As conventional energy resources are limited and polluting, new energy resources, being renewable and environmentally friendly, have been receiving increasing attention in recent years. However, no study on new energy investment, which acts a significant role in promoting the development and use of new energy resources, has been conducted. To cover this gap, an applicable decision support model is established by integrating Z-numbers, regret theory and elimination and choice translating reality III (ELECTRE III) to address new energy investment risk evaluation problems. In this way, Z-numbers are used to describe the decision-making information involved in the problems, a suggested method is combined with regret theory to determine the utility, rejoice and regret values of Z-information, and ELECTRE III is introduced to handle multiple criteria evaluation comprehensively. To elucidate and validate the application of the established model, a case study for new energy investment in Qingshuitang Industrial Zone is conducted and in-depth results analysis and discussion are implemented. The study shows that solar energy is the best investment project and environment is the most important investment factor. Moreover, the results demonstrate that the established model can effectively support new energy investment decision-making and it performs better than other existing methods.