scholarly journals Assessment of arrays of in-stream tidal turbines in the Bay of Fundy

2013 ◽  
Vol 371 (1985) ◽  
pp. 20120189 ◽  
Author(s):  
Richard Karsten ◽  
Amanda Swan ◽  
Joel Culina
Keyword(s):  
Power Generation ◽  
Electricity Generation ◽  
Bay Of Fundy ◽  
Blockage Ratio ◽  
Limit Value ◽  
Tidal Turbines ◽  
Actuator Disc ◽  
Flow Through ◽  
Turbine Arrays ◽  
The Impact

Theories of in-stream turbines are adapted to analyse the potential electricity generation and impact of turbine arrays deployed in Minas Passage, Bay of Fundy. Linear momentum actuator disc theory (LMADT) is combined with a theory that calculates the flux through the passage to determine both the turbine power and the impact of rows of turbine fences. For realistically small blockage ratios, the theory predicts that extracting 2000–2500 MW of turbine power will result in a reduction in the flow of less than 5 per cent. The theory also suggests that there is little reason to tune the turbines if the blockage ratio remains small. A turbine array model is derived that extends LMADT by using the velocity field from a numerical simulation of the flow through Minas Passage and modelling the turbine wakes. The model calculates the resulting speed of the flow through and around a turbine array, allowing for the sequential positioning of turbines in regions of strongest flow. The model estimates that over 2000 MW of power is possible with only a 2.5 per cent reduction in the flow. If turbines are restricted to depths less than 50 m, the potential power generation is reduced substantially, down to 300 MW. For large turbine arrays, the blockage ratios remain small and the turbines can produce maximum power with a drag coefficient equal to the Betz-limit value.

Design of a Tidal Turbine Array for the Bohai Strait, China

2018 ◽  
Author(s):  
Lei Chen ◽  
Paul A. J. Bonar ◽  
Thomas A. A. Adcock
Keyword(s):  
Design Strategies ◽  
Stream Power ◽  
Tidal Turbines ◽  
Actuator Disc ◽  
Tidal Turbine ◽  
Tidal Stream ◽  
Flow Through ◽  
Turbine Arrays ◽  
Theoretical Results ◽  
Bohai Strait

In this paper, we consider array design strategies to maximise the power available to turbines placed in the Bohai Strait, which is considered to be one of China’s most promising candidate sites for tidal stream power. The discontinuous Galerkin version of the open-source hydrodynamic model ADCIRC is used to simulate flow through the strait and tidal turbines are introduced using a sub-grid scale actuator disc model. New design algorithms based on key theoretical results are used to build large arrays, which are then compared in terms of both the collective power output and the power produced per turbine. The results of the analysis are used to draw general conclusions about the optimal design of tidal turbine arrays.

Changes in extreme surface solar radiation in EURO-CORDEX Regional Climate Models

2021 ◽  
Author(s):  
Blanka Bartok
Keyword(s):  
Climate Change ◽  
Power Generation ◽  
Solar Radiation ◽  
Solar Energy ◽  
Electricity Generation ◽  
Climate Models ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Surface Solar Radiation ◽  
The Impact

<p>As solar energy share is showing a significant growth in the European electricity generation system, assessments regarding long-term variation of this variable related to climate change are becoming more and more relevant for this sector. Several studies analysed the impact of climate change on the solar energy sector in Europe (Jerez et al, 2015) finding light impact (-14%; +2%) in terms of mean surface solar radiation. The present study focuses on extreme values, namely on the distribution of low surface solar radiation (overcast situation) and high surface solar radiation (clear sky situation), since the frequencies of these situations have high impact on electricity generation.</p><p>The study considers 11 high-resolution (0.11 deg) bias-corrected climate projections from the EURO-CORDEX ensemble with 5 Global Climate Models (GCMs) downscaled by 6 Regional Climate Models (RCMs).</p><p>Changes in extreme surface solar radiation frequencies show different regional patterns over Europe.</p><p>The study also includes a case study determining the changes in solar power generation induced by the extreme situations.</p><p> </p><p> </p><p>Jerez et al (2015): The impact of climate change on photovoltaic power generation in Europe, Nature Communications 6(1):10014, 10.1038/ncomms10014</p><p> </p>

scholarly journals Does Combined Heat and Power Play the Role of a Bridge in Energy Transition? Evidence from a Cross-Country Analysis

2019 ◽  
Vol 11 (4) ◽  
pp. 1035 ◽  
Author(s):  
Hyo-Jin Kim ◽  
Jeong-Joon Yu ◽  
Seung-Hoon Yoo
Keyword(s):  
Power Generation ◽  
Renewable Energy ◽  
Electricity Generation ◽  
Nuclear Power ◽  
Energy Transition ◽  
Parameter Estimate ◽  
Combined Heat And Power ◽  
Cross Country ◽  
The Impact

