BSI PD IEC TR 63043:2020
$215.11
Renewable energy power forecasting technology
Published By | Publication Date | Number of Pages |
BSI | 2020 | 142 |
This Technical Report, which is informative in its nature, describes common practices and state of the art for renewable energy power forecasting technology, including general data demands, renewable energy power forecasting methods and forecasting error evaluation. For the purposes of this document, renewable energy refers to variable renewable energy, which mainly comprises wind power and photovoltaic (PV) power – these are the focus of the document. Other variable renewable energies, like concentrating solar power, wave power and tidal power, etc., are not presented in this document, since their capacity is small, while hydro power forecasting is a significantly different field, and so not covered here.
The objects of renewable energy power forecasting can be wind turbines, or a wind farm, or a region with lots of wind farms (respectively PV systems, PV power stations and regions with high PV penetration). This document focuses on providing technical guidance concerning forecasting technologies of multiple spatial and temporal scales, probabilistic forecasting, and ramp event forecasting for wind power and PV power.
This document outlines the basic aspects of renewable energy power forecasting technology. This is the first IEC document related to renewable energy power forecasting. The contents of this document will find an application in the following potential areas:
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support the development and future research for renewable energy power forecasting technology, by showing current state of the art;
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evaluation of the forecasting performance during the design and operation of renewable energy power forecasting system;
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provide information for benchmarking renewable forecasting technologies, including methods used, data required and evaluation techniques.
PDF Catalog
PDF Pages | PDF Title |
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2 | undefined |
4 | CONTENTS |
9 | FOREWORD |
11 | INTRODUCTION |
12 | 1 Scope 2 Normative references 3 Terms, definitions and abbreviated terms |
13 | 3.1 Terms and definitions |
15 | 3.2 Abbreviated terms |
17 | 4 General introduction to renewable energy power forecasting 4.1 History of RPF 4.1.1 General |
18 | 4.1.2 Development of wind power forecasting |
19 | 4.1.3 Development of PV power forecasting 4.2 Use of RPF 4.2.1 General |
20 | 4.2.2 RPF for system operations 4.2.3 RPF for power trading |
21 | 4.2.4 RPF for operations and maintenance 4.3 Methods for forecasting renewable power 4.3.1 General 4.3.2 Classification of forecasting methods Tables Table 1 – Classification of RPF methods |
23 | 4.3.3 Classification based on time scale Figures Figure 1 – Forecasting of PV power at different spatial and temporal scales Figure 2 – Introduced data for PV power forecastingat different spatial and temporal scales |
24 | 4.3.4 Classification based on spatial range 4.3.5 Classification based on the forecasting model |
26 | 4.3.6 Classification based on the forecasting form |
27 | 4.4 Summary 5 NWP technology 5.1 General 5.2 Concept and characteristics of NWP |
28 | Figure 3 – Typical process for running a regional model |
29 | 5.3 Influence on RPF accuracy 5.3.1 Sensitivity analysis Figure 4 – Power curve of typical wind turbines |
30 | 5.3.2 Error source analysis Figure 5 – Characteristics of three kinds of forecasting errors |
31 | 5.4 Technology progress for improving NWP 5.4.1 General 5.4.2 Global model |
32 | Figure 6 – Evolution of ECMWF’s forecasting skillsfor the 500 hPa potential height [35], [54] Table 2 – Features of global NWP models |
33 | 5.4.3 Regional model 5.5 Key techniques for improving the forecast accuracy of regional models 5.5.1 Improve the accuracy of the initial conditions |
34 | 5.5.2 Ensemble prediction systems |
35 | Figure 7 – Ensemble forecasting sketch [54] |
39 | Table 3 – Comparison of different ensemble predictionmethodologies and their attributes [46], [73] |
40 | 5.5.3 Establish regional customized forecasting model Figure 8 – Illustration of parameterization schemesfor sub-grid physical processes [54] |
41 | 5.5.4 NWP post-processing 5.6 Summary 6 Statistical methods 6.1 General |
42 | 6.2 Methods |
