Feasibility study of renovation of a residential building in near zero-energy building

Abstract

In this feasibility study, a renovation of a residential building in near zero-energy building was studied.

For this purpose, a selection of available on the market solar and wind energy conversion systems was taken. The shortlisted systems were, then, compared along key criteria that define their fit and efficiency for application in on-site energy generation. The consumption and electricity prices used for the purposes of this study were forecasted for the entire project period. These forecasts, together with the results from the energy conversion systems comparison, were then implemented in a simulation model that extrapolates over the period of 25 years the performance of various alternatives for the renovation of the residential building.

Based on the simulation results, the most efficient, and, therefore, optimal, configuration of renewable energy sources for the studied site, in terms of maximum on-site generation, is the use of a combination of wall and roof-installed photovoltaic panels. Moreover, the energy storage option is not feasible for any of the simulated configurations. Finally, the electricity purchase contract for the building should be based on the spot market price formation.

The overall implementation of the optimal configuration requires EUR 70387.97 of initial costs. The total net present cost is equal to EUR 201503.00, whereas the levelized cost of electricity is equal to EUR 0.117. During the project implementation, 50344.48 kWh will be purchased from the grid and 36461.58 kWh will be sold, yielding 13882.90 kWh of net purchase. The fraction of renewables in the overall consumption, during the entire project, will be 55.16 percent. The payback period of the system configuration exceeds the project implementation period.

The study was funded by Aalto University Student Union (AYY).