Variability of Technical Challenges across neighbourhoods in transitioning to Solar-Powered Positive Energy Districts

Positive Energy Districts (PEDs) are a transformative approach to urban energy systems, targeted towards energy self-sufficiency, reduced carbon emissions, and improved energy equity. They aim to generate as much energy as they consume, often by integrating renewable energy sources, energy storage, and demand-side management. Among various renewable energy technologies, solar photovoltaics (PV) are increasingly deployed on rooftops to meet the neighbourhood’s electricity demand, while heat pumps are utilised for efficient space heating. The electricity generated from solar PV can power heat pumps, improving overall energy efficiency for a building. However, widespread solar PV adoption, especially during the summer months, generates excess energy that can lead to grid congestion. Therefore, not all neighbourhoods in a city may transition into a PED without substantial grid upgrades or expansions. In this study, we aim to identify neighbourhoods where solar PVs and heat pumps can achieve a net-positive energy balance in an optimum way.

We analyse the energy demand of buildings in the neighbourhoods of Den Burg Texel, an island in The Netherlands,  focusing on identifying optimal neighbourhoods for PED implementation. To assess the feasibility of neighbourhoods for PED implementation, we simulate the electricity demand profiles of the buildings, combining typical electricity usage and potential demand from heat pumps. Using a 5R1C building thermal model, we simulate heat demand profiles for residential neighbourhoods, incorporating local weather data, building geometries, and occupancy patterns. We model three levels of insulation: existing, usual refurbishment, and advanced refurbishment, based on TABULA database (Loga et al., 2016).  To evaluate renewable energy potential, we simulate solar PV generation with varying penetration levels, accounting for roof orientation, shading, and local climate conditions. For this analysis, we use the Time Series Initialization for Buildings (tsib) Python package (Kotzur, 2018), with local weather inputs from COSMO-REA6 reanalysis data.

We compute technical indicators such as unfulfilled demand, loss of power supply probability, excess energy, grid stability, and storage capacity requirements for all neighbourhoods. Our analysis suggests that integrating rooftop solar PV systems and heat pumps, along with insulation refurbishments, can significantly increase energy self-sufficiency in all the neighbourhoods.  However, adopting solar PVs and using heat pumps in poorly insulated buildings can increase grid congestion, especially during peak generation or high heating demand in winter. Building refurbishments that lower the heat demand helps mitigate the challenges by reducing energy consumption. Based on the technical indicators, we identify neighbourhoods where solar PV systems and heat pumps can achieve a net-positive energy balance while minimising the challenges. Finally, we discuss how different neighbourhood characteristics influence the technical feasibility of the transition of a neighbourhood into a PED.

Kotzur, L. (2018). Future grid load of the residential building sector (PhD Thesis). RWTH Aachen University. https://scholar.archive.org/work/6ffkvyknnjgc3hb5uewdaklxua/access/wayback/http://publications.rwth-aachen.de/record/752116/files/752116.pdf

Loga, T., Stein, B., & Diefenbach, N. (2016). TABULA building typologies in 20 European countries—Making energy-related features of residential building stocks comparable. Energy and Buildings, 132, 4–12. https://doi.org/10.1016/j.enbuild.2016.06.094