shopping malls and many private commercial buildings, etc.
GDCSB’s plant at the University
Technology Petronas started operation
in 2001. This is the smallest of the company’s five cogenerated gas district cooling
plants, built to supply quality electricity
for the university. It operates on island
operation during normal mode condition
with standby supply from Tenaga Nasional
Bhd., the main utility company in Malaysia.
Daily gas turbine operations supply the
university and internal plant load. Waste
heat from gas turbines is used to generate
steam through heat recovery steam generators for chilled-water production by
steam absorption chillers that operate
mainly in the daytime. The thermal energy
storage tank is used to supply chilled
water during they day; the four electrical centrifugal chillers charge the tank
at night.
Due to the seasonal nature of the
activities at the university, the electricity
and chilled-water demand varies throughout the year. The requirement increases
considerably during peak academic
activities – from the third week of January
through the end of May and from the
third week of July to the end of October.
For 2007, the minimum electric energy
requirement was 2. 56 x 103 MWh during
November (off-peak demand), and the
maximum electric energy requirement
was 3. 35 x 103 MWh during February
(peak demand). The gas district cooling
One of the concerns faced by
these plants is the standby
maximum demand charge
imposed by Tenaga Nasional
Berhad (TNB), Malaysia’s sole
provider of power supply.
operation serves the university’s academic
blocks, totaling about 104,000 sq m ( 1. 1
million sq ft) of space; a mosque that can
accommodate 5,000 persons; a library; a
6,000-seat auditorium; and offices.
Operational Issues
One of the concerns faced by these
plants is the standby maximum demand
charge imposed by Tenaga Nasional Berhad
(TNB), Malaysia’s sole provider of power
supply (see table 1). The rates imposed
are rather high and could affect the
operators’ cash flow. Yet the standby
charges were discussed and agreed on
by TNB and the plant owners prior to
the plants’ construction.
For example, in the case of the university plant, if breakdown occurs and
TNB provides backup power, TNB will
charge 17.30 Malaysian ringgits ($5.30) for
each k W per month, besides the charges
on k Wh supplied. On the other hand, the
high rate of maximum demand has led
the operators to strive for minimum
breakdown and hence high reliability of
each plant. The frequency of plants not
meeting demand and having to rely on
TNB power and incur standby charges is
very low.
