Grid Integration of Renewable Energy in India under Mitigation of High Penetration Challenges of Renewables into the Grid: Storage, Demand Response and Interconnections

1. ADMINPL01 - Mitigation of High Penetration Challenges of
Renewables into the Grid: Storage, Demand Response and
Interconnections
21PESGM2656
Grid Integration of Renewable Energy in India
Subrata Mukhopadhyay
Netaji Subhas University of Technology (NSUT)
In association with
Sushil K Soonee, and S R Narasimhan,
Power System Operation Corporation (POSOCO) Ltd.
Ashok K Rajput, and Bikash C Mallick
Central Electricity Authority (CEA)

2. Indian Grid…One of the World’s Largest
Source: GO15
Source: IEA Key World Energy Statistics 2020 & IHA 2020
Hydro Status Report
(2018 data, 2019 provisional data)
2
3
electricity generation
installed generation capacity
transmission system
electricity consumption
5
hydro generation
4 wind generation
9
solar generation
1
national synchronous grid
renewable energy generation
pumped storage installed capacity
6

3. 3 GW+
383 GW+
generation capacity
189 GW+
peak demand
> 4 TWh
daily energy met
440,000 ckm+
EHV transmission
1.3 Billion+
international exchanges
95 GW+
renewables
10 +
HVDCs
3.2 million km²
area footprint
annual market trades
50,000+
market transactions
2
power
exchanges
people served
120 TWh+
~ 100 GW market participants
6000+
Dimensions
inter-regional capacity
3

4. Outline
• Introduction
• Progress of Power Development in India
• Development of Renewable Resources
– Progress Achieved so far in India
– Jawaharlal Nehru National Solar Mission (JNNSM)
– Configuration & Integration
• Need for Interconnection – Integration
– RE-Grid Integration Challenges
– Required Grid Support
– Grid-Friendly RE Generation
• Role of Energy Storage
– Price Trend for capital Cost
– Indian Market Opportunities for Battery Storage
• India Smart Grid Roadmap
• Integration of Renewable Energy Sources
– Perspective transmission plan by 2030 with RES
4

5. Outline (Contd.)
• Hybrid Systems – Key Drivers
– Benefits of Hybrid System
– Technology Overview
– Estimated Typical Hybrid Generation Trend
– ReGen Wind – Solar Hybrid Project at Vagarai
– Typical Key Areas of Cost Savings in the ReGen Hybrid Prototype
– Future Prospects for Hybrid with Storage
– Global Scenario
– Re-Powering Old Wind Farms with Hybrids
• Regulation and Certification
– Salient Features of Regulation
– Additional Provisions
– Regulatory Provisions in India
– Renewable Energy Certification (REC) Mechanism
• Conclusions
• References
5

6. Progress of Power Development in India
• Generation
– Rapid growth in capacity and Unit sizes, increased private sector
participation
• Transmission
– Development of state-grids, regional grids and then ultimately aiming
towards national grid formed on 31 December 2013
– Future: 1,200 kV ac and + 800 kV dc as private sector and JV
participation is gradually picking up
• Distribution
– APDRP (Accelerated Power Development and Reform Program)
promotes high availability of distribution system.
– Private sector participation is quite encouraging.
• Co-generation
– Particularly in heavy industries
– With adequate protection and advancement of technology, in fact
renewable energy or green energy sources are finding path to
penetrate power sector in a big way.
6

7. Certain Salient Features
• Both - Peak Power Shortage as well as Energy Shortage
negligible (overall <0.5%)
• Promotion of Renewable Energy Resources on huge scale
• Initial development of Renewable concentrated following
isolated systems
• With advancement of technology, connectivity has improved
• Gradual evolution of intelligent or smart grid
• Roof-top solar plant at consumer premises
• Advanced Metering System (AMI)
– Possibility of bi-directional power and energy flow
• Still very much limited on the use of Electric Vehicles
7

8. Development of Renewable Resources
• Predominant Types
– In India, Solar PV (Photo-Voltaic) Systems, and Wind Power Systems are the
predominant ones.
– IEEE 1547 Standard
–
Solar
Energy
Map of
India
Wind
Energy
Map of
India
8

