۱- Introduction

۲- Background

۳- Methods

۴- Results

۵- Discussion

۶- Conclusions

References

Abstract

Limiting global warming to 1.5 °C requires a substantial decrease in the average carbon intensity of buildings, which implies a need for decision-support systems to enable large-scale energy efficiency improvements in existing building stock. This paper presents a novel data-driven approach to strategic planning of building energy retrofitting. The approach is based on the urban building energy model (UBEM), using data about actual building heat energy consumption, energy performance certificates and reference databases. Aggregated projections of the energy performance of each building are used for holistic city-level analysis of retrofitting strategies considering multiple objectives, such as energy saving, emissions reduction and required social investment. The approach is illustrated by the case of Stockholm, where three retrofitting packages (heat recovery ventilation; energy-efficient windows; and a combination of these) were considered for multi-family residential buildings constructed 1946–۱۹۷۵٫ This identified potential for decreasing heat demand by 334 GWh (18%) and consequent emissions reduction by 19.6 kt-CO2 per year. The proposed method allows the change in total energy demand from large-scale retrofitting to be assessed and explores its impact on the supply side. It thus enables more precisely targeted and better coordinated energy efficiency programmes. The case of Stockholm demonstrates the potential of rich urban energy datasets and data science techniques for better decision making and strategic planning.

Introduction

Reaching the Paris Agreement goal of limiting climate change well below 2
C requires transformation of energy systems globally. The world is becoming increasingly urbanised, with more than 50% of the global population currently living in cities (X. Wang et al., 2017). Thus, sustainable and viable cities play an important role in energy system transformation. In 2014, buildings accounted for 31% of final energy use and 8% of energy-derived CO2 emissions globally. Coal and gas are commonly used for supplying heating and cooling. The more stringent target for global warming, of 1.5
C, implies that the carbon intensity of buildings must be limited to on average 36 g/ kWh. This can be achieved through a combination of reduced heating and cooling demand, and/or transforming supplying energy to buildings (Rogelj et al., 2018). In buildings, about 50% of the energy demand comes from space heating and cooling and 16% from water heating (IEA, 2017a). While conserving energy through the use of more efficient appliances could play an important role (Huebner et al., 2016), heating and cooling account for almost 80% of direct CO2 emissions from buildings (IEA, 2017a). Therefore, reducing the space heating and cooling demand, combined with decarbonisation of district heating and electricity generation, is recognised as an essential strategy in realising a vision of ‘decarbonised buildings’ (EU Commission, 2016).