The deep renovation of high-rise apartment buildings to create positive-energy neighborhood

Abstract

Decarbonizing cities requires transforming existing high-density residential districts into low-carbon or Positive Energy Neighborhood (PENs). This is particularly challenging in cold climates, where high seasonal heat demand, limited solar availability, and aging building stock constrain both energy performance and on-site renewable energy generation. This study evaluates the feasibility of transforming a high-rise residential neighborhood in Estonia into a PEN through deep renovation and local renewable energy integration. A multiscale approach was applied, combining building-level energy performance modelling with neighborhood-scale renewable energy supply analysis. The results show that deep renovation measures, including improved insulation and high-efficiency heating and ventilation systems, can reduce building energy demand by 60%–70%. Rooftop photovoltaic (PV) systems can supply 12%–27% of post-renovation electricity demand when combined with efficient district heating. Facade-integrated PV systems can increase renewable electricity coverage to as much as 85%; however, their energy yield decreases by 24% because of non-optimal orientation and solar exposure. The findings show that achieving PEN status in cold-climate high-rise building neighborhoods is not possible through building-integrated renewable energy alone and requires additional off-site or neighborhood-scale renewable energy generation. Meeting winter heating demand with renewable sources would require land areas approximately 20 times larger than the building footprint for biomass sources and twice the footprint for ground-source heat systems. This study proposes an integrated pathway for transitioning high-rise residential neighborhoods toward PENs by combining deep building renovation, improved indoor environmental quality, and neighborhood-scale renewable energy deployment. The results highlight the importance of aligning technical, spatial, social, and ecological strategies within urban planning to enable scalable implementation of positive energy neighborhoods in cold climates.