District Heating for Graz from Mellach CCGT

The production of environmentally friendly district heating in the new VERBUND thermal plant at Mellach has been taken up just in time to combat the freezing winter temperatures. This combined cycle power plant at the same time generates electricity and heat, which is utilised in the households, offices and large industrial complexes of Graz.

For several weeks, tens of thousands of households in the district heating network of Graz have been supplied with environmentally friendly district heating from the new CCGT at Mellach. With that, the commissioning of Austria's most cutting-edge thermal power plant has passed the transition to a successful trial operation just in time to embrace the new year's first real cold wave. Around half of the heat transported to Graz from Mellach already comes from the new power plant; the other half from the existing district heating plant.

An essential advantage of the new combined cycle gas power plant at Mellach is the particulate-matter-free generation of district heating for Graz. The energy source of natural gas, which is low in CO2, allows for the simultaneous power-heat co-generation of electricity and heat, which is fed into the grid of Graz via the district heating network at around 130 degrees Celsius. This saves enormous amounts of energy and thus guarantees the clean and efficient district heating supply of Austria's second largest urban area.

A reliable balance for the fluctuating electricity generation from wind and solar power

The combined cycle gas turbine power plant at Mellach represents VERBUND's replacement of five old power plant systems at once, thus saving some two million tons of CO2 annually. Austria's most modern thermal power plant does not merely work independently of external influences such as annual fluctuations or weather conditions. The CCGT at Mellach also fills in every time the wind is not sufficient for wind power plants, or if solar radiation is too weak for solar power plants.

During the three-year construction period for the new power plant, more than three million work hours were achieved on the construction site of Mellach alone. During peak times, up to 1,200 skilled workers were occupied at the same time on Styria's largest construction site. Major components of the power plants, such as, for example, the two block transformers, manufactured in Austria. The total investment volume for the combined cycle power plant at Mellach amounts to 550 million Euro.