Towards a Positive Energy District: Energy Efficiency Strategies for an Existing University Campus

Developing positive energy districts (PEDs) is a key strategy in the global energy transition to reduce the high energy use and greenhouse gas emissions from the built environment. While the creation of new, energy-efficient urban areas as PEDs is essential, transforming existing districts is even more challenging, as they contain buildings of different types, ages, and energy performance levels. This study investigated energy efficiency improvements to facilitate the transition of an existing university campus toward PED operation. The NTNU Gløshaugen campus in Trondheim, Norway, was analyzed using a calibrated multi-building energy model (MBEM) developed using the URBANopt tool. Buildings were clustered into four age-based cohorts to assess the impact of targeted energy conservation measures (ECMs) on different construction periods. In addition, three energy efficiency scenarios were evaluated over the period 2025–2030 to capture the combined effects of new construction and renovation of existing buildings. Results showed that applying envelope improvement ECMs was more effective in older buildings, where lower baseline energy performance allowed for higher relative reductions in energy use. By the end of the simulation period, the specific energy use of the entire campus decreased from 252.2 kWh/m² in 2025 to 161.7 kWh/m² under moderate and 85.9 kWh/m² under deep retrofit conditions. These improvements create more favorable conditions for meeting the remaining energy demand through renewable sources, achieving an overall renewable coverage of 97%, and moving the campus closer to meeting PED targets.