Wind Sources Research Articles

Comparative Investigation of On-Grid and Off-Grid Hybrid Energy System for a Remote Area in District Jamshoro of Sindh, Pakistan

To meet electricity requirements and provide a long-term, sustainable existence, remote areas need to promote renewable projects. Most of the time, wind and solar power sources are selected as renewable energy technologies to help satisfy some of the power requirements. Alternative approaches should be employed, considering the inconsistent characteristics among those resources, to offer efficient and long-lasting responses. Electricity production needs to be conducted with the help of a wide range of energy sources to be productive and efficient. As a result, the current research concentrates on feasible analyses of interconnected hybrid energy systems for such remote residential electricity supply. To help a remote area’s establishment decide whether to adopt renewable electricity technology, this paper evaluates the techno-economic effectiveness of grid-connected and standalone integrated hybrid energy systems. The electricity requirements for the entire selected remote area were determined first. Furthermore, the National Aeronautics and Space Administration, a national renewable energy laboratory, was used to evaluate the possibilities of green energy supplies. A thorough survey was performed to determine which parts were needed to simulate the interconnected hybrid energy systems. Employing the HOMER program, we conducted a simulation, optimizations, and economic research. Considering the net present cost, cost of energy, and compensation time, an economic comparison was made between the evaluated integrated hybrid systems. The assessment reveals that perhaps the grid-connected hybrid energy system is the best option for reliably satisfying remote areas’ energy needs.

Experimental and simulation study on a rooftop vertical-axis wind turbine

Abstract In this study, a small vertical-axis wind turbine (VAWT) was successfully designed and tested to produce electrical energy using renewable wind energy after being installed on the roof of buildings. The VAWT was constructed according to the existing wind source in the Tabuk region in Saudi Arabia. The use of VAWT on roofs is a sustainable solution for producing clean electricity and contributing to a portion of the local electricity consumption. A rooftop wind turbine test was performed to determine the behavior and output of a VAWT under non-constant wind speeds under natural conditions. To verify the resistance of the shear stress and pressure, a computational fluid dynamics (CFD) simulation on the airfoil was conducted. The experimental test results showed that the VAWT can reach its rated power at 9 m/s. The minimum wind speed needed for power production was 3 m/s. The maximum power coefficient obtained during testing was approximately 0.45 at a tip speed ratio of around 1.94. The simulation mesh is constructed with Ansys mesh. Two dimensional (2-D) mapped face meshing, fine, high smoothing mesh was constructed with 50 division numbers and a bias factor of about 150. The grid with 15,000 cells generated the same results as the higher number of cell grids. The simulation equivalent force was about 2.8 N for a single blade, such as 8.5 N in total, which presents an error of about 3%. The CFD simulation and experimental tests on existing forces confirm that the VAWT structure’s resistance can be guaranteed at high wind speeds.

Interchange reconnection as the source of the fast solar wind within coronal holes

The fast solar wind that fills the heliosphere originates from deep within regions of open magnetic field on the Sun called ‘coronal holes’. The energy source responsible for accelerating the plasma is widely debated; however, there is evidence that it is ultimately magnetic in nature, with candidate mechanisms including wave heating1,2 and interchange reconnection3–5. The coronal magnetic field near the solar surface is structured on scales associated with ‘supergranulation’ convection cells, whereby descending flows create intense fields. The energy density in these ‘network’ magnetic field bundles is a candidate energy source for the wind. Here we report measurements of fast solar wind streams from the Parker Solar Probe (PSP) spacecraft6 that provide strong evidence for the interchange reconnection mechanism. We show that the supergranulation structure at the coronal base remains imprinted in the near-Sun solar wind, resulting in asymmetric patches of magnetic ‘switchbacks’7,8 and bursty wind streams with power-law-like energetic ion spectra to beyond 100 keV. Computer simulations of interchange reconnection support key features of the observations, including the ion spectra. Important characteristics of interchange reconnection in the low corona are inferred from the data, including that the reconnection is collisionless and that the energy release rate is sufficient to power the fast wind. In this scenario, magnetic reconnection is continuous and the wind is driven by both the resulting plasma pressure and the radial Alfvénic flow bursts.

