An Integrated Multi-Time-Scale Modeling for Solar Irradiance Forecasting Using Deep Learning

For short-term solar irradiance forecasting, the traditional point forecasting methods are rendered less useful due to the non-stationary characteristic of solar power. The amount of operating reserves required to maintain reliable operation of the electric grid rises due to the variability of solar energy. The higher the uncertainty in the generation, the greater the operating-reserve requirements, which translates to an increased cost of operation. In this research work, we propose a unified architecture for multi-time-scale predictions for intra-day solar irradiance forecasting using recurrent neural networks (RNN) and long-short-term memory networks (LSTMs). This paper also lays out a framework for extending this modeling approach to intra-hour forecasting horizons thus, making it a multi-time-horizon forecasting approach, capable of predicting intra-hour as well as intra-day solar irradiance. We develop an end-to-end pipeline to effectuate the proposed architecture. The performance of the prediction model is tested and validated by the methodical implementation. The robustness of the approach is demonstrated with case studies conducted for geographically scattered sites across the United States. The predictions demonstrate that our proposed unified architecture-based approach is effective for multi-time-scale solar forecasts and achieves a lower root-mean-square prediction error when benchmarked against the best-performing methods documented in the literature that use separate models for each time-scale during the day. Our proposed method results in a 71.5% reduction in the mean RMSE averaged across all the test sites compared to the ML-based best-performing method reported in the literature. Additionally, the proposed method enables multi-time-horizon forecasts with real-time inputs, which have a significant potential for practical industry applications in the evolving grid.Comment: 19 pages, 12 figures, 3 tables, under review for journal submissio

Study of the Wind Speed Forecasting Applying Computational Intelligence

The conventional sources of energy such as oil, natural gas, coal, or nuclear are finite and generate environmental pollution. Alternatively, renewable energy source like wind is clean and abundantly available in nature. Wind power has a huge potential of becoming a major source of renewable energy for this modern world. It is a clean, emission-free power generation technology. Wind energy has been experiencing very rapid growth in Brazil and in Uruguay; therefore, it’s a promising industry in these countries. Thus, this rapid expansion can bring several regional benefits and contribute to sustainable development, especially in places with low economic development. Therefore, the scope of this chapter is to estimate short-term wind speed forecasting applying computational intelligence, by recurrent neural networks (RNN), using anemometers data collected by an anemometric tower at a height of 100.0 m in Brazil (tropical region) and 101.8 m in Uruguay (subtropical region), both Latin American countries. The results of this study are compared with wind speed prediction results from the literature. In one of the cases investigated, this study proved to be more appropriate when analyzing evaluation metrics (error and regression) of the prediction results obtained by the proposed model

Data driven tools to assess the location of photovoltaic facilities in urban areas

Urban sustainability is a significant factor in combating climate change. Replacing polluting by renewable energies is fundamental to reduce the emission of greenhouse gases. Photovoltaic (PV) facilities harnessing solar energy, and particularly self-consumption PV facilities, can be widely used in cities throughout most countries. Therefore, locating spaces where photovoltaic installations can be integrated into urban areas is essential to reduce climate change and improve urban sustainability. An open-source software (URSUS-PV) to aid decision-making regarding possible optimal locations for photovoltaic panel installations in cities is presented in this paper. URSUS-PV is the result of a data mining process, and it can extract the characteristics of the roofs (orientation, inclination, latitude, longitude, area) in the urban areas of interest. By combining this information with meteorological data and characteristics of the photovoltaic systems, the system can predict both the next-day hourly photovoltaic energy production and the long-term photovoltaic daily average energy production.This work has been supported by the project RTI2018-095097-B-I00 at the 2018 call for I+D+i Project of the Ministerio de Ciencia, Innovación y Universidades, Spain. Funding for open access charge: Universidad de Málaga/CBUA, Spain

Forecasting photovoltaic power generation with a stacking ensemble model

Nowadays, photovoltaics (PV) has gained popularity among other renewable energy sources because of its excellent features. However, the instability of the system’s output has become a critical problem due to the high PV penetration into the existing distribution system. Hence, it is essential to have an accurate PV power output forecast to integrate more PV systems into the grid and to facilitate energy management further. In this regard, this paper proposes a stacked ensemble algorithm (Stack-ETR) to forecast PV output power one day ahead, utilizing three machine learning (ML) algorithms, namely, random forest regressor (RFR), extreme gradient boosting (XGBoost), and adaptive boosting (AdaBoost), as base models. In addition, an extra trees regressor (ETR) was used as a meta learner to integrate the predictions from the base models to improve the accuracy of the PV power output forecast. The proposed model was validated on three practical PV systems utilizing four years of meteorological data to provide a comprehensive evaluation. The performance of the proposed model was compared with other ensemble models, where RMSE and MAE are considered the performance metrics. The proposed Stack-ETR model surpassed the other models and reduced the RMSE by 24.49%, 40.2%, and 27.95% and MAE by 28.88%, 47.2%, and 40.88% compared to the base model ETR for thin-film (TF), monocrystalline (MC), and polycrystalline (PC) PV systems, respectively

An Indirect Forecasting System of the Power from a Solar Panel Array Based on Modified Fuzzy Neural Network

