A case study of outlier event on solar irradiance forecasts from the two NWPs with different horizontal resolutions

Takumi Takashima,Hideaki Ohtake,Takashi Oozeki,Yoshinori Yamada,Joao Gari da Silva Fonseca

doi:10.1051/rees/2016049

Abstract

Photovoltaic (PV) power generation is directly effected by global horizontal irradiance (GHI) and has also large variations in spatial and/or temporal scales. For a safety control of an energy management system (EMS), a day-ahead forecast or several hour forecast of solar irradiance by a numerical weather prediction model (NWP) becomes important for a control of reserve capacity (thermal power generation, etc.). In particular, a large forecast error of PV power and/or GHI forecasts has to be prevented in the EMS. The Japan Meteorological Agency (JMA) developed two NWPs with different horizontal resolutions. First one is a mesoscale model with horizontal grid spacing of 5 km and second one is a local forecast model with that of 2 km. The two NWPs have been used as an operational model in JMA. In this study, GHI forecasts obtained from the two models are validated and conducted a case study for large forecast error (outlier events) case of GHI.

Highlights

Many photovoltaic (PV) systems have been installed in Japan islands since an introduction of feed-intariff in 2012
For a method of global horizontal irradiance (GHI) day-ahead forecasts, it is known that a numerical weather prediction model (NWP) is a useful tool
Authors performed a validation of GHI day-ahead forecasts from the Japan Meteorological Agency (JMA) NWPs and investigated forecast error characteristics [1,2] in cooperation with the JMA

Summary

Introduction

Many photovoltaic (PV) systems have been installed in Japan islands since an introduction of feed-intariff in 2012. Forecast results from NWPs include sometimes large forecast errors (or outlier events). For the safety EMS, outlier events of GHI day-ahead forecasts should be avoided. The Japan Meteorological Agency (JMA) developed some kind of NWPs and operationally has used their NWPs to prevent natural disasters. Authors performed a validation of GHI day-ahead forecasts from the JMA NWPs and investigated forecast error characteristics [1,2] in cooperation with the JMA. Outlier event of GHI forecasts has not been investigated enough. A case study of GHI large forecasts errors obtained from two NWPs with different horizontal grid spacing is performed in this study

Observation

Definition of large forecast error

Overview

Time series of GHI

Cloud fields from MSM and LFM