Net Capacity Factor Research Articles

An approach to assess offshore wind power potential using bathymetry and near-hub-height reanalysis data

Offshore wind power is emerging option in wind industry due to relatively consistent wind behavior over ocean. This study aims to access offshore wind resource employing a novel approach using bathymetry data, in-situ measured and 5th generation European Reanalysis (ERA-5) wind data. The measured wind data for four near-coast locations was used in Exclusive Economic Zone (EEZ) of Pakistan. The percentage bias for wind speed and wind direction of ERA-5 data compared to measured data for coastline location is −0.2% and −0.9% respectively, which shows suitability of ERA-5 data for offshore resource assessment with acceptable accuracy. Annual mean wind speed and wind power density of the EEZ is 6.1 m/s and 263 W/m2 respectively. The northeastern part of the EEZ near coastline of Sindh province is most suitable for offshore wind farms. An offshore wind farm site suitable for monopile foundation having wind power class as Fair was selected. The performance of more than 400 commercial wind turbines was evaluated and a 4.5 MW turbine having highest net capacity factor (NCF) was selected. The capacity factor of suggested wind farm having installed capacity of 540 MW is computed as 55% which can avoid 1.45 million tons in CO2eq emissions annually.

Performance and economic evaluation of a wind energy system: A case study

ABSTRACT Wind energy has a significant role in promoting for sustainable development. Growth in power generation from wind has become a competitive and acceptable renewable energy resource. Wind energy can be shared in securing sustainable and safe energy supply. The first step of a wind energy project is the evaluation of wind speed characteristics and the condition of the site. In this paper, a small wind farm is proposed to be installed in two selected sites in the north of Iraq (Dokan 35.9496° N, 44.9621° E and Chamchamal 35.5292° N, 44.8217° E at Al- Sulimania Governorate. Ten 50 kW wind turbines are considered, and their performance is primarily evaluated. Wind energy parameters and the capacity factor are calculated for a year. The shape and scale factors for both sites (Dokan and Chamchamal) were found 2.092, 5.233, and 2.104,5.325, respectively. The net capacity factor for both sites was found 16.94% and 18.08% and the estimated cost of energy laid in the range (0.04 USD/kWh-0.06 USD/kWh) which is in good agreement with other researcher achievements. Both sites possess fair condition for installing wind turbines. An increase in the capacity factor by 5% leads to reduce the payback period by 30%.

Evaluasi Keandalan PLTA Bakaru

One form of water energy utilization is done by building a Hydroelectric Power Plant (PLTA) in Indonesia, the Bakaru PLTA is one of the projects within PT. PLN (Persero). This project is a Hydro Power Plant Master project with a SULSELRABAR transmission located 246 km from the city of Makassar. The operation of the Bakaru hydropower system is certainly expected to work optimally, reliably and efficiently. Therefore, evaluation or data on the performance of the generator itself is needed. This study was conducted to determine the condition of the Bakaru hydropower plant based on the equivalent availability factor (EAF) and Net Capacity Factor (NCF) and Cost of Production (BPP). The data used is operating data on the Bakaru hydropower plant for 1 year. The data was obtained by using the documentation technique, while the data analysis was carried out using the Microsoft Excel program. After conducting research, it can be concluded that the condition of the Bakaru hydropower plant in 2017 is considered normal, seen from the EAF value reaching 94.15% and the average EFOR value of 2.4% with the number of Service Hours (SH) of 16,912.93 hours from 2 units. with the percentage of Service Hours to Period Hours reaching 96.53%. Meanwhile, the Net Capacity Factor of the Bakaru hydropower plant in 2017 reached 85.83%, with a total gross energy production of 945,372.50 MWh. This value exceeds the target that has been set.

Spatial impacts of technological innovations on the levelized cost of energy for offshore wind power plants in the United States

Recent studies predict significant decreases in the future levelized cost of energy (LCOE) of offshore wind energy, much of which is attributed to anticipated cost reductions from technological innovation. This study evaluates the spatial variability of LCOE caused by technology-induced decreases in a range of capital, operational, and financial cost categories. A spatial cost model of fixed-bottom and floating offshore wind plants is used to model the impact across thousands of potential United States sites. A specified change in an individual turbine subsystem cost produces a range of LCOE outcomes due to the varying geospatial characteristics of the considered sites and the nonlinear, interactive dependency on these input parameters; for example, a 10.8% improvement in net capacity factor can reduce LCOE by between 6% and 20% at different sites. This work expands upon the existing offshore wind literature, which typically evaluates cost sensitivities at a single site and does not consider the spatial variance in LCOE. The results suggest that the impact of technological innovations can be considerable and should be considered on a spatial as well as temporal basis when prioritizing technology innovation research or funding decisions to advance offshore wind technologies in the United States.

