Renewable Based Power Plants Research Articles

Enhancement of frequency transient response using fuzzy-PID controller considering high penetration of doubly fed induction generators

In modern power systems, renewable-based power plant such as wind power system is integrated significantly. Among numerous types of wind power systems doubly fed induction generators (DFIG) is becoming favorable in the last few years. However, adding a wind power plant could give a new challenge to the power system, especially in frequency stability. Hence, it is important to control the frequency of the power system to be able to find its initial condition in every condition. Generally, the frequency of the power system can be controlled by using automatic generation control (AGC). AGC is used to maintain the balance between generating capacity and the load by adding integral control to the governor. However, with more and more wind power systems in the grid conventional AGC is unsuitable. Hence, it is important to have an advanced AGC based on the artificial intelligence method. This paper proposed the application of fuzzy-proportional integrator derivative (fuzzy-PID) for AGC in power systems considering the high penetration of wind power systems. From the simulation results, it is found that the proposed method can reduce the overshoot and accelerate the settling time of frequency better than using conventional AGC.

Thermodynamic and thermoeconomic analysis and optimization of a renewable-based hybrid system for power, hydrogen, and freshwater production

To address environmental pollution effectively, it is crucial to promote the increased utilization of renewable energy sources. Furthermore, an appealing opportunity arises from enhancing the efficiency of renewable-based power plants while diversifying their product output. This study introduces a hybrid system that revolves around renewable resources, with a primary focus on evaluating power generation, hydrogen production, and freshwater extraction. The designed system seamlessly integrates a flash-binary geothermal power plant with a solar system, incorporating cutting-edge phase-change material storage technology. Hydrogen is generated through a combination of steam-methanol reforming and pressure swing adsorption processes. Freshwater is procured utilizing humidification-dehumidification and multi-effect desalination units. In terms of power generation, the system leverages the capabilities of the geothermal power plant alongside a modified Kalina cycle. The performance of this integrated system is rigorously evaluated through a combination of thermodynamic and thermoeconomic approaches. An exergy-economic optimization scenario is employed to determine the most efficient operational mode. The results of this comprehensive analysis reveal that the system can produce 0.0224 kg/s of hydrogen, 8.017 kg/s of freshwater, and generate 215.9 W of net power. Impressively, it achieves an exergy efficiency of 58.3% at a unit cost of $32.23/GJ in the base mode. Furthermore, the optimal operating state boosts efficiency to 60.59%, with a unit cost of $32.22/GJ. Notably, adjustments in the selling price of hydrogen have a significant impact on the system's financial metrics. As the price of hydrogen rises from $5 to $6/kg, the payback period reduces from 4 to 3 years, and the net present value surges from $5.81 million to $10.16 million.

Performance evaluation and optimization of a multigeneration hybrid system for power, hydrogen, cooling, and freshwater production from renewable sources

Designing a hybrid system emerges as a highly efficient strategy for augmenting the performance of renewable-based power plants, owing to their adaptability in integrating diverse subsystems. In this study, a new multigeneration system is introduced, showcasing its capability to concurrently generate power, hydrogen, cooling, and freshwater through a synergy of methanol-steam reforming, modified absorption refrigeration cycles, humidification-dehumidification, and multi-effect desalination. The operational foundation of the system is rooted in the harmonious integration of solar and geothermal energy sources. To comprehensively evaluate the proposed system's performance, a combination of exergy and economic analyses is employed. This research studies the impacts of varying key parameters on the system's operation. Notably, the water-to-methanol ratio is identified as the most influential variable affecting reformer performance, underscoring the pivotal role of reforming pressure. The estimated total fixed cost of the system stands at $4.039 million, with a calculated payback period of 6 years and a net present value of $3.454 million. Furthermore, in its optimized state, the system achieves an impressive exergy efficiency of 49.80 % and a unit product cost of $32.38/GJ. These findings unequivocally validate the feasibility and economic viability of the proposed hybrid renewable-based power generation system. In conclusion, the amalgamation of solar and geothermal energy, coupled with meticulous parameter optimization, substantiates the potential of this innovative system to serve as a sustainable and economically viable solution for power generation.