9. National Solar Mission
• Targets
– Launched in 2009 set for 22 GW solar power (20 GW grid connected plus 2
GW off-grid), including 20 million solar lights in the country by 2022
– Installation of 20 million square meters of solar thermal collector area
– The first phase of the mission (up to 2013 out of total 3 phases, ending further
in 2017, & 2022) targeted setting up of 1,100 MW grid connected solar plants,
including 100 MW capacity plants as rooftop and small solar plants.
• Plus, 200 MW capacity equivalent off-grid solar applications and 7 million square
meters solar thermal collector area targeted in the first phase of the mission
• The National Solar Mission also to support research and capacity building activities
in solar energy.
– An amount of Rs. 43.37 Billion approved for the first phase of the mission.
• Subsequently in June 2015 national solar mission capacity increased from the
current 22 GW to 100 GW by 2022. The 100 GW solar power capacity has been
divided into rooftop solar electricity generation (40 GW) and large and medium-
scale grid-connected solar projects (60 GW). (Also, side-by-side there is addition of
60 GW of Wind and 15 GW from other Renewables, thus in total 175 GW).
9

10. Configuration & Integration
• For a typical 1 MW generation, there is a central power plant consisting of
several solar panels.
– Solar cells are arranged in arrays which are in turn arranged in a panel.
A set of solar panels have a common circuit breaker.
– These breakers are then connected to individual inverters. Inverters
are then connected to the transformers rated 300/415 V, 250 KVA.
– The outputs of these transformers are connected to the Low Tension
Switchgear, which in turn is connected to another transformer rated
0.415/11 kV, 1250 KVA.
– Then there is a High Tension switchgear which is connected to the grid.
• Being static in nature, integration with grid doesn’t create much problem
with assured amount of energy delivered in most of the day-time of the
year.
• In fact by December 2009, first 2 MW grid-connected solar plant set up at
Jamuria, near Asansol, West Bengal, India in its first three month of
operation generated over three hundred thousand units of power.
10

11. Large Scale Solar Installations in India
• Bhadla Solar Park – 2,245 MW - Claimed to be the largest solar power plant in the
world, the Bhadla Solar Park is located in Bhadla village, in Rajasthan’s Jodhpur
district spanning over 14,000 acres
• Shakti Sthala solar power project – 2,050 MW - The 2,050 MW Shakti Sthala
solar power project in Pavagada taluk, Tumakuru district, Karnataka.
• Ultra Mega Solar Park – 1,000 MW - Situated in Orvakal, Kurnool district,
Andhra Pradesh, which is another leading Indian state in terms of solar power, the
1,000 MW Ultra Mega Solar Park spans an area of more than 5,932
• Rewa Solar Power Project – 750 MW - Madhya Pradesh’s 750 MW Rewa Solar
Power Project is spread over an area of 1,590 acres and is operated by Rewa Ultra Mega
Solar Ltd. as one of the major power suppliers to the Delhi Metro.
• Kamuthi solar power plant – 648 MW - Kamuthi, in Ramanathapuram district
of the southern state of Tamil Nadu houses the fifth-largest solar power plant in India.
Dedicated to the nation by Adani Group’s Adani Green Energy (Tamil Nadu) Ltd, the
648 MW solar power plant, which consists of 2.5 million solar panels, while covering an
area of 2,500 acres, was set up with an investment of about Rs. 4,550 in 2016
11

12. Configuration & Integration (Contd.)
• Due to various initiatives taken reduction in price of both solar and wind energy
achieved, typically to the level of Indian Rupees (INR) 2.44 and 2.43 per kWh of
energy respectively during the short period from 2014 to 2018
12

13. Role of Energy Storage in Indian Grid 13

14. Marketing Opportunities for Storage Batteries
12
As per IESA (India Energy Storage Alliance) energy storage market
in India to grow to about 20 GW by 2022 driven by
• Energy Access
• Renewable integration
• Ancillary Services
• Commercial &Industrial customer demand
• Telecom sector
• Agricultural applications
• Electric Transportation

15. Indian Smart Grid Roadmap
15

16. Wind – Solar Hybrid Project at Vagarai, TN (by ReGen)
16

17. True Hybrid - Two technologies may work in tandem and use
common components to produce a single electrical output more
efficiently than either approach could on its own.
PV
DC junction
Step-up to 1200V DC-link
Wind Generator
Rectifier
Step-up to 1200V DC-link
D
C
L
i
n
k
Inverter
Y
a
r
d
HV – Line
DC MFT
(solar)
DC MFT
(Wind)
AC Meter
17
Technology Overview for the Hybrid System

18. Typical Hybrid Generation Trend 18
0
200
400
600
800
1000
1200
1400
1600
0:00 3:00 6:00 9:00 12:00 15:00 18:00 21:00 0:00
Power
in
kW
Hour of day [hr]
Avg. annual hourly power gen comparison (1.5 MW Wind +
0.75 MW Solar)
Wind only Solar only Hybrid

19. Typical Hybrid Generation Trend (Contd.)
19
Plug & Play System:
In case of ReGen’s hybrid wind-solar technology, as the integration of wind
and solar is being done at DC level, it is possible to integrate storage also at
the intermediate DC bus without any major modifications.
Prospects for Hybrid with storage

