Analysis of High-Speed Electrical Generators for Utility Applications

2013 ◽  
Author(s):  
Miroslav P. Petrov
Keyword(s):  
Electricity Generation ◽  
High Speed ◽  
Renewable Energy Sources ◽  
Scale Up ◽  
Energy Utilization ◽  
Superior Performance ◽  
Electricity Production ◽  
Small Scale ◽  
Technical Challenges ◽  
Compact Design

High-speed alternators are believed to be well developed nowadays, following the improvement in performance and decrease of costs for electronic power converters and permanent magnet materials. Their compact design and their ability to vary the rotational speed in off-design conditions promise superior performance when compared to conventional generators. High-speed alternators are only available in limited sizes for small-scale applications, whereas improvements in efficiency and optimized part-load behavior are particularly important especially for small-scale electricity generation. Enhanced energy utilization for electricity production by small utility plants or by distributed units located at private homes or commercial buildings, based on thermodynamic cycles powered by natural gas or various renewable energy sources, is possible to be achieved through a wider application of grid-integrated high-speed technology. This study presents a critical review of previous research and demonstration work on high-speed electrical machines and a summary of the technical challenges limiting their performance and their expansion into larger sizes. Conclusions are drawn for finding appropriate solutions for practical high-speed electricity generation units and their readiness for a much wider deployment. Closer analysis is attempted on the thermal and mechanical integrity of high-speed alternators and the technical challenges that slow down their scale-up to MW-size units for utility applications. The necessary research and development work that needs to be done in the near future is outlined and discussed herein.

scholarly journals Energy Production from Biogas: Competitiveness and Support Instruments in Latvia

2016 ◽  
Vol 53 (5) ◽  
pp. 43-53
Author(s):  
G. Klāvs ◽  
A. Kundziņa ◽  
I. Kudrenickis
Keyword(s):  
New Technologies ◽  
Local Economic Development ◽  
Renewable Energy Sources ◽  
Distribution Network ◽  
Scale Up ◽  
Electricity Production ◽  
Small Scale ◽  
Gas Distribution ◽  
Ex Post ◽  
The Impact

Abstract Use of renewable energy sources (RES) might be one of the key factors for the triple win-win: improving energy supply security, promoting local economic development, and reducing greenhouse gas emissions. The authors ex-post evaluate the impact of two main support instruments applied in 2010-2014 – the investment support (IS) and the feed-in tariff (FIT) – on the economic viability of small scale (up to 2MWel) biogas unit. The results indicate that the electricity production cost in biogas utility roughly corresponds to the historical FIT regarding electricity production using RES. However, if in addition to the FIT the IS is provided, the analysis shows that the practice of combining both the above-mentioned instruments is not optimal because too high total support (overcompensation) is provided for a biogas utility developer. In a long-term perspective, the latter gives wrong signals for investments in new technologies and also creates unequal competition in the RES electricity market. To provide optimal biogas utilisation, it is necessary to consider several options. Both on-site production of electricity and upgrading to biomethane for use in a low pressure gas distribution network are simulated by the cost estimation model. The authors’ estimates show that upgrading for use in a gas distribution network should be particularly considered taking into account the already existing infrastructure and technologies. This option requires lower support compared to support for electricity production in small-scale biogas utilities.

High-Speed Steam Turbine Systems for Small-Scale Power Generation Applications

2012 ◽  
Author(s):  
Miroslav P. Petrov ◽  
Jens Fridh ◽  
Ake Göransson ◽  
Torsten H. Fransson
Keyword(s):  
Power Generation ◽  
Steam Turbine ◽  
High Speed ◽  
Waste Heat ◽  
Electrical Power ◽  
Energy Utilization ◽  
Electricity Production ◽  
Small Scale ◽  
Low Grade ◽  
Steam Turbines

Energy utilization from low-grade fuels of either fossil or renewable origin, or from medium-temperature heat sources such as solar, industrial waste heat, or small nuclear reactors, for small-scale power generation via steam cycles, can be reasonably enhanced by a simple technology shift. This study evaluates the technical feasibility of a compact power generation package comprising a steam turbine directly coupled to a high-speed alternator delivering around 8–12 MW of electrical power. Commercial or research-phase high-speed electrical generators at MW-scale are reviewed, and a basic thermodynamic design and flow-path analysis of a steam turbine able to drive such a generator is attempted. High-speed direct drives are winning new grounds due to their abilities to be speed-controlled and to avoid the gearbox otherwise typical for small system drivetrains. These two features may offer a reasonable advantage to conventional drives in terms of higher reliability and better economy. High-speed alternators with related power electronics are nowadays becoming increasingly available for the MW-size market. A generic 8 to 12 MW synchronous alternator running respectively at 15,000 to 10,000 rpm, have been used as a reference for evaluating the fundamental design of a directly coupled steam turbine prime mover. The moderate steam parameter concept suits well for converting mid-temperature thermal energy into electrical power with the help of low-tech steam cycles, allowing for distributed electricity production at reasonable costs and efficiency. Steam superheat temperatures below 350°C (660°F) at pressures of maximum 20 bar would keep the steam volumetric flow sufficiently high in order to restrain the turbine losses typical for small-scale turbines, while helping also with simpler certification and safety procedures and using primarily established technology and standard components. The proposed steam turbines designs and their characteristics thereof have been evaluated by computer simulations using the in-house code ProSteam and its sub-procedures AXIAL and VaxCalc, by courtesy of Siemens Industrial Turbomachinery and its steam turbine division located in Finspong, Sweden. The first results from this study show that high-speed steam turbines of the proposed size and type are possible to design and manufacture based on conventional components, and can be expected to deliver a very satisfactory performance at variable power output.