A brief overview of solar and wind-based green hydrogen production systems: Trends and standardization

Coupling water electrolyzers with solar and wind sources may be a promising solution in the near future for utilizing excess renewable energy. Indeed, many researchers have investigated various green hydrogen production systems, but a systematic approach should be developed to compare them. In addition, it is crucial to understand which solar and wind-based green hydrogen production systems have been studied and the literature gap on this topic. This review presents the latest research on green hydrogen production systems integrated with solar and wind technologies. One of the most significant novelties of this paper is to suggest a preliminary pathway and standardization strategy for the comparison of different green hydrogen production systems based on solar and wind sources. Various data and information are extracted from the most relevant papers in this field, such as renewable systems investigated, the location of the studied system, connection with the electrical grid, research type developed, final utilization of hydrogen considered, and performance indicators employed. This work will be an introductory guide for the community interested in green hydrogen production systems.

Energy impact assessment of electric vehicle insertion in the Brazilian scenario, 2020 – 2050: a machine learning approach to fleet projection

The transportation sector stands out on the world stage as one of the largest consumers of energy and the trend towards electrification of the light vehicle fleet is proving to be challenging, given the impacts generated by growing demand of energy and mainly in the generation of electricity. In Brazil, the electricity generation mix comprises around 83% of renewable sources, basically composed of hydraulic, wind and biomass sources, making it reasonable to consider the electrification of the transportation sector as one of the measures to be adopted in the promotion of sector sustainability. This article contributes to energy planning through the long-term projection of the Brazilian fleet of light vehicles, and the simulation of their impacts on energy demand, in three scenarios of insertion of plug-in electric vehicles. In this sense, statistical methodologies applied to historical data series and supervised Machine Learning algorithms for curve fitting were used, as well as the well-to-wheels approach in the fuel life cycle to estimate the energy demand. The projections included three scenarios for the insertion of electric vehicles with annual increases in demand for electricity generation which would correspond to 0.6%, 0.9% and 4.2% of additional electricity generation demand in the year 2050, with reference to the year 2020. The electrification of the fleet also proved to be advantageous in terms of reducing the use of fossil fuels and promising in terms of sustainability in the transport sector. The results of these studies will provide fundamental information for energy planning, as well as for public policy decision-making.

Combined “Renewable Energy–Thermal Energy Storage (RE–TES)” Systems: A Review

Current industrial civilization relies on conventional energy sources and utilizes large and inefficient energy conversion systems. Increasing concerns regarding conventional fuel supplies and their environmental impacts (including greenhouse gas emissions, which contribute to climate change) have promoted the importance of renewable energy (RE) sources for generating electricity and heat. This comprehensive review investigates integrating renewable energy sources (RES) with thermal energy storage (TES) systems, focusing on recent advancements and innovative approaches. Various RES (including solar, wind, geothermal, and ocean energy sources) are integrated with TES technologies such as sensible and latent TES systems. This review highlights the advantages and challenges of integrating RES and TES systems, emphasizing the importance of hybridizing multiple renewable energy sources to compensate for their deficiencies. Valuable outputs from these integrated systems (such as hydrogen production, electric power and freshwater) are discussed. The overall significance of RES–TES hybrid systems in addressing global energy demand and resource challenges is emphasized, demonstrating their potential to substitute fossil-fuel sources. This review provides a thorough understanding of the current state of RES–TES integration and offers insights into future developments in optimizing the utilization of renewable energy sources.

Challenges in Assessing the Behaviour of Nodal Electricity Prices in Insular Electricity Markets: The Case of New Zealand

In this new era of energy transition, access to reliable and correctly functioning electricity markets is a huge concern for all economies. The restructuring path taken by most electricity markets involves the movement towards green generation structures and the increasing integration of wind and solar photovoltaic energy sources. Furthermore, it involves the electrification of energy systems, which implies a substantial increase in electricity demand levels. It is also important to add that electricity use has been pivotal in achieving efficient productivity levels in many sectors and is thus crucial to boosting economic activity. Nevertheless, this shift in generation structures has raised several challenges in electricity markets, mainly because the electricity produced from wind and solar photovoltaics is intermittent. In turn, adopting green power sources has been claimed to increase electricity price volatility and thus increase pricing risks. Therefore, to ensure that the right market signals are being sent to investors, the behaviour of electricity prices should be carefully assessed. There are three main types of pricing mechanisms commonly used in electricity markets: zonal, uniform and nodal. This study provides a short literature survey on these three pricing mechanisms. Our analysis has revealed that the assessment of the behaviour of nodal electricity price volatility is rarely studied in the literature. This fact has motivated the exploration of this topic and the consideration of the New Zealand electricity market case. The New Zealand electricity market is an energy-only system with no interconnections with other electricity markets. Furthermore, it has plenty of electricity produced from hydropower, which has a high potential to reduce price volatility through its backup role. The nodal pricing mechanism is complex, and data on it are hard to process. This paper elucidates the main challenges in processing electricity big data. Three different procedures to make this data more useable are described in detail. The main conclusions of this paper highlight the need to access easy-to-manage data and identify certain variables that significantly affect nodal prices for data which are unavailable.