An advanced secondary voltage control strategy for future power systems

The network voltage control together with the regulation of reactive power, has always been recognized as vital feature of power systems. It is aimed at containing the bus voltage within acceptable limits for guaranteeing system security, first and then assessing power quality. The voltage control is a key field in which several Transmission System Operators are currently investing resources to be well prepared in managing power systems with a high share of renewable energy sources, overcoming the drawbacks of the existing architectures. As is well known the voltage control is realized through a hierarchical structure, which is based on classical primary control, secondary control, and tertiary optimization. The secondary control is concerned with the regional level, implying proper coordination at both the geographical and temporal level. Due to its central role in power system operation, the secondary voltage control cannot be excluded from the effects of the dramatic changes that power systems are experiencing worldwide, even though regulators work by implementing well consolidated methodologies and strategies which show excellent performances. The motivation for this study in fact relies on the observation of some oscillatory phenomena in some areas of the Italian power system characterized by a high number of regulating resources highly coupled each other on the basis of the grid topology: despite these oscillatory phenomena are not so frequent, with the increasing of regulating resources enslaved by secondary regulation (such as renewable-based power plants) could potentially be worsened in the near future. Thus, in this paper, an optimal control strategy is proposed by tailoring a proper linear quadratic integral control which allows guaranteeing the desired profile for pilot buses voltage, ensuring a time response of aperiodic type without any oscillations. The aim of the proposed approach is to preserve the strengths of the existing secondary voltage regulation while enhancing the overall stability so enabling the progressive large penetration of renewable energy sources-based power plants and minimize the occurrence of oscillatory phenomena especially in highly electrically coupled areas. The robustness of the proposed regulation is verified first with respect to the WSCC 9-bus test system and successively on an actual regional area of Italian transmission network.

DER Participation in Ancillary Services Market: An Analysis of Current Trends and Future Opportunities

In an effort to push for low-carbon transition, national governments and regulatory authorities are working to define market structures and legislative frameworks able to effectively support the spreading of electricity production from renewables. To this purpose, the opening of national Ancillary Services Markets (ASMs) to Distributed Energy Resources (DERs) plays a key role. However, pricing schemes and rules in place (e.g., incentives) can act as a barrier to the supply of regulation services by small-sized and renewable-based power plants. In this context, the present work evaluates the economic opportunities for DERs provided by the provision of tertiary reserve and balancing control in the Italian ASM. The research is carried out through the collection and processing of price data from the Italian electricity and gas markets over 4 years (2019–2022). Considering a reference architecture where DER units bid on the market through a Balancing Service Provider, the potential revenues on the ASM of a non-programmable or partially programmable DER unit are compared to the earnings expected of a conventional power plant in order to highlight whether unfair competition can represent a barrier. Then, possible evolutions in the current remuneration schemes are analyzed, to evaluate whether they can be able to support a better DER integration. From the analysis, it emerges that, even if negative prices could be useful to increase the competitiveness of RES-based power plants for downward regulation, the loss of the incentives can act as a deterrent to the offering of services on the market by DERs. Therefore, other regulatory options, such as the incentives retention in case of downward regulation, could also be needed.

A Comparative Review on Energy Storage Systems and Their Application in Deregulated Systems