scholarly journals Improvement of Biogas Quality and Quantity for Small-Scale Biogas-Electricity Generation Application in off-Grid Settings: A Field-Based Study

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3088
Author(s):  
Henry Wasajja ◽  
Saqr A. A. Al-Muraisy ◽  
Antonella L. Piaggio ◽  
Pamela Ceron-Chafla ◽  
Purushothaman Vellayani Aravind ◽  
...  
Keyword(s):  
Electricity Generation ◽  
Relevant Literature ◽  
Electrical Power ◽  
Process Efficiency ◽  
Electricity Production ◽  
Small Scale ◽  
Buffer System ◽  
Biogas Plants ◽  
Operational Practices ◽  
Pre Treatment

Small-scale electrical power generation (<100 kW) from biogas plants to provide off-grid electricity is of growing interest. Currently, gas engines are used to meet this demand. Alternatively, more efficient small-scale solid oxide fuel cells (SOFCs) can be used to enhance electricity generation from small-scale biogas plants. Most electricity generators require a constant gas supply and high gas quality in terms of absence of impurities like H2S. Therefore, to efficiently use the biogas from existing decentralized anaerobic digesters for electricity production, higher quality and stable biogas flow must be guaranteed. The installation of a biogas upgrading and buffer system could be considered; however, the cost implication could be high at a small scale as compared to locally available alternatives such as co-digestion and improved digester operation. Therefore, this study initially describes relevant literature related to feedstock pre-treatment, co-digestion and user operational practices of small-scale digesters, which theoretically could lead to major improvements of anaerobic digestion process efficiency. The theoretical preamble is then coupled to the results of a field study, which demonstrated that many locally available resources and user practices constitute frugal innovations with potential to improve biogas quality and digester performance in off-grid settings.

scholarly journals The Cost-Benefit Analysis of the Electricity Production from Small Scale Renewable Energy Sources in the Conditions of Romania

2019 ◽  
Vol 32 ◽  
pp. 385-389 ◽  
Author(s):  
Pavel Atănăsoae ◽  
Radu Dumitru Pentiuc ◽  
Dan Laurențiu Milici ◽  
Elena Daniela Olariu ◽  
Mihaela Poienar
Keyword(s):  
Renewable Energy ◽  
Cost Benefit Analysis ◽  
Renewable Energy Sources ◽  
Cost Benefit ◽  
Electricity Production ◽  
Energy Sources ◽  
Small Scale ◽  
Benefit Analysis ◽  
The Cost

scholarly journals Barriers and Solutions for Increasing the Integration of Solar Photovoltaic in Kenya’s Electricity Mix

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5502
Author(s):  
Dominic Samoita ◽  
Charles Nzila ◽  
Poul Alberg Østergaard ◽  
Arne Remmen
Keyword(s):  
Geothermal Energy ◽  
Trade Balance ◽  
Electricity Generation ◽  
Renewable Energy Sources ◽  
Electricity Production ◽  
Solar Photovoltaic ◽  
Solar Pv ◽  
Storage Solutions ◽  
Electricity Mix ◽  
National Trade

Currently, Kenya depends mainly on oil, geothermal energy and hydro resources for electricity production, however all three have associated issues. Oil-based electricity generation is environmentally harmful, expensive and a burden to the national trade balance. The rivers for hydropower and their tributaries are found in arid and semi-arid areas with erratic rainfall leading to problems of supply security, and geothermal exploitation has cost and risk issues amongst others. Given these problems and the fact that Kenya has a significant yet underexploited potential for photo voltaic (PV)-based power generation, the limited—although growing—exploitation of solar PV in Kenya is explored in this paper as a means of diversifying and stabilising electricity supply. The potential for integration of PV into the Kenyan electricity generation mix is analysed together with the sociotechnical, economic, political, and institutional and policy barriers, which limit PV integration. We argue that these barriers can be overcome with improved and more robust policy regulations, additional investments in research and development, and improved coordination of the use of different renewable energy sources. Most noticeably, storage solutions and other elements of flexibility need to be incorporated to balance the intermittent character of electricity generation based on solar PV.

