Comprehensive Modeling of Optimal Paths to Reach Nearly Zero Energy Buildings (nZEBs) for New Constructions in Europe

As established by the recast of the European Union (EU) Directive on Energy Performance of Buildings (EPBD), all new buildings have to be nearly zero energy buildings (nZEBs) by the end of 2020. However, reaching this result considering cost-optimality is still an open challenge. Balancing renewable power generation with energy efficiency to reach the nZEB target is a key goal of all EU Member States. We describe results obtained from the modeling of nZEBs for new constructions in Europe using the energy performance software EnergyPlus. The model performs hourly sequential simulations showing how to best achieve nearly zero energy home design at the lowest possible cost in 36 representative locations across Europe. We adapted the model to run in a new residential building prototype using local hourly climatic data, relevant construction methods, cost data and unit energy consumption. A novel aspect is the inclusion of future climate change relative to estimated cooling loads. We also performed a sensitivity analysis both on energy and economic parameters as well as PV costs, accounting for the need of short term electrical storage. A key finding of the research is that energy reductions of 80% and beyond are economically feasible for new constructions, although the mix of selected measures varies strongly with climate. Results show how a broad approach to efficiency mixed with renewables is feasible in each location at different costs. In particular, we illustrate how exclusion of lighting and appliances results in suboptimal solutions, especially for electricity use which has a huge impact on greenhouse gas emissions.