In an era of energy transition involving an increase in renewable energy and a reduction in coal-fired power generation and nuclear power generation, the role of combined heat and power (CHP) as a bridging energy is highly emphasized. This article attempts to look empirically into the impact of increasing the share of renewable energy in total electricity generation on CHP share in total electricity generation in a cross-country context. Data from 35 countries during the period 2009–2015 were used, and the least absolute deviations estimator was applied to obtain a more robust parameter estimate. The results showed that a 1%p increase in the share of renewable energy significantly increased the CHP share by 0.87%p. Therefore, the hypothesis that CHP serves as bridge energy in the process of energy transition was established.

An Assessment of the Potential of Tidal Power From Minas Passage, Bay of Fundy, Using Three-Dimensional Models

2011 ◽  
Author(s):  
Richard Karsten
Keyword(s):  
Numerical Simulations ◽  
3D Structure ◽  
Three Dimensional ◽  
Tidal Currents ◽  
Total Power ◽  
Bay Of Fundy ◽  
Three Dimensional Model ◽  
Cross Sectional ◽  
Flow Through ◽  
The Impact

Large tidal currents exist in Minas Passage, which connects Minas Basin to the Bay of Fundy off the northwestern coast of Nova Scotia. The strong currents through this deep, narrow channel make it a promising location for the generation of electrical power using instream turbines. These strong currents are clearly illustrated in the results of a high-resolution, three-dimensional model of the flow through Minas Passage presented here. The simulations also clearly indicate the asymmetry of the flood and ebb tides and the 3D structure of the flow. A previous study has indicated that as much as 7000 MW could be extracted from the tidal currents through Minas Passage. However, this estimate was based on a complete fence of turbines across the passage, in essence a tidal barrage. In this paper, the power potential of partial turbine fences is examined. In order to estimate the power potential of turbine arrays, the theory of partial turbine fences is adapted to the particular dynamics of Minas Passage. The theory estimates the potential power of the fence and the change in flow that would result. The results are presented in terms of the portion of the cross-sectional area that the turbines occupy and the drag coefficient of the turbines. When the turbine fence occupies a large portion of the passage, the potential power of the fence rises significantly, to a value much larger than estimates based on the kinetic energy flux. The increase in power comes from the increased tidal head that a large turbine fence creates and the resulting increase in the turbine drag. We also present the efficiency of the turbine fence — given as the ratio of the power associated with the turbine drag over the total power extracted from the flow — and the impact of the turbines on the tidal flow. The results of the theory are compared to numerical simulations of the flow through the passage with turbines represented as regions of increased drag. The numerical simulations give power values that are three to six time as high as the theory suggests is possible. This discrepancy is examined by plotting the changes in tidal currents caused by the turbine fence.

The Control of Non-Axisymmetric Flow in Axial Turbomachinery Using Circumferentially Varying Stator Exit Angles

2000 ◽  
Author(s):  
Jonathan Taylor ◽  
Tom Hynes
Keyword(s):  
Design Method ◽  
Axisymmetric Flow ◽  
Three Dimensional ◽  
Design Strategies ◽  
Inlet Distortion ◽  
Alternative Approach ◽  
Blade Row ◽  
Actuator Disc ◽  
Flow Through ◽  
The Impact

Turbomachinery operating in distorted flowfields is often very close to the sources of the distortion, and can influence the flowfield distortions at its inlet and outlet. Several techniques are available to reduce the impact of an upstream-running outlet distortion on the turbomachinery by introducing circumferential variation in the most downstream stator row. However, these techniques assume that the upstream-running distortion is not changed by the modifications to the turbomachinery, and none of them addresses the issue of inlet distortion, either on its own or in combination with outlet distortion. A methodology to design circumferentially varying stator angles has been developed. This is based on a two-dimensional linearisation of the distorted flow through the turbomachinery, combined with information from three-dimensional flowfield calculations. The resulting new design method has been applied to an installed lift fan operating with considerable inlet and outlet distortion. The distorted flow through the lift fan is computed by a three-dimensional numerical method incorporating an actuator disc blade row model. The new design method is then used to produce several redesigned builds with circumferentially varying stator exit angles. The three-dimensional flow through the new builds is computed, and compared with flow through the axisymmetric fan. The calculations show that existing non-axisymmetric design strategies may not be applicable to installations having large flowfield distortions. An alternative approach based on unsteady rotor loading is presented, and relatively small stator exit angle variations are shown to produce significant reductions in this quantity.