Интеллектуальные системы прогнозирования вырабатываемой электроэнергии массивом солнечных панелей повышают эффективность солнечной электростанции и, таким образом, актуальны в соответствии с пунктом 20А Стратегии научно-технологического развития РФ. Вырабатываемая массивом солнечных панелей электроэнергия имеет сложную нелинейную динамику с неопределенностями, обусловленными изменением облачности. В связи с этим идентифицировать систему прогнозирования вырабатываемой электроэнергии массивом солнечных панелей классическими методами с заданной точностью нельзя, в то время как нейросети обеспечивают требуемую точность. Системы прогнозирования вырабатываемой электроэнергии массивом солнечных панелей на основе нейросетей в сравнении с традиционными методами обеспечивают требуемую точность прогноза, способствуя безопасному и эффективному управлению электрическими сетями, интегрирующими солнечные электростанции. В условиях неопределенности на основе модифицированной нечеткой нейросети, обеспечивающей средствами рекуррентных нейронов и механизма внимания эффективное формирование и передачу скрытого представления информации как сигнала выходного слоя скрытых рекуррентных нейронов глубоких нейросетей, на основе выходов которых алгоритмом нечетко-возможностной свертки генерируется прогнозируемое значение вырабатываемой электроэнергии массивом солнечных панелей. Модифицированная нечеткая нейросеть эффективно выделяет на основе архивных данных существенные функциональные аспекты прогнозирования вырабатываемой электроэнергии массивом солнечных панелей, включая аспекты идентификации облачности часа. Полученные результаты экспериментального моделирования системы прогнозирования на сутки вперед вырабатываемой электроэнергии массивом солнечных панелей на основе модифицированной нечеткой нейросети демонстрируют ее робастность и снижение среднеквадратичной ошибки прогноза в среднем в три и шесть раз в сравнении с рекуррентными нейросетями и стандартной моделью авторегрессии скользящего среднего в условиях неопределенностиForecasting systems of the power from a solar panel array based on neuronets increase the efficiency of a solar plant. Therefore, these systems are relevant in accordance with item 20A of the strategy of scientific and technological development of the Russian Federation. The power from a solar panel array has complex non-linear dynamic with uncertainties due to changes in cloudiness. Thus, it is impossible to approximate this complex dynamic with classical methods with a given accuracy, while neuronets provide the required accuracy. For identification of a forecasting system of the power from a solar panel array, intelligent methods in comparison with traditional methods provide the required accuracy by contributing to the safe and effective management of electric grids that integrating solar power plants. Under uncertainties by means of recurrent neurons and the attention mechanism the effective generation and transmission of a hidden information representation as a signal of the output layer of hidden recurrent neurons of deep neural networks, on the basis of the outputs of which a modified fuzzy neural network generated the forecasted value of power from a solar panel array by the fuzzy-possible convolution algorithm. The modified fuzzy neural network effectively distinguishes from the data significant functional aspects of forecasting of the power from a solar panel array, including aspects of identifying the cloudiness of the hour. The experimental modelling results of the indirect day ahead forecasting system of the power from a solar panel array based on the modified fuzzy neural network demonstrate its robustness and a decrease in the mean square error of its forecast by an average of three and six times in comparison with recurrent neural networks and a standard model of moving average autoregression under uncertaintie

A Moment in the Sun: Solar Nowcasting from Multispectral Satellite Data using Self-Supervised Learning

ABSTRACT Solar energy is now the cheapest form of electricity in history. Unfortunately, signi.cantly increasing the electric grid’s fraction of solar energy remains challenging due to its variability, which makes balancing electricity’s supply and demand more di.cult. While thermal generators’ ramp rate—the maximum rate at which they can change their energy generation—is .nite, solar energy’s ramp rate is essentially in.nite. Thus, accurate near-term solar forecasting, or nowcasting, is important to provide advance warnings to adjust thermal generator output in response to variations in solar generation to ensure a balanced supply and demand. To address the problem, this paper develops a general model for solar nowcasting from abundant and readily available multispectral satellite data using self-supervised learning. Speci.cally, we develop deep auto-regressive models using convolutional neural networks (CNN) and long short-term memory networks (LSTM) that are globally trained across multiple locations to predict raw future observations of the spatio-temporal spectral data collected by the recently launched GOES-R series of satellites. Our model estimates a location’s near-term future solar irradiance based on satellite observations, which we feed to a regression model trained on smaller site-speci.c solar data to provide near-term solar photovoltaic (PV) forecasts that account for site-speci.c characteristics. We evaluate our approach for di.erent coverage areas and forecast horizons across 25 solar sites and show that it yields errors close to that of a model using ground-truth observations

A Multivariate Prediction Model for Short-Term Photovoltaic Plant Generation Using Bi-LSTM and CNN

The short-term prediction of the energy produced by a photovoltaic plant is a widely studied topic, and it is an important issue for the stability of the grid and its correct operation, as well as for reducing the operating costs and increasing the lifetime of the elements that make up it. The creation of a tool to more accurately predict the solar generation of the PV plant, specifically the prediction of ramps 5-10 minutes in advance. In this work, a multivariate prediction model is presented that combines images, historical production data, and solar position at each moment. The model consists of two parts: image processing, with a convolutional neural network (CNN) and time series processing using a Bidirectional Long Short-Term Memory (Bi-LSTM) capable of detecting long-term nonlinear features. CNNs will be trained to automatically detect the relationship between the images taken of the sky and cloud movement and the current power of the solar array. Then, the recurrent neural networks (RNNs) created will be used to give rise to a 5-minute prediction and a 10-minute prediction. The prediction results are compared using different error metrics, like skill score and the mean squared error (RMSE)