Modification of the Vertical Axis with Variations in the Number of Blades of the Savonius Wind Turbine

The potential wind speed in Indonesia is generally low at 3 m/s to 7 m/s so that this type of vertical axis turbine is considered very suitable for use in wind conditions in Indonesia. There are several types of vertical axis wind turbines. One type of vertical axis wind turbine is the Savonius wind turbine. Many advantages that this type of wind turbine has, such as being able to receive wind from all directions, easy and cheap to manufacture, and can rotate at a fairly low angular speed. This test was carried out to determine the performance of conventional and modified savonius turbines with 2 and 3 blades variables in each turbine blade shape. The form of modification made is by changing the shape of the blade twisting by 45o. The turbine is carried out on a laboratory scale with a wind source using a fan that is directly opposite the turbine. The results showed that the highest turbine power occurred in a modified 2-blade turbine, namely 1.88 Watt with a torque value of 0.04 Nm and a shaft rotation of 450 rpm. The highest rotation value is also obtained by 2 modified blades at a wind speed of 6 m/s producing 896 rpm. However, the highest torque value is obtained by a conventional 2-blade turbine with a value of 0.136 Nm. The highest turbine efficiency in each turbine is obtained by a modified 2 blade turbine with an efficiency value of 36.92% while the highest turbine efficiency for a modified 3 blade turbine reaches 11.69% which is considered less efficient than other turbines.

Accounting for differential rotation in calculations of the Sun’s angular momentum-loss rate

Context. Sun-like stars shed angular momentum due to the presence of magnetised stellar winds. Magnetohydrodynamic models have been successful in exploring the dependence of this ‘wind-braking torque’ on various stellar properties; however the influence of surface differential rotation is largely unexplored. As the wind-braking torque depends on the rotation rate of the escaping wind, the inclusion of differential rotation should effectively modulate the angular momentum-loss rate based on the latitudinal variation of wind source regions. Aims. Here we aim to quantify the influence of surface differential rotation on the angular momentum-loss rate of the Sun, in comparison to the typical assumption of solid-body rotation. Methods. To do this, we exploited the dependence of the wind-braking torque on the effective rotation rate of the coronal magnetic field, which is known to be vitally important in magnetohydrodynamic models. This quantity has been evaluated by tracing field lines through a potential field source surface (PFSS) model, driven by ADAPT-GONG magnetograms. The surface rotation rates of the open magnetic field lines were then used to construct an open-flux weighted rotation rate, from which the influence on the wind-braking torque could be estimated. Results. During solar minima, the rotation rate of the corona decreases with respect to the typical solid-body rate (the Carrington rotation period is 25.4 days), as the sources of the solar wind are confined towards the slowly rotating poles. With increasing activity, more solar wind emerges from the Sun’s active latitudes which enforces a Carrington-like rotation. Coronal rotation often displays a north-south asymmetry driven by differences in active region emergence rates (and consequently latitudinal connectivity) in each hemisphere. Conclusions. The effect of differential rotation on the Sun’s current wind-braking torque is limited. The solar wind-braking torque is ∼10 − 15% lower during solar minimum, (compared with the typical solid body rate), and a few percent larger during solar maximum (as some field lines connect to more rapidly rotating equatorial latitudes). For more rapidly rotating Sun-like stars, differential rotation may play a more significant role, depending on the configuration of the large-scale magnetic field.

Green steel: Synergies between the Australian iron ore industry and the production of green hydrogen

Green steel, produced using renewable energy and hydrogen, presents a promising avenue to decarbonize steel manufacturing and expand the hydrogen industry. Australia, endowed with abundant renewable resources and iron ore deposits, is ideally placed to support this global effort. This paper's two-step analytical approach offers the first comprehensive assessment of Australia's potential to develop green steel as a value-added export commodity. The Economic Fairways modelling reveals a strong alignment between prospective hydrogen hubs and current and future iron ore operations, enabling shared infrastructure development and first-mover advantages. By employing a site-based system optimization that integrates both wind and solar power sources, the cost of producing green steel could decrease significantly to around AU$900 per tonne by 2030 and AU$750 per tonne by 2050. Moreover, replacing 1% of global steel production would require 35 GW of well-optimized wind and solar photovoltaics, 11 GW of hydrogen electrolysers, and 1000 square kilometres of land. Sensitivity analysis further indicates that iron ore prices would exert a long-term influence on green steel prices. Overall, this study highlights the opportunities and challenges facing the Australian iron ore industry in contributing to the decarbonization of the global steel sector, underscoring the crucial role of government support in driving the growth and development of the green steel industry.

