The Ottana solar facility: dispatchable power from small-scale CSP plants based on ORC systems

The Ottana solar facility aims to demonstrate the capabilities of concentrating solar technologies to provide dispatchable power and ancillary services at distribution level. The facility includes a 630 kW Concentrating Solar Power (CSP) plant with thermal storage coupled with a 400 kW Concentrating Photovoltaic (CPV) plant with electrochemical storage. The CSP + CPV plant aims to study the ability of the integrated concentrating solar systems to deliver scheduled power profiles for the following day on the basis of weather forecasting data. The CSP section is based on linear Fresnel collectors using thermal oil as heat transfer fluid and a two-tank direct Thermal Energy Storage (TES) system with a storage capacity of about 15 MWht. The power generation is carried out by a 630 kW Turboden 6HR Special ORC unit. This paper focuses on a description of the CSP plant section and on the analysis of its expected performance. In particular, the control strategy developed for determining the daily power profiles starting from the weather forecasting data is presented. Moreover, the first operating results and the expected performance of the CSP plant are reported and discussed.