What is the missing piece for building ‘green’?

Despite the emerging business case for ‘green’ or NZC buildings, the perception that such buildings have a higher capital cost with low returns on investment remains a barrier. An initial scoping exercise, in support of the C40 Buildings Programme, highlighted the common concern that ‘green’ or NZC building requirements would financially burden and constrain development, particularly in a time of recession. This prompted the implementing team at Sustainable Energy Africa with the eThekwini advisor for the C40-SEA New Buildings Programme, to explore the question in some detail, hoping to establish an evidence-base of the cost differential between ‘standard specification’ buildings and NZC buildings.

A model was developed to compare standard specification and NZC building costs, using information provided by the Green Building Council (GBC) South Africa and AECOM South Africa.The model shows cumulative discounted costs for construction (financed over a specified number of years), PV capex (where applicable; also financed) and electricity consumption; per m2 floor area; over a 30-year time period; for various building types (residential, office, retail and school); for (1) standard buildings, (2) energy efficient buildings and (3) energy efficient buildings with rooftop PV.

In summary, the model results indicate: