On November 15 Solar City Copenhagen hosted a conference on CO2 neutral city development with invited guests from the Salzburg region and contributions from Danish architects and cooperative housing societies. The event was also the official opening of the Concerto II project “Green Solar Cities” in Valby and Salzburg.

“The ambition is that Copenhagen should rank as an environment metropole by the year 2015 – and we mean business,” said the Mayor of the Environmental Administration, Klaus Bondam, in his opening speech at the cityhall. One of the goals is to set up Copenhagen as a centre of the world’s climate politics and to reduce the city’s present CO2 emission by 20 per cent by the year 2015.

EXPERIENCES FROM SALZBURG
The guests from Salzburg could report on convincing results that stem from a persistent effort. Landesrat Walter Blachfellner described a point system that rewards energy and environment improvements financially. The system has resulted in a 69 per cent reduction in the energy consumption of the region’s social housing estates. More than half of the newly built housing estates have solar energy and/or biomass as their prime source of heat.

The city of Salzburg has succeeded in bringing down the energy consumption through a combination of innovation, motivation and control, according to Martin Panosch from the Housing and Building Administration. By far the majority of the publicly owned buildings have had remote-read meters installed. 90 per cent of the city’s energy and water consumption is monitored every 15 minutes by a central computer – and the system reacts every time an abnormality is registered, so that the problem may be solved. “Bitte sofort überprüfen,” it says on the monitor. The cost of the system is 1.5 million euros. But the energy savings amount to half a million euros a year. This payback time of just three years is crucial since the city is not rich, Martin Panosch explained.

The cooperative housing societies GSWB and Heimat Österreich presented a number of examples of low-energy renovation and new building. GSWB, the administrator of almost 22,000 flats, has installed solar collectors of almost 6,000 square metres since 1998. Heimat Österreich has a prefab construction which is ready for occupation. It is built according to the passive-house principle: The dwellings need only the heat which comes from the inhabitants and their instruments. The ventilation reclaims the heat. The domestic water is heated with the help of solar collectors and wood pellets.

VISIONS OF VALBY
In Denmark, the development has been at a standstill since the late nineties, according to Peder Vejsig Pedersen, Cenergia. However, the new Planning Act opens up for tighter energy measures, and with the EU-supported Concerto II project Copenhagen now has a unique chance of turning energy-efficient buildings and renewables into mainstream as has been the case in Austria, he said.

The Concerto II programme rewards energy conservation measures with a support of 33 per cent within a framework of 35 euros per square meter – and a possible support of half the price on newly installed photovoltaics. The vision for Valby is 15 per cent solar power by the year 2015. The intermediate aim is 600 low-energy dwellings and integration of solar collectors and 2000 square meter photovoltaics in the buildings as well as a biogas system, project coordinator Jakob Klint explained.

EXPERIENCES AND PERSPEKTIVES OF LOW-ENERGY HOUSE BOUILDING
Following a seven year standstill, the interest in environment-friendly low-energy house building is now growing – and it actually pays off, explained director Palle Jørgensen from the housing association Ringgaarden i Aarhus. Earlier this year Ringgaarden recieved the EU energy and environment award for the 130 low-energy dwellings which are being built in Lystrup as part of the European Sustainable Housing programme. Even though the financial prospects are good, it is hard to get going due to the preliminary expenses, he explained.

The two architectural practices Nielsen & Rubow and Lundgaard & Tranberg each gave their version of the prospects for environment-friendly and energy-efficient house building. Though differing in approach, they all agreed that consideration for the environment should be seen not as a restriction but as a challenge to create something new and better. Low energy consumption and sustainable function must be incorporated in the buildings from the start – as an added quality or as a correction which one barely notices.

Nielsen & Rubow have designed the solar-roof dwellings, which consist of prefabricated, highly insulated units mounted on top of old blocks – thereby adding extra energy-efficient flats to the block as well as extra insulation to the dwellings below. Lundgaard & Tranberg presented a new type of energy glass which is so efficient that a low-energy glass house has been built as an experiment. Until now, however, the results have not been convincing.

VISIONS OF CARLSBERG
Entasis presented their ideas behind the new district plan for the former Carlsberg brewery site.
Social and ecological sustainability is a key factor of the ongoing design phase. The roofs of all new buildings will be fitted with photovoltaics, and it is the ambition that the entire neighbourhood should be CO2 neutral by the year 2015.


Panel: Peder Vejsig Pedersen (Cenergia), Jørgen Nue Møller (Fonden for Billige Boliger) Gert Nielsen (Boligselskabernes Landsforening), Klaus Bondam (Mayor of the Technical and Environmental Administration in Copenhagen), Lars Holten Petersen (Carlsberg), Palle Jørgensen (The housing asssociation Ringgården) and Knud Pedersen (Dong Energy).

PANEL DISCUSSION
The morning’s many contributions ended with a panel discussion with representatives from the local authorities, the social housing sector, developers and energy suppliers. Here, the chances of strengthening the concept of renewable energy through renovation and new building were discussed.
The Government and the Parliament should concentrate much more on sustainable building, agreed the participants of the panel discussion. One should not be afraid of making demands on the building owners through tighter energy and environmental requirements in the building code.
It is necessary to focuse one’s attention on the finances in building and renovation projects: The building expenses of building and renovation will be a bit higher, and therefore better funding is called for. But, as a rule, it will pay in time through considerable energy savings – year after year.