A Micro-Scale Swimmer Propelled by Traveling Surface Waves

2011 ◽  
Author(s):  
Izhak Bucher ◽  
Eyal Setter
Keyword(s):  
Travelling Wave ◽  
Superior Performance ◽  
Small Scale ◽  
Micro Scale ◽  
Viscous Forces ◽  
Macro Scale ◽  
Robotic Devices ◽  
Compact Design ◽  
Micro Organisms ◽  
Efficient Power

Micro-scale slender swimmers are frequently encountered in nature and recently in micro-robotic applications. The swimming mechanism examined in this article is based on small transverse axi-symmetrical travelling wave deformations of a cylindrical long shell. In very small scale, inertia forces become negligible and viscous forces dominate most propulsion mechanisms being used by micro-organisms and robotic devices. The present paper proposes a compact design principle that provides efficient power to propel and maneuver a micro-scale device. Shown in this paper is a numerical analysis which couples the MEMS structure to the surrounding fluid. Analytical results compare the proposed mechanism to commonly found tail (flagella) driven devices, and a parametric comparison is shown suggesting it has superior performance. Numerical studies are preformed to verify the analytical model. Finally, a macro-scale demonstrator swimming in an environment with similar Reynolds numbers to the ones found in small scale is shown and its behavior in the laboratory is compared to the theory.

scholarly journals Cost-Benefit Analysis of Small-Scale Rooftop PV Systems: The Case of Dragotin, Croatia

2021 ◽  
Vol 11 (19) ◽  
pp. 9318
Author(s):  
Mladen Bošnjaković ◽  
Ante Čikić ◽  
Boris Zlatunić
Keyword(s):  
Renewable Energy Sources ◽  
Electricity Consumption ◽  
Electricity Production ◽  
Small Scale ◽  
Optimal Size ◽  
Pv System ◽  
Load Curve ◽  
Pv Systems ◽  
Hourly Data ◽  
Daily Load

A large drop in prices of photovoltaic (PV) equipment, an increase in electricity prices, and increasing environmental pressure to use renewable energy sources that pollute the environment significantly less than the use of fossil fuels have led to a large increase in installed roof PV capacity in many parts of the world. In this context, this paper aims to analyze the cost-effectiveness of installing PV systems in the rural continental part of Croatia on existing family houses. A typical example is a house in Dragotin, Croatia with an annual consumption of 4211.70 kWh of electricity on which PV panels are placed facing south under the optimal slope. The calculation of the optimal size of a PV power plant with a capacity of 3.6 kW, without battery energy storage, was performed by the Homer program. The daily load curve was obtained by measuring the electricity consumption at the facility every hour during a characteristic day in the month of June. As most of the activities are related to electricity consumption, repeating during most days of the year, and taking into account seasonal activities, daily load curves were made for a characteristic day in each month of the year. Taking into account the insolation for the specified location, using the Internet platform Solargis Prospect, hourly data on the electricity production of selected PV modules for a characteristic day in each month were obtained. Based on the previous data, the electricity injected into the grid and taken from the grid was calculated. Taking into account the current tariffs for the sale and purchase of electricity, investment prices, and maintenance of equipment, the analysis shows that such a PV system can pay off in 10.5 years without government incentives.

scholarly journals Municipal Solid Waste as a valuable recycled asset for small-scale electricity production in rural communities

2019 ◽  
pp. 92-106
Author(s):  
Valter Silva ◽  
João Cardoso ◽  
Paulo Brito ◽  
Luís Tarelho ◽  
José Luz
Keyword(s):  
Rural Communities ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Economic Model ◽  
Electricity Generation ◽  
Integrated System ◽  
Waste To Energy ◽  
Electricity Production ◽  
Small Scale ◽  
Biomass Supply