Small-Scale Solar–Bio-Hybrid Power Generation Using Brayton and Rankine Cycles

This study conducted a detailed technical analysis of small-scale solar–bio-hybrid power generation systems using Rankine (steam turbine) and Brayton (gas turbine) cycles. Thermodynamic models were developed to characterize the state of working fluid and select the most suitable solar collection technology for individual power generation systems. Net capacity factor of power generation and utilization efficiencies of solar and biogas energy were used as parameters to evaluate energy generation and conclude the preferred system configuration. The analysis concluded that the steam turbine system has better global efficiency (67.7%) than the gas turbine system (55.7%), while the gas turbine system has better electricity generation efficiency (27.0%) than that (5.6%) of the steam turbine system. The effects of different climates on the selection of suitable hybrid systems were also investigated to delineate suitability and feasibility of different hybrid systems. In addition, the method used in this study can also be applied to investigate and optimize other small-scale hybrid renewable energy generation systems.

The calculation of the campaign of reactor RITM-200

In this paper, the campaign of RITM-200 reactor was calculated. The duration of the campaign was determined taking the net capacity factor into consideration. The calculated duration concurred with the known data. The neutron parameters were calculated using the effective temperature method. The presence of burnable absorber rods was taken into account. Their effect was considered using the diffusional approach. The iterative computations were used to finally determine the temperature of the neutron gas. At the end, the reactivity curve displaying different effects inside fuel, namely fuel and gadolinium burn-out, the poisoning and slagging was drawn.

Evaluacija potencijala energije vetra u indijskoj državi Tamil Nadu korišćenjem analize kretanja brzine vetra

An accurate estimate of wind resource assessment is essential for the identification of potential site for wind farm development. The hourly average wind speed measured at 50 m above ground level over a period of 39 years (1980-2018) from 25 locations in Tamil Nadu, India have been used in this study. The annual and seasonal wind speed trends are analyzed using linear and Mann-Kendall statistical methods. The annual energy yield, and net capacity factor are obtained for the chosen wind turbine with 2 Mega Watt rated power. As per the linear trend analysis, Chennai and Kanchipuram possess a significantly decreasing trend, while Nagercoil, Thoothukudi, and Tirunelveli show an increasing trend. Mann-Kendall trend analysis shows that cities located in the southern peninsula and in the vicinity of the coastal regions have significant potential for wind energy development. Moreover, a majority of the cities show an increasing trend in the autumn season due to the influence of the retreating monsoons which is accompanied with heavy winds. The mean wind follows an oscillating pattern throughout the year at all the locations. Based on the net annual energy output, Nagercoil, Thoothukudi and Nagapattinam are found to be the most suitable locations for wind power deployment in Tamil Nadu, followed by Cuddalore, Kumbakonam, Thanjavur and Tirunelveli.

Assessment of wind energy potential across varying topographical features of Tamil Nadu, India

Wind energy is one of the abundant, cheap and fast-growing renewable energy sources whose intensive extraction potential is still in immature stage in India. This study aims at the determination and evaluation of wind energy potential of three cities located at different elevations in the state of Tamil Nadu, India. The historical records of wind speed, direction, temperature and pressure were collected for three South Indian cities, namely Chennai, Erode and Coimbatore over a period of 38 years (1980-2017). The mean wind power density was observed to be highest at Chennai (129 W/m2) and lowest at Erode (76 W/m2) and the corresponding mean energy content was highest for Chennai (1129 kWh/m2/year) and lowest at Erode (666 kWh/m2/year). Considering the events of high energy-carrying winds at Chennai, Erode and Coimbatore, maximum wind power density were estimated to be 185 W/m2, 190 W/m2 and 234 W/m2, respectively. The annual average net energy yield and annual average net capacity factor were selected as the representative parameters for expressing strategic wind energy potential at geographically distinct locations having significant variation in wind speed distribution. Based on the analysis, Chennai is found to be the most suitable site for wind energy production followed by Coimbatore and Erode.

