Scenario modelling for short to long term rollout of Concentrating Solar Power (CSP) in South Africa

[摘要] ENGLISH ABSTRACT: South Africa is currently in the process of greatly expanding its electricitygenerating infrastructure. A significant portion of the new capacity will be madeup out of renewable energy systems. The aim of this study was to investigatepotential benefits and pitfalls of introducing concentrating solar power (CSP) intothe South African electricity generating system, by making use of spatio-temporalmodelling. Government policy for the expansion of the generating fleet is definedin the Integrated Resource Plan for electricity (IRP). A draft update of the IRPthat describes a number of possible scenarios for the composition of thegenerating fleet was released in 2013. Three of these were selected and modelledfor the 2030 and 2050 fleet composition and projected demand for the purpose ofthis study. The effect of implementing a two tier tariff designed to incentiviseelectricity production during evening peak by CSP plants was also investigated.All modelling was done on an hourly basis. Spatio-temporal modelling was usedto model wind, photovoltaic and CSP electricity production. The balance of thegenerating system was modelled using a behavioural model. The systemperformance was compared across scenarios by using the following systemadequacy measures: electricity shortfall, open cycle gas turbine capacity factorand coal plant capacity factor.Comparing CSP plants that were optimised to be remunerated under a two tiertariff with plants that were optimised to minimise levelized cost of electricityshowed that imposing the tariff had a significant impact on plant configurationand electricity production. Using CSP plants that were under a rigid two tier tariffwas also found to have a negative impact on system adequacy measures in asystem with a high renewable energy uptake. The results were reasonable for asystem with a moderate uptake in renewable energy and good for a system with alow uptake. For example: acceptable levels of electricity shortfall in a projectedsystem would be equal to 20 GWh per year. With the two tier tariff in place thelow uptake scenario averaged 32.9 GWh, the moderate uptake scenario 99.6 GWhand the high uptake scenario 5059.7 GWh for 2050.Results for the two higher uptake scenarios were improved significantly byredeploying a large portion of the CSP plants as base load units that wereresponsive to system needs. The results for a system with a high uptake ofrenewable generating capacity was still not at acceptable levels (e.g. 844.52 GWhshortfall), but the moderate uptake system performed well. This may indicate thatthe higher the uptake is of renewable energy, the more flexible the electricityoutput of the CSP will have to be for optimal overall system performance. Whilethis flexibility is technically feasible, according to this study a rigid remunerationstructure will not incentivise the CSP plants to act on this capability.

[发布机构] Stellenbosch University