PADDY RESIDUE AS FEEDSTOCK IN ELECTRICITY GENERATION: REDEMPTION OF LIFE CYCLE EMISSIONS AND COST ANALYSIS

2018 ◽  
Vol 13 (Number 1) ◽  
pp. 55-67
Author(s):  
Shafini M. Shafie ◽  
Zakirah Othman ◽  
N Hami
Keyword(s):  
Power Generation ◽  
Life Cycle ◽  
Cost Analysis ◽  
Positive Feedback ◽  
Energy Supply ◽  
Electricity Generation ◽  
Economic Sector ◽  
Ghg Emission ◽  
Coal Fuel ◽  
Biomass Resources

Malaysia has an abundance of biomass resources that can be utilised for power generation. One of them is paddy residue. Paddy residue creates ahuge potential in the power generation sector. The consumption of paddy residue can help Malaysia become less dependent on conventional sources of energy, mitigate greenhouse gas(GHG) emission, offer positive feedback in the economic sector, and at the same time, provide thebest solution for waste management activities. The forecast datafor 20 years on electricity generation wasused to calculate the GHG emission and its saving when paddy residue is used for electricity generation. The government’scost saving was also identified when paddy residue substituted coal fuel in electricity generation.This paper can provide forecast information so that Malaysia is able to move forward to apply paddy residue as feedstock in energy supply. Hopefully, the data achieved can encourage stakeholder bodies in the implementation of paddy residue inelectricity generation since there is apositive impact towardscost and emission saving.

scholarly journals Decarbonization of Residential Building Energy Supply: Impact of Cogeneration System Performance on Energy, Environment, and Economics

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2538
Author(s):  
Praveen K. Cheekatamarla
Keyword(s):  
Carbon Dioxide ◽  
Power Generation ◽  
Energy Consumption ◽  
Carbon Footprint ◽  
Residential Buildings ◽  
Building Energy ◽  
Primary Energy ◽  
Primary Energy Consumption ◽  
Cogeneration System ◽  
The Impact

Electrical and thermal loads of residential buildings present a unique opportunity for onsite power generation, and concomitant thermal energy generation, storage, and utilization, to decrease primary energy consumption and carbon dioxide intensity. This approach also improves resiliency and ability to address peak load burden effectively. Demand response programs and grid-interactive buildings are also essential to meet the energy needs of the 21st century while addressing climate impact. Given the significance of the scale of building energy consumption, this study investigates how cogeneration systems influence the primary energy consumption and carbon footprint in residential buildings. The impact of onsite power generation capacity, its electrical and thermal efficiency, and its cost, on total primary energy consumption, equivalent carbon dioxide emissions, operating expenditure, and, most importantly, thermal and electrical energy balance, is presented. The conditions at which a cogeneration approach loses its advantage as an energy efficient residential resource are identified as a function of electrical grid’s carbon footprint and primary energy efficiency. Compared to a heat pump heating system with a coefficient of performance (COP) of three, a 0.5 kW cogeneration system with 40% electrical efficiency is shown to lose its environmental benefit if the electrical grid’s carbon dioxide intensity falls below 0.4 kg CO2 per kWh electricity.

Thermal performance comparison of different sun tracking configurations

2019 ◽  
Vol 88 (2) ◽  
pp. 20902
Author(s):  
O. Achkari ◽  
A. El Fadar
Keyword(s):  
Thermal Performance ◽  
Electricity Generation ◽  
Arid Regions ◽  
Performance Comparison ◽  
Water Desalination ◽  
Parabolic Trough ◽  
Parabolic Trough Collector ◽  
The Impact ◽  
The Mathematical Model ◽  
Good Agreement

Parabolic trough collector (PTC) is one of the most widespread solar concentration technologies and represents the biggest share of the CSP market; it is currently used in various applications, such as electricity generation, heat production for industrial processes, water desalination in arid regions and industrial cooling. The current paper provides a synopsis of the commonly used sun trackers and investigates the impact of various sun tracking modes on thermal performance of a parabolic trough collector. Two sun-tracking configurations, full automatic and semi-automatic, and a stationary one have numerically been investigated. The simulation results have shown that, under the system conditions (design, operating and weather), the PTC's performance depends strongly on the kind of sun tracking technique and on how this technique is exploited. Furthermore, the current study has proven that there are some optimal semi-automatic configurations that are more efficient than one-axis sun tracking systems. The comparison of the mathematical model used in this paper with the thermal profile of some experimental data available in the literature has shown a good agreement with a remarkably low relative error (2.93%).

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