The global energy problem is frequently spotlighted nowadays. Over the last decades, the energy demand has considerably increased. The European Union imports approximately 50 % of its energy and this number is estimated to increase to 70 % by 2030. This puts the European Union in a dependent and hence economically vulnerable position. Most of the energy imports concern fossil fuels which contribute to global warming. One of the answers to overcome these problems lays in the exploitation of renewable energy sources. Although huge amounts of power are available in the ocean waves, wave energy is probably the least-known resource among the renewable energies. Several conversion technologies have been invented, such as overtopping devices, oscillating water columns and point absorber systems. Point absorber systems consist of small buoys oscillating in the ocean waves. By damping their motion, electricity is produced. Similar to wind energy farms, point absorbers are intended to operate in arrays to produce considerable amounts of power. Some devices are even composed of several, interacting point absorbers, integrated in one unit. The design and optimization of single and multiple, closely spaced point absorbers is the subject of this thesis.