Long Term Planning for Indian Power Sector with
Integration of Renewable Energy Sources
Subrata Mukhopadhyay
Praveen Gupta, Brijesh K Arya
ICE Dept., Netaji Subhas University of Technology
Ashok K Rajput, Vijay Menghani
New Delhi, India
Planning Wing
subrata@ieee.org
Central Electricity Authority
Pankaj Batra, Sandesh Sharma
New Delhi, India
Central Electricity Authority
ceirpcea@nic.in, arya_bk@rediffmail.com
New Delhi, India
rajput.ashok@gmail.com, menghani@cercind.gov.in
pan_batra@hotmail.com, ssandesh@yahoo.com
Abstract— India being a developing country has the need of
both addition in generation and replacing the old ones
commensurate with ever-increasing demand in the domestic,
agricultural, commercial, and industrial sectors. With Demand
Side Management (DSM) resorted to effectively, however, there
exists potential of shaving peak, and consequently to some extent
energy in this important infrastructure of economy. Having an
installed capacity of about 81 GW from Renewable Energy
Sources (RES) out of a total of 360 GW by July 2019 it has an
ambitious plan for significant addition of renewables reaching the
level of 175 GW (100 GW from solar including 40 GW of rooftop,
60 GW from wind, 10 GW from bio-mass, and 5 from small
hydro), and 275 GW respectively by the end of country’s 13th
(March 2022) and 14th five-year plan (March 2027). Thus, as
estimated, by 2030 it may be in a position to contribute about 48%
from renewables only. This is based on detailed studies on load
forecasting in different sectors geographically over pan-India in
different time-frame followed by estimation of potential from
RES. The latter consist of development from solar, wind, biomass,
waste, etc. both off-grid and on-grid. Finally planning has been
carried out simulating likely scenario at different point of time
with system having sizeable penetration of renewables in the
overall requirement of generation to meet the electricity demand.
Technological developments, standardization, and regulatory
measures have paved the way for large-scale integration of
renewables to the Extra High Voltage (EHV) grid by pooling the
surplus from one region for haulage to other regions for
distribution of electricity. In the process gradually conventional
fossil-fuel based generating plants are being phased out, though it
continues with still addition of the backlog in the system. However,
in the process Plant Load Factor (PLF) of such type of generation
is coming down enabling lessening pollution too. With economy of
scale and more accuracy achieved in predicting intermittent
generation from renewables, it has already been possible to
achieve much reduction in per unit charges of electricity from
RES, notably from both, solar and wind.
In the paper based on Long-Term Load Forecasting, results of
studies to find out optimal mix of existing conventional fossil-fuel
based generation integrated with renewables from various sources
have been depicted based on computation. While carrying out
studies specifically for the two periods ending on March 2022 and
March 2027, development envisaged in respect of renewables has
been taken into account, and so the reduction in demand due to
DSM. Corresponding peak demands projected to be met appear
to be about 226 GW and 299 GW with annual energy requirement
to the tune of 1,566 and 2,047 Billion Units (BU) of electricity.
Reduction in peak demand of 9 GW and 12 GW and energy
requirement of 206 and 273 BU too is expected on account of DSM.
As per studies projected renewables would be accounting for
175 GW out of a total of 479 GW by March 2022, while 275 GW
out of 619 GW by March 2027. Consequently, in terms of installed
capacity overall percentage of non-fossil-fuel based generation
would rise to 49.3% and 57.4% respectively. However,
considering additional coal-based capacity requirement vis-à-vis
under construction as well as retirement of old ones, overall
contribution of energy from this segment would remain
significant, although with reduced average Plant Load Factor
(PLF). Considering the transition period of 10-12 years from now,
Long-Term studies have been carried out corresponding to the
time-frame 2029-30 to find out the optimal mix of primarily RES
and fossil-fuel based Thermal plants. Thereafter for the year
2029-30 corresponding to the various critical days how such
planned system meets the peak load as well as fulfil energy
requirement has been studied. From the results it is observed that
48% of energy is expected to come from RES with installed
capacity touching about 65% of the total installed capacity of 831
GW by 2030, predominantly with Solar. The latter has significant
role in meeting the daily load demand vis-à-vis energy out of
different types of generation. But in the studies with projection of
data, at the time of actual peak of the day, occurring typically in
the evening, there is almost no contribution from Solar. So,
though installed its presence could not been considered at the time
of peak demand. This is indeed a big constraint with further
growth in load due to economic development or otherwise and
desirability of phasing out fossil-fuel based power plants. Under
such circumstances flattening of load curve by the extensive use
of Pumped-Storage Hydro (PSH) plants, BESS, etc. are definitely
the viable option as alternatives, as considered.
