Page 312 - Sustainable Cities and Communities Design Handbook

286 Sustainable Cities and Communities Design Handbook

producers are also anticipated. Since 2007, the IPPs have overtaken the CEB
as the major generator of electricity in Mauritius (Elahee, 2011). They have
maintained this trend since then and generated 59.2% of the total electricity
needs of the country in 2013. They operate five thermal plants, four of which
are annexed to sugar mills. One of the IPPs has proposed to import wood chips
on a trial basis as a greener alternative to coal. The fifth plant runs solely on
coal on a year-round basis.
The location of Mauritius just above the Tropic of Capricorn means that

average daily temperatures around 30 C are common during the hot and
humid summer season from November to April. During this period, the
availability of adequate energy sources to cater to the average and peak
demands for electricity caused by heavy air-conditioning loads (CEB, 2013)
represents the main challenge for power system planners in Mauritius. The
load duration curve indicates that the base load, semiload, and peak load for
Mauritius are, respectively, 170 MW, between 170 and 370 MW, and above
370 MW, respectively. Contractual agreements between the CEB and IPPs
presently require CEB to provide for peak and semipeak loads, whereas the
typically cheaper base load electricity is provided by the IPPs. This scenario is
not ideal for the CEB as it neither fully exploits its generating capacity nor
benefits financially. Nevertheless, the urgency to meet the ever-increasing
demand of electricity led the government to offer financial incentives to the
IPPs to produce electricity. Concurrently, it represented a unique opportunity
to exploit a green resource in the form of bagasse for electricity generation.
The IPPs that owned the sugar factories were thus motivated to invest heavily
in either new steam generators or upgrade to higher pressure and higher
temperature boilers and use condensing extraction steam turbines.
The effective capacities of existing power plants in Mauritius, the types of
load they serve, and their ownerships are given in Table 15.1. Although the
total effective capacity of CEB is higher than that of the IPPs, the latter export
all of their surplus generated electricity to the grid, which serves the base load
as per the PPAs. The CEB supplies the demand mostly during peak periods,
implying a low utilization factor. Kerosene-propelled gas turbines are operated
only during peak times or in case of unexpected breakdowns from other power
plants as their unit cost of generated electricity is higher. In contrast, the lower
cost of coal has seen it become the preferable option for serving base loads.
Thus coal has gradually replaced heavy fuel oil (HFO) in the overall thermal
electricity production with its share rising from 42% in 2006 to 50% in 2015
(SM, 2015a, 2016a).
Fig. 15.5 illustrates that the maximum peak demand has been increasing on
an average by 3% annually during the period 2006e15, corresponding to an
effective yearly growth of about 9 MW (SM, 2015a, 2016a). Meanwhile,
authorities have ensured reliable electrical supply by upgrading the total
effective capacity to keep pace with the peak demand (SM, 2015a, 2016a). In
2015, the recorded peak load was 459.9 MW, whereas while the combined