Electrical energy is critical to the advancement of both social and economic growth. Because of its importance, the electricity industry has historically been controlled and operated by governmental entities. The power market is being deregulated, and it has been modified throughout time. Both regulated and deregulated electricity markets have benefits and pitfalls in terms of energy costs, efficiency, and environmental repercussions. In regulated markets, policy-based strategies are often used to deal with the costs of fossil fuel resources and increase the feasibility of renewable energy sources. Renewables may be incorporated into deregulated markets by a mix of regulatory and market-based approaches, as described in this paper, to increase the systems economic stability. As the demand for energy has increased substantially in recent decades, particularly in developing nations, the quantity of greenhouse gas emissions has increased fast, as have fuel prices, which are the primary motivators for programmers to use renewable energy sources more effectively. Despite its obvious benefits, renewable energy has considerable drawbacks, such as irregularity in generation, because most renewable energy supplies are climate-dependent, demanding complex design, planning, and control optimization approaches. Several optimization solutions have been used in the renewable-integrated deregulated power system. Energy storage technology has risen in relevance as the usage of renewable energy has expanded, since these devices may absorb electricity generated by renewables during off-peak demand hours and feed it back into the grid during peak demand hours. Using renewable energy and storing it for future use instead of expanding fossil fuel power can assist in reducing greenhouse gas emissions. There is a desire to maximize the societal benefit of a deregulated system by better using existing power system capacity through the implementation of an energy storage system (ESS). As a result, good ESS device placement offers innovative control capabilities in steady-state power flow regulation as well as dynamic stability management. This paper examines numerous elements of renewable integrated deregulated power systems and gives a comprehensive overview of the most current research breakthroughs in this field. The main objectives of the reviews are the maximization of system profit, maximization of social welfare and minimization of system generation cost and loss by optimal placement of energy storage devices and renewable energy systems. This study will be very helpful for the power production companies who want to build new renewable-based power plant by sighted the present status of renewable energy sources along with the details of several EES systems. The incorporation of storage devices in the renewable-incorporated deregulated system will provide maximum social benefit by supplying additional power to the thermal power plant with minimum cost.

Exergoeconomic analysis and optimization of a high-efficient multi-generation system powered by Sabalan (Savalan) geothermal power plant including branched GAX cycle and electrolyzer unit

Employing suitable subsystems to reach high efficiency and low cost in renewable-based power plants is more crucial. The geothermal energy heat source is located in many countries, but this has never been investigated to run a multi-generation system, including a branched GAX cycle and an electrolyzer. In this path, a high-efficient multi-generation system powered by a Sabalan (Savalan) geothermal power plant consisting of a single flash cycle, a branched GAX cycle, and an electrolyzer is presented and scrutinized from thermodynamic and exergoeconomic viewpoints. In the end, a two-objective optimization, by using the Total Unit Cost of Product (TUCP) and energy efficiency as objectives, is utilized to find the optimum operating conditions. Critiques and studies of variables reveal that the produced hydrogen rate remains unchanged at 5.655 kg/h by changing the degassing value and temperature of the generator, condenser 2, and evaporator. By increasing the flash tank pressure from 5.2 bar to 7 bar, the cooling and heating loads rise about 108.4%, while the net electricity falls from 3977 kW to 3506 kW. Interestingly, the TUCP has a minimum value at the evaporator temperature of 273 K and condenser 2 temperature of 322.3 K. The optimization results indicate the values of the produced hydrogen rate and net electricity with 5.85 kg/h and 4187 kW are more than those of the base case. Also, the optimal values are 7.046 $/GJ, 36.82%, and 65.42% for the TUCP and energy and exergy efficiencies, respectively.

An Extreme Learning Machine Based Adaptive VISMA for Stability Enhancement of Renewable Rich Power Systems

Maintaining power system stability in renewable-rich power systems can be a challenging task. Generally, the renewable-rich power systems suffer from low and no inertia due to the integration of power electronics devices in renewable-based power plants. Power system oscillatory stability can also be affected due to the low and no inertia. To overcome this problem, additional devices that can emulate inertia without adding synchronous machines can be used. These devices are referred to as virtual synchronous machines (VISMA). In this paper, the enhancement of oscillatory stability of a realistic representative power system using VISMA is proposed. A battery energy storage system (BESS) is used as the VISMA by adding an additional controller to emulate the inertia. The VISMA is designed by using Fruit Fly Optimization. Moreover, to handle the uncertainty of renewable-based power plants, the VISMA parameters are designed to be adaptive using the extreme learning machine method. Java Indonesian Power Grid has been used as the test system to investigate the efficacy of the proposed method against the conventional POD method and VISMA tuning using other methods. The simulation results show that the proposed method can enhance the oscillatory stability of the power system under various operating conditions.

