The feasibility of zero-emission neighbourhood renovation of apartment buildings in a cold climate

• Transform 22 apartment buildings into Positive Energy Neighbourhood (PEN). • Applies Life-Cycle Assessment to quantify embodied and operational carbon in renovations. • Identifies critical land-use barriers for achieving net-zero emissions in dense urban areas. • Proposes policies mandating renewable energy in building renovations. • Offers a novel framework for net-zero urban districts in cold climates. The role of cities is instrumental in achieving the climate neutrality of building stock by 2050. This study evaluates the renovation potential of a group of 22 apartment buildings in Tartu, Estonia, and particularly feasibility of a transformation to a Positive Energy Neighbourhood (PEN). The challenges of urban density and cold climate are emphasised, representing a vital case for the European Union's "Zero Emission Districts and Neighbourhoods for Sustainable Urban Development" initiative. To assess the feasibility and implications of achieving PEN standards, an analysis was conducted in a densely populated urban area enhancing energy efficiency, evaluating land use implications, and achieving carbon neutrality. This study applies Life-Cycle Assessment to discuss four renovation scenarios: (1) baseline, (2) the minimum requirement set by the Estonian long-term renovation strategy, (3) the performance of nearly zero-energy buildings (nZEB), and (4) PEN. The findings show that while PEN is achievable, the extensive land area required for renewable energy production or nature-based carbon sinks challenges its feasibility in dense urban environment. The results reveal that the minimum energy efficiency level required by the long-term renovation strategy does not reduce the whole-life emissions, therefore it is crucial for renovation grants to also require investments in on-site renewable energy production. Transitioning urban neighbourhoods into zero-emission districts requires integrated strategies that combine energy-efficient renovations, renewable energy deployment, and innovative urban planning. The results of this study imply that decarbonisation policies should not be driven merely by the net-zero emissions balance due to the disproportionate land-use impact of offset measures.