Power system expansion planning in
Pakistan, in Interim period – i.e. period before open access
Introduction
Power sector additions in the last five years
have been impressive; by 2018 the gap between demand and supply will almost be
bridged. This impressive performance has been marred by some missteps, planning
has been a weak area and power sector decisions have been taken without needed
analysis and due process.
Pakistan’s
power sector structure moved from a vertically integrated utility to a single
buyer model. Induction of private sector necessitated that the decision making
process needed to involve sensibilities and concerns of various players, use of
Long term system expansion optimization software was discontinued. NTDC Planning
do undertake a master planning exercise that uses optimization software but
this is not a document that figures in the decision making process and is in
any case updated after every few years and is therefore not current at all
points in time. Power sector generation capacity, decision making is in any
case fragmented, WAPDA, NTDC, PPIB, AEBD, Provincial Government Energy
Departments, AJ&K and GB Power departments, Ministry of Finance, Planning
Commission all play a role in this decision making, which is not closely
coordinated. Mainly because in the period of shortages any capacity addition
was welcome, now that the capacity gap is being bridged , such decisions are
coordinated with CPPA/NTDC who verify that the capacity addition is required as per the demand forecast and other works in
progress.
The
decision to liberalize the market was taken years ago and along with that
decision it was deemed unnecessary to continue the use of WASP and a central
power system expansion planning. It was considered that the private sector will
take care of such needs. The privatization got stuck and after a partial
incomplete transition the effort was stalled, in this period capacity was
procured by both the private sector and the public sector routes. Addition of
large hydroelectric structures was dealt by WAPDA, in the public sector. This
period saw a very weak planning regime and possibly due to that there were gaps
in supply and demand and other errors were also made.
The system is stated to become a mutli-buyer
market in the near future, where investment decisions’ will be taken by a
multitude of players using different techniques and software. The present
arrangement has not entirely worked in so far as capacity additions are
concerned .There , however, has been an error made in adding to much capacity ,
and also by adding too much base load capacity, both actions have financial
implications. The interim period ( before open access ) requires that planning error should not be
made, it is proposed that:
1. .GM
Planning NTDC Office should be equipped with WASP ( or some other
generation expansion optimization tool) . Capacity building would be required
to enable professionals to use WASP. WASP should be used as a verification
tool. Decisions like how much base load capacity is to be added in each year
should be taken by using WASP.
2. Base load Capacity: Thar (and other domestic) coal should have
priority when base load capacity is required to be added. RLNG based base load
should be considered for diversification purposes Intermediate and peak load capacity should be
: hydropower ; biomass including bagasse( but excluding Bagasse with imported
coal)
3. Foreign exchange needs
to be shadow priced to present the cost of making capital investments based on
foreign currency.
4. Institutional arrangements: NTDC
Office of GM Planning should be entrusted with planning of the power system,
the following is recommended: NTDC Power Planning (NTDCPP) be spin off as an
independent authority, with the mandate to carry out; least cost expansion
planning; transmission system planning; secondary system planning. In the
interim period generation expansion planning
should utilize WASP ( NTDC is familiar with WASP although WASP does have
some limitations related to modeling hydroelectric power capacity) ; the system
is evolving into a multi buyer system , with this transition centralized power
system planning will not be desirable , NTDC Power Planning needs to acquire
other software which is utilized for modeling
new generation addition to the system in a mutli buyer market , this
service ( and other services) should be provided at cost ; NTDCPP is currently
under staffed , positions sanctioned should be filled with immediate effect ;
for NTDCPP to act as a planning expert there is need to provide more trained
staff to man the generation expansion and transmission expansion planning
functions ; have been less than proficient in use of software to carry out
secondary system planning, There is need to shift the function of secondary transmission
planning to .NTDCPP.