The potential of renewable-based power plant development towards Bali green and independent electricity supply

This paper presents results of a study on the potential for renewable energy-based power plants development in Bali. The renewable energy-based power plants is developed in order to stop dependence of electricity supply from outside Bali and to increase the share of renewable energy in the power supply mix to achieve Bali green and independent electricity and for climate change mitigation. . In this study, AIM-Enduse model was used to estimate the potential of renewable energy-based power plants and GHG emissions reduction from the deployment of renewables in Bali’s power supply mix. There were three scenarios for representing renewable energy-based power plants development in Bali, i.e. baseline (business as usual) and two scenarios (CM1 and CM2) of the deployment of renewables in the power supply mix. The CM1 described conservative scenario of the deployment of renewable in the energy supply mix of Bali’s power plants while CM2 represented optimistic scenario. Since the renewable is considered as carbon neutral, therefore these scenarios can also relate to the mitigation actions to reduce GHG emissions. Under the CM1, GHG emissions reduction potential from the deployment of renewable energy technology in Bali’s power plants and the conversion of coal to natural gas power plants is accounted to about 22% (1.5 MtCO2e) in 2030 and can be targeted up to 32% (4.0 MtCO2e) in 2050. The deployment of renewable energy under the CM1 is 0.96 GW in 2030 and 1.92 GW in 2050. Under the CM2, the GHG emissions reduction potential from the deployment of renewable energy technology in Bali’s power plants and the conversion of coal to natural gas power plants is accounted to about 23% (2.16 MtCO2e) in 2030 and targeted to achieve 27% (4.75 MtCO2e) in 2050. The deployment of renewable energy under the CM2 is more ambitious compared to those in CM2, i.e. 1.39 GW in 2030 and 2.36 GW in 2050.

Simulation and modeling of a combined biomass gasification-solar photovoltaic hydrogen production system for methanol synthesis via carbon dioxide hydrogenation

One solution to achieving a large scale distribution, transportation and storage of renewable energy is methanol production from renewable-based power plants integrated with hydrogenation. In this study, a novel non-combustion heat-carrier biomass gasifier system is proposed, coupled with a large-scale solar power plant and alkaline water electrolysis system, for methanol production from syngas, water and carbon dioxide. Aspen Plus, MATLAB and TRNSYS are used to simulate and assess the performance of each component of the proposed system, under different climatic conditions of Toronto, Canada, and Crotone, Italy. In both localities, the best energy performance that minimizes the grid energy interaction factor is obtained with a photovoltaic station of 50.4 MW coupled to biomass gasification, which leads to 0.60 kWh and 0.57 kWh, respectively, in Toronto and Crotone, of electricity sent to or drawn from the grid for each kWh required by the electrolyser. However, higher profitability may be achieved in both localities with a single biomass gasification system which brings an enhanced benefit of 0.56 M€ in Toronto and 0.44 M€ in Crotone for each kW installed. It is expected that the developed modelling approach and these four newly formulated dimensionless indicators, i.e., the satisfied load fraction, utilization factor, grid energy interaction factor, and grid economic interaction value can be used to evaluate large-scale integrated renewable-based power systems.

On the water footprint in power production: Sustainable design of wet cooling towers

Renewable based power plants must be installed where the main resource is available. The weather affects the design and the water footprint of these plants. Two types of power cycles, a regenerative Rankine cycle, representing biomass and solar thermal plants, and the combined cycle, corresponding to biogas or gasification based processes, are studied. The facilities are modeled unit by unit in detail to compute the cycle yield, the condenser duty, the water consumption and the natural draft wet cooling tower geometry for its sustainable design. Hot regions, appropriate for solar facilities, and humid regions require larger and more expensive towers. Areas with high solar availability also show larger consumption of water presenting a tradeoff for a future renewable based power system. In addition, design guidelines and surrogate models to estimate water consumption, cooling tower size and its cost as a function of the climate have also been developed. The surrogates are useful for the analysis on the water footprint of a renewable based power system that substitutes the fossil based one.

Utilizing the HSVC of the micro hydro power plant to improve frequency stability response

One of the popular renewable-based power plants that are appropriate to be installed in developing countries such as Indonesia due to its stability, efficient operation, and economic point of view is Micro-Hydro Power Plant (MHPP). Frequency stability of power plant systems refers to the ability of the generator to maintain a steady frequency during and post faults and rapid dynamic load. To keep the stability of power system frequency from fluctuations, generating units change their power output automatically according to the change of the system frequency or load by balancing the active power with the loads. To keep the stability frequency on MHPP, active power fast control is employed in this study, and all the systems of MHPP and the frequency control are carried out and simulated extensively using MATLAB/Simulink. With the active power control through a fast valving mechanism using the HSVC method, the duration of stability frequency response is faster compared to the system without fast control.

