Review and validation of Solar Thermal Electricity potential methodologies

Abstract With the strong dependence of national economies on energy, interest in solar energy potential assessments is increasing in countries with high solar radiation levels. This article reviews four methodologies proposed in the literature by four different organizations (IDAE, Greenpeace, NREL, and DLR) and proposes a new one (LRS) for assessing the potential of Solar Thermal Electricity (STE) generation in a given country. Derived from these five methodologies, nine cases are studied (IDAE, GP2, NREL1, NREL3, DLR2, DLR2′, LRS1, LRS2, and LRS3). In this study, we followed a two-step STE potential assessment procedure. In the first step, suitable areas for locating STE plants in the country are identified. In the second step, STE plants are assumed to be built and operated in the suitable areas selected in the first step, and the annual electricity generated by these hypothetical plants is estimated. To compare the assessed methodologies, all cases have been applied to the same test country: Spain. Because a relatively large number of commercial STE plants are in operation in Spain, the location of these commercial plants was used to define a simple but effective validation test. A validation process is proposed for the IN-OUT decision based on the buffers containing each existing STE plant. Inside each buffer, a mix of suitable and unsuitable pixels is often included. Thus, the process starts with the decision whether a plant could be considered “IN” the suitable area or not. After the evaluation of the percentage of pixels considered as suitable inside the buffer, and comparing with only the power block pixel location, the second option was selected since it provides good results and simplifies any further treatment. The validation process also considers a minimum of near 90% of the STE plants “IN” suitable areas in order to consider a specific case valid. This means that if a case leaves out more than 10% of the real STE plants, it was considered far from reality and rejected. Cases IDAE, NREL3, DLR2, and the new LRS3 have been validated using the described validation procedure and the last three have very close results with similar levels; this is an important outcome that aims to compare potential assessments performed in different countries by different institutions.