Wind and Solar Irradiance Gridded Data to Support Assessment of Renewable Energy Resources in Greece

Common practice suggests that the assessment of wind and solar energy resources is based on data obtained from existing weather stations operated by the national meteorological services and other public services. Usually, these stations are placed at populated locations (for example airports, ports, urban, rural and protected areas) to support weather analysis, forecasts and warnings, local weather-dependent operations and research in meteorology, climatology and hydrology. Practically, the observed data collected from these stations are not suitable for wind farms and solar panel sitting and installations. Moreover, time series of direct observations are not always available for sufficiently long periods; they have too sparse coverage and are generally not representative of specific areas. To overcome the shortcomings of the direct observations, alternative source of accurate data is required. This paper addresses a particular example of considering numerical weather prediction models as alternative source of wind and solar irradiance data. The mesoscale meteorological model of the POSEIDON weather forecasting system has been appropriately configured to simulate historical records of the atmospheric conditions across the Mediterranean region at 10 km grid spacing and for a long period (1995-2004). The European Centre for Medium-Range Forecasts (ECMWF) ERA-40 reanalysis data and the ECMWF operational analyses were used to initialize the mesoscale model and to update its boundaries. Therefore, the mesoscale model downscales the global data by producing fine-scale weather patterns consistent with the coarse-resolution features in the forcing data. Furthermore, a Geographical Information System (GIS) technique has been developed in order to allow for solar energy resource maps to be overlaid with other spatial datasets such as topographical and land use data. This will provide valuable and much needed information for the processing, analysis and mapping of possible scenarios for solar energy applications. Thus, the benefits of renewable energy across Greece could be highlighted.