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associated to long transmission
systems could be an asset for the
energy renaissance of the sub-Saha-
ra region, with social and economic
development of its inhabitants.
From studies on the development of
long DC transmission systems in Afri-
ca [7], the figures 11 and 12 show
the cost relevant to the transmission
for the delivered kWh and the total
Fig. 10 - Some eco towers in Italy, France, US and South Africa cost of delivered kWh as a function
of the production cost; this with 2
an huge but largely unexploited potential of both main extreme hypotheses relevant to annual ra-
fossil and renewable resources, which, connected tes (AR) and cost of losses (CL). The 6% value of
to the development of powerful/long transmission AR corresponds to a discount rate close to 3.5-
systems, could create strong inter-regional exchan- 4% over 25 years, as indicated by IMF for special
ges of electrical energy. This could bring substantial projects with grants/soft financing, while the 10.5
contributions to the eradication of poverty and ac- % is related to private financing.
cess to electricity to 600 million people of the sub- Considering the huge hydro potentials in those
Sahara region. The construction of hydro power countries (RDC with Inga, Ethiopia, Cameroon, An-
plants, or of power plants in general, and of OHTLs gola) and the large new gas discoveries, appropria-
is a labor intensive activity providing local jobs. te utilization of these resources to feed different re-
Considering the hydro potential with the economic gions in sub-Sahara seems mandatory (figure 13).
development of large plants with high load factors With a 2 c$/kWh production cost (cheap large
and the discovery of enormous gas reserves (e.g. hydro), electricity can be delivered at 3÷3.5 c$/kWh
Mozambique), which could provide cheap con- for 1000 MW at 1000 km or 4000 MW at 3000 km.
ventional electricity in some areas, possible plants With a 4 c$/kWh production cost (GTCCPP with

Fig. 11 - Transmission cost of delivered kWh on the AC side of the receiving end; optimum voltage level for different powers (P) and length [7]

Fig. 12 - The cost of energy delivered on the AC side of receiving end as a function of generation cost [7]

Impiantistica Italiana - Marzo-Aprile 2018 39