The envisioned expansion of the installation of offshore wind farms in the North and Baltic Sea as part
of the restructuring of the German electricity production towards a higher share of renewable energy
should not reduce the reliability of the electric power supply. This expansion on the one hand should
happen at the lowest possible cost, while, on the other hand, the return on investment of new offshore
wind farms must remain sufficiently attractive to induce the required significant investment.
To determine the influence of the feed-in-tariff, the wind conditions in North Sea and Baltic Sea, the
existing generation system, and the physical boundary conditions on the future development of offshore
wind energy converters, several separate models were developed in MATLAB© in the course of this
dissertation:
• An optimization algorithm for multi-dimensional problems, able to efficiently and reliably determine
the Pareto-front for optimization tasks with an arbitrary number of parameters and objective
functions.
• A method to calculate the contribution of a single power plant or a given generation system to
the guaranteed capacity, based on the existing generation system in Germany in the years 2006 to
2010. Four different indicators can be determined.
• A cost model to calculate the costs for the main components of an offshore wind energy converter,
including grid connection and installation, based on a limited number of design criteria.
• A scaling model for wind turbine power curves, enabling estimation of realistic power curves for
prospective wind energy converters, featuring arbitrary nominal power and rotor diameter, based
on the power curves of existing wind energy converters.
• An error correction function based on neural networks for the wind measurement data from the
FINO research platforms, enabling the reconstruction of missing data from neighboring sensors.
• An implementation of the German feed-in-tariff, considering all major drivers and returning the
present value of an investment for both available compensation options.
Based on the optimization conducted with the combined model, conclusions for the future development
of offshore wind power in Germany are derived:
• Low specific power of at most 250W=m2 results in the best economic results for both the investor
and the community, as well as in a high contribution to security of supply.
• To further increase the contribution of offshore wind parks to power system stability, a reduction
of specific power is more effective than an increase in hub height.
• A reduction of specific power results in a considerable reduction of return on investment and a
moderate increase of cost of energy.
• For a given location the turbine design with the highest return on investment corresponds to the
design with the lowest cost of energy, for all cases considered.
• Raising the capacity credit results in moderately increased cost of energy.
• Rising the hub height above 150m increases the cost of energy and lowers the return on investment.
• The distance-to-coast component of the German feed-in-tariff does not contribute to a sensible
design of offshore wind projects.
• The introduction of a "‘steadying"’ component to the feed-in-tariff can lead to design changes that
will result to an increased contribution of offshore wind energy converters to security of supply.
• The optimal offshore wind energy converter for projects in the German exclusive economic zone
has a nominal power of 7MW to 10MW with a rotor diameter between 160m and 240m. | English |