Carbon capture from natural gas combined cycle power plants: Solvent performance comparison at an industrial scale

Natural gas is an important source of energy. This article addresses the problem of integrating an existing natural gas combined cycle (NGCC) power plant with a carbon capture process using various solvents. The power plant and capture process have mutual interactions in terms of the flue gas flow rate and composition vs. the extracted steam required for solvent regeneration. Therefore, evaluating solvent performance at a single (nominal) operating point is not indicative and solvent performance should be considered subject to the overall process operability and over a wide range of operating conditions. In the present research, a novel optimization framework was developed in which design and operation of the capture process are optimized simultaneously and their interactions with the upstream power plant are fully captured. The developed framework was applied for solvent comparison which demonstrated that GCCmax, a newly developed solvent, features superior performances compared to the monoethanolamine baseline solvent

Energy challenges for ICT

The energy consumption from the expanding use of information and communications technology (ICT) is unsustainable with present drivers, and it will impact heavily on the future climate change. However, ICT devices have the potential to contribute signi - cantly to the reduction of CO2 emission and enhance resource e ciency in other sectors, e.g., transportation (through intelligent transportation and advanced driver assistance systems and self-driving vehicles), heating (through smart building control), and manu- facturing (through digital automation based on smart autonomous sensors). To address the energy sustainability of ICT and capture the full potential of ICT in resource e - ciency, a multidisciplinary ICT-energy community needs to be brought together cover- ing devices, microarchitectures, ultra large-scale integration (ULSI), high-performance computing (HPC), energy harvesting, energy storage, system design, embedded sys- tems, e cient electronics, static analysis, and computation. In this chapter, we introduce challenges and opportunities in this emerging eld and a common framework to strive towards energy-sustainable ICT

Demand-Response Application in Wastewater Treatment Plants Using Compressed Air Storage System: A Modelling Approach

Wastewater treatment plants (WWTPs) are known to be one of the most energy-intensive industrial sectors. In this work, demand response was applied to the biological phase of wastewater treatment to reduce plant electricity cost, considering that the daily peak in flowrate typically coincides with the maximum electricity price. Compressed air storage system, composed of a compressor and an air storage tank, was proposed to allow energy cost reduction. A multi-objective modelling approach was applied by analyzing dierent scenarios (with and without anaerobic digestion, AD), considering both plant characteristics (in terms of treated flowrate and influent chemical oxygen demand, COD, concentration) and storage system properties (volume, air pressure), together with the current Italian market economic conditions. The results highlight that air tank volume has a strong positive influence on the obtainable economic savings, with a less significant impact held by air pressure, COD concentration and flowrate. In addition, biogas exploitation from AD led to an improvement in economic indices. The developed model is highly flexible and can be applied to dierent WWTPs and market conditions

The architecture of pneumatic regenerative systems for the diesel engine

For vehicles whose duty cycle is dominated by start-stop operation, fuel consumption may be significantly improved by better management of the start-stop process. Pneumatic hybrid technology represents one technology pathway to realise this goal. Vehicle kinetic energy is converted to pneumatic energy by compressing air into air tank(s) during the braking. The recovered air is reused to supply an air starter, or supply energy to the air path in order to reduce turbo-lag. This research aims to explore the concept and control of a novel pneumatic hybrid powertrain for a city bus application to identify the potential for improvements in fuel economy and drivability. In order to support the investigation of energy management, system architecture and control methodologies, two kinds of simulation models are created. Backward-facing simulation models have been built using Simulink. Forward-facing models have been developed in the GT-POWER and Simulink co-simulation. After comparison, the fully controllable hybrid braking system is chosen to realize the regenerative braking function. A number of architectures for managing a rapid energy transfer into the powertrain to reduce turbo-lag have been investigated. A city bus energy control strategy has been proposed to realize the Stop-Start Function, Boost Function, and Regenerative Braking Function as well as the normal operations. An optimisation study is conducted to identify the relationships between operating parameters and respectively fuel consumption, performance and energy usage. In conclusion, pneumatic hybrid technology can improve the city bus fuel economy by at least 6% in a typical bus driving cycle, and reduce the engine brake torque response and vehicle acceleration. Based on the findings, it can be learned that the pneumatic hybrid technology offers a clear and low-cost alternative to the electric hybrid technology in improving fuel economy and vehicle drivability

Techno-economic analysis of hybrid adiabatic compressed-air and biomass gasification energy storage systems for power generation through modelling and simulation

