During harvesting and production, refrigeration, the chilled water plant and compressed air are the biggest energy users. Other energy-intensive processes include stalk removal, filtration, blending and moving wine between tanks.
During the storage season, the chilled-water plant is generally shut down and compressed-air systems only used to operate valves involved in mixing and blending between tanks. Refrigeration is still required for the cold-stabilisation process, in which white wine is chilled to near freezing point to prevent potassium bitrate residues forming when bottles reach consumers.
Through the Industrial Energy Efficiency (IEE) Project, Durbanville Hills and its staff were introduced to energy systems management (EnMS) and energy systems optimisation (ESO). The company then approached the NCPC-SA for a site assessment, and has since had an in-depth investigation into its energy consumption done.
In three years, Durbanville Hills implemented six energy-saving projects, cutting electricity costs from R155.19 to R97.61 per tonne of wine produced. GHG emissions were reduced from 103.37 to 87.60 tonnes of CO2 per year per tonne of wine produced.