This thesis analyzes investment incentives of strategic firms in industries where either demand is uncertain, or the good produced is economically non-storable and demand fluctuates. In those industries, investment is a long run decision, whereas production has to be adjusted short-run. Prominent examples are recently liberalized utilities such as the electricity sector. Regulated monopolies have been replaced by a small number of competing firms, which often are considered to behave strategically in order to exercise market power. Whereas the regulatory regimes prior to liberalization induced generous (over-)investment choices, we observe increasing unease of experts and policy makers regarding investment incentives in liberalized electricity markets. The first three chapters of this thesis (part one) analyze total capacity choice of strategic firms prior to producing for the spot market. We first determine the equilibrium of the market game. In the remainder of the first part we analyze the interdependency of enhanced spot market competition and firms overall capacity choice. We first analyze the impact of complete elimination of market power at the spot market giving rise to marginal cost pricing. We then consider the impact of price caps at the spot market. And finally we study the impact of reduced market power at the spot markets due to forward contracting. In the second part of the thesis firms can invest into several technologies. This allows them to determine not only their total capacity but also it's precise composition. In the absence of strategic interaction, for a single regulated firm, this has already been thoroughly analyzed in the so called peak load pricing literature, which has been widely applied for electricity markets prior to liberalization. In order to accommodate for the completely changed situation after liberalization, however, we extend this framework to the case of strategically interacting firms. Based on data of the German electricity market, we then illustrate and empirically quantify our theoretical results. We determine firms’ investment choices for different market structures and quantify the impact of spot market interventions on investment decisions and welfare. This allows us to quantify the potential for the exercise of market power, in the long run, when firms’ investment decisions are taken into account.