Keywords— Duck Curves, Indian Power Sector, Intended
Nationally Determined Contribution, Long-Term Planning,
Renewable Energy Sources
978-1-7281-6664-3/20/$31.00©2020IEEE
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I.
INTRODUCTION
In recent times world has seen paradigm shift in utilization
of resources to produce electricity in terms of power as well as
energy. This is on account of apprehension of limited
availability of fossil-fuels in future, be it in the form of coal in
different forms or liquid petroleum products or gas. From the
point of view of pollution due to emission in air too these
resources are definitely not desirable. On the other hand, for
sustainable as well for producing what is termed as green
energy, i.e., pollution free, new and renewable sources have
surfaced in for harnessing from wind, solar, biomass, waste, etc.
With technological developments over the years they have
become cheaper as well as competitive to replace gradually
conventional fossil-fuel based plants to generate electricity.
Again, as much of investment has gone so long for establishing
the latter type of plants that are still in a position to provide
electricity with economic price, by overnight they cannot be
dispensed with to provide space for the renewable ones. Thus,
there is a transition period.
For the developed countries in the world it is more of
replacement with low percentage of increase in peak demand
and energy consumption. But for developing countries, like,
India, it is to some extent replacement of the old assets, while
quite significant addition to generation capacity is also required
to meet ever increasing demand for economic growth. With
such two-fold requirement it is obvious to look for in a timeframe of 10 to 12 years ahead how the scenario would be with
the admixture of renewable forms of energy and conventional
fossil-fuel based ones which have not outlived life. Thus it
requires a close look to consider scenario sometime in the year
2029-30 time-frame. With commitment of reduction in Carbon
emission while basically addition in the form of replacement
may be restricted, but need not be stopped completely.
However, Plant Load factor (PLF) as a measure of utilization
would definitely come down. Also, with conservation in fossilfuel for still for some time more grid support could be provided
by this form of generation of energy to face eventuality like,
weather condition on which major renewable sources, wind and
solar, depend. It may be beyond such period of 10 to 12 years,
with more development of storage facilities in the form of
Hydro-Pumped Storage (HPS), Battery Energy Storage
Systems (BESS) gradually the need for such back-up from
fossil-fuel based generation would cease to exist.
In a paper [1] earlier depicting present state of operation,
under long-term perspective at the end of every five-year plan,
i.e., 2021-22 and 2026-27 possible requirement as envisaged
has been shown. Projecting further considering intermittency
and energy content it has been estimated that for India, Intended
Nationally Determined Contribution (INDC) from sources
other than the fossil-fuel could be 40% by 2030. Keeping in
mind hence through this paper details are reported about the
results of Long-Term studies corresponding to the time-frame
2029-30 based on Long-Term Load Forecasting as shown
under the 19th Electric Power Survey (EPS) by the Central
Electricity Authority (CEA) in India [2]. Then under short-term
studies during the Financial Year 2029-30 itself how the power
sector would eventually meet peak demand and energy in
different critical days with varied generation from Renewable
Energy Sources (RES) with fossil-fuel based generation still in
the system. In the studies while optimal mix of generation
capacity has been tried to be achieved, single-demand node for
the entire country has been considered for load-generation
balancing, without taking into account transmission systems in
the optimization process.
II.
OBJECTIVES AND SCOPE
Keeping in mind the present state of affairs and considering
2021-22 as base year, objectives have been set for finding the
optimal generating capacity by the year 2029-30. The latter is
in terms of RES as expected to be harnessed and fossil-fuel
based generation still available taking into account plants that
have not outlived economically, and with minimum addition.
Methodology adopted for such planning exercise is as realized
through the software ORDENA. Modelling the RES,
optimizing transportation cost of fuel with emission
considered, the software performs generation expansion
planning. Through the iterative process it optimizes to find
least cost of energy generation considering investment in
meeting peak demand and supplying electrical energy
requirement. While doing so it selects most optimal generation
capacity mix, the relevant financial parameters, and takes care
of technical and operational constraints. Hourly economic
generation dispatch too is carried out to arrive at overall most
suitable condition in an integrated manner.
III.
