Aggregation Method of Multi-Criteria Evaluations in New and Renewable Energy Power Plants: A Case Study

The multi-criteria evaluation methods of complex systems such as the new and renewable technologies gradually spring up. The feasibility of energy power plants is evaluated and considered from many aspects, such as technology, economic cost and environment protection. However, the energy power plants’ ranking results in different methods or different weighs can be different. Accordingly, the sequencing results should be aggregated and analyzed, and then an integrated result should be given out. Aiming to get the specific evaluation result, 10 kinds of energy power plants, such as hydro, nuclear, wind, geothermal and biomass plants are considered and evaluated. The singular value decomposition method is employed to aggregate the evaluation results in grey relational method, PROMENTHEE II method, and other results from literature. The integrated evaluation result shows that the hydro and nuclear power plants are located on the first place and the renewable energy power plants have great potential development in the future.

Dynamic Modeling of a Wind Hydrogen System

Dynamic behaviors of an integrated wind hydrogen system have been modeled mathematically. It is based on a combination of fundamental theories of mechanics, thermodynamics, mass transfer, fluid dynamics, and empirical electrochemical relationships. The model considers wind hydrogen system to be composed of three subsystems, i.e., a wind generator, an electrolyzer, and a hydrogen tank. An additional pressure switch model is presented to visualize the hydrogen storage dynamics under a constant outflow condition. Validation of the wind hydrogen model system is evaluated according to the measured data from the manufacturer’s data. Then, using wind power as the primary energy input and hydrogen as energy storage simulated the power system. Finally, flow and electrical characteristics and efficiencies of each subsystem as well as the entire system are presented and discussed. The present model will integrate with fuel cell systems to realize the stand-alone renewable power generator in the future work.

Catalothermionic Power Generator Based on Internal Electron Emission in Ni/SiC Heterojunction Nanostructures

We report on the unusual properties of single-faced SiC metal-semiconductor heterojunction nanostructures manifested by the ability to atalyze the hydrogen oxidation reaction, and also maintain internal electron emission over the Schottky barriers. As a result a stationary current has been detected in the preheated nanostructure when exposed to the oxyhydrogen gas mixture flux. The structures maintain both the non-adiabatic and electron-phonon channels of energy transfer, and the results of studies indicate the possibility for a very efficient conversion of chemical energy released in the catalytic oxidation of hydrogen into electricity.

Analysis of the Thermodynamic Performance of Kalina Cycle System 11 (KCS11) for Geothermal Power Plant: Comparison With Kawerau ORMAT Binary Plant

Since the first geothermal power plant was built at Larderello (Italy) in 1904, many attempts have been made to improve conversion efficiency. Among innovative technologies, using the Kalina cycle is considered as one of the most effective means of enhancing the thermodynamic performance for both high and low temperature heat source systems. Although initially used as the bottoming cycle of gas turbines and diesel engines, in the late 1980s the Kalina cycle was found to be attractive for geothermal power generation [1, 2, 3]. Different versions (KSC11, KSC12 and KSC13) were designated. Comparison between Kalina cycle and other power cycles can be found in later studies [4, 5, 6]. Here we examine KSC11, because it is specifically designed for geothermal power generation, with lower capital cost [3]. We compare this design with the existing Kawerau ORMAT binary plant in New Zealand. In addition, parametric sensitivity analysis of KCS11 has been carried out for the specific power output and net thermal efficiency by changing the temperatures of both heat source and heat sink for a given ammonia-water composition.

The Role of State Policy in Renewable Energy Development

State policies can support renewable energy development by driving markets, providing certainty in the investment market, and incorporating the external benefits of the technologies into cost/benefit calculations. Using statistical analyses and policy design best practices, this paper quantifies the impact of state-level policies on renewable energy development in order to better understand the role of policy on development and inform policy makers on the policy mechanisms that provide maximum benefit. The results include the identification of connections between state policies and renewable energy development, as well as a discussion placing state policy efforts in context with other factors that influence the development of renewable energy (e.g. federal policy, resource availability, technology cost, public acceptance).

Improved Efficiency of Dye Sensitized Solar Cells Using Aligned Carbon Nanotubes

Dye sensitized solar cells (DSSCs) offer many advantages in comparison to their Si-based counterparts, including lower cost of raw materials, faster manufacturing time, and the ability to be integrated with flexible substrates. Although many advances have been made in DSSC fabrication over recent years, their efficiency remains lower than commercially available Si photovoltaic cells. Here we report improved efficiency of TiO2/anthocyanin dye solar cell using aligned arrays of carbon nanotubes (CNTs) as a counter electrode. Dense vertically oriented CNT arrays are grown directly on the counter electrode using microwave plasma chemical vapor deposition and a tri-layer (Ti/Al/Fe) catalyst. The resulting arrays are 30 micrometers in height and have a number density of approximately five hundred million per square millimeter. By directly growing the CNTs on the counter electrode substrate, electrical interface conductance is enhanced. The performance of both as-grown and N-doped (using a nitrogen plasma) CNT arrays is reported. The fabricated DSSCs are tested under AM1.5 light. Increased short circuit current is observed in comparison to graphite and Pt counter electrodes. We attribute this improvement to the large surface area created by the 3D structure of the arrays in comparison to the planar geometry of the graphite and Pt electrodes as well as the excellent electrical properties of the CNTs.

