Solar thermal power plants using dish-engine systems have conventionally used multiple dishes of an optimum size. In a few recent developments, dish sizes up to 500 m(2) have been attempted in order to scale up power generation. Although using very large dishes may have a few advantages, the cost implications need to be analyzed before implementing such designs. An optimum dish size may provide the key advantage for dish-engine power plants to compete with grid power, but determining it poses a serious challenge. As dish-engine power plants call for heavy investments, it becomes important to design dishes to endure excessive wind loads, to prevent an overnight obliteration. A simple cost model is presented in this paper, in which the structural problem is modeled mathematically and optimized for minimum cost subject to wind-load resistance constraints. This paper demonstrates how cost optimization can be used as an effective decision making tool for selecting the right dish size. The optimization results indicate that very large dishes of conventional designs may not be cost-effective if they have to withstand heavy wind loads. (C) 2017 Elsevier Ltd. All rights reserved.