LONG-TERM STUDIES FOR OPTIMAL GENERATION MIX
FOR 2029-30
Present scenario of Indian Power Sector as on 31 July 2019
[3] is as given below, basically for reference, to get an idea
about contribution from RES in the generation mix and supply
position to meet the peak demand and energy requirement.
Installed Capacity: 360 GW (including 81 GW Renewable, of
which 37 GW Wind, 30 GW Solar, and rest others) while Peak
Demand Shortage and Energy Shortage less than 1% as
reported by CEA. The generation capacity mix as projected for
the year 2021-22, i.e., at the end of current 13th five-year plan
in the National Electricity Plan (NEP) [4] has been considered
as the base year for the studies.
Therefore, the studies cover period from 2022-23 to 202930 to arrive at the power and energy scenario for the year 202930. Projected installed capacity by the end of 2021-22 as per
NEP is 479.419 GW considering 51.301 GW Hydro, 217.302
GW Thermal (Coal), 25.736 GW Thermal (Gas), 10.080 GW
Nuclear, 175 GW Renewable Energy as base capacity.
Estimated peak electricity demand (GW) and energy
requirement in Billion Unit (BU) in the year 2021-22, 2026-27
and 2029-30 are as given in Table I. As per 19th EPS it is based
on assessment of demand for 2029-30 with a Compound
Annual Growth Rate (CAGR) of peak demand of 4.4%, and
for energy 4.38% during 2027-32.
TABLE I. PEAK DEMAND AND ENERGY
Year
2021-22
2026-27
2029-30
Peak Electricity
Demand (GW)
225.751
298.774
339.973
Electrical Energy
Requirement (BU)
1566
2047
2325
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However, considering contribution from roof-top solar
generation of about 75 BU that was taken as negative demand
in the 19th EPS, overall energy requirement for the year 202930 has been assumed to be 2400 BU while peak load during
2029-30 as 340 GW. Based on hourly demand profile faced at
present, most probable demand profile has been arrived at by
extrapolating and considering peak electricity demand and
energy required in 2029-30. Accordingly, likely hourly
demand curve for a typical day in October 2029 is as shown in
Fig. 1.
been estimated to be 22% and 25.21%. Seasonally following
have been the divisions:
Summer: April-June, Monsoon: July-September, Autumn:
October-November, Winter: December-January, Spring:
February-March
Hydro energy availability varies significantly across the
year depending upon monsoon rains. With a view to having
major contribution of it during daily peak, for RE generation
each season has been further divided into blocks for increasing
granularity and precision. It is to focus on the time of
availability for deriving maximum benefit. Curtailment of
maximum Wind-based generation capacity of 140 GW by the
year 2029-30 as projected has been maintained.
For BESS considerations are downward trend in capital
cost, sizing based on 100% depth of discharge (though actual
size may increase by 25% to cater for 80% depth of discharge
and hence 25% cost enhancement considered), and 4-hour
cycle time by the year 2029-30.
With these inputs, studies lead to an optimal mix as shown
in Fig. 2 and 3 with different type of generation in participation
in terms of GW, and generation dispatch capability in GWh.
Fig 1. Hourly demand curve for a typical day in October 2029.
Additionally, under construction and planned capacity
addition of 13.762 GW of Hydro, 6.8 GW of Nuclear, and
retirement of Coal-based units of 25.572 GW have been
considered for 2022-23 onward.
Technologies considered for Renewable are Solar, Wind,
Biomass, and Small Hydro, while for conventional (as
continuing) Coal, Gas, Nuclear, and Hydro (of large size), and
for storage Pumped-Hydro, and Battery Energy. Study further
encompassed unit-wise characteristic, installed capacity yearwise with fuel type and heat rate as well as outage rate and
maintenance duration, fuel cost, operation and maintenance
cost, unit start-up and shut-down time with cost, ramp rate,
minimum technical loading, capital cost, peak contribution,
hydro storage, emission factor, etc. in respect of existing as
well as under construction and planned plants.
So far as Renewable Energy (RE) technologies and Battery
Energy Storage System (BESS) are concerned reducing trend
of capital cost has been considered. Only 660 MW and 800
MW coal-based supercritical units have been considered with
flexible-operation up to minimum technical load with due
consideration of loss in efficiency. However, no addition in
gas-based plant over 25 GW has been considered. Nuclear
addition too has been limited up to what has been approved in
principle. So far as Hydro capacity is concerned 64.008 GW
consisting of 22.9% of storage, 43% of run-off-the-river with
small pondage, 6.6% run-off- the-river, 18.6% of multipurpose type, and 9% of pumped storage considered along
with small hydro totaling 5 GW of the run-off-the-river type.