5. Induction
of small hydroelectric , wind, solar power plants has been stalled due to
non availability of transmission interconnection to the grid .All of these
including biomass based power generation are indigenous resources of energy and
are therefore contributors towards increase
in local content in energy utilization. All of these except biomass are
seasonal and are not base load plants. There is reluctance in allowing a free
field to solar and wind on grounds of: seasonality of supply; and transmission
constraints presently a committee in the MoE decides quantum of wind energy to
be added each year. With loaming capacity surplus and NEPRA’s decision to only
add wind and solar capacity after competitive bidding all these renewable
resources will find scant space in new capacity addition. NTDC needs to use
WASP to determine quantum of base load capacity tom be added and also to
determine the amount of renewable capacity to be added .Decisions related to
what capacity is to be added should be made much in advance and should not be
sudden and abrupt , hurting investor confidence . Evacuation of power
limitations is one reason cited for the reluctance to add renewable to the
system, intermittent nature ( except biomass which is base load) is stated to
be the other reason, cost considerations have been addressed mainly by the fast
reducing cost of wind and solar power plants. GOPA study commissioned by USAID
stated that there are very little system constraints against adding about 2224
MWs renewable capacity. Beyond that major reinforcements to the system will be
required. The recommendations of the GOPA study (these are presented below) need
to be implemented. Wind potential is located in areas which are either far away
from the grid system or are located in areas where surplus power is available,
therefore there is need to transmit this power to load centers using primary
transmission.
6. Capacity building and enhancement- NTDC
Planning needs that the already approved positions are filled with qualified
staff with immediate effect. There is also need to enhance the man power assigned to NTDC Planning to take up the additional generation
expansion and transmission system expansion planning, along with capacity
enhancement a proper detailed and
sustained effort is to be made to build capacity in NTDC planning
Gopa Study: GOPA
study presents an analysis of the Pakistan Grid with reference to RE
interconnection. The conclusions reached are:
1.
2224 MW wind and
solar capacity can be added, with the following grid additions: 25 MVAr
capacitors at Bhan Saedabad grid station; 120 MVAr Thyristor controlled reactor (TCR) inductive 200 MVAr MSC Capacitive SVC at Lal
Suhanra.; Power system stabilizers (PSS) at two synchronous generators at Hub
and Jamshoro. ; And operation of some renewable generators in voltage droop
control mode would be beneficial.
2.
In the next phase
major additional reinforcements are required these would allow the full 4067
(phase I) of renewable generation to be added but it will also facilitate
addition totally 9332 MW (including the 4067 MW capacity discussed earlier) of
renewable energy to be added. Improvements required are : Lal Suhanra region requires reinforcement of
220kV system where a new collection substation is to be installed and two radial 220kV lines are closed to form
a ring This requires addition of 80 km
double circuit 220kV transmission lines , 5 km single circuit 220kV
transmission line and 5 additional 220/132 kV power transformers including
transformer bays . Reinforcements of the Southern wind corridor requires a new
500kV Jhampir grid station , 90 km 220kV and 500kV transmission lines , a
200MVAr capacitor at Jhampir and 100 MVAr shunt capacitors at Gharo are
required . 600MVAr SVC (600MVAr TCR and
300MVAr TSC) at Shikarpur are also required.
3.
Spinning reserve
requirements will increase to 1500 MW 500MW more than required by the system in
2018, Thus RE will need an additional 500 MW spinning reserves.
4.
Dispatch will,
require to: re-execute wind and OV prediction at 1-4 hours ahead; and shorten
the dispatch cycle from 30 min to 15 min.
5.
Wind and PV
generators need to have provisions for operation in defined conditions. (Modern
VRE plants connect to the grid using electronic power converters or inverters;
these can be programmed to allow the way in which a VRE power plant behaves on
the power grid to be controlled.)
6.
Addition of
specified levels of RE generation results in a higher NPV as compared to the
one without RE capacity.
There is consensus on the fact that addition of up to
30% RE capacity is possible with needed inductive loads and SVCs but higher
than that capacity will require new approaches on operating and extending
grids. Variability of RE due to weather Introduces uncertainty in generation
output .These could affect 70% of solar capacity due to cloud cover and 100% of
wind capacity due to still days. This requires base load capacity that can
follow load to be interconnected, these are costs. To reduce reserves and spinning
reserve costs it is recommended that: there needs to be improvement in weather
and wind forecast accuracy; forecasts should be for shorter periods than a day
Conclusions
There
is need to put in place a set up for power system generation expansion
planning in the interim period. This is
necessary because mistakes that were made in the last five years are not
repeated in the future. This will need reintroduction of WASP as an
optimization tool, and capacity building and enhancement of planning function
currently housed in NTDC. There is need to spin off this unit (along with load
flow capability) into a separate national organization.
