Positive Energy Buildings, PEB, is a relatively new and more ambitious energy target than the Nearly Zero Energy buildings, NZEB. Currently, there is no official definition at EU level. However, there are several projects investigating the PEB concept. According to the EU EXCESS project (1,2), ‘‘a positive energy building (PEB) is an energy efficient building that produces more energy than it uses via renewable sources, with high self-consumption rate and high energy flexibility, over a time span of one year. A high-quality indoor environment is an essential element in the PEB, maintaining the comfort and well-being of the building occupants. The PEB is also able to integrate future technologies, such as electric vehicles with the motivation to maximize the onsite consumption and also share the surplus renewable energy”. As mentioned in (3): ‘Technically, a PEB is a Net ZEB with an increased capacity of the renewable energy generation inside the boundary of the building in order to surpass the annual equality of the net energy balance’.
The EU energy and environmental policy framework aims to make Europe the first climate neutral continent. The development of advanced energy technologies and the massive retrofitting of the building stock as foreseen by the European Strategic Energy Plan and the European Green Deal create new advanced targets regarding energy and emissions status of the current and mainly of the future buildings leading to increased spread of PEBs (4,5).
The PEB concept is based mainly on the use of intensive energy conservation measures to decrease as much as possible the energy needs of buildings combined with renewable energy systems installed in the buildings’ boundaries, producing excess energy that either is stored within the building area, is transferred to the grid, or both. The concept of PEBs is illustrated in Figure 1 (2).
The decrease of the energy demand of the buildings through the intensive and efficient use of energy conservation measures, is the core requirement of a PEB, in line with the "energy efficiency first" principle (6). Decisions on the level of the selected energy conservation measures as well as options for on-site renewable energy sources should be based on cost optimality, as proposed by the Energy Performance of Buildings Directive (2).
Figure 1: The PEB concept. Source: (2).
To note that as of 2030, according to the EPBD proposal, new buildings shall not cause any on-site carbon emissions from fossil fuels. In the context, it seems logical that PEB projects will phase out fossil-fuel boilers and promote systems with no direct GHG emissions, such as heat pumps and other renewable-based technologies.
A PEB can be autonomous - imports no energy from the grid or off-site sources as it produces on-site enough renewable energy to cover its energy needs. However, the surplus of energy can be exported to the grid. The storage components are included in the boundary of the building.
A PEB can be dynamic - interacts with the energy grid, other off-site renewable sources and buildings by importing and exporting energy. In this case, the combined on-site and off-site generation of renewable energy shall cover the energy needs of the building. The storage component can be located outside the boundaries of the building.
Figure 2: Positive-energy Own-consumption in Offices. Will house the Cite Regionale de l Environnement d Ile-de-France from 2014 for a lease period of nine years, (8)
The main purpose of this document is to provide knowledge, information and a reference for the decision makers, city authorities, planners and building professionals to design and implement PEBs across different climatic and location-based conditions.
Figure 3 : Operational Principle of the Cite Regionale de l Environnement d Ile-de-France, (8).
Figure 4 : Student housing in Ghent, Belgium, (9)
Figure 5: Positive Energy Home, Sterksel, The Netherlands, (10)