Household Energy Use – The Case of Switzerland

Modern societies need a considerable amount of energy, which is almost entirely used the three sectors industry (including services), mobility and household, at roughly equal parts. Thus, the energy consumed at home forms a substantial part of the entire final energy use.

In this posting we study the situation in Switzerland which is one of the most competitive and industrialized countries of Europe, though not being a member of the EU. All raw data for the subsequent investigation stem from Swiss Statistics which provides excellent information on all areas of consumption. In particular, we will focus on the period 2000-2010. The above-mentioned sectors had the following shares in the total final energy consumption in 2010: industry and services 35 %, mobility 34 % and household 30 %.

Total household energy use went up by 14.1% during the first decade of this century. However, this obvious increase does not take into account that the number of people living in Switzerland has also risen during that period. Thus, the relevant figure to look at is the consumption per capita, and here the situation looks quite different as can be seen in Fig. 1.

The trend line makes clear that the specific energy use per person has gone down over the years. The steep increase since 2007 is well in line with the number of heating degree days (HDD) following a similar pattern as can be seen in Fig. 2. Apparently, it has become colder between 2007 and 2010.

Fig. 2 Heating degree days (HDD) and heating effort in Swiss households.

The similarity between the red curves in Figs. 1 and 2 is not accidental, as more than 72 % of total household energy are used for heating purposes (in 2010). Thus, changes in the number of heating degree days should be reflected in the heating effort. Warm water makes up for another 12 % of household use while the remaining 16 % are shared among various sectors such as lighting, cooking, washing, drying, etc.

A closer look at the figures for warm water reveals that consumption has remained relatively stable (Fig. 3).  Taking into account the growing number of households (+ 11 %) during the period in question naturally leads to the conclusion that each household uses less and less warm water.

Fig. 3 Total energy used for warm water and consumption per household (/HH).

Fig. 4 shows the contribution of other sources of household energy use. Their aggregated consumption volume is relatively moderate as stated above. Nevertheless, as a whole they are not to be neglected although their individual shares are not as important as the ones for heating and warm water.

Fig. 4 Household energy use (except heating and warm water).

Whereas lighting, cooking and refrigerating (including freezing) have remained virtually unchanged over the years, washing (including drying) and miscellaneous have increased dramatically by 52 % and 32 %, respectively. This is well in line with a growing population as more people require more clothing to be washed. So there are some areas of energy consumption being more sensitive to the number of persons involved while others like lighting tend to be rather independent of population figures.

Thus, as stated in my previous posting, growing energy consumption figures (in absolute terms) should not be obscured by ignoring the simultaneous changes in the number of consumers. On an individual basis, we gradually tend to use less energy. This is the good news. But, of course, the crucial question is how much further we can get in becoming more energy efficient. Or, to put it differently, is there a limit and, if yes, where is it?

Energy Efficiency – Potential Household Savings in Sweden

In a recent report we analysed the savings potential of the Swedish housing sector. Sweden has committed herself to save some 12.8 Mtoe of primary energy up to 2020. Taking into account that the country used some 51.4 Mtoe in 2010, and with a consumption goal in 2020 of about 41 Mtoe, this means that savings of some 20 % within the remaining decade are at stake.

One of the biggest savings potentials is supposed to be hidden in the building stock. Household energy use accounts for 23 % of the total final energy consumption in Sweden and the largest part of it is eaten up by heating purposes. In the following we look into the consumption figures for heating and warm water in Swedish households. The raw data for our investigation have been taken from Eurostat, Statistics Sweden and the Swedish Energy Agency.

The average energy consumption in kWh/sqm according to year of construction is distributed as follows:

Fig. 1 Average annual energy consumption for heating and warm water in Sweden.

The latest construction types use significantly less energy per sqm than the older ones. This is in line with our expectations. For single dwellings average consumption has dropped by some 40 % from 153 kWh/sqm to 91 kWh/sqm. For multi-dwellings the decrease was not as dramatic. Nevertheless, average consumption went down from its maximum value of 170 kWh/sqm to 125 kWh/sqm (26 %).

The consumption figures per category are displayed in Fig. 2.

Fig. 2 Energy consumption for heating and warm water by year of construction.

Taking the latest construction technology as a reference, we may calculate how much energy could be saved if the entire building stock was refurbished according to that standard. The results are shown in Fig. 3.

Fig. 3 Calculated savings potential by year of construction.

As regards the single housing sector refurbishing the oldest part of it would account for 50 % of the total savings potential of that sector. Obviously, the younger part of the building stock would only contribute very little (2 %) to the entire potential.  In total, we could expect to save some 9.9 TWh for single dwellings and 5.5 TWh for multi-dwellings. Thus the entire savings potential from the housing sector would amount to 15.4 TWh which corresponds to 24 % of all energy used for heating and warm water.

This is an impressive number although in terms of Mtoe its equivalent is a mere 1.3 Mtoe. Thus we may conclude that renovating the Swedish housing stock would provide savings of about 10 % of the entire reduction goal set by the Swedish government (12.8 Mtoe). Having said that we have to admit that the biggest part of the task is still to be done.