Small scale hybrid concentrated solar power - biomass system. Development, time dependent modelling and validation

Proceeding from the sustainable development principle and the current energy issues, in the present work a small-scale fully renewable power plant was designed, modelled in a time-dependent environment and validated. The plant is design in order to produce both thermal and electric power either in on- or off-grid configuration. With respect to the state of the art, the power plant is composed by standard and well-known technologies. The novelties brought with the present study are entailed in the arrangement and size of the technologies themselves. Thus the selected parabolic trough solar field is a small size one, i.e. 1,2 MW, on the contrary of the usual multi-MW design. Moreover, the solar section is co-powered with a biomass furnace in place of the typical fossil fuel power generators. Finally, a steam engine is used in a saturated steam Rankine cycle substituting the most common configuration based on steam turbine and superheated steam cycle. In order to properly evaluate the plant performances, a time-dependent simulation tool was used, allowing to take into account the meteorological variations during a one year period, which has a direct influence on the solar field, affecting the whole system behaviour. Three different working configurations were proposed, with the aim to assess the plant flexibility to different working conditions, e.g. off-grid or grid-connected. In particular the proposed models are a baseline configuration with constant power outputs, an electric or thermal power tracking scenario coupled with end-users load, and a desalt scenario for electric power and desalted seawater production. The study shows the capability of the plant to follow different managements, demonstrating its suitability to work in several environments, thus it is effectively reproducible in different countries.