Energy storage has gained an increasing attention as a technology to smoothen out the variations associated with renewable energy power sources and adapt them into a dispatchable product to meet variable demand loads. An energy storage system can be a hybrid or stand alone. There is a rising interest for hybrid energy storage systems cited close to local consumers which is able to exploit the amount of local renewable sources on site, to provide demand side flexibility and also help to decarbonize the heating sector. The thesis is based on modelling and simulation of overall thermodynamic performance and economic analysis of an integrated hybrid energy storage system consisting of adiabatic compressed air energy storage (A-CAES), biomass gasification system with a wood dryer coupled to a syngas-diesel fuelled electric generator for the dual production of electricity and low temperature hot water for domestic use. The first part of the research work involves the modelling of the latent heat (LH) thermal energy storage (TES) for the A-CAES component. Implicit finite difference technique was applied to discretize the energy equations of the heat transfer fluid and phase change material and the resulting equations solved using a developed Matlab computer code. The developed model of the LH TES was validated using experiment measurement from literature and its performance assessed using charging rate, energy efficiency and exergy efficiency. The second part consists of modelling of biomass gasification through a developed Matlab computer code. Kinetic free stoichiometric equilibrium modelling approach was adopted. The developed model showed good agreement with two different experimental measurements. Predictions that can be done with the model include syngas yield, temperature profiles of the pyrolysis, oxidation and reduction zones respectively including syngas yield, carbon conversion efficiency and lower calorific value of the syngas. In the third part, thermodynamic modelling of the overall novel integrated system is developed. It combines the models of different components of the integrated system earlier developed. The system designed for a maximum capacity of 1.3 MW is to utilize the high syngas temperature from the biomass gasifier and the relatively hot dual fuel engine (DFE) exhaust temperature to heat up the compressed air from the A-CAES component during the charging and discharging modes, respectively. Also, the heat contained in the DFE jacket water is recovered to produce low temperature hot water for domestic hot water use. Key output parameters to assess the performance of the hybrid systems are total system efficiency (TSE), round trip efficiency (RTE) of the A-CAES, electrical efficiency, effective electrical efficiency, and exergy efficiency for the system. Furthermore, exergy destruction modelling is done to ascertain and quantify the main sources of exergy destruction in the systems components. Finally, an economic feasibility of the overall system is presented using the electricity and heat demand data of Hull Humber region as a case study. The results of this study reveals that it is technically possible to deploy the proposed system in a distributed generation to generate dispatchable wind power and hot water for domestic use. The total energy and exergy efficiency of the system is about 37.12% and 28.54%, respectively. The electrical and effective electrical efficiency are 29.3 and 32.7 %, respectively. In addition, the round trip efficiency of the A-CAES component of the system is found to be about 88.6% which is higher than that of a standalone A-CAES system, thus demonstrating the advantage of the system to recover more stored wind electricity than in conventional A-CAES system. However, the TSE of the system is less than that of a conventional A-CAES system but comparable to similar hybrid configurations. The exergy destruction of the hybrid system components is highest in the biomass gasifier followed by the DFE and the least exergy destruction occurs in the HAD. Furthermore, economic analysis results show that the system is not profitable for commercial power generation unless a 70% of the total investment cost is waived in the form of subsidy. Expectedly, the cost of electricity (COE) of £0.19 per kWh is more than the range of the mean electricity tariff for a medium user home in the UK including taxes which is £0.15 per kWh. With a subsidy of 70%, the system becomes profitable with a positive NPV value of £137,387.2 and COE of £0.10 per kWh at the baseline real discount rate of 10%. The main contribution of the thesis is that it provides an intergraded realistic tool that can simulate the future performance (thermodynamic and economic) of a hybrid energy storage system, which can aid a potential investor to make informed decision on the profitability and financial outlays for the investmen

Modeling of Energy Storage Systems for Building Intergation

An advanced Energy Storage device modeling, namely, Zinc Bromide, is proposed to integrate a new software Smartbuilds, developed by Marquette University, based on an integrated building. Smartbuilds will provide the platform to integrate all the components of the proposed Building which incorporate with renewable energy and energy storage system. The zinc bromide modeling results show that the battery’s open-circuit voltage is a direct function of the state of charge (SOC) of the battery. Furthermore, resistance is also a function of sate of charge at constant temperature. A Coulomb Counting technique is used to adjust the estimated SOC according to battery current. Simulation studies are made with Matlab/Simulink. Proposed Zinc bromide battery model has been compared with Energyplus, building energy simulation program, battery model and it has been translated to Energyplus battery model to integrate in Energyplus. Example case studies are provided to show the results