3. Solar thermal power generation systems with various solar concentrators
In a solar thermal power generation system, solar radiation is collected by using various types of solar concentrator or solar ponds . This solar energy is converted into thermal energy (heat) by increasing temperature of the fluid (heat transfer mediums). This heated fluid may be directly used in any of the thermodynamic power cycles such as Reheat and Regenerative Rankine Cycle, Brayton/Joule Cycle, and Stirling Cycle, or passes through a heat exchanger to heat a secondary fluid (working fluid) which is used in the power DMXAA to produce mechanical energy. Finally, mechanical energy is converted into electricity by means of an alternator.
The solar concentrator is intracellular route the major component of the solar thermal power generation system. There is a temperature limitation of each solar collector. A temperature up to 100 °C can be achieved with flat-plate solar collectors applicable for the Organic Rankine Cycle used in the small solar thermal power plants of about 10 kW. Other four types of solar collector are primarily used in the solar thermal power generation systems of medium (up to 400 °C) and high (above 400 °C) temperature ranges:•Parabolic trough concentrator (cylindrical parabolic solar collector).•Central tower receiver concentrator.•Parabolic dish concentrator.•Linear Fresnel reflecting concentrator.
3.1. The 1998–2004 subperiod: Laying the ground of the Spanish CSP sector
As background to this initial 1998–2004 stage it is worth considering some policy milestones that prepared the way for the subsequent Spanish CSP Z-FA-FMK policy.
Thus, in November 1997 the European Commission produced a White Paper for a Community Strategy and Action Plan for RE . It raised the goal of covering 12% of the primary energy demanded in the European Union (EU) in 2010 with renewable energies. Unlike other more mature power generation technologies, no specific contribution was outlined for CSP. Nevertheless, it was counted among the minority renewable technologies that could offer significant potential in the future. In the belief that a least one of these technologies could be exploited commercially over the coming decade, a marginal contribution of 1 GW by 2010 was assumed for them. This 1 GW power goal by 2010 at European level, although not exclusive for CSP, could be considered as a precursor of the targets set for CSP by the regulatory frameworks and energy plans to come.