Wind Generation Sources Research Articles

Time-domain harmonic state estimation of three-phase power networks including wind generation sources

Time-domain harmonic state estimation of three-phase power networks including wind generation sources

The role of natural gas in facilitating the transition to renewable electricity generation in South Africa

As is being done in most of the world, South Africa has commenced the transition from a fossil fuel-based electricity generation system to one based on renewable sources to meet greenhouse gas emission reduction goals. This paper explores the role of natural gas in South Africa to support the transition to a renewable energy-driven power grid. Specifically, the paper quantifies the firm and dispatchable power requirement to accommodate variability in solar and wind generation sources based on real-time series data from current renewable energy power plants for the country, and demonstrates that natural gas could be one of the elements to meet the medium-term need for this dispatchable power requirement, based on current regional gas resources. A range of alternative natural gas sources are considered in this analysis, covering existing gas resources from Mozambique, deep-water offshore potential from the southern Cape, shale gas from the Karoo basin, as well as liquefied natural gas imports. In addition, the alternatives to natural gas to supply the required dispatchable energy are considered. The analysis shows that the major challenge is to have sufficient gas storage available to be able to provide gas at the very high instantaneous rates required, but where the gas is only used for short periods of time and at low annual rates.

Distributed wind and solar power for grid sustainability and emission reduction

AbstractThis article intends to maximize the amount of solar and wind power produced while minimizing the tested network's annual energy loss. It also wants to improve the voltage profile and reduce the dependence on the upstream network. Two types of distributed generation sources, that is, wind DGs and solar DGs, are investigated. In this article, the network loads vary according to the local consumption pattern. This research shows that the optimal utilizing of solar and wind distributed generation sources causes energy loss to decrease by about 43% and 94%, respectively. Besides, the grid will receive 1109.49 GWh of energy from the upstream power grid without distributed generation sources. In contrast, solar and wind generation sources receive only 801.47 and 125.84 GWh, respectively. Additionally, in solar and wind scenarios, micro‐grid sends 71.62 and 102.42 GWh energy to the upstream network. Also, by calculating the emission reduction, it was observed that by installing 465.45 MW of the wind turbine units in the area under consideration, the country's CO2 equivalent is reduced by 754,586 tons, and the country's primary energy is reduced by 263,916 TOE.

Adaptive energy consumption scheduling of multi-microgrid using whale optimization algorithm

In this paper, we investigated the day-ahead scheduling of network consisting of several distributed generation sources and connected loads. This scheduling is an optimization problem that has two objective functions, namely, operating costs and the cost caused by the emission of pollutants. In this scheduling, while introducing a new structure for micro-grid utilization, the possibility of exchanging power among networks and exchanging power between networks and the upstream distribution network is provided. The uncertainty of distributed wind generation sources and solar units has been investigated using appropriate probabilistic distributions. Incent-driven load-responsiveness management programs have been used as to encourage subscribers to reduce their power consumption during high-load hours. Whale optimization algorithm has been used for scheduling of network.

Control and stability analysis of DC microgrid system including wind and solar generation sources and grid‐connected voltage source converter

SummaryThe study system in this paper is a grid‐connected DC microgrid system comprising PV and wind generation sources, resistive and constant power loads (CPLs), and grid‐connected VSC. The VSC keeps the DC link voltage constant, and the wind and PV sources operate in maximum power point tracking (MPPT) mode, and thus, the DC–DC converters related to these sources act such as controlled current sources behaving similar to negative CPLs. The study system suffers from the stability under high CPL penetration and weak AC grid conditions. Hence, this paper investigates and enhances the system stability under both high CPL penetration and weak AC grid conditions. To do this, modal and small‐signal stability analysis of the system is carried out, and then, as the main findings, impacts of the wind and PV sources output powers, CPL power, and AC grid short‐circuit power on the system stability are studied. Next, as the main contribution, VSC control structure is modified by adding stabilizing signals to enhance the system stability under high CPL penetration, reduced output powers of the wind and PV sources, and weak AC grid conditions. At the end, several simulation results verify the theoretical results at different conditions.

Reducing carbon dioxide emissions beyond 2030: Time to shift U.S. power-sector focus

Despite the impending withdrawal of the U.S. from the Paris Agreement and the replacement of Obama's Clean Power Plan (CPP) with Trump's Affordable Clean Energy rule, the carbon-dioxide (CO2) emission-reduction targets set as the contribution of the U.S. power sector to meet the Agreement goal appear likely to be met. Using data from the U.S. Energy Information Administration's Annual Energy Outlook (AEO) reports, we evaluate the impact of projected natural gas prices on these emissions. We find that while lower natural gas prices have historically resulted in lower CO2 emissions, the projections from the 2017 and 2019 AEOs differ dramatically in both the projected gas price and the associated impact on CO2 reduction. This change in the marginal emission-reduction rate relative to the natural gas price coincides with decreasing capital costs for solar and wind generation sources. As such, the contribution of the power sector to the Paris Agreement targets for 2020 and 2025, and the CPP 2030 target may be meet as early as 2020. With fulfillment of the shorter-term reduction targets now at hand without additional U.S. legislative or regulatory action, policy analysis should turn toward the strategies required to meet the longer-term, deeper-reduction targets.

EFFECT OF BATTERY ENERGY STORAGE SYSTEMS ON THE VALUE OF AN INTERMITTENT WIND ENERGY SOURCE IN ISOLATED SYSTEMS

The increase in environmental protection awareness and the progressive exhaustion of conventional fossil energy sources have increased interests in integrating wind energy sources into existing power systems. Despite the various benefits of wind power, the intermittency and unpredictability of wind power generation cause operational concerns and waste usable capacity as the installation of the wind generation sources increases. To enhance the value of an intermittent wind energy source by using a battery energy storage system (BESS), an iterative algorithm that combines improved dynamic programming and a hybrid direct search method were developed for solving the optimal wind- thermal- battery coordination scheduling (WTBCS) problem in power systems. Key concerns in BESSs and the integration of wind energy and electric power systems were investigated and discussed using the proposed WTBCS software. In addition, the developed WTBCS software is useful in assessing the effect and economic benefits of installing BESSs and wind farms. Numerical experiments were conducted to provide information for both operational and planning problems in isolated power systems, such as the Penghu power system.

Options to Improve the Quality of Wind Generation Output Forecasting with the Use of Available Information as Explanatory Variables

Development of wind generation, besides its positive aspects related to the use of renewable energy, is a challenge from the point of view of power systems’ operational security and economy. The uncertain and variable nature of wind generation sources entails the need for the for the TSO to provide adequate reserves of power, necessary to maintain the grid’s stable operation, and the actors involved in the trading of energy from these sources incur additional of balancing unplanned output deviations. The paper presents the results of analyses concerning the options to forecast a selected wind farm’s output exercised by means of different methods of prediction, using a different range of measurement and forecasting data available on the farm and its surroundings. The analyses focused on the evaluation of forecast errors, and selection of input data for forecasting models and assessment of their impact on prediction quality improvement. DOI: 10.12736/issn.2300-3022.2015203