Measuring energy efficiency: Indicators and potentials in buildings, communities and energy systems

The European Commission implemented a strategy for Climate Action in 2008. According to that strategy, the Member States will reduce their collective greenhouse gas emissions by at least 20% and boost the share of renewable energy to 20% of total consumption by 2020. In addition, the European Union has set an indicative objective to reduce its primary energy consumption by 20% compared with the projected 2020 energy consumption. This stresses the need to increase energy efficiency in the EU. However, until now there has been no common methodology on how to measure energy efficiency or evaluate the savings achieved by it. The research project “Measuring and potentials of energy efficiency (EPO)” was launched in January 2008 to facilitate development in this field. The main objective of the research was to develop a general approach to measure energy efficiency. Furthermore, the research aimed to develop an approach which could be used to calculate the potential achieved by improved energy efficiency. Measuring energy efficiency and potentials are connected closely to each other in the sectors of energy production and distribution, industry, buildings, communities, transportation, and logistics. This report is a stateof-art description and a summary of the research findings in buildings, communities and energy systems made by VTT. Energy systems consist of many energy chains or routes, which include alternative energy sources and process technologies, distribution and storage systems and end use equipments using electricity and producing, heat, light or movement. Almost all energy sources utilize many alternative routes, which may bifurcate and join together again on the way to the end user. Energy efficiency in different energy chains was investigated in batch-surveys on the energy sector. Technical possibilities in energy chain have been evaluated for scenario calculation of energy saving potential in the future. Efficiency impacts to primary energy demand were also evaluated. Emissions of different energy production ways give the value for environmental impacts and further the impacts of making more effective energy chains. A calculation model was made called “EPOLA”, which is used with scenario technique to analyse impacts of making more efficient national energy chains and to find out the most efficient ways to realise them. Energy production chain has many indicators, which can be presented in consumption/produced-MWh that is one produced energy unit needs fuel, transportation, service, and human resources as well as transfer losses, emissions, and wastes. Indicator of quality of products, availability, reliability and on-peak period has to be present in another way. Indicators during building like material/produced-MW that is one built power unit needs materials like concrete, steel, copper, plastic, glass, etc. Energy is also required when building. The indicators of driving and building can be compared to each other in different energy production alternatives or to make bench marking with same kind and age energy production somewhere else. Energy use in communities (city regions, cities, towns, and other urban areas as well as rural communities) takes place in both buildings and infrastructure, during construction, use, maintenance, repair, renovation, demolition and recycling as well as during transportation of people and goods. That is why energy efficiency of communities must be a composition of energy used during the lifecycle of several physical elements brought together for the community. Energy efficiency of communities can be defined as a ratio between an input of energy consumption or emissions, and an output of services, such as number of inhabitants and jobs or floor square metres. There are several energy efficiency indicators which consist of different parts and phases. Indicators complete each other. System boundaries for measuring energy efficiency of communities can be defined on the grounds of planning levels and areas or from functional bases. Communities may have a relatively high potential for energy efficiency improvements. Potential seems to be highest in the operation phase of structures and in transportation. Buildings have a relatively high potential for energy efficiency improvements compared to other sectors of the economy. Indicators are needed to measure both current energy efficiency and improvement potential. Various indicators serve different purposes and interests in the buildings sector depending on the needs of the indicator’s user, who may range from the user of the building to the regulator, just to mention two of the typical stakeholders of a building. Defining a uni-