Techno-economic analyses of solar thermal process heat integration at South African beverage producers

Abstract

South Africa's industrial sector relies primarily on coal and gas to meet process heat requirements (700–750 petajoules per annum). Much of this energy is used to fire steam boilers operated at less than 200 °C. This study determines the viability of solar thermal technologies as a replacement for fossil fuels for the supply of steam in large beverage facilities in South Africa. The Gauteng and Western Cape provinces are considered, which account for two-thirds of South Africa's beverage production. The sizing of collector fields and potential solar fractions are determined using typical ready-to-drink beverage packaging hall energy requirements. The cost of heat from parabolic trough collector systems is modelled using quasi-dynamic simulations in Polysun, and heat storage configurations are optimised. This study demonstrates that solar thermal projects would be viable alternatives to heavy fuel oil, diesel, gas, and even coal - should the cost of coal remain above US$250 /tonne (2020 real-term values). Transition to solar thermal energy for process heat in this sector is thus strongly recommended.