Parabolic Sun Tracking Solar Distillation System

The main aim of the present study is to draw attention to the possibilities and to the measures of appropriate utilization of renewable energy to achieve what is called “water self-sufficient” for arid regions in Jordan. Also to put efforts of increasing the use of renewable energy sources to lower cost of potable water pumping and gives more economical benefits. Another aim of the current research is to utilize the new control algorithm and the developed computer capabilities in the field of sun tracking in order to improve the efficiency of solar distillers. The new tracking method is utilized for water distillation taking advantage of high possible concentration of parabolic trough collector to reach high levels of daily yield per square meter. The present research utilizes the techniques of image processing to catch the core of the sun as the target, also used artificial intelligence techniques to predict the sun position in abnormal conditions (i.e. cloudy, dusty, rainy). The results of sun tracking using image processing found to be accurate and reliable according to the self monitoring of the focus point validated by the solar radiation results. Water distillation yield shows high percentage output of distillate of about 65% of water supplied to distiller. Mechanical design was tested for high ability to withstand the extra loading. It was found that the output yield reached to noticeable levels, because of the use of the parabolic collector that promoted the solar still efficiency.

Multi Criteria Evaluation Model of Renewable Energy Power Plants Based on ELECTRE Method

The feasibility evaluation of renewable energy power plants from multi criteria is necessary to save energy, protect environment and develop technology. This paper employs the improved elimination et choice translating reality (ELECTRE) method to evaluate 10 kinds of energy power plants in five criteria. The plants includes the coal fired, solar-thermal, geothermal, biomass, nuclear, photovoltaic solar, wind, ocean, hydro and natural gas combined cycle power plants. The evaluation criteria reflects four aspects from the technology, economy, environment and society. The concrete criteria are efficiency, installation, electricity cost, CO2 emission, and land requirement. Finally, the multi criteria evaluations show that the hydro power plant in the renewable energy are the optimal schemes at present.

Increasing Efficiencies of Thermoelectric Devices Through Angular Interface Geometries

The phonon Boltzmann transport equation model is used to evaluate the reduction of out-of-plane thermal conductivity and subsequent increase in thermoelectric figure of merit when an angular interface is patterned between a germanium thin-film and silicon substrate. According to the acoustic mismatch model, the angular structure reduces the out-of-plane thermal conductivity by spatially redistributing phonons traveling in the out-of-plane direction. Simulation results demonstrate a 43% reduction in out-of-plane thermal conductivity when operating in the fully ballistic regime. This decrease in phononic thermal conductivity would result in an increase of intrinsic thermoelectric efficiency by a factor of 1.75.

A Small-Scale Solution for a Big Energy Problem: Renewable Distributed Energy

A Small-Scale Solution for a Big Energy Problem: Renewable Distributed Energy. Locally generated biomass, industrial and municipal wastes, coal and plastics have a significant part to play in providing a source of reliable and economic energy in the US. The ability to use these materials reliably and cleanly can be addressed with small-scale gasification technology to provide distributed generation. A technology that has improved on the historical success of gasification to provide these elements is TURNW2E™ Gasification. This technology is specifically designed to convert locally available energy resources into a clean fuel gas which is then subsequently used for heat and or power generation. This technology has the ability to operate cleanly and interchangeably using waste materials and /or coal. With the ability to produce power economically from 100 kW to 5 MW it can provide distributed generation at institutions, DOD facilities, and industrial complexes. This creates a reliable and economical energy source for the user, while disposing of wastes in an environmentally sound manner. This replaces landfill use with the energy transformation process of gasification, which provides enormous environmental benefits, including the elimination of carcinogens and reduction of greenhouse gas emissions caused by incineration processes. The use of renewable biomass and wastes provides a sustainable source of electricity that is unrestricted by grid access, providing tremendous potential to reduce US fuel imports. Using this approach, the user can create jobs and power in a sustainable scenario; without sending precious energy dollars overseas, using this process in a distributed manner will help strengthen our nation’s economy, and provide improvements to the quality of life wherever it is installed. By having the ability to use many different feedstocks, the technology can enable the avoidance of landfilling MSW and industrial wastes, including tires; it can use waste wood such as railroad ties, beetle-infested pine, and forestry wastes, farm wastes and natural disaster debris to generate renewable energy for local use or sale to the grid. Materials for processing are varied, and thus, the technology flexibility enables small-scale use in a wide range of installations, a landfill site, transfer station, farm, hospital, manufacturing facility, resort, DOD base, island community, university, and local municipal site. TURNW2E™ Gasification is available at commercial scale and is currently installed at two facilities overseas, with three US facilities planned for ’09. A training and continuing education /R&D facility is underway in the US.