44 | 6.3 Applications 6.3.1 General 6.3.2 Time series models |
46 | Figure 9 – MAE (% of capacity) versus look-ahead time for 0 h to 3 h forecasts of the 15 min average wind power production from the TWRA aggregate over the one-year period from October 2015 to September 2016 for each of 5 source-dependent sets of predictors employed in the predictor source category experiment [96] |
47 | Figure 10 – Percentage MAE reduction over persistence by look-ahead time achieved by each source-dependent set of predictors for 0 h to 3 h forecasts of the 15 min average TWRA aggregate (capacity of 2 319 MW) power production over the one-year period from October 2015 to September 2016 [96] |
48 | Figure 11 – Percentage MAE reduction by look-ahead time achieved by building forecasting models with the XGBoost method versus MLR for the “Add existing external data” (set #4) and “Add targeted sensors” (set #5) predictor sets for 0 h to 3 h forecasts of the 15 min average TWRA aggregate (capacity of 2 319 MW) power production over the one year period from October 2015 to September 2016 [96] |
49 | 6.3.3 Model output statistics (MOS) Figure 12 – Percentage MAE reduction by look-ahead time achieved by using the “rate of change” (indirect forecasting) versus “the 15 min average power generation” (direct forecasting) as the target predictand for the XGBoost model for 0 h to 3 h forecasts of the 15 min average TWRA aggregate (capacity of 2 319 MW) power production over the one year period from October 2015 to September 2016 [96] |
50 | Figure 13 – Mean absolute error (MAE) in m/s of two 0 h to 18 h NWP-MOS forecasts of the maximum wind gust in a 15 min period for 33 sites over a 32-case sample of high wind events as a function of training sample size |
51 | Figure 14 – Percentage reduction in the mean absolute error of NWP-based 0 h to 15 h wind power forecasts for the Tehachapi Wind Resource Area (TWRA) over a one-year period resulting from the application of 26 statistical forecasting methods to the output from the United States National Weather Service’s High Resolution Rapid Refresh (HRRR) model [96] |
53 | 6.3.4 Ensemble composite models (ECM) Figure 15 – Percentage reduction in the mean absolute error (MAE) of wind power forecasts relative to a baseline of a raw NWP forecast for three NWP models when a MOS procedure is applied to the NWP output (larger percentages are better) |
55 | 6.3.5 Power output models |
56 | 7 Wind power forecasting (WPF) technology 7.1 General 7.2 Short-term WPF 7.2.1 Relationship between wind power output and meteorological elements Figure 16 – Input and output parameters of the three-days-ahead WPF |
57 | Figure 17 – Wind power output at different wind speeds underair density of 1,225 kg/m3 (a typical 2 MW wind turbine) |
58 | Figure 18 – EC distribution of a wind farm at different wind speeds and directions |
59 | 7.2.2 Framework of short-term WPF Figure 19 – Wind speed and wind power curvesof wind turbines at different air densities |
60 | 7.2.3 Short-term WPF methods Figure 20 – Typical framework of short-term WPF |
61 | Figure 21 – Principle of short-term WPF based on physical approaches |
62 | Figure 22 – Flowchart of short-term WPF based on statistical approaches Figure 23 – Short-term WPF model based on ANN |
64 | 7.3 Ultra-short-term WPF Figure 24 – Input and output parameters of the 4 h ultra-short-term WPF |
65 | Figure 25 – Flowchart of ultra-short-term WPF |
66 | Figure 26 – Generalized combination methods of ultra-short-term WPF |
67 | 7.4 Probabilistic WPF 7.4.1 General 7.4.2 Basic concepts and model framework definition Figure 27 – Methods used for probabilistic forecasting |
68 | 7.4.3 Uncertainty modeling approaches Figure 28 – Overview of probabilistic wind power forecasting |
69 | 7.4.4 Probabilistic WPF model Figure 29 – Wind power probability distribution forecasting results Table 4 – Output modes of probabilistic forecasting |
70 | Figure 30 – Filtering approach with ensemble NWP as input |
71 | Figure 31 – Dimension reduction approach with ensemble NWP as input Figure 32 – Direct approach with ensemble NWP as input |
73 | 7.5 Wind power ramp event forecasting 7.5.1 General 7.5.2 Quantitative description of wind power ramp events |
74 | Figure 33 – Two ramp events of a wind farm |
75 | Table 5 – Advantages and disadvantages of ramp events definitions |
76 | 7.5.3 Forecasting methods of wind power ramp events |
