Laufnitzdorf run-of-river power plant back in operation following modernisation

Today, Governor Mario Kunasek and State Councillor Willibald Ehrenhöfer, together with the Executive Board and management of VERBUND, officially opened the Laufnitzdorf hydroelectric power plant on the River Mur in Frohnleiten, which had undergone extensive modernisations. With new generator sets and the new weir power plant, Laufnitzdorf can meet the annual electricity needs of 40,000 households with a capacity of 24.3 megawatts, making it the largest hydropower plant on the River Mur.

It was Styria’s largest power plant modernisation project: VERBUND invested 65 million euros in modernising the 95-year-old Laufnitzdorf hydroelectric power plant in Frohnleiten, which, following today’s ceremonial recommissioning, is now the hydropower plant with the highest generating capacity on the entire River Mur.

“A secure and reliable energy supply is crucial for the future of our country. We must make the best possible use of our domestic resources, strengthen our electricity supply and become more independent. The Laufnitzdorf power plant modernisation by VERBUND is an important step in this direction. It will enable electricity to be generated for around 40,000 households in future. This strengthens security of supply, supports our regional economy, and safeguards economic value and jobs. My particular thanks go to VERBUND and everyone involved in the project, whose commitment has made this important investment possible and will help secure Styria’s energy future for the long term,” says Governor Mario Kunasek.

“We cannot talk about Styria as a strong business location without also discussing a secure and affordable energy supply. During these economically challenging times in particular, we must create the right framework conditions to ensure that our businesses can remain competitive. A high-performing energy sector is a crucial stabilising factor and a key foundation for sustainable growth. The Laufnitzdorf power plant is a prime example of how the potential of existing infrastructure can be utilised to the fullest extent through the use of innovative technology. In doing so, we combine security of supply with Styrian expertise and make an important contribution to the future viability of our business location,” says State Councillor Willibald Ehrenhöfer.

In the 1930s, Laufnitzdorf was Austria’s largest run-of-river power plant

The Laufnitzdorf power plant in Frohnleiten is now one of 43 hydropower plants in the VERBUND Styrian power plant group and a true workhorse of renewable electricity generation: Since the Mur hydroelectric power plant went into operation in October 1931 with a capacity of 18 megawatts, more than 10 billion kilowatt hours of electricity have been produced in Laufnitzdorf from Styrian hydropower.

“The Laufnitzdorf power plant is one of the oldest facilities in VERBUND’s power plant portfolio and was Austria’s largest run-of-river power plant when it was commissioned. It was here at this power plant, almost a hundred years ago, that Viktor Kaplan oversaw the installation of the turbines he had invented and which bear his name. Today, Kaplan turbines are in use in all major run-of-river power plants, and these power plants are not only the most important pillar of renewable electricity generation, but also the backbone of Austria’s high level of security when it comes to electricity supply,” says Achim Kaspar, VERBUND’s COO and the Executive Board member responsible for hydropower. Prof. Gerlind Weber, Viktor Kaplan’s granddaughter, also attended today’s recommissioning ceremony.

New generator sets for the workhorse of green electricity generation

In autumn 2024, VERBUND launched Styria’s largest modernisation project. New turbines and generators were installed in the historic, listed powerhouse, with the two new generator sets designed to match the appearance of the original generator sets. “The history of this power plant challenged us to reconcile heritage protection requirements with the aim of achieving the highest possible efficiency,” says Karl Heinz Gruber, managing director of VERBUND Hydropower. “The result is an impressive increase of more than 30% in the output of the entire facility.”

Unique in Austria: The roller weir in Mixnitz

In parallel with the work at the main power plant, the weir rollers at the Mixnitz weir – which are unique in Austria – have also been completely replaced over the past two years. The two new closure segments each weigh 120 tonnes and were transported to the weir complex via special haulage operations and hoisted into the 95-year-old structure using heavy-duty cranes. As required under heritage protection rules, all the new concrete work was artificially aged so that there is no recognisable visual difference to the existing structure

In addition, a new weir power plant was built in the area of the weir. Along the seven-kilometre-long diversion canal, which carries water from the weir to the powerhouse, four bridges were replaced, refurbished or widened. The canal was also fenced off over long stretches, and firefighting water supply points were installed for the fire service.

Environmental improvements and compensatory measures along the River Mur as far as Niklasdorf

In addition to the extensive technical project measures, a wide range of environmental improvements and compensatory measures were implemented.

The original fish pass in the vicinity of the Mixnitz weir was removed and rebuilt as a combination of a near-natural bypass stream and vertical-slot basins. The 70 basins, each with a slot width of 35 centimetres, are designed to allow huchen up to one metre long to pass through.

Numerous ecological compensatory measures were implemented at the diversion channel, in the area of the weir and along the Mixnitz reservoir, including the creation of dragonfly habitats, the provision of deadwood, bank restoration and new planting. Outside the project area, the Silbersee oxbow lake in the municipality of Niklasdorf, was enhanced as a biodiversity hotspot.

Hydropower as the backbone of renewable electricity generation in Styria

The VERBUND Styria power plant group comprises 43 hydropower plants, including 36 run-of-river power plants and seven storage power plants. “Alongside new construction projects, we have been investing specifically in the modernisation and improved efficiency of Styrian hydropower for more than twenty years. After all, the power of the River Mur has been harnessed for domestic renewable electricity generation for more than a century,” says Michael Amerer, managing director of VERBUND Hydropower, at the official opening of the modernised Laufnitzdorf hydroelectric power plant.