Modular AC coupled hybrid power systems for the emerging GHG mitigation products market

Bioenergy systems particularly waste to energy (WTE) systems are increasingly gaining prominence. Market for modular hybrid energy systems (HES) combining renewable energy sources including WTEs is potentially large. Novel configuration of AC coupling for HES is discussed. Emerging opportunities for market development of hybrid energy systems under green house gas mitigation initiatives particularly Kyoto flexibility mechanisms is analysed

Techno-economic and greenhouse gas savings assessment of decentralized biomass gasification for electrifying the rural areas of Indonesia

This study explored the feasibility of decentralized gasification of oil palm biomass in Indonesia to relieve its over-dependence on fossil fuel-based power generation and facilitate the electrification of its rural areas. The techno-feasibility of the gasification of oil palm biomass was first evaluated by reviewing existing literature. Subsequently, two scenarios (V1 and V2, and M1 and M2) were proposed regarding the use cases of the village and mill, respectively. The capacity of the gasification systems in the V1 and M1 scenarios are determined by the total amount of oil palm biomass available in the village and mill, respectively. The capacity of the gasification systems in the V2 and M2 scenarios is determined by the respective electricity demand of the village and mill. The global warming impact and economic feasibility (net present value (NPV) and levelized cost of electricity (LCOE)) of the proposed systems were compared with that of the current practices (diesel generator for the village use case and biomass boiler combustion for the mill use case) using life cycle assessment (LCA) and cost-benefit analysis (CBA). Under the current daily demand per household (0.4 kWh), deploying the V2 system in 104 villages with 500 households each could save up to 17.9 thousand tons of CO2-eq per year compared to the current diesel-based practice. If the electricity could be fed into the national grid, the M1 system with 100% capacity factor could provide yearly GHG emissions mitigation of 5.8 × 104 ton CO2-eq, relative to the current boiler combustion-based reference scenario. M1 had a positive mean NPV if the electricity could be fed into the national grid, while M2 had a positive mean NPV at the biochar price of 500 USD/ton. Under the current electricity tariff (ET) (0.11 kWh) and the biochar price of 2650 USD/ton, daily household demands of 2 and 1.8 kWh were required to reach the break-even point of the mean NPV for the V2 system for the cases of 300 and 500 households, respectively. The average LCOE of V2 is approximately one-fourth that of the reference scenario, while the average LCOE of V1 is larger than that of the reference scenario. The average LCOE of M1 decreased to around 0.06 USD/kWh for the case of a 100% capacity factor. Sensitivity analysis showed that the capital cost of gasification system and its overall electrical efficiency had the most significant effects on the NPV. Finally, practical system deployment was discussed, with consideration of policy formulation and fiscal incentives

Energy for Development: The Potential Role of Renewable Energy in Meeting the Millennium Development Goals

This report identifies renewable energy options that are currently in wide use in some regions and that are now ready for large-scale introduction in many areas of the developing world. Through 26 case studies, the report cites biogas, small hydro, solar, wind, ethanol, and biodiesel, among other technologies, as viable options for poverty alleviation in developing countries.As their cost has declined and their reliability has improved, renewable energy technologies have often emerged as more affordable and practical means of providing essential energy services. Although the strongest renewable energy growth has been in grid-connected power systems and liquid fuels for transportation, several technologies are well-suited to providing modern energy services for low-income people. Scaling up a broad portfolio of renewable energy options can make a major contribution to achieving the Millennium Development Goals, concludes the report.The creation of REN 21 was sponsored by the German Federal Ministry for Economic Cooperation and Development and the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety. Formally established in Copenhagen in June 2005, REN 21 is now supported by a steering committee of 11 governments, five intergovernmental organizations, five non-governmental organizations, and several regional, local and private organizations

Recovery of mixed rare earth oxide and fine powder of metallic iron from spent NdFeB magnet of wind turbines

NdFeB magnet is used in various application such as generators, electric vehicles, hard disc, rare earth roll magnetic separator etc. due to its excellent magnetic properties. Currently, ~26% of rare earths produced worldwide are used for the production of NdFeB magnet, but less than 1% of the rare earths are recycled after completing their life cycle. Due to continuous increase in demand of rare earths and scarcity of their primary resources, end-of-life NdFeB magnet emanated as potential source of rare earths. Therefore, now-a-days research is primarily focused on the utilization of waste NdFeB magnets for recycling and recovery of valuables metals in the usable form. Investigation has been carried out to separate rare earth oxide and metallic Fe directly by magnetic separation after selective oxidation of rare earths in NdFeB magnet. But the magnetic separation is ineffective due to partial oxidation of iron. In the present study, the rare earths are recovered selectively during leaching from the roasted NdFeB magnet powder and the leach residue of iron oxide is utilized to produce fine powder of metallic iron. Mixed oxide of rare earths of 99% purity is obtained from the rare earth rich leach liquor. The reduction of the leach residues has been studied using waste graphite of spent electrodes of arc furnace as reductant, in horizontal tubular furnace at different temperature and for various time period. It is found that 93% of iron oxide reduces to fine powder of metallic iron. The fine powder obtained after reduction, has been characterized by XRD which confirm the conversion of iron oxide to metallic iron phase. Thus, the present investigation highlights the recovery of mixed rare earth oxide and fine powder of metallic iron obtained as valuables from waste NdFeB magnet, which can be utilized directly as raw material for the production of fresh magnet