77 | 7.6 WPF for wind farm clusters 7.6.1 General 7.6.2 Basic concepts of WPF for wind farm clusters |
78 | 7.6.3 Overall framework of the WPF for wind farm clusters |
79 | Figure 34 – Overall framework of the WPF system for wind farm clusters Table 6 – Data sources of WPF for wind farm clusters |
80 | 7.6.4 Physical hierarchy of WPF for wind farm clusters Figure 35 – Physical levels of WPF for wind farm clusters |
81 | 7.6.5 WPF methods of wind farm clusters Figure 36 – Flow chart of the accumulation method |
82 | Figure 37 – Flow chart of the statistical upscaling method |
83 | Figure 38 – Flow chart of the space resource matching method Table 7 – Comparison of WPF methods for wind farm clusters. |
84 | 7.7 Other WPF techniques 7.7.1 Medium-term and long-term WPF 7.7.2 WPF for offshore wind farms |
85 | 7.8 Summary 8 PV power forecasting technology 8.1 General 8.2 Short-term PVPF 8.2.1 General 8.2.2 Meteorological influence factors of PV power generation |
86 | Figure 39 – Volt-ampere characteristic curve of PV modulescorresponding to different irradiance |
87 | Figure 40 – Volt-ampere characteristics of PV modules at different temperatures |
88 | 8.2.3 Basic concepts for short-term PVPF |
89 | 8.2.4 Short-term PVPF model Figure 41 – Short-term forecasting models of PV power generation |
91 | 8.2.5 Trends in PVPF development and key technical issues 8.3 Ultra-short-term PVPF 8.3.1 General Figure 42 – PV short-term power physical forecasting method technical route |
92 | 8.3.2 Basic concepts for ultra-short-term PVPF 8.3.3 Ultra-short-term PVPF models |
93 | Figure 43 – Basic technology roadmap for pv power ultra-short-term forecasting Figure 44 – Ultra-short-term PVPF based on machine learning model |
94 | 8.3.4 Trends in development and key technical issues 8.4 Minute-time-scale PVPF |
95 | 8.4.1 Basic concepts for minute-time-scale solar power forecasting 8.4.2 Technique routine of minute-time-scale solar power forecasting |
96 | 8.4.3 Trends in development and key technical issues Figure 45 – Minute-time-scale solar power forecasting technique process |
97 | 8.5 Probabilistic PVPF 8.5.1 Basic concepts of PV power probabilistic forecasting |
98 | 8.5.2 Probabilistic PVPF model Figure 46 – Example of probabilistic PV model Figure 47 – Forecasting process of physical PV power probabilistic forecasting model |
99 | Figure 48 – Forecasting process of statistical probabilistic PVPF model |
100 | 8.5.3 Trends in development and key technical issues 8.6 Distributed PVPF 8.6.1 General |
101 | 8.6.2 Basic concepts for distributed PVPF 8.6.3 Distributed PVPF methods |
102 | Figure 49 – Framework of clustering statistical forecastingmethod for distributed PVPF |
103 | Figure 50 – Framework of grid forecasting method for distributed PVPF |
104 | 8.6.4 Trends in development and key technical issues 8.7 Summary Figure 51 – Comparison between the forecasting resultsof the clustering statistical method and the grid forecast method |
105 | 9 Renewable energy power forecasting (RPF) evaluation 9.1 General |
106 | 9.2 Deterministic forecasts of continuous variables 9.2.1 General 9.2.2 Metrics 9.2.3 Mean bias error |
107 | 9.2.4 Mean absolute error 9.2.5 Root mean square error |
108 | 9.2.6 Skill score 9.2.7 Correlation coefficient |
109 | 9.2.8 Maximum prediction error 9.2.9 Pass rate |
110 | 9.2.10 95 % QDR |
111 | 9.2.11 Customized metrics 9.3 Deterministic forecasts of categorical (event) variables 9.3.1 General |
112 | 9.3.2 Occurrence/non-occurrence metrics 9.3.3 Frequency bias 9.3.4 Probability of detection Table 8 – Contingency table for forecasts ofthe occurrence/non-occurrence of an event |
113 | 9.3.5 False alarm ratio 9.3.6 Critical success index 9.3.7 Equitable threat score 9.3.8 Heidke skill score |
114 | 9.4 Probabilistic forecasts of categorical (event) variables 9.4.1 General 9.4.2 Overall performance |
118 | 9.4.3 Reliability |
119 | 9.4.4 Resolution Figure 52 – Example of a reliability diagram for two probabilistic forecasts(Forecast A and Forecast B) of a binary event |
120 | 9.5 Probabilistic forecasts of continuous variables 9.5.1 General 9.5.2 Overall performance |
121 | 9.5.3 Reliability 9.5.4 Resolution 9.6 Sources of forecast error |
122 | 9.7 Comparison of forecast performance |
123 | Table 9 – A summary of recommended metrics for frequently used forecast types |
124 | 9.8 Selection of an optimal forecast solution |
125 | 10 Conclusions and recommendations |
128 | Bibliography |