Map-based data on the energy consumption of residential buildings

In Finland, everyday residential life accounts for more than 30% of the greenhouse gas emissions from private consumption. Within the Academy of Finland’s Research Programme on Climate Change (FICCA), a model has been developed that facilitates the computational estimation of the energy consumption and emissions for all residential buildings in any given area. The model was developed for the purpose of assessing the reductions in emissions achieved through new user-oriented innovations.

The databases on Finland’s residential building stock provide a good foundation for the acceleration of energy innovations and changes. The building and dwelling register maintained by the Population Register Centre contains the location coordinates and other relevant details of Finland’s building stock. The EKOREM model developed at Tampere University of Technology facilitates the estimation of the energy consumption and greenhouse gas emissions of these buildings.

“By combining the register data with the EKOREM model, we designed a model for the calculation of energy consumption and emissions from all residential buildings in any given area,” explains researcher Maija Mattinen of the Finnish Environment Institute (SYKE). She is involved in the LAICA research project within the Academy of Finland’s FICCA program. The project focuses on innovative user practices and the assessment of their impact on reductions in emissions from residential buildings.

The calculation model has already been applied to the Kaukajärvi district of Tampere. There are 700 residential buildings and 11,000 residents in the Kaukajärvi district. Of the heat production methods used in Kaukajärvi, district heating is the most important, but electric heating, ground source heat pumps, oil heating or wood-based heating are also being used in part of the properties in the area.

The differences between buildings in terms of energy consumption and emissions are affected by, among other factors, the age and structural solution of the building, the number of residents and the form of heating used. According to the calculations, there is considerable variation between the residential buildings concerning the use of net effective heating energy and the resulting greenhouse gas emissions. If, for example, we compare two houses along the same road, it may be that the one house, when compared to a neighbouring low-emission house, consumes three times more heating energy and produces four times more greenhouse gas emissions per square metre on an annual basis. On the other hand, there are also similarities between the houses in an area that are constructed during a specific time period.

“The model provides us with map-based data on the energy consumption and greenhouse gas emissions of the residential houses. The data can also be utilised in the future when discussing and planning the basic repairs and upgrades of energy systems and buildings in specific residential areas,” says Ari Nissinen, Senior Research Scientist at SYKE.

The model is, however, only being used for research purposes at the moment, and the process of updating the base information available in the register will still need to be developed further. The accuracy of the model will also be further analysed and improved.

The model has also been applied to the assessment of emission reductions in different types of heat pumps within the various climatic zones in Finland. Both the regular air source heat pump and the Finnish innovation, the ground and air source heat pump, were examined.

“Like the air source heat pump, the ground and air source heat pump does not require a water-circulated heating system, and so it is also suitable for houses with electric heating. One of its other benefits, in comparison with the regular air source heat pump, is that the heating efficiency is not dependent on the temperature of the air. An air source heat pump doesn’t, in fact, work when the need for heat is the greatest; in other words, when the winter temperatures are at their lowest,” states Nissinen. The ground and air source heat pump is expected to reduce greenhouse gas emissions by 1.5 times when compared to regular air source heat pumps.

For the purposes of the calculation, a life cycle assessment method was applied that took into account all of the heat pump materials, including the required ground loop piping. “The prevention of refrigerant leakage proved to be a critical factor in terms of greenhouse gas emissions. If all the system’s refrigerant leaked, as a consequence of, for example, careless maintenance or waste handling, the resulting emissions would equal more than 10% of the total emissions over a normal 20-year life cycle,” says Mattinen.

The LAICA project will continue to assess the emission reductions resulting from different user-oriented residential innovations and will also take on the analysis of the timing of electricity consumption. The extensive research project is being implemented as a joint initiative by the Aalto University School of Business, the Finnish Environment Institute and the National Consumer Research Centre. The project will continue until the end of 2014. Tampere University of Technology has participated in the development of the computations and demonstrations related to residential buildings.