In addition, import of about 4.356 GW from neighboring
countries has been taken into account.
With actual 8760 hourly generation profiles of solar and
wind, annual Capacity Utilization Factor (CUF) of them has
Fig. 2. Installed capacity of generation by types.
Fig. 3. Generation dispatch in terms of energy by types.
From the results following may be observed:
• Addition of Coal-based plants is not significant as
compared to the solar and wind capacity addition.
• The model selects BESS from the year 2026-27
onward, due to the reduction in cost of Solar, and
BESS.
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•
Model has not selected any new Hydro or Nuclear
power plants apart from already planned ones.
• It is seen that installed capacity of RES will
become 440 GW by the end of year 2029-30, thus
it is more than 50% of total installed capacity of
831 GW.
Accordingly, Table II, and III respectively give the likely
installed capacity with the details of various types and
corresponding gross generation of energy from them.
TABLE II. LIKELY INSTALLED CAPACITY BY 2029-30
Generation Type
Capacity in GW
Percentage Mix (%)
Hydro *
73.445
8.8
Coal + Lignite
266.827
32.1
Gas
24.350
2.9
Nuclear
16,880
2.0
Solar
300.000
36.1
Wind
140.000
16.8
Biomass
10.000
1.2
Total
831.502
100.0
Battery Energy
34,000MW/
Storage
136,000MWh
* including small hydro of 5 GW and hydro imports of
4.356 GW
Fig. 4. Generation dispatch for the entire week.
TABLE III. LIKELY GROSS GENERATION IN 2029-30
Generation Type
Hydro
Coal + Lignite
Gas
Nuclear
Solar
Wind
Biomass
Total
Energy (BU)
197
1247
50
101
583
304
26
2508
Generation (%)
8
50
2
4
23
12
1
100
Fig. 5. Hourly generation dispatch on 07 October 2029.
IV. SHORT-TERM STUDIES BASED ON HOURLY GENERATION
DURING 2029-30
For these studies, various scenarios corresponding to critical
days of 2029-30 have been considered, as mentioned below one
after the other.
A. Peak-day / maximum energy day (07 October 2029)
It is the most critical day from power planning perspective
for the peak demand condition. 340 GW peak demand expected
to occur on 07 October 2029 in the evening hours has been
considered. In fact, scenario for the entire week with 3 days
before and after has been simulated for the studies as depicted
in Fig. 4 for the 6 hourly generation dispatch. Fig. 5 shows the
condition on 07 October 2029 at hourly interval. Fig. 6 in this
context gives RE generation with curtailment of about 4.47%
as a result of not being fully absorbed. This is due to the shape
of load curve, constraint of minimum technical loading of
thermal plants (55%) even when Capacity Utilization Factor
(CUF) for Wind and Solar are respectively 9.98% and 20.72%.
At the same time gross Plant Load factor (PLF) of thermal
capacity is likely to be 72.72%. This too is in spite of battery
getting charged during availability of solar generation (as
shown by the Duck Curve) to dispatch during non-solar hours.
Fig. 6. Renewable Energy generation with curtailment on peak-day.
B. Maximum Renewable Energy (Wind and Solar) generation
day (03 July 2029)
Ironically when maximum Renewable Energy generation
is likely to be available, hydro generation too is at its
maximum. As a result, hourly generation computed has been
as shown in Fig. 7. Consequently, curtailment of the RE
generation has been observed to be going up to quite a high
value of 17.16% as given by Fig. 8.
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27 January 2030, with considerably lower solar and wind
generation, there is no curtailment at all.
For all the above-mentioned cases peak demand and
requirement of energy have been fully met with RE generation
curtailment in the range of 0 to 17.56%, as mentioned.
Fig. 7. Generation dispatch with maximum Renewable Energy.
Additionally, considering technological advancements
further for thermal plants enabling to reduce further minimum
technical loading from 55% in steps to 50%, and 45% with
flexibility in operation, as expected RE generation curtailment
could be reduced. It is also valid with nuclear plant participating
with flexible operation. A reduction of about 3% in RE
generation curtailment has been observed for every step of 5%
reduction in minimum technical loading of thermal plants.
