This paper summarizes the results of the operation of the two solar power plants of the SSPS project (Small Solar Power Systems) at Almeria, carried out within the framework of the International Energy Agency. Using the experimental values from the CRS plant, it appears that its yearly gross output could have been similar to that of the DCS plant but at higher internal electricity consumption, particularly due to the trace heating of the heat transfer medium (sodium). The technical reasons for the poor efficiency of the SSPS installation were largely that the solar climate was less favorable than assumed, dirt accumulated on the mirrors at a more rapid rate than foreseen, the nonsolar specific components were badly matched and yielded low efficiencies, and thermal inertia was crucial and almost overlooked in the planning state. A detailed loss analysis is presented in the article.