Climate, land, energy and water strategies: City of Cape Town

Client: International Atomic Energy Agency

Period: March 2012-March 2015

Project leader: Alison Hughes

Project team: Alison Hughes, Fadiel Ahjum, Adrian Stone, Charles Fant (MIT)

The broad aim of the research is to apply the CLEW modelling framework to analyse climate, land, energy and water interactions and implications associated with the socio-economic development of the City of Cape Town.

The approach can be summarised as follows:

  • Construct the reference system diagram (RSD), which includes the main components of the energy, water and land, at a level of detail that can capture the key policy questions and uncertainties.
  • Assemble data on current and historical energy, water and land use patterns in relation to the socio-economic development of the City of Cape Town, and current technologies.
  • Assemble data on future technologies that may enter the system within the planning horizon.
  • Project plausible pathways of development for the City of Cape Town, and the resulting energy, water and land resources that are required to support these development pathways.
  • Use the CLEWS  framework to analyse the impact of different policies on water, energy and land requirements for the city's sustainable development.

The initial phase of the project considered the City's energy consumption for water and sanitation services with an emphasis on water supply augmentation options for the near future (2011-2030). This phase, detailed below, was completed in December 2012 and comprises the UCT Masters thesis titled: Energy for Urban Water Services: a City of Cape Town Case Study.

There are 12 major high potential agricultural production areas in the Western Cape some of which are proximate to or even surrounded by Cape Town suburban areas. This includes wine growing areas and vegetable production in The Phillipi Horticulture Area (PHA). The latter has become the centre of a public debate as the pressure to develop sites for housing, particularly low cost housing increases. The need for housing is in competition to the need for sources of affordable fresh produce, the need to reduce the energy used in food supply chains and most of all the pressure on fresh water supplies for all activities in the region.

This work proposes to examine CLEW trade-offs in the context of urban food security (i.e. urban horticulture) vs residential housing in the City of Cape Town. As such the study will explore the CLEW implications for the City given scenarios for either the relocation or conversion of central urban horticultural land into housing; or conversely the development of housing on the urban periphery. Specifically, to quantify the energy and water trade-offs  for the alternate land-use scenarios within the metropolitan boundary for the provision of water and sanitation, public transport, and food production.

Current work tasks:

  • Integrate the existing and separate older LEAP and WEAP City models into a single integrated LEAP-WEAP model.
  • Utilising  the software tools LEAP, WEAP and  SAPWAT extend and refine the existing LEAP-WEAP  City model to incorporate urban horticultural  zones (e.g. yield, crop irrigation demands) and land areas suitable for residential housing.
  • Quantify the energy tradeoffs in water and sanitation services, transport and food production for the scenarios.