The impact of hydro-biofuel-wind-solar energy consumption and coal consumption on carbon emission in G20 countries.

Globally, as a renewable source of energy, biofuel, wind, solar, and hydro energy have been increasingly valued by a range of businesses. There is no denying the advantages of using renewable energy in terms of preventing climate change and protecting the environment. Therefore, this article investigates the relationship among hydro, solar, biofuel, wind, coal consumption, and CO2 emissions in 19 G20 member countries between 2000 and 2019. The results of dynamic fixed effects and the system-generalized method of moments suggest that solar energy and biofuel usage have a negative and statistically significant influence on carbon emissions. On the other hand, the impact of wind energy consumption on carbon dioxide emissions is positive and statistically significant. However, hydro energy consumption is statistically insignificant. The significance of this study is to include wind energy, solar energy, and hydro energy as new indicators for a group of 19 G20 member countries. Furthermore, this research paper also includes coal consumption in the existing model to confirm that CO2 emissions may rise if more coal is consumed. Growing the solar-hydro-biofuel-wind industry can reduce nonrenewable energy consumption and has tremendous potential to diminish carbon dioxide emissions.

A multi-objective optimization model for the coordinated operation of hydropower and renewable energy

The rapid growth of wind and solar energy sources in recent years has brought challenges to power systems. One challenge is surging wind and solar electric generation, understanding how to consume such generation is important. Achieving the complementarity of hydropower and renewable energies such as wind and solar power by utilizing the flexible regulation performance of hydropower is helpful to provide firm power to help renewable energy consumption. However, the multi-energy complementary operation mode will change the traditional hydropower operation mode, causing challenges to the comprehensive utilization of hydropower. In this paper, a multi-objective optimal scheduling model is built by considering coordinated hydro-wind-solar system peak shaving and downstream navigation. First, the Gaussian mixture model is adopted to quantify the uncertainty of wind and solar power. Then, a hydro-wind-solar coordinated model was built to obtain the standard deviation of the residual load and the standard deviation of the downstream water level. Finally, the ε-constraint method is used to solve for the Pareto optimality. The results demonstrate the following: 1) The proposed model can effectively determine hydropower output schemes that can coordinate wind and solar power output to reconcile peak shaving and navigation; 2) The downstream hydropower stations’ reverse regulation of the upstream hydropower station is a positive factor in reconciling conflicts; and 3) Reasonable planning of wind power and solar power is helpful for hydro-wind solar power complement operation.

A bi-level optimization method for voltage control in distribution networks using batteries and smart inverters with high wind and photovoltaic penetrations

In electrical distribution systems, the voltage quality problem considers the most restrictive issue that hinders high photovoltaic (PV) and wind integration. Therefore, this study aims at providing a reliable control method for the voltage problem in distribution networks embedded with high PV and wind sources. The proposed voltage management strategy consists of two controlling stages. The first stage uses battery energy storage systems (BESS), while the second stage employs the smart PV inverters' reactive power injection capability. For BESS operation, a bi-level optimization method based on metaheuristic optimization algorithms (MOA) is developed to regulate the voltage levels by governing the batteries charging/discharging rates. The bi-level optimization problem aims to maximize PV and wind energy exploitation while improving the voltage profile. In this study, a detailed comparison is conducted between three MOA: Social Spider Optimization, Particle Swarm Optimization, and Cuckoo Search Optimization. In addition, considering the uncertainty associated with PV system generation, a PV generation forecast is embedded in the voltage control strategy to reinforce the decision-making process of BESS operation. The efficacy of the proposed method is deployed on a modified IEEE-34 bus test feeder with real-world load and PV and wind power generation data. Experimental results show the effectiveness of the proposed method and indicate that proper coordination between the BESS and smart PV inverters is beneficial for distribution system operations that seamlessly integrate PV and wind energy. Overall, the proposed voltage management strategy can be used to control the voltage to any desired range at different locations.

