Hybrid power generation concept for small grids

Abstract

The increasing power consumption and the targets of emissions reduction in the world has lead to further investigations in utilizing renewable energy sources. However, fluctuations in the power generation with renewables occur. Therefore, it is important that the power supply for the grid is reliable in order to avoid shortage of supply.

The aim of this thesis is to study the feasibility of constructing a hybrid power plant consisting of solar and wind power combined with liquid or gas fueled combustion engines for a small grid. Due to the restriction of small grids, islands and off-grid sites, especially industrial sites, create a perfect location for this hybrid power generation concept. Also, the good weather conditions on islands, especially in the sun-belt area increase the profitability of investing in hybrid power plants. The own consumption of existing power plants is also studied and by adding a CSP system that generates hot water for engine and fuel tank pre-heating, especially for power plants in stand-by mode locating in sunny areas, the efficiency is improved.

The fast starting and load following combustion engines are perfectly fitting together with the fluctuating renewable power generation and thus the stored fuel will work as storage system, responding to power demand very fast.

The main results of this thesis origins from the simulations of the hybrid power plant with both liquid fuel combustion engines and solar and wind power. The proper share of renewable power generation and power generated by engines at a particular time are shown. Payback time calculations for ideal hybrid power generation concepts and for the CSP system for minimizing own consumption are made as well. The results show that hybrid power plants on islands and off-grid solutions are extremely cost-effective, with a payback time of only six years. Thus, investment in hybrid power plants is recommended.