Municipal solid waste provides an opportunity for electricity production. This strategy provides the rural communities a potential waste-to-energy opportunity to manage its costly residues problem, turning them into a valuable recycled asset. To address this issue, a techno-economic study of an integrated system comprising gasification of Acacia residues and Portuguese Municipal Solid Waste (PMSW) with an Internal Combustion Engine-Generator (ICEG) for electricity generation at small-scale (100 kW) was developed. Current studies only devote attention to biomass residues and do not explore MSW potential to eschew biomass supply shortage. Conventional systems are generally part of biomass supply chains, limiting flexibility and all year operation for their operators. Experimental data was gathered at a downdraft gasifier to provide a clear assessment of particle and tar concentration in the syngas and levers conditioning a satisfactory ICE operation. Once the potential of using Acacia residues and PMSW has been proven during gasification runs testing, and validation, a set of new conditions was also explored through a high-fidelity CFD model. We find that residues blends have the highest potential to generate high-quality syngas and smallest exposure to supply disruption. Despite both substrates showing potential at specific conditions, they also present individual drawbacks which will be best mitigated by executing a hybrid supply comprising the mix of substrates. An economic model coupling the financial indicators of net present value (NPV), internal rate of return (IRR) and the payback period (PBP) considering a project lifetime of 25 years was developed. Cost factors include expenses with electricity generation, initial investment, amortizations and operation and maintenance (containing fuels costs). Revenues were estimated from electricity generated and sales to the national grid. A sensitivity analysis based on the Monte Carlo method was used to measure the economic model performance and to determine the risk in investing in such venture. The risk appraisal yielded favorable investment projections, with an NPV reaching positive values, an IRR superior to the discount rate and PBP lower than the project life span. This work allowed to confirm the positive effect of the generation of energy from downdraft gasification plants on a small-scale. Regardless of the project’s feasibility, the economic performance depended to a large extent on the electricity prices which present considerable variability and are subject to political decisions.

scholarly journals Techno-Economic Assessment of the Use of Syngas Generated from Biomass to Feed an Internal Combustion Engine

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3097 ◽  
Author(s):  
J. R. Copa ◽  
C. E. Tuna ◽  
J. L. Silveira ◽  
R. A. M. Boloy ◽  
P. Brito ◽  
...  
Keyword(s):  
Economic Model ◽  
Electricity Generation ◽  
Net Present Value ◽  
Combustion Engine ◽  
General System ◽  
Economic Assessment ◽  
Electricity Production ◽  
Small Scale ◽  
Cost Factors ◽  
Fuel Costs

The focus of this study is to provide a comparative techno-economic analysis concerning the deployment of small-scale gasification systems in dealing with various fuels from two countries, Portugal and Brazil, for electricity generation in a 15 kWe downdraft gasifier. To quantify this, a mathematical model was implemented and validated against experimental runs gathered from the downdraft reactor. Further, a spreadsheet economic model was developed combining the net present value (NPV), internal rate of return (IRR) and the payback period (PBP) over the project’s lifetime set to 25 years. Cost factors included expenses related to electricity generation, initial investment, operation and maintenance and fuel costs. Revenues were estimated from the electricity sales to the grid. A Monte Carlo sensitivity analysis was used to measure the performance of the economic model and determine the investment risk. The analysis showed an electricity production between 11.6 to 15 kW, with a general system efficiency of approximately 13.5%. The viability of the projects was predicted for an NPV set between 18.99 to 31.65 k€, an IRR between 16.88 to 20.09% and a PBP between 8.67 to 12.61 years. The risk assessment yielded favorable investment projections with greater risk of investment loss in the NPV and the lowest for IRR. Despite the feasibility of the project, the economic performance proved to be highly reliant on the electricity sales prices subdue of energy market uncertainties. Also, regardless of the broad benefits delivered by these systems, their viability is still strikingly influenced by governmental decisions, subsidiary support and favorable electricity sales prices. Overall, this study highlights the empowering effect of small-scale gasification systems settled in decentralized communities for electric power generation.

scholarly journals Electricity Generation and Energy Cost Estimation of Large-Scale Wind Turbines in Jarandagh, Iran

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Kasra Mohammadi ◽  
Ali Mostafaeipour ◽  
Yagob Dinpashoh ◽  
Nima Pouya
Keyword(s):  
Wind Energy ◽  
Wind Power ◽  
Cost Estimation ◽  
Energy Cost ◽  
Electricity Generation ◽  
Large Scale ◽  
Wind Farm ◽  
Energy Utilization ◽  
Electricity Production ◽  
Energy Output

Currently, wind energy utilization is being continuously growing so that it is regarded as a large contender of conventional fossil fuels. This study aimed at evaluating the feasibility of electricity generation using wind energy in Jarandagh situated in Qazvin Province in north-west part of Iran. The potential of wind energy in Jarandagh was investigated by analyzing the measured wind speed data between 2008 and 2009 at 40 m height. The electricity production and economic evaluation of four large-scale wind turbine models for operation at 70 m height were examined. The results showed that Jarandagh enjoys excellent potential for wind energy exploitation in 8 months of the year. The monthly wind power at 70 m height was in the range of 450.28–1661.62 W/m2, and also the annual wind power was 754.40 W/m2. The highest capacity factor was obtained using Suzlon S66/1.25 MW turbine model, while, in terms of electricity generation, Repower MM82/2.05 MW model showed the best performance with total annual energy output of 5705 MWh. The energy cost estimation results convincingly demonstrated that investing on wind farm construction using all nominated turbines is economically feasible and, among all turbines, Suzlon S66/1.25 MW model with energy cost of 0.0357 $/kWh is a better option.

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