Design and Fabrication of an Automatic Trash Remover for Open Channel Waterway for Micro Hydropower Plant Application

Mitigation of catastrophic impacts of exhausted pollutants from conventional based power plants could be done by extensively used of renewable energy-based power plants. One of the promising renewable-based power plants that already have technology maturity is hydropower. However, large scale hydropower is based on an appropriate site and not economically effective for isolated and remote small communities. As anticipation, to fulfill the power requirements of these communities, micro-hydropower plants (MHPPs) are applied due to its inexpensive capital and low maintenance cost. Normally, MHPPs projects are finalized from civil construction to powerhouse. A simple trash filter is usually located before the intake of the penstock. This simple trash filter usually causes a problem related to trash collection that blocks the water debit into the penstock intake. The low debit, might cause the turbine's rotation will be reduced which in turn downgrade the voltage and frequency. Low voltage and frequency might harm consumers. In this paper, a new control mechanism based on Arduino Mega of automatic trash removed is introduced.

A short- and long-term demand based analysis of a CO2 concentrated solar power system with backup heating

Daily minute-based (i.e., short-term) and typical meteorological year (TMY) hourly-based (long-term) analyses are presented for a recompression cycle with direct CO2 heating in a parabolic collector field. The cycle is assisted by a backup heating unit, which is composed of a two-tank molten salt thermal storage and an auxiliary heating process representing, for example, a fossil fuel burner. The analyses also considered that the cycle is subjected to two distinct demand profiles, one that is constant throughout the day and another that varies hourly. The multitude of conditions modeled allowed the results to explore the effect of different solar irradiation profiles, seasonality and solar multiple factor. The analysis revealed that for short and long-term analysis the proper size of the solar collector field, here presented by the solar multiple, is strongly related to the demand profile as well as to the time frame considered within the analysis, i.e. short-term or TMY. The results also indicated that when the recompression cycle operates under same solar multiple factor with either a variable or a constant demand, the latter configuration is less dependent of auxiliary heating while the former presents higher performance values. Ultimately, the analysis reinforces the need for considering realistic inputs (e.g., irradiation, demand, etc.) when dealing with renewable-based power plants.

A Study on V2G Based Frequency Control in Power Grid with Renewable Energy

Abstract Although renewable energy based power generation is the most promising and sophisticated solution to the future society owing to its small amount of emission of the greenhouse effect gas, it has a great disadvantage of varied output. For instance, the large amount of existing PVs already gives a serious destabilizing effect on the western Japanese power systems. It is of great concern how future power grid can be operated securely when great amount of renewable based power plants are installed. One of the promising countermeasures against this problem is the utilization of battery energy storage, where its highly costly impact, which comes from the necessary battery storage installation, can be mitigated if the electric vehicles are used for this stabilizing control. This paper proposes a new method for the above stated technical challenge. So called Euler equation in the field of calculus of variation is solved numerically satisfying equality and inequality constraints based on the assumed scenario of usable electric vehicles, providing the most desirable charge/ discharge plan. Numerical study is done to confirm the fundamental feasibility of the proposed method. This method is a great candidate to be applied to general cases of many realistic constraints.

The role of bioenergy in the German “Energiewende”—whose demands can be satisfied by bioenergy?

The transformation of the energy system and especially the electricity system into a renewable-based system requires systemic changes of the different system components. The planned progressive decommissioning of fossil- or nuclear-based power plants implies that renewable-based power plants need to take over their functions. This article examines the possible role of bioenergy-based plants during the different phases of the energy system transformation. Our findings provide strong evidence that bioenergy can supply the necessary balancing and ancillary services in order to guarantee system stability and security of supply while simultaneously covering electricity and heat demand. Only in a later stage of the transformation process, it seems to be necessary to operate in a mainly demand-oriented mode. Besides the economic dimension, the political and scientific debate must take the various systemic and environmental impacts of bioenergy into account to maintain the ability of bioenergy to serve the energy system. The economic points of failure of the recent policy are being pointed out and it is shown that recent legislation is expected to lead to a decrease of the installed bioenergy power.

