We consider here two options for generating electricity with alternative primary energy sources that can potentially replace fossil energy sources:
- Concentrated Solar Power (CSP): power tower systems similar to the one considered for the 50 MW Bokpoort CSP power plant in South Africa under the UN's CDM programme (UNFCC 2012-TR). For this scenario, we used technical data referring to the similar 20MW Gemasolar plant in Spain with molten salt storage and wet cooling (Torresol Energy 2011) and spatial data from the Centre for Renewable and Sustainable Energy Studies (CRSES) of Stellenbosch University.
- Woody biomass for electricity production: dry woodchips production from forestry residue in South Africa. For this scenario, we used technical data from the literature (Torresol Energy 2011; Larrain and Escobar 2012 (CSP); Pimentel et al. 2002; Buhholz et al. 2012) and spatial data from the Centre for Renewable and Sustainable Energy Studies (CRSES) of Stellenbosch University.
The EROI value ranges of the hypercycle for the two alternative primary energy sources are: 12-20:1 for CSP and 7-11:1 for woody biomass for electricity. Thus, both alternatives have a significantly lower EROI of the hypercycle compared to the present electricity production in South Africa (46:1). Hence, a significant deployment of these two alternative primary energy sources would reduce the overall strength of the South African exosomatic hypercycle (SEH) in relation to electricity production. As a consequence, a larger share of the production factors available to South Africa would have to be invested in generating electricity (since the requirement of production factors per unit of energy carrier supplied is larger than the average of the hypercycle allocated to the production of electricity) rather than using them for producing and consuming goods and services.