Integrating large quantities of supply-driven renewable electricity generation remains a political and operational challenge. One of the main obstacles in Europe to installing at least 200 GWs of power from variable renewable sources is how to deal with the insufficient network capacity and the congestion that will result from new flow patterns. We model the current methodology for controlling congestion at international borders and compare its results, under varying penetrations of wind power, with a model that simulates an integrated European network that utilises nodal/localised marginal pricing. The nodal pricing simulations illustrate that congestion - and price - patterns vary considerably between wind scenarios and within countries, and that a nodal price regime could make fuller use of existing EU network capacity, introducing substantial operational cost savings and reducing marginal power prices in the majority of European countries.

Renewable energy sources (RES) play an increasing role in many electricity systems thanks to climate and support policies and subsequent cost reductions in recent years. Compared to conventional generation technologies, RES has two main important distinctive features: First, their cost pattern is characterized by high investment and negligible variable costs and second, their operational decision is governed by weather conditions limiting their availability. In this paper, we aim to analyze the role of RES in electricity markets focusing on the interplay of investment and dispatch decisions under different levels of market competitiveness and different support schemes; namely, feed-in tariff, feed-in premium, and investment subsidies. To this end, we develop a two-stage model of endogenous investment and operation with both intermittent and conventional technologies to obtain analytical solutions for investment and operation decisions. We show that there are feedback effects between the investments of different firms, and between the different technologies of the same firm. Exercise of market power results in underinvestment in the conventional technology; but the effect on renewables is ambiguous due to the interplay of opposing investment incentives. The results furthermore highlight that for the optimal design of a support policy the underlying competiveness of the market needs to be considered.

In this thesis current questions regarding the functionality of liberalized electricity markets are studied addressing different topics of interest in two main directions: market power and competition policy on electricity wholesale markets, and network investments and incentive regulation. The former is studied based on the case of the German electricity market with respect to ex-post market power analysis and ex-ante remedy development. First an optimization model is designed to obtain the competitive benchmark which can be compared to the observed market outcomes between 2004 and 2006. In a second step the horizontal breaking up of dominant firms (divestiture) is simulated applying equilibrium techniques (the classical Cournot approach and the Supply Function Equilibrium approach). The later issue of transmission capacity investment is addressed by highlighting the complexity of network investments in electricity markets and by analyzing a regulatory mechanism with a two part tariff approach. The technical characteristics of power flows are combined with economic criteria and tested for different network settings.

In an electricity system, demand and supply have to be balanced in real time. Since most energy is traded before real time already in forward, day-ahead and intraday markets imbalances can occur. To ensure the balance between demand and supply even if power plants deviate from their schedules, the system operator procures balancing capacity and energy in balancing markets. The market outcomes may significantly differ from one country to the other depending on the underlying generation technologies and market design. In this paper, we have a look at the balancing market prices of a hydro-dominated electricity system using Switzerland as a case study. By using a short-term hydropower operation model and a set of Swiss hydropower plants, we are able to identify a competitive benchmark for Swiss balancing market prices defined by the opportunity costs of hydropower for providing balancing capacity. Our results show that Swiss balancing market prices are influenced by several drivers but do not hint at any market imperfections.

Wind energy has become the major renewable energy source in Germany with an installed capacity of more than 20 GW and an annual output of about 40 TWh in 2007. In this paper we analyze the extent to which wind energy can replace fossil capacities based on wind injection and demand data for 2006 through June 2008. The results indicate that the wind potential in Germany will not allow a significant reduction of fossil capacities. We also assess the potential savings due to wind energy. The German market is modeled with and without wind input to estimate the net savings of fossil fuels in the observation period. We find that the cost-saving potential for electricity production is quite significant in the study period and exceeds the subsidies.

Natural gas plays an important role in many European energy systems especially with regard to the envisioned transition towards a less carbon intensive energy supply. Being dependent on imports - especially from Russia - this raises questions about the future development and security of Europe's gas supply. Using a numerical network model of the European gas system we assess 1) the potential impact of infrastructure extensions for Europe's gas supply and 2) the role of supply security policies in coping with a disruption of Russian imports via the Ukraine. Our results indicate that overall the European gas infrastructure is sufficient for average market conditions. Due to the strong dependency on Russian imports, however, disruptions during the winter months could lead to load curtailment. Projected network extension (Southern Gas Corridor, Nord Stream 2, and new LNG terminals) or a strategic storage policy coordinated across Europe has the potential to reduce this shortage. The positive impact of an extended network, however, also depends on the capability of the global gas market to provide flexible gas that can be reallocated towards Europe. The majority of demand curtailment can already by countered by a relatively modest amount of strategic storage (20% to 30%) if their use during crisis situations is coordination across European countries.

This paper, which examines the impacts of phasing out nuclear power in Germany, is the first to include an analysis of energy supply security and critical line flows in both the German and Central European electricity networks. The technical-economic model of the European electricity market, ELMOD, is used to simulate alternative power plant dispatch, imports, exports, and network use for a representative winter day. The results suggest that the shutdown of Germany's nuclear plants will result in higher net imports, especially from the Netherlands, Austria, and Poland, and that electricity generation from fossil fuels will increase slightly in Germany and in Central Europe. We find that no additional imports will come from nuclear plants since they are already fully utilized in the merit order, and that electricity prices will rise on average by a few Euros per MWh. We conclude that closing the seven nuclear power plants within the government's moratorium will cause no significant supply security issues or network constraints and an eventual full phase-out seem to be possible due to the completion of several new conventional power plants now under construction. Finally, we suggest that a nuclear phase-out in Germany within the next 3-7 years will not undermine security of supply and network stability in Germany and Central Europe.