Building renovation is a key measure to reduce energy consumption and Greenhouse gas (GHG) emissions, and ease the transition to a fully renewable energy system. This paper applies the IEA EBC Annex 75 methodology for investigating the cost optimal and environmental trade-off between investment in energy efficiency measures on the building envelope and energy supply, on a residential neighbourhood in Norway. Combination of different energy efficiency measures and energy supply systems are investigated with an optimal investment model. The cost and environmental impact of the combinations are evaluated. An important outcome is that within the evaluated combinations, the choice of energy supply system has little impact on the cost effectiveness of the energy efficiency measures. However, it has a significant impact on the GHG emissions. The results also highlight the importance of performing energy efficiency measures in coordination with other renovating measures, both regarding cost effectiveness and environmental impact. The results will not give a finite answer to what is the best solution but serves at a useful set of inputs for overall evaluations.
Cost optimal investment in energy efficiency measures and energy supply system in a neighbourhood in Norway