In Csepel, Alpiq operates the most flexible gas-fired combined cycle power station in Hungary

Nowadays many gas-fired combined cycle power stations are unprofitable and have been taken out of service. But in Hungary, Alpiq demonstrates that it is possible to do things differently. Since the beginning of 2014, Csepel II has the broadest control bandwidth and the highest degree of flexibility of all gas-fired combined cycle power stations in Hungary.

Since the end of 2002, Alpiq has been operating one the most modern and powerful gas-fired combined cycle power stations in Hungary on the banks of the Danube in Budapest. It reliably provides the industrial companies and inhabitants of Budapest's southern district with electricity and district heating. With an output of 403 megawatts (MW), Csepel II covers between 5 and 7 percent of Hungary's electricity consumption. Ever since the power station was built, it is considered to be a prime example of a high degree of flexibility and efficiency.

Positive exception to the rule

In recent years the expansion of new renewable energies (particularly wind and solar energy from Germany) has made many of the most up-to-date gas-fired combined cycle power stations unprofitable. Power stations that are fired with natural gas have lost their function as pure suppliers of energy (electricity and heat) and were increasingly forced to provide load balancing for the electricity grid.  Simultaneously the electricity prices came under increasing pressure. For these reasons many gas-fired combined cycle power stations are now no longer in service. These changes in the electricity market have also presented Alpiq with great challenges. Even Csepel II in Hungary is part of the secondary control loop and at the direction of the national grid operator MAVIR, it has to throttle back or increase its electricity generation at just a few minutes' notice.

Meeting strict environmental regulations

The design of the Csepel II power station enabled Alpiq to make rapid adjustments to the output and to simultaneously increase its power bandwidth. This was possible because the turbines were able to be driven individually even at low loads. However, for Csepel II, this led to conflicts with environmental regulations. A power station that is fired with natural gas emits CO2, carbon monoxide and nitrogen oxide. Until recently it was not possible to meet the strict environmental regulations at loads of less than 50 MW, because the emission of carbon monoxide can only be decreased through improved combustion, which requires a higher output. Therefore, maintaining a low level of emissions at Csepel II even at slow turbine speeds required an optimisation of the turbines' control software and adjustments to the steam injection valves.

Technical optimisation ensures profitability

At the end of 2013, these technical improvements successfully passed testing by MAVIR and received official certification at the beginning of 2014. Hence the Csepel II gas-fired combined cycle power station now has the broadest control bandwidth in Hungary and is today the most competitive gas-fired power station in the country. Thanks to its interruption-free operation, the power station reliably and economically supplies its district heating customers in Budapest.