The potential assessment of pump hydro energy storage to reduce renewable curtailment and CO2 emissions in Northwest China

Pumped hydro energy storage (PHES) can effectively alleviate the renewable curtailment and resource waste caused by expansion of wind and solar-based renewable energy (RE) sources. However, the influences of regional hydrological characteristics, operational characteristics of PHES units, and power supply-demand balance on the regulating effect of PHES have been neglected. In this paper, an improved hybrid power system dispatch model (Dispa-set) that considers regional hydrological characteristics, unit operational characteristics, and RE curtailment penalty is proposed. The potential and limitations of PHES on reducing renewable curtailment and carbon emissions in four Northwest provinces (FNP) during the 14th Five-Year Plan (FYP) are evaluated through 6 sub-scenarios. Studies have shown that increasing PHES can effectively reduce renewable curtailment and carbon emissions, but uncoordinated development of PHES and RE results in resource waste and slows down carbon reduction. For example, a 10% increase in PHES during the 14th FYP could increase renewable curtailment in Qinghai by 1.1% and CO2 emissions in Gansu by 0.05%, due to uncoordinated development, demand for electricity supply, and regulated power sources. Therefore, combining PHES development with regional hydrological and operational characteristics is essential to achieve coordinated development with RE and unlock technology, economic, and environmental benefits.

Stochastic scheduling of power system in the presence of electric vehicle and renewable sources considering security and economic indexes using an improved mutation particle swarm optimization (M-PSO) algorithm

Increased air pollution and global temperature as well as motor vehicle fuel consumption have depleted fossil fuel resources and increased environmental problems caused by the consumption of such fuels. In addition to methods such as combined heat and power (CHP) technology and distributed generation (DG) of energy at the consumption site, renewable energy sources and EVs are considered suitable methods for achieving this goal, which is prepared by the grid or battery electric energy. Generation uncertainty due to the lack of solar radiation and constant wind blow at different hours of the day is the only challenge for using renewable energies. Moreover, system reliability is a concept that refers to the safe and reliable operation of the system. In general, the wider and more important the system, the more attention that is paid to calculating its reliability in planning and decision making. This study aims to examine the problem of probabilistic power system planning by calculating the power system reliability, evaluating the effect of the presence of these vehicles on security and economic indicators and renewable energy sources, and modeling uncertainties using a Least Squares Generative Adversarial Network (LSGANs) method with generating various scenarios for solar irradiance and wind speed. Furthermore, the Kantorovich distance matrix (KDM) is used to reduce the number of generated scenarios. In the proposed model, the conditional value-at-risk (CVaR) method is implemented to assess and control the risk caused by uncertainties of the proposed problem. Using the power stored in the EV battery is evaluated to cover wind and solar energy source uncertainties.

2D-Channel-Forming Catechol-Based Polyphosphates as Solid Polymer Electrolytes and Their Microstructure-Assisted Li-Ion Conductivity

Electrochemical energy storage devices are the much-required technology for potential applications in renewable energy systems from intermittent wind and solar sources and portable applications in electric vehicles. This paper describes the synthesis, characterization, and Li-ion conductivity of catechol-based copolymer of polyphosphates (P1–P4) for solid polymer electrolyte (SPE) applications in Li-ion batteries. The synthesized polymers are thermally stable with a high molecular weight and porous nature and their particles have a rodlike morphology. The Li-ion conductivity of one of the SPEs produced using P3 with 20 wt % of LiTFSI is 1.4 × 10–3 S cm–1 at 80 °C, while P1 having 40 wt % of LiTFSI shows the conductivity of 1.2 × 10–3 S cm–1 at 80 °C. The remaining polymers (P1–P4) show good conductivity at room temperature (∼10–4 S cm–1). The results demonstrate the highest Li-ion conductivity among those reported in the literature so far at 80 °C. The high conductivity achieved is attributed to the microstructure of polymer molecules dictated by the bulky and rigid groups as a co-monomer, which creates perpetual voids in the polymer matrices. Galvanostatic charge–discharge cycling studies on the coin cells fabricated using SPE1 exhibit constant overpotential values and stable cycling behavior for about 2000 cycles.

