Decarbonising Riga's housing stock: solar integration and energy sharing in multi-apartment buildings

Extended abstract 4-293-26

Latvia has the second-highest share of flat-dwellers in the EU, with over 64% of residents living in apartment buildings – a pattern especially pronounced in Riga, where roughly 90% of the building stock predates 1990. Multi-apartment buildings sit at the centre of Riga's decarbonisation agenda: at least 6,000 require renovation, and a far greater number fall short of optimal energy performance.

Complex property relations and fragmented housing management have long represented structural barriers to local renovation projects. The recent energy crisis has shifted energy governance higher on the urban policy agenda, as rising prices brought building-level energy systems into sharper focus and opened space for energy-community approaches combining renewable energy integration with efficiency measures.

Residents of multi-apartment buildings might appear well positioned to form energy communities, given their proximity and shared interests. In practice, however, solar energy sharing remains difficult to implement. Building envelopes and electrical installations may require targeted upgrades before renewable integration is feasible, while collective self-consumption continues to face legal and regulatory barriers across many EU member states – a situation recently flagged by the European Court of Auditors.

Renewable energy integration in multi-apartment buildings thus represents both a technical challenge and a policy frontier, requiring configuration-specific models and scenarios. This study addresses the topic from two angles. First, it maps city-wide needs for decarbonising heat supply through local renewable energy and system integration. Second, it examines an energy-sharing concept for multi-apartment buildings, accounting for the specific conditions governing customer connections, metering, and energy-market data exchange.

The analysis prioritises buildings with domestic hot-water heating and electric vehicle charging, where daytime consumption can improve the local use of rooftop PV generation. Realising the full benefits of rooftop PV would also require enabling individual apartment-level consumption – feasible under the current framework primarily in buildings with a single distribution system connection point.

These findings inform the design of municipal and national support measures for renewable energy integration in multi-apartment buildings and contribute to the broader objective of enabling energy-sharing frameworks and affordable energy solutions under the Citizen Energy Package.

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