With the phased occupation of the Suurstoffi site, Zug Estates came a step closer to its vision of operating the properties without the use of external sources of energy and with no emission of greenhouse gases.
With its zero-zero vision, the Zug Estates Group wants to operate the buildings in its portfolio in a sustainable, carbon-free manner and without external energy supplies. As well as setting social objectives, the company is thus adopting a holistic approach to sustainable management.
The Zug Estates Group has deliberately chosen not to use sustainability labels common in the construction business as they are awarded on the basis of projected figures. However, since 2010 it has had its energy and water consumption and the CO2 emissions at its sites measured annually by the Center for Interdisciplinary Building Technology of Lucerne University of Applied Sciences (HSLU).
Ecological objectives of Zug Estates
Use of renewable energy sources; energy and resource-efficient usage
Minimization of CO2 emissions, other combustion gases and fine particles; reduction of noise and light emissions
Materials and products:
Use of materials low in pollutants, energy-efficient technologies, products and equipment; use of renewable materials; short transportation routes
Biodiversity and water:
Implementation of suitable measures in landscape design to preserve biodiversity
Primary energy consumption reduced again
In 2014 consumption of non-renewable primary energy for heating per square meter of rental space fell significantly for the entire portfolio for the fourth time in succession: by nearly 10% compared with 2013 and by as much as 29% compared with 2010 (adjusted for heating degree days). There was a comparable reduction in greenhouse gas emissions alongside the fall in primary energy consumption. In addition to the greater proportion of energy-efficient rental space at the Suurstoffi site, numerous small measures at the Zug site also contributed. The 2012 switchover to green electricity instead of the normal electricity mix available from the Wasserwerke Zug (WWZ) utility company also made a difference.
Area heated by renewable energy doubles
Whereas 87% of the entire rental space was still heated with natural gas (64%) or heating oil (23%) in 2013, this fell to 75% (natural gas 55%, heating oil 20%) in 2014. This means that the area heated by renewable sources has almost doubled since the last reporting period. The main reason for this change in the energy mix is that additional, more energy-efficient, rental spaces at the Suurstoffi site are now in use. Downhole heat exchanger pumps provide heating and hot water there. These are run on electricity from the WWZ grid (green electricity) and from photovoltaic panels on the buildings. In the current reporting period, photovoltaic panels provided 37% of the electricity used by the Suurstoffi heat pumps, and this is set to rise to about 80% when the photovoltaic-thermal (PVT) system comes into operation. The aim is that all the electricity required for the production of heating will be provided by photovoltaics by the time construction is completed in 2020/21.
Electricity consumption down by a quarter in five years
Over all the sites, electricity consumption per square meter of rental space fell by 9% compared with the previous reporting period, despite rising occupancy levels. Consumption by the tenants can be influenced only indirectly, by fitting economical electrical appliances and lighting. Demand for general electricity per square meter is a more meaningful indicator. This fell by a 12% compared with 2013 and by 23% compared with 2010. A corresponding reduction was observed in CO2 emissions, too. Specific water consumption in cubic meters per square meter of rental space has stabilized since 2012 at the Zug city center site and the Oberentfelden factory site. There was a slight increase at the Suurstoffi site compared with the previous period connected with the rental of the spaces available there.
Simultaneous production of heating and power
The very latest technology for producing energy from sunlight has been widely installed at the Suurstoffi site. PVT modules produce power and heating simultaneously. More solar energy can thus be harvested from the same surface area. Furthermore, the solar cells do not become as hot because the "waste" heat is constantly being removed. This extends their life and increases their electricity production efficiency by about 5% over the year. On hot summer days the extra amount produced can be as much as 15%. The heat thus collected is then fed into the anergy grid installed on the site. The buildings draw on this for heating and service water via heat pumps. In summer, the surplus heat produced by the PVT system is directed into the ground; it can then be recovered in winter. To the best of our knowledge, the PVT system at the Suurstoffi site is currently the largest in the world.
Key figures for PV and PVT systems
in kWh p.a.
in kWh p.a.
|PV system 1||3 484||595||552 000||–||2012/2013|
|PVT system 2||2 704||424||365 000||1 626 000||2014/2015|
|Total share||6 188||1 019||917 000||1 626 000||–|
|1 Photovoltaic system|
2 Thermal photovoltaic system