Slow solar wind sources

Context. The origin of the slow solar wind is still an open issue. One possibility that has been suggested is that upflows at the edge of an active region can contribute to the slow solar wind. Aims. We aim to explain how the plasma upflows are generated, which mechanisms are responsible for them, and what the upflow region topology looks like. Methods. We investigated an upflow region using imaging data with the unprecedented temporal (3 s) and spatial (2 pixels = 236 km) resolution that were obtained on 30 March 2022 with the 174 Å channel of the Extreme-Ultraviolet Imager (EUI)/High Resolution Imager (HRI) on board Solar Orbiter. During this time, the EUI and Earth-orbiting satellites (Solar Dynamics Observatory, Hinode, and the Interface Region Imaging Spectrograph, IRIS) were located in quadrature (∼92°), which provides a stereoscopic view with high resolution. We used the Hinode/EIS (Fe XII) spectroscopic data to find coronal upflow regions in the active region. The IRIS slit-jaw imager provides a high-resolution view of the transition region and chromosphere. Results. For the first time, we have data that provide a quadrature view of a coronal upflow region with high spatial resolution. We found extended loops rooted in a coronal upflow region. Plasma upflows at the footpoints of extended loops determined spectroscopically through the Doppler shift are similar to the apparent upward motions seen through imaging in quadrature. The dynamics of small-scale structures in the upflow region can be used to identify two mechanisms of the plasma upflow: Mechanism I is reconnection of the hot coronal loops with open magnetic field lines in the solar corona, and mechanism II is reconnection of the small chromospheric loops with open magnetic field lines in the chromosphere or transition region. We identified the locations in which mechanisms I and II work.

Trends of patents on wind power electric generator

This article discusses the patents related to wind energy to identify technologies, their degree of development as well as their applications and trends. The research was carried out with Google Patents, which delivered more than 700 results from worldwide intellectual property offices. The terms Wind & Power & Electric & Generator were reviewed, analyzed, and classified. Patents were identified with a significant focus on Machines, Structure, Applications in Vehicles, Methods, and Control, that apply the concept of a horizontal axis wind turbine – HAWT (93.8%), followed by a vertical axis wind turbine - VAWT (5.6%) and incipient development in non-rotational systems (static) - WS (0.6%). Finally, a summary of the functional components of a wind energy system is included as a conceptual model for the development of a vertical axis wind source (VAWS).

Protection Challenges on Integration of Distributed Sources to Power system network: A Review

— Electricity generation has to be increased to meet various type of future load demand like LED lightning, Electrical 
 Vehicles, mobiles, communication network, non linear load etc. Automation is essential requirement now a days in each sector. 
 To provide automation at residential, commercial and industrial sectors electrical energy is required. To meet energy 
 requirement of various sector utility grid is integrated with DG Sources, which mainly include renewable energy sources like 
 solar, wind and other environment friendly sources either in large scale or small scale depends on the location and availability. 
 This type of technology leads power system to era of smart grid. Smart grid technology provides features like digitization, two 
 way communication, distributed generation, adaptive islanding, self monitoring and self mitigating, fully controllable compare to 
 conventional Grid. Though smart grid technology is advantageous but due to integration of distributed generation at 
 transmission and distribution system will increase protection challenges in the power network. This paper gives an insight of 
 different protection issues which occur at transmission, distribution and Micro grid network. The paper also focuses on the 
 techniques and solution of the various protection challenges.

Assessment of renewable energy generated by a hybrid system based on wind, hydro, solar, and biomass sources for decarbonizing the energy sector and achieving a sustainable energy transition

The EU must incorporate as many renewable sources as possible (such as hydropower, wind power, solar power and biomass) into a complex energy mix in order to meet its 2030 targets for renewable energy share of final gross energy consumption and carbon neutrality of the energy sector by 2050. This study analyze the share of these renewable energy sources in Romania’s energy mix in 2018. It is obvious that wind energy and solar energy are complementary in terms of generating the electricity required for consumption. Because of the highly variable and unpredictable nature of these two energy sources, they carry more weight when one is scarce. Furthermore, hydro energy, which appears to be less volatile, showed important seasonal and hourly variability. This article presents the development of renewable energy sources for the generation of electricity within the country’s energy complex and respectively the degree to which they can meet the energy demand throughout the year in order to reduce as much as possible the degree to which fossil fuels are used for energy production. Romania has a large number of renewable energy technologies integrated into its energy mix, but the degree of development and proportion with which they cover the energy demand varies greatly. In addition, given the variable and unpredictable nature of wind and solar energy, the study attempts to provide information on the extent to which these renewable energy sources can be reliable in covering energy demand.