Project Description

Buildings manage urban energy

The student residence complex GreenHouse in the Seestadt Aspern district of Vienna, with 313 apartments covering 7,000 sqm, consumes, controls and trades its energy requirements completely automatically, and also plays a flexible role in stabilising the power grid. This student residence has been built according to the passive house standard. The building’s electricity comes from photovoltaic panels mounted on the roof. The heating and hot water requirements are sourced from district heating. If 20% of the buildings in Vienna were equipped with the same energy management system used here, this could result in annual profits of EUR 30 million.

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Project details

An intelligent building energy management system (BEMS) was developed in the course of the Aspern Smart City Research ASCR research project. This energy-based innovation is now being tested at the GreenHouse development. The first successful energy transactions performed using the energy pool manager highlight the market potential of this concept for Vienna.

Besides optimising its own energy consumption, the focus of the research question posed by ASCR is on how the flexibility of buildings can be used in future to stabilise the local medium and low-voltage grids and how buildings can act as active participants in the power market.

An energy pool manager – such as the Wien Energie’s FlexPool – acts as an interface between individual buildings and the electricity exchange. At the heart of the system is the FlexPool software, which centrally manages the facilities. It regulates flexible generation plants when additional electricity is needed in the grid, and automatically ensures that the corresponding amount is fed in.

The virtual power station already offered by FlexPool allows commercial customers to sell excess power as balancing energy to generate additional revenues and to help stabilise the grid. In future, such energy pool managers will also intelligently integrate and coordinate tens of thousands of solar power plants and heat pumps.

The more decentralised power generation becomes, the more integrated the overall system will need to be. The plan is to feed an additional 30 TWh of renewables into the grid by 2030. This can lead to grid instability. In order to continue to ensure grid stability, all of the components need to be taken into account – power generation plants, consumers, storage facilities and entire buildings. The reason for this is that the buildings sector is a key element of a successful transformation to an energy system characterised by rising volatility and numerous decentralised facilities.

The building energy management system (BEMS) integrated into the GreenHouse student residence already plays an ideal role in optimising the building’s energy consumption and generation. The building also communicates with the electricity grid, exchanging valuable information such as forecast consumption levels. This is not only important in terms of climate protection. The use of this energy management system also makes it possible to achieve significant cost savings. The dynamism offered by variable electricity prices and the quality of the forecasts have a considerable impact on these cost savings.

By relying on the efficient use of a battery storage unit and avoiding drawing power during peak periods, the student residence saves up to EUR 5,000 a year in energy costs. Tests to confirm the plausibility of drawing power to later be used as balancing energy have also been performed. Depending on the state of the market, energy can either be fed into or sourced from the grid in order to generate revenues.

In Europe, around 40% of all end energy is used in buildings. The potential for optimisation here is significant. Building energy management systems (BEMS) calculate forecast energy requirements at regular intervals taking into account usage patterns, energy-saving behaviour, energy production, weather forecasts and possible in-built flexibilities. As a result, it is possible to forecast when and how much excess energy could be fed into the grid.

Ulli Sima

“The solutions tested during the ASCR project are the key to our future energy system and offer enormous potential. If 20 percent of buildings in Vienna were equipped with ASCR technology, annual profits of EUR 30 million could be generated. That’s what our initial calculations predict. This would allow energy to be used efficiently, CO2-neutrally and profitably in the interests of climate protection, the city and its inhabitants.”

Ulli Sima, Vienna city councillor responsible for the environment and Wiener Stadtwerke

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