Towards nearly zero energy buildings in Europe – a focus on retrofit in non-residential buildings

Written by Energy Agency Styria

Aim of the recent published paper of the European Commission’s Joint Research Centre, Institute for Energy, Transport and Climate is to provide an overview of the status of implementation of nZEBs in Europe with a focus on retrofit in non-residential buildings. 

The building sector is a strategic focus of the European policies, aiming to achieve a sustainable and low carbon economy by 2020. Key instrument towards this goal is the Energy Efficiency Directive EED, which includes plans to increase the energy efficiency on a European level. The EED requires member states to establish long-term strategies until 2020 and beyond for accelerate the renovation rates of residential and commercial buildings. Focus is the improvement of the overall buildings quality in terms of efficiency and renewable energies used. From January 2014 member states are asked to ensure annual renovation rates of 3% of the total floor area of heated/cooled buildings owned by public authorities.

Another central policy document is represented by the recast of the Energy Performance of Building Directive (EPBD), which introduces nearly zero energy buildings (nZEB) and requires, that all new buildings have to be nZEB by 31st December 2020. Besides those efforts, it is necessary to tackle the high energy consumption of existing buildings. Overall, buildings contribute with about 40% to the total European final energy consumption, making the building stock responsible for 36% of the European CO2 emissions.

The progress made by the European Member states towards the establishment of NZEB definitions is summarized in diverse National plans. When comparing the stated national threshold values for maximum primary energy demand, the different definitions in relation to energy calculations reveals that included energy uses are heating, domestic hot water (DHW), ventilation, and cooling. The most common choice regarding the energy balance calculation is the difference between primary energy demand and energy generated, over a one year period, and considering annual constant weightings/factors (e.g., primary energy factors). Additionally, almost all Member States prefer the application of low energy building technologies and available on-site RES. The used technologies are PV, solar thermal, air- and ground-source heat pumps, geothermal, passive solar, passive cooling, wind power, biomass, biofuel, micro combined heat and power (CHP), and heat recovery. Nevertheless, a huge variability can be found among European countries also in relation to energy performance requirements and calculation methodologies available around NZEBs.

Additionally, the paper states that the attention, given to nZEBs increased over the last decades, due to the fact that the potential to decrease energy consumption and increase use of renewables can be considered as quite big. In recent years, most Member States introduced measures addressed to the energy improvement of the existing building stock and new strategies have been defined, in compliance with the EED. As a result, Member States are more aware of the huge impact of the existing building stock, but they need to further strengthen the adopted measures to successfully stimulate cost-effective renovation.

Concluding it can be said, that Member States need to design consistent policy instruments (policy packages considering technical, economic and financial aspects) to provide the required long-term stability to investors in efficient buildings. There is also the need to adopt detailed roadmaps towards NZEBs, including quantitative targets, and implement monitor systems to obtain consistent data on policy impacts towards a comprehensive retrofit implementation.

The full paper is available at EC.EUROPA.EU