Improving the conceptual understanding of the Darajat Geothermal Field

The Darajat Geothermal Field is the largest vapor-dominated geothermal field in Indonesia with an installed power generation capacity of 271 MWe. For the past 23 years, it has averaged about 90% net capacity factor since commercial operations started in 1994. From the initial 55 MWe, new increments of generation were added in 2000 (95 MWe) and in 2007 (110 MWe; later increased to 121 MWe in 2009). The drilling of wells to support these new increments of generation and continuous resource monitoring has provided key data for integration into the conceptual model and resource simulation modelling.Recent reservoir characterization studies enabled the delineation of surface structures that impact the geothermal system, correlation of surface and subsurface rocks, determination of the orientation of fractures that correlate with feed zones encountered by wells, and better imaging of the reservoir through use of advanced geophysical interpretation methods. The above analyses have helped better define the conceptual model of the Darajat Field and provided information in targeting future make-up wells.Star Energy Geothermal Darajat II (SEGD) takes a proactive approach to manage anticipated and emerging resource performance issues. A good example of this approach is provided by adjustments to the injection of steam condensate from the power plants. Injection initially utilized low productivity wells in the central portion of the field. Field monitoring through geochemical, downhole, and wellhead pressure-temperature (“PT”) measurements indicated that this injection strategy had the potential to adversely affect production from nearby wells by suppressing aquifer boiling and lowering reservoir pressure. Consequently, in 2012, condensate injection was shifted to a new location near the Northeast margin of the field to utilize a well with deep entries. Based on experience and supported with case histories from other vapor-dominated fields, primarily The Geysers, deep injection beneath the feed zones of the production wells is effective at minimizing the impacts of injection breakthrough. Following the change in injection strategy, the central portion of the field has experienced renewed boiling, while only one production well is exhibiting early symptoms of chemical breakthrough from injection in the Northeast.Going forward, expected reservoir management challenges include requirements to add new well pads and target production wells into undrilled areas, localized increased influx of external fluids as the reservoir pressure drops, and reservoir dry-out leading to high superheat levels and reduced well productivity. By continuing to leverage lessons learned to further improve reservoir management processes along with the proactive response to field management issues, SEGD anticipates that Darajat can maintain its production at current levels for the forseeable future.

The Salak Field, Indonesia: On to the next 20 years of production

The Salak Geothermal Field is the largest producing geothermal field in Indonesia with an installed power generation capacity of 377 MWe. After more than 23 years of commercial operations and through vigilant resource management, the Salak Field is still performing well. Since 1994, when commercial production started, the net capacity factor has averaged about 91% annually. After the last turbine uprating in 2005, the net capacity factor has improved to an annual average of 95%. By 2019, a substantial injection realignment will be implemented which will move all condensate injection outside the field production boundary and shift most brine injection outside and to the southeast margin. This project will mitigate brine injection impact to the AWI 7 and 8 wells and hasten development of the steam cap in the western portion of the field. With this injection realignment, reservoir simulation forecasts show the Salak geothermal resource will likely be able to continue steam production at its current level in the foreseeable future.Similar to other long-producing geothermal fields, Salak has encountered resource management challenges, such as, injection breakthrough, influx of marginal recharge, wellbore scaling, and production of significant amounts of non-condensable gas (“NCG”), in response to commercial production. To address these challenges, an extensive reservoir monitoring program and integration of new make-up drilling results enabled updates and fine-tuning of the conceptual model of the field. Key updates include increased understanding of the distribution of the producing effective fractures and their permeability in the reservoir, identification of injection capacity outside the commercial field boundary in the Cianten Caldera, and improved understanding of NCG interference in the steam cap and injection and natural recharge impacts on the field. These insights and the updated conceptual understanding of the Salak geothermal system coupled with reservoir simulation have provided a credible forecast of the Salak reservoir’s future performance for decision-makers to have the necessary confidence to fund the injection realignment project. Additionally, the refined conceptual model provides the reservoir management team with a means to plan and target development make-up wells and effectively focus future data gathering and reservoir monitoring activities.

Performance estimation of Ntaruka hydropower plant and its comparison with the prediction results obtained by SPSS

Hydroelectricity has long been used in Rwanda. The Ntaruka hydropower plant was constructed during the colonial period in the northern part of Rwanda and it is still in operation. This paper evaluates the annual performance of this power plant and highlights several factors, which are vital for future predictions in the energy generation. Literature search and review coupled with energy generation analysis and forecasting were used for the study. Data were collected through site visits and discussions with the staff of the Rwanda Energy Group. Analysis were made by considering some performance factors of the power plant such as net capacity factor, plant use factor, power factor, voltage profile, frequency profile, general energy profile, and annual energy generation profile taking cognizance of hydropower plant installed capacity. Based on the available monthly operation hours of the power plant and its annual energy generation data between 2011 and 2014, predictions were made using the Statistical Package for Social Sciences (SPPS version 20.0) to forecast future energy generation for the power plant. Results show that the annual energy generation of the power plant varies between 1277 and 4524 MWh, with an average of 2912 MWh within the above years, which is much closer to the average real energy generation obtained between 2011 and 2015 and, therefore, the power plant is in good operating condition. Further research is recommended to consider using staffing levels, plant availability factors, and economic efficiency to determine the economic effectiveness and performance indices of the hydropower plant.

