Generating low-cost national energy benchmarks: A case study in commercial buildings in Cape Town, South Africa

• Municipality datasets provide opportunity for generating building energy benchmarks.
• Statistics are presented for electricity consumption for retail and office buildings.
• Benchmarks were developed for annual electricity use in retail and office buildings.
• Simple improvements to database could enable rapid generation of energy benchmarks.

National benchmarks are a valuable tool for assessing and monitoring energy consumption in existing building stocks worldwide, but can be time consuming and expensive to generate. I explore a low-cost alternative by coordinating building related data collected by municipalities in South Africa for billing and rates purposes, to create energy use intensities (EUI) for the existing building stock. For a sample of commercial buildings in Cape Town, I link electricity data supplied by the municipality billing department with gross floor area data from the municipality valuation (rates) department, to establish EUIs. From these I calculate benchmarks that represent typical annual electricity usage for retail and office buildings in Cape Town. In addition I identify a number of improvements to data quality and access that would enable South Africa to realise the current opportunities that exist in the structure of its building data collection. In doing so South Africa can potentially leapfrog many other countries in the development of performance-based benchmarks and rating tools for a range of building activities, positioning it at the forefront of building energy-data collection.