Residential buildings consume approximately 20% of the total primary energy use in Europe. In Finland, the residential sector uses 35% of total electricity consumption. Our current energy profile is carbon intensive and relies on the consumption of fossil fuels. For this reason, households are notable contributors of climate change. As part of Europe’s energy roadmap for 2050, it has been suggested that the greenhouse gas emissions associated with buildings have to be reduced by 90% compared to 1990 levels.

The purpose of my research was to evaluate how smart buildings can contribute to decreasing electricity consumption, and reducing their impacts on climate change and environmental degradation. The ‘smartness’ of buildings is provided by a home energy management system, which is aware of the state of the electricity network, including the balance of demand and response, and the real-time price of electricity. Based on these data, the control system can give recommendations to inhabitants to reduce electricity use or shift it to times, when electricity is cheapest. Such systems can provide significant savings to the consumer and reduce their electricity bills.

In addition, I assessed the real-time environmental impacts of electricity, based on the types of fuels used to generate electricity at any given moment, the life-cycle environmental impact of these fuels and the electricity generation process. I used a cycle analysis tool, which utilises 18 environmental indicators, to find out the real-time environmental impacts of smart buildings. These dynamic indicators have not been applied in these studies before before. In order to get insights into the impacts of human behaviour itself, a smart building simulation model was created. With the help of this model, I could evaluate how people would interact with the smart system, and how their willingness to change their electricity use could contribute to reducing their environmental impacts.

My research showed that increased awareness could contribute to a reduction of electricity consumption in homes, although only to a minor extent (3% at most). In terms of reducing environmental impacts, important issue is not only how much electricity we consume, but rather when do we consume it. This is because in peak consumption times, such as mornings and evening, the electricity tends to carry higher environmental load, and is also more expensive. An important function of smart technologies, therefore, is to flatten the load profile. Smart grids perform best in this term, for example by shifting the load from the evening to the night time, when consumption is the lowest.

The highest level of control is when smart devices control every single appliance in the household.  However, I found that such an extensive control level does not yet make sense, due to the energy demand of individual control devices, such as sensors and smart plugs. This is especially the case for smaller households. For a single person household, the electricity consumption actually increased 15% with a fully controlled home. Considering that household size in Finland has been decreasing for the last 10 years, currently being at 2.03 inhabitants, the appropriate level of control in smart houses needs to be considered carefully. In general, larger households have a better chance of saving money and reducing environmental impacts by using smart technologies.

The smart technologies have a great potential to decrease the electricity demand of the residential sector and reduce associated environmental impacts. However, before smart technologies can make a real impact, the energy consumption of home management systems will need to decrease considerably.

Jean-Nicholas Louis, doctoral student at the Energy and Environmental Engineering Research group, University of Oulu

Jean-Nicolas Louis will defend his dissertation titled “Dynamic environmental indicators for smart homes: Assessing the role of Home Energy Management Systems in achieving decarbonization goals in the residential sector‘ at the University of Oulu on 2nd of December. The opponent will be Dr. Sarah Darby from Oxford University, Environmental Change Institute, Deputy Leader of the Energy Programme. The electronic version of the dissertation is available via the link above.