Wind turbine rank method for a wind park scenario

Purpose This paper aims to present a method of the wind turbine ranking, either stall or pitch-regulated wind turbine (WTG), to determine the suitability of wind turbine in a selected site. Design/methodology/approach The method included the wind park target capacity, the maximum hub-height, the standard rotor diameter and the characteristic of wind speed on the site. As the method had been applied to a wind park, with more than one wind turbine, the wake losses had been considered by subtracting the gross capacity factor. Besides, the turbine-site matching index (TSMI) was computed by dividing the net capacity factor with the total installed capital cost per kilowatt. Findings The components of the total installed capital cost were cost of turbine, installation, as well as operation and maintenance. Meanwhile, the target capacity index (TCI) was calculated by dividing the estimated wind park capacity with the target wind park capacity. Originality/value Both TSMI and TCI were used together to rank the wind turbines. Furthermore, a site in the eastern part of Kudat was selected as the case study site, where ten models of wind turbines were tested and ranked.

An improved global wind resource estimate for integrated assessment models

This paper summarizes initial steps to improving the robustness and accuracy of global renewable resource and techno-economic assessments for use in integrated assessment models. We outline a method to construct country-level wind resource supply curves, delineated by resource quality and other parameters. Using mesoscale reanalysis data, we generate estimates for wind quality, both terrestrial and offshore, across the globe. Because not all land or water area is suitable for development, appropriate database layers provide exclusions to reduce the total resource to its technical potential. We expand upon estimates from related studies by: using a globally consistent data source of uniquely detailed wind speed characterizations; assuming a non-constant coefficient of performance for adjusting power curves for altitude; categorizing the distance from resource sites to the electric power grid; and characterizing offshore exclusions on the basis of sea ice concentrations. The product, then, is technical potential by country, classified by resource quality as determined by net capacity factor. Additional classifications dimensions are available, including distance to transmission networks for terrestrial wind and distance to shore and water depth for offshore. We estimate the total global wind generation potential of 560 PWh for terrestrial wind with 90% of resource classified as low-to-mid quality, and 315 PWh for offshore wind with 67% classified as mid-to-high quality. These estimates are based on 3.5MW composite wind turbines with 90m hub heights, 0.95 availability, 90% array efficiency, and 5MW/km2 deployment density in non-excluded areas. We compare the underlying technical assumption and results with other global assessments.

Characterizing power performance and wake of a wind turbine under yaw and blade pitch

AbstractWind turbine wakes have been recognized as a key issue causing underperformance in existing wind farms. In order to improve the performance and reduce the cost of energy from wind farms, one approach is to develop innovative methods to improve the net capacity factor by reducing wake losses. The output power and characteristics of the wake of a utility‐scale wind turbine under yawed flow is studied to explore the possibility of improving the overall performance of wind farms. Preliminary observations show that the power performance of a turbine does not degrade significantly under yaw conditions up to approximately 10°. Additionally, a yawed wind turbine may be able to deflect its wake in the near‐wake region, changing the wake trajectory downwind, with the progression of the far wake being dependent on several atmospheric factors such as wind streaks. Changes in the blade pitch angle also affect the characteristics of the turbine wake and are also examined in this paper. Copyright © 2015 John Wiley & Sons, Ltd.

Is $50/MWh solar for real? Falling project prices and rising capacity factors drive utility‐scale PV toward economic competitiveness

AbstractRecently announced low‐priced power purchase agreements (PPAs) for US utility‐scale photovoltaic (PV) projects suggest $50/MWh solar might be viable under certain conditions. To explore this possibility, this paper draws on an increasing wealth of empirical data to analyze trends in three of the most important PPA price drivers: upfront installed project prices, operations, and maintenance (O&M) costs, and capacity factors. Average installed prices among a sample of utility‐scale PV projects declined by more than one third (from $5.8/WAC to $3.7/WAC) from the 2007–2009 period through 2013, even as costlier systems with crystalline‐silicon modules, sun tracking, and higher inverter loading ratios (ILRs) have constituted an increasing proportion of total utility‐scale PV capacity (all values shown here are in 2013 dollars). Actual and projected O&M costs from a very small sample of projects appear to range from $20–$40/kWAC‐year. The average net capacity factor is 30% for projects installed in 2012, up from 24% for projects installed in 2010, owing to better solar resources, higher ILRs, and greater use of tracking among the more recent projects. Based on these trends, a pro‐forma financial model suggests that $50/MWh utility‐scale PV is achievable using a combination of aggressive‐but‐achievable technical and financial input parameters (including receipt of the 30% federal investment tax credit). Although the US utility‐scale PV market is still young, the rapid progress in the key metrics documented in this paper has made PV a viable competitor against other utility‐scale renewable generators, and even conventional peaking generators, in certain regions of the country. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.