PORR CEO Karl-Heinz Strauss sees the project as an important step towards reducing emissions on construction sites. “The use of alternative energies is one of the most effective levers available to us as a construction company in reducing our carbon footprint”. For example, PORR has a successful rollout underway of its photovoltaic systems – eleven new rooftop and ground-mounted systems will be installed this year – and is carrying out pilot projects to test alternative drive systems on construction sites. Other important measures for reducing CO₂ include using recycled building materials as well as LEAN construction and digitalisation to optimise processes. For example, both pilot construction sites in Vienna Penzing are being backfilled with recycled concrete from the PORR site in Vienna Simmering.

“Climate protection is people protection – that’s why we’re pulling out all the stops in Vienna to reduce damaging greenhouse gas emissions”, said Councillor for Climate Protection Jürgen Czernohorszky. “We are on the right track, as shown by the 12% decrease in greenhouse gas emissions in 2023 – twice the Austrian average. To ensure that climate protection in Vienna does not stand still and advances dynamically, Vienna is the first federal state to have enshrined its climate targets in a dedicated climate law, due to be passed by the state parliament in the spring”.

Electrical equipment only

Two locations in Penzing, Vienna’s 14th district, set the stage for the project: Waldweg and Alpengartenstraße are where around 200 metres of water pipes will be replaced on behalf of Wiener Wasser, the City of Vienna’s waterworks. The works will run from March to probably August 2025 as part of the pipe network renovation programme, in order to safeguard the long-term supply of fresh spring water. The road surface will then be restored by the City of Vienna’s department of road management and construction so that all road users can once again travel safely and comfortably.

The equipment for the construction work will all be electric only, including an excavator, a tandem vibratory roller, an asphalt paver and five electric vehicles. This not only reduces CO₂ emissions but also minimises noise pollution for residents. The containers in use on the construction site will be powered by green electricity. Trucks fuelled with HVO100 will be used to transport the excavated and backfilled materials. This results in up to 90% fewer CO₂ emissions than conventional diesel.

Cooperation between industry and science

“A lot of research is already underway on this topic in Vienna, but this is the first time a carbon-neutral construction site is being implemented in practice”, said Margarete Kriz-Zwittkovits, Vice President of the Vienna Economic Chamber. “Viennese companies are always at the forefront when it comes to innovation. This pilot project is an important step for our climate and for opening up new market opportunities. Cooperation between industry and science is the basis for the international competitiveness of our companies and for safeguarding Vienna as a business location long term”.

The Vienna Economic Chamber has commissioned the Vienna University of Technology to monitor the pilot project and oversee the science. Particular focal points for research include how suitable the electrical equipment is for construction operations as well as general work processes. Feedback from the staff operating the devices will be especially important. The first findings are expected at the end of May when the first construction site is completed.