Participation of wind power plants in system frequency control: Review of grid code requirements and control methods

Abstract Active power reserves are needed for the proper operation of an electrical system. These reserves are continuously regulated in order to match the generation and consumption in the system and thus, to maintain a constant electrical frequency. They are usually provided by synchronized conventional generating units such as hydraulic or thermal power plants. With the progressive displacement of these generating plants by non-synchronized renewable-based power plants (e.g. wind and solar) the net level of synchronous power reserves in the system becomes reduced. Therefore, wind power plants are required, according to some European Grid Codes, to also provide power reserves like conventional generating units do. This paper focuses not only on the review of the requirements set by Grid Codes, but also on control methods of wind turbines for their participation in primary frequency control and synthetic inertia.

Electricity Generation Expansion Planning with Environmental Impact Abatement: Case Study of Bangladesh

This paper analyzes utilization of renewable energy with domestic coal in place of import coal and oil in Bangladesh Power System from 2010-2030. Therefore, the modelling of long-term renewable and domestic coal utilization is examined in terms of expansion cost and environmental impacts. The results show that in 2030, the required electricity generation to fulfil future demand is estimated 162 TWh. Under the BAU scenario, the share of coal is 33% of total electricity generation mix. However, under the null coal import scenario the installed power plant from renewable sources increase to be 47 GW and coal utilization decreases to be 35 GW or 16% of total electricity generation share. The null coal import scenario reduces coal utilization by up to 52%. Under the limited coal and oil import scenarios, the share of coal becomes 60 GW or 27% of total electricity generation mix. In the economic and environmental perspective, more renewable based power plants need to be developed in order to reduce import coal and oil utilization in power generation. In the end of planning horizon, the BAU scenario emits as much as 96 million tons of CO2 equivalents, while the null coals import scenario successes to reduce emissions by 39 million tons from the BAU scenario's emissions.

CO2 mitigation model of future power plants with integrated carbon capture and storage in Thailand

Thailand currently relies on natural gas, coal, and oil for electricity production. Natural gas and oil fields are the plentiful domestic energy resources in the Gulf of Thailand, but are projected to be available only in the next decade. Using domestic natural gas would reduce national energy security. Due to its low price, coal will dominate in electricity generation in Thailand. However, more utilization of coal results in increasing CO2 emissions. To comply with the low-carbon society policy of the Royal Thai Government, carbon dioxide capture and storage (CCS) for the future committed power plants in Thailand is introduced and analysed using the market allocation model, a least-cost energy planning tool. In this study, CO2 mitigation scenarios include integrated CCS to new gas- and coal-based power plants, nuclear power and renewable-based power plants and these were introduced as mitigation options. In energy-demand forecasting, share of coal-based plants is projected to increase from 0.72% in 2006 to 14.97% in 2030, while the share of gas-based plants decreases from 79.24 to 53.25% in the same period. This study also presents possible gas and oil fields for storing CO2 in the deep saline aquifer in the Gulf of Thailand. Results show the optimal CO2 incremental cost and revenue when applied with clean development mechanism and feed-in-tariff for renewable energy and the CCS project in Thailand.

Renewable-energy integration assessment through a dedicated computer program

This article is intented to present an approach to assess the possibilities of renewable resources through the dynamics of stand-alone and system-integrated renewable-based power plants. Mainly solar and wind energy will be considered leading to the computer program devoted to the simulation of both solar photovoltaic power plants and wind energy converters. Besides, the assessment of the integration of these kinds of intermittent resources into hybrid systems, either pure renewable with hydro-pumped storage units or along with conventional power systems, is the main objective of the program. Finally, the program is aimed at scenario assessment, allowing different energy-mix scenarios to be compared involving both renewable and conventional power plants. Because of the complexity of the problem in a real case, it is useful to stress the rough assessment that will be made in this first version. Examples are provided involving the main topics dealt with.