In order to understand how companies make investment decisions under conditions of deep uncertainty, we interviewed a number of actors in the Dutch electricity sector. Most of the economic literature that is devoted to this question is prescriptive in nature, describing rational methods to the investment decision process (such as real options and portfolio analyses). While these analysis tools play a role in the investment decision, the actual process is much more complicated. The reason is that the investor never has all the information that he would need to make a rational decision. Our research shows that the investment process is guided by a set of satisficing goals, rather than profit maximization; a multi-stage project management approach is used to cope with the lack of information; and the resources for information processing limit the scope of the analysis. We find several differences between companies in their decision making process and goals. These are a consequence of company characteristics such as the company size, ownership, vertical integration and geographic focus. The chosen electricity generation technology and inter-organizational dynamics also affect the investment process.