Implementation of environmentally significant activities is often associated with the need to attract significant investment from different sources, both public and private. However, investors should be interested in the profitability of their investments and receiving definite guarantees. To this end, the article describes the method of estimating the cost-effectiveness of the investment attractiveness of the procedure, which is used today in domestic practice (Russia). Then it has been found how to change this procedure to allow estimating the high risk and uncertainty of projects. In particular, the authors suggest using an objective function, which they have developed for the evaluation of investment projects. The main goal of the objective function is not only to improve the production, but also to improve the ecological situation in the region.