Impact of fuel supply impedance and fuel staging on gas turbine ...

1 Introduction
1.1 Technology background: Electrical energy, efficiency <strong>and</strong>
environmental protection
In times <strong>of</strong> a worldwide increasing dem<strong>and</strong> for electricity, the power industry
faces the challenge <strong>of</strong> ensuring the <strong>supply</strong> <strong>of</strong> economic <strong>and</strong> sustainable <strong>supply</strong>
<strong>of</strong> energy. According to the International Energy Agency [3] the global primary
energy dem<strong>and</strong> will rise by about 50% between now <strong>and</strong> 2030. Over 70% <strong>of</strong> the
increase will come from the emerging countries, with China alone accounting
for 30%. Fossil <strong>fuel</strong>s will still form the backbone <strong>of</strong> the electrical energy <strong>supply</strong>
<strong>and</strong> remain the dominant source <strong>of</strong> energy. Their share <strong>of</strong> the worldwide electrical
energy dem<strong>and</strong> will slightly increase from 80% to 81% in 2030 [3]. Considering
the limited reserves <strong>of</strong> raw material, the goal <strong>of</strong> an economic <strong>supply</strong> <strong>of</strong>
electrical energy becomes a challenging task, assuming that fossil <strong>fuel</strong> prices
will increase in the long run. Also an sustainable production <strong>of</strong> electricity is
difficult to achieve given that burning fossil <strong>fuel</strong>s raises the concentration <strong>of</strong>
greenhouse gas carbon dioxide (CO 2 ) <strong>and</strong> other air pollutants such as unburnt
hydrocarbons (UHC), sulfur oxide (SO x ), carbon monoxide (CO) <strong>and</strong> nitrogen
oxide (NO x ), especially nitric oxide (NO). The effects <strong>of</strong> the pollutants include,
among others, global warming <strong>and</strong> acid rain (see e.g. Turns [128]).
Protecting the climate <strong>and</strong> natural resources will therefore play an increasing
role in the prospective utilization <strong>of</strong> fossil <strong>fuel</strong>s. The European Union has recently
decided to reduce greenhouse gases by 20% until 2020 (compared to
1990). To achieve high <strong>supply</strong> dependability, cost effectiveness <strong>and</strong> environmental
sustainability, the German power generation industry, for instance, focuses
on an energy mix. The energy mix consists <strong>of</strong> coal, nuclear power, natural
gas <strong>and</strong> renewable energies. In this context, electrical power production
using combined-cycle plants plays an increasing role. According to the ”Ver-
1