Beside continuous implementation of concentrating solar power plants (CSP) in Europe, which stipulate cost reduction by mass production effects, further R&D activities are necessary to achieve the cost competitiveness to fossil power generation. Therefore the cost range of 15–20 cents€/kWh for the currently planned CSP systems in Europe has to be decreased by a factor of 2–4. The European Concentrated Solar Thermal Roadmap (ECOSTAR) study that is conducted by leading CSP research institutes in Europe intends to stipulate the direction for R&D activities in the context of cost reduction. It uses a common methodology approach, based on an annual performance model to identify the most essential technical innovations that will reduce the cost of seven different CSP system concepts, which are currently under promotion world wide. The potential of innovative concepts for solar light weight concentrators, low-cost thermal energy storage concepts, solar receivers/absorbers and power cycles are in the main focus of interest. The results of the study include a description of the value of CSP power, the sensitivity of the electricity cost information, a list of innovations that have been investigated and recommendations for the focus of further R&D work.Copyright © 2005 by ASME