Impact on RE absorption at any point of time may vary
depending on capacity of thermal plants running as well as
available RE generation. On the other hand for the maximum
peak demand day (07 October 2029) and maximum RE
generation day (03 July 2029) due to part-load operation on
account of reduced efficiency too CO2 emissions increase by
about 1% and 1.2% respectively.
Finally, to meet the contingency of 10% reduction in RE
generation or / and 6% reduction in Hydro generation (going by
the weather and inflow of water data for several years) cases
have been studied to find curtailment of RE generation and
alternate source of supply through utilization of thermal
resources. While with 10% reduction in RE generation, on allIndia peak demand day as well as minimum RE generation day,
RE generation has been found to be fully absorbed with no
curtailment. For 6% reduction in Hydro generation on peak
demand day it shows still a curtailment of RE generation by
4.77%, though 1% increase in Thermal generation is required.
But reduction in both, RE as well as Hydro generation when
considered, RE curtailment is almost negligible with enhanced
support of Thermal generation to the tune of 1.5%.
Fig. 8. Curtailment of Renewable Energy with maximum availability.
In similar way maximum Solar generation day (25 March
2030) when considered it has been observed that CUF of solar
is about 28%, even when hydro generation is minimal at least
in the northern part of the country. With overall wind generation
already less, it leads to RE generation curtailment of about
16.76%. Likewise, minimum Solar generation day (08 August
2029) has yielded CUF of solar capacity only 14.25% due to
significant availability of hydro and wind. Obviously,
curtailment of renewable Energy too is minimal at 0.93%.
For the minimum energy demand day (14 December 2029),
ironically 14th December being national energy conservation
day in India, RE curtailment is to the tune of 5.98%. Again, with
minimum overall RE generation day (01 February 2030), CUF
of solar and wind is 16.13% and 10.54% respectively with RE
generation fully absorbed with no curtailment and PLF of
thermal plants about 71.77%. In the last case of maximum
variation in net demand or demand days (such as 26 October
2029, and 27 January 2030), with demand variation
respectively from 124 GW to 284 GW, and from 231 GW to
320 GW, contribution of thermal is significantly high to meet
the evening peak on 26 October 2029. As a result, RE
curtailment is about 17.56%. However, on the other such day,
In the process overall it has been observed that out of a total
installed capacity of 831.502 GW, installed capacity of fossilfuel based plants and non-fossil-fuel based plants would likely
to be 291.177 GW, and 540.325 GW, thus having share of about
65% by the latter. However, on energy front the latter may
contribute still about 48%. Similarly, CO2 emission annually is
estimated to go from 1026 MT (in 2021-22) to 1154 MT (in
2029-30).
V. CONCLUSIONS
Like different countries world-over, India in a bid to take
part in the usage of electrical energy from the fossil-fuel based
plants is gradually shifting to sustainable green mode of energy
production, from the point of view of gradual extinction of
fossil-fuels and pollution that the same cause. In order to fulfill
the commitment toward India’s Intended Nationally
Determined Contribution (INDC), based on load forecasted,
with a reasonable period of 10-12 years ahead, i.e., by 2029-30,
as per studies conducted, it is possible to meet the load with
about 65% of installed capacity from non-fossil-fuel based
power plants out of a total capacity of 831.502 GW. At the same
time, it is also in a position to contribute about 48% of energy
requirement, out of a total energy requirement of 2508 BU.
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However, in the cases of certain credible contingencies to
be met, sensitivity studies show enhanced usage of already
available fossil-fuel based plants up to 1.5% to meet peak
demand as well as energy requirement. Even with technological
progress in lowering the minimum technical loading of thermal
plants, it is possible to reduce curtailment of Renewable Energy
generation in the system. System is aided in flexible operation
further with 34 GW of Battery Energy Storage Systems with 4hour capacity, i.e., 136 GWh. System so planned is in a position
to meet peak demand as well as energy requirement, be it on a
peak demand or energy day, maximum Renewable Energy
generation day, minimum Renewable Energy generation day,
maximum Solar generation day, minimum Solar generation
day, minimum Energy Demand day, maximum Variation in
Demand day. With such resilient system, for contingencies,
like, reduced Renewable Energy generation or / and Hydro
generation, leveraging is possible with the available Thermal
plants. Thus, though in general usage of fossil-fuel based
generation would be curtailed to a great extent, plants as such
cannot be dispensed with totally.
ACKNOWLEDGMENT
The authors wish to acknowledge their respective
organizations CEA, and NSUT and their esteemed colleagues
for making available relevant information and support toward
preparation of the paper.
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