A Unique Hybrid Propulsion System Design for Large Space Boosters

A study was made of the application of hybrid rocket propulsion technology to large space boosters. Safety, reliability, cost, and performance comprised the evaluation criteria, in order of relative importance, for this study. The effort considered the so called classic hybrid design approach versus a novel approach which utilizes a fuel-rich gas generator for the fuel source. Other trades included various fuel/oxidizer combinations, pressure-fed versus pump fed oxidizer delivery systems, and reusable versus expandable booster systems. Following this initial trade study, a point design was generated. A gas generated-type fuel grain with pump fed liquid oxygen comprised the basis of this point design. This design study provided a mechanism for considering the means of implementing the gas generator approach for further defining details of the design. Subsequently, a system trade study was performed which determined the sensitivity of the design to various design parameters and predicted optimum values for these same parameters. The study concluded that a gas generator hybrid booster design offers enhanced safety and reliability over current of proposed solid booster designs while providing equal or greater performance levels. These improvements can be accomplished at considerably lower cost than for the liquid booster designs of equivalent capability

Preliminary analysis of space mission applications for electromagnetic launchers

The technical and economic feasibility of using electromagnetically launched EML payloads propelled from the Earth's surface to LEO, GEO, lunar orbit, or to interplanetary space was assessed. Analyses of the designs of rail accelerators and coaxial magnetic accelerators show that each is capable of launching to space payloads of 800 KG or more. A hybrid launcher in which EML is used for the first 2 KM/sec followed by chemical rocket stages was also tested. A cost estimates study shows that one to two EML launches per day are needed to break even, compared to a four-stage rocket. Development models are discussed for: (1) Earth orbital missions; (2) lunar base supply mission; (3) solar system escape mission; (4) Earth escape missions; (5) suborbital missions; (6) electromagnetic boost missions; and (7) space-based missions. Safety factors, environmental impacts, and EML systems analysis are discussed. Alternate systems examined include electrothermal thrustors, an EML rocket gun; an EML theta gun, and Soviet electromagnetic accelerators

Model-Free Methods to Analyze Pmu Data in Real-Time for Situational Awareness and Stability Monitoring

This dissertation presents and evaluates model-free methodologies to process Phasor Measurement Unit (PMU) data. Model-based PMU applications require knowledge of the system topology, most frequently the system admittance matrix. For large systems, the admittance matrix, or other system parameters, can be time-consuming to integrate into supporting PMU applications. These data sources are often sensitive and can require permissions to access, delaying the implementation of model-based approaches. This dissertation focuses on evaluating individual model-free applications to efficiently perform functions of interest to system operators for real-time situational awareness. Real-time situational awareness is evaluated with respect to central digitization where the PMU data is archived, and delays from telecommunication and system architecture are not considered. The PMU data available to utilities is often a subset of the overall system. Even without full observability, PMU data for observable portions of the system provides valuable, high-resolution information about the current system state. Methods are needed that can analyze and generate critical insight about the system in real-time to assist in detection and mitigation of major system events. All chapters address methodologies that can derive their output solely from the PMU signals. These methodologies are evaluated for their reliability and computational efficiency, considering a specific task of interest. Inter-area oscillations and poorly damped electromechanical modes are dangerous when undetected for extended periods of time, eventually leading to blackouts when unstable parameters are present. Prony Analysis and Matrix Pencil Method were selected in Chapter 4 for their proven effectiveness of estimating the dominant modes of an input signal; for purposes of this dissertation, the signal of interest for oscillation analysis is real power. The speed of convergence, accuracy of the methods, and viability when applied to utility PMU data were assessed to determine suitability to online system operation. Matrix Pencil Method was determined to provide more robust and computationally efficient estimation of key system modes for both simulated and real utility PMU data. The biorthogonal discrete wavelet transform, which can correlate frequency data to a time-domain solution, was utilized in Chapter 3 to create a methodology for event detection and classification for a subset of selected events. The derived methodology was shown to be effective for identification and classification of load and capacitor switch events, as well as breaker operation and faults. Methods to mimic the power flow Jacobian from discrete measurements are derived to assess system stability and eigenvalues in Chapter 2. These methods were effective for fast detection of unstable system parameters. Chapter 5, the most significant contribution of this dissertation, details derivations of a mathematical reduced system model and power flow Jacobian variants for more robust instability detection, system weak point identification, mitigation techniques, and state estimation capabilities. Considering the functions of all evaluated and developed model-free methodologies, event detection, event classification, detection of poorly damped oscillatory modes, and instability detection and mitigation can be achieved for situational awareness

Experimental Investigation of the Performance and Exhaust Emissions of a Spark-Ignition Engine Operating with Different Proportional Blends of Gasoline and Water Ammonia Solution

This paper aims to investigate the impact of water ammonia solution (WAS)-gasoline fuel (GF) blends on SI engine exhaust emission and engine performance characteristics and compare the obtained results with those using base gasoline. This investigation used a single-cylinder, four-stroke, air-cooled, and SI engine coupled with an AC generator to achieve this experimental work. Water ammonia solution fuel was blended with neat gasoline in volume rates of 5, 10,15,20, and 25%. The experimental investigation was conducted at an off-road engine under a constant engine speed of 3000 rpm and different load conditions. The results show that the use of ammonia solution as an addition to gasoline fuel increase the overall thermal efficiency, and G75Was25 blend obtained the maximum increase ratio of overall efficiency by 38.96% at maximum load condition in comparison to neat gasoline and reduce the specific fuel consumption compared with that of gasoline fuel. This alteration results in an elevation in CO, HC, and NOx emissions