Scenarios for a South African CSP Peaking System in the Short Term

AbstractThe South African Integrated Resource Plan is a policy document, which by law allocates the energy resources that will be built to meet the future electricity needs of South Africa. The current Integrated Resource Plan indicates the electricity generation types that will be built from 2010 to 2030. It states that most of the future peak load will be met by Open Cycle Gas Turbines which operate using diesel and represents an allocation of 4,930M W. Further, the Integrated Resource Plan does not identify CSP as a potential peaking solution and allocates 1,200M W of capacity to CSP. This represents less than 2% of total capacity in 2030.This paper investigates the feasibility of utilizing CSP Plants as peaking plants in the short to medium term based on a proposition that under certain scenarios, a fleet of unsubsidized CSP peaking plants could drop the LCOE of the current Integrated Resource Plan. This is done by modeling a contemporary CSP tower system with Thermal Energy Storage. The Gemasolar CSP plant is used as the reference plant in order to obtain operating parameters.Our analysis suggests that at current fuels costs, diesel powered Open Cycle Gas Turbines produce electricity in excess of 5.08 ZAR/kWh (∼0.63 US$/kWh), significantly above current CSP energy generating costs. This is the context that informed the undertaking of this study, to influence policy and provide technical evidence that CSP can guarantee and deliver energy at competitive costs in the short term. Two alternate scenarios show a lower LCOE for providing peak power. The most promising is a combined distributed CSP system wit h diesel powered Open Cycle Gas Turbine system as backup. The LCOE for this system is 2.78 ZAR (∼0.34 $/kWh) or a drop of 45% when no fuel price inflation is considered. This system also increases security of supply due to a lower dependence on fuel prices