Performance Influences of Hydrogen Enriched Fuel on Heavy-Duty Gas Turbines in Combined Cycle Power Plants

Kurzfassung

In order to meet the ambitious reduction targets for future CO2 emissions and fossil fuel consumption, the extension of renewable power systems is mandatory. One main issue is the fluctuating and unpredictable availability of renewable energy. With a higher portion of renewable energy, a secure electricity supply becomes more challenging. On days with high electricity demand but low availability of renewable energy, fossil back up power plants with high flexibility and efficiency are needed. Most applicable for this requirements are combined cycle power plants, which provide both high flexibility and efficiency. On the other hand potential renewable energy is wasted during days with low electricity demand but high available renewable energy, because electricity cannot be stored yet economically in such vast amounts. In order to use the available renewable energy more efficiently, hydrogen could be produced via electrolysis during phases of surplus available renewable energy. The hydrogen serves as a high density energy storage, which can be used as an alternative fuel in combined cycle power plants for a highly efficient reconversion into electricity if necessary. In this study it is analyzed how the usage of hydrogen as the burner fuel will influence the performance of combined cycle power plants. Therefore the on- and off-design performance of a state of the art combined cycle power plant will be calculated at different ratios of hydrogen mixtures with natural gas. The thermodynamic calculations are made with the performance software GTlab of the German Aerospace Center. Furthermore the natural gas and CO2 savings for different hydrogen ratios will be quantified. The results show that the usage of hydrogen enriched fuel increases the combined cycle efficiency and power output. Accordingly a considerable reduction in CO2 emissions and fossil fuel consumption is possible.