang Cai ◽  
Jianfeng Chen ◽  
Zhiliang Wang

A coupled nonisothermal gas flow and geomechanical numerical modeling is conducted to study the influence of fractures (joints) on the complex thermohydromechanical (THM) performance of underground compressed air energy storage (CAES) in hard rock caverns. The air-filled chamber is modeled as porous media with high porosity, high permeability, and high thermal conductivity. The present analysis focuses on the CAES in hard rock caverns at relatively shallow depth, that is, ≤100 m, and the pressure in carven is significantly higher than ambient pore pressure. The influence of one discrete crack and multiple crackson energy loss analysis of cavern in hard rock media are carried out. Two conditions are considered during each storage and release cycle, namely, gas injection and production mass being equal and additional gas injection supplemented after each cycle. The influence of the crack location, the crack length, and the crack open width on the energy loss is studied.


Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4054 ◽  
Author(s):  
Youssef Benchaabane ◽  
Rosa Elvira Silva ◽  
Hussein Ibrahim ◽  
Adrian Ilinca ◽  
Ambrish Chandra ◽  
...  

Remote and isolated communities in Canada experience gaps in access to stable energy sources and must rely on diesel generators for heat and electricity. However, the cost and environmental impact resulting from the use of fossil fuels, especially in local energy production, heating, industrial processes and transportation are compelling reasons to support the development and deployment of renewable energy hybrid systems. This paper presents a computer model for economic analysis and risk assessment of a wind–diesel hybrid system with compressed air energy storage. The proposed model is developed from the point of view of the project investor and it includes technical, financial, risk and environmental analysis. Robustness is evaluated through sensitivity analysis. The model has been validated by comparing the results of a wind–diesel case study against those obtained using HOMER (National Renewable Energy Laboratory, Golden, CO, United States) and RETScreen (Natural Resources Canada, Government of Canada, Canada) software. The impact on economic performance of adding energy storage system in a wind–diesel hybrid system has been discussed. The obtained results demonstrate the feasibility of such hybrid system as a suitable power generator in terms of high net present value and internal rate of return, low cost of energy, as well as low risk assessment. In addition, the environmental impact is positive since less fuel is used.


2019 ◽  
Vol 142 (4) ◽  
Author(s):  
Roberto José Batista Câmara ◽  
Júlio F. Carneiro ◽  
George Augusto Batista Câmara ◽  
Paulo Sérgio Rodrigues de Araújo ◽  
Paulo Sérgio de M. V. Rocha ◽  
...  

Abstract The incorporation of renewable energy into the future world energy matrix challenges its efficient use because renewable energy is not always available due to its dependence on natural factors such as wind and sunlight. This work develops a new resource management system to evaluate the renewable energy resources stored in salt caves using power-to-gas (P2G) and compressed air energy storage (CAES) technologies in the initial phase of a project (sub-commercial phase). To fulfill this objective, bibliographical research, document analysis, and consultations with specialists were used as the methodological basis. Two systems were identified to be used as a reference for the proposed methodology: Petroleum Resources Management System (PRMS) and CO2 Storage Resources Management System (SRMS). A classification framework is proposed for energy storage and an application of the framework is presented for a case study in Portugal. Similar to these reference systems, a sub-commercial project momentum was established, and three stages called total potential resource (R3), total probable resource (R2), and total proved resource (R1) were defined. The results support corporate and governmental decision-making on project continuity for both the market and governments, thus demonstrating their importance in new global energy reality. It is recommended to define the sub-commercial stage as well as the mapping of R2 in the Brazilian territory as was done recently in Europe.


Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4188 ◽  
Author(s):  
Kangyu Deng ◽  
Kai Zhang ◽  
Xinran Xue ◽  
Hui Zhou

Renewable energy (wind and solar power, etc.) are developing rapidly around the world. However, compared to traditional power (coal or hydro), renewable energy has the drawbacks of intermittence and instability. Energy storage is the key to solving the above problems. The present study focuses on the compressed air energy storage (CAES) system, which is one of the large-scale energy storage methods. As a lot of underground coal mines are going to be closed in China in the coming years, a novel CAES system is proposed for application in roadways of the closing coal mines. The new system combines pumped-hydro and compressed-air methods, and features constant air pressure and temperature. Another specific character of the system is the usage of flexible bags to store the compressed air, which can effectively reduce air leakage. The governing equations of the system are derived, and the response of the system is analyzed. According to the equations, for a roadway with depth of 500 m and volume of 10,000 cubic meters, the power generation capacity of the CAES system is approximately 18 MW and the generating time is 1.76 h. The results show that the new CAES system proposed is reasonable, and provides a suitable way to utilize the underground space of coal mines.


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