20. Integration of Renewable Energy Sources
• India is poised to have wind power and solar-based Renewable Energy
Sources (RES) of about 35% and 21% in terms of capacity and energy
respectively of the total generation of electricity by 2030.
• This share will be more than 50% and 33% by 2050 with envisaged RES
Capacity of 775 GW (including hydro 57 GW).
• Detailed studies with projected installed capacity in the base cases
corresponding to the period ending in March 2022, and March 2027 are
with RE of 175 GW out of a total of about 479 GW and 275 GW out of 619
GW respectively. Accordingly, India’s Intended Nationally Determined
Contribution (INDC) in terms of the quantified division between installed
capacity of fossil-fuel and non-fossil-fuel based generation in GW and
percentage thereof is shown in the Table as follows.
20

21. Integration of Renewable Energy Sources (Contd.)
• s.
21

22. Integration of Renewable Energy Sources (Contd.)
• Due to intermittency of RES, 40% of requirement is expected to come from non-
fossil fuels by 2030 with RE of 350 GW or so as projected further. As a result,
besides retirement of fossil-fuel based generation, existing ones too would be
operating at low PLF. For a peak day in 2021-22 (March 27, 2022) as an example
diurnal meeting of load demand by different types of generation, based on
studies with projection of data, may be as given below.
22

23. Overall Planning Studies
• Long-Term Studies for Optimal Generation Mix for 2029-30
• Short-Term Studies Based on Hourly Generation During 2029-
30
– Peak-day / Maximum Energy demand day (07 October 2029)
– Maximum Variable Renewable Energy (VRE) -Wind and Solar
Generation-day (03 July 2029)
– Maximum Solar Generation-day (25 March 2030)
– Minimum Solar Generation-day (08 August 2029)
– Minimum Energy Demand-day (14 December 2029)
– Minimum VRE Generation-day (01 February 2030)
– Maximum Variation in net demand / demand days (26 October 2029,
27 January 2030)
23

24. Long Term Studies for Optimal Generation Mix for 2029-30
• Present scenario: Installed Capacity in India : 383 GW (including 95 GW of
Renewable) as on 31 May 2021 as reported by Central Electricity Authority (CEA)
• Generation capacity mix as projected for 2021-22 (end of 13th 5-year plan) shown
in the national Electricity Plan (NEP) as base year with
– installed capacity of 476.439 GW consisting of Hydro (excluding hydro
imports, but including Hydro-Pumped Storage), Thermal (Coal, and Gas),
Nuclear, and Renewable Energy Sources (RES)- Solar, Wind, Biomass, and
Small Hydro, as detailed below:
24

25. Long Term Studies… (Contd.)
• Studies cover period from 2022-23 to 2029-30 for peak power and energy
requirement
• Roof-top generation of 75 BU adjusted with load while overall energy requirement
is 2,400 BU and peak demand 340 GW, as per 19th Electric Power Survey (EPS)
• Planned capacity addition of about 11.9 GW Hydro, 8.9 GW Nuclear, 8.63 GW
Thermal (Coal, but not Gas), retirement of coal-based units of 25.252 GW from
2022-23 onward considered, along with some candidate plants in Thermal and
Hydro too as inputs
• Peak Electricity Demand and Electrical Energy Requirement given for 2021-22,
2026-27, & 2029-30, latter being based on assessment with Compound Annual
Growth rate (CAGR) for peak demand 4.4% and for energy 4.33% during 2027-32,
as shown below
25

26. Long Term Studies… (Contd.)
• Demand profile extrapolated for a day in October 2029
26

27. Long Term Studies… (Contd.)
27

28. Long Term Studies… (Contd.) 28

29. Long Term Studies… (Contd.)
• Likely Installed Capacity by 2029-30
29

30. Long Term Studies… (Contd.)
• Likely Gross Generation in 2029-30
30

31. Short Term Studies Based on Hourly Generation during 2029-30
• Peak-day / Maximum Energy-day (07 October 2029)
• 340 GW peak in the evening, entire week 3 days before & 3 days after shown
Generation dispatch for the entire week (6 hourly basis)
31

32. Short Term Studies… (Contd.) 32
Renewable Energy generation with absorption on peak-day

33. Short Term Studies… (Contd.)
33
Hourly generation dispatch on 07 October 2029

34. Perspective Transmission Plan by 2030 with RES
• When conventional form of generation addition is
considered, together it necessitates augmentation of Extra
High Voltage (EHV) transmission system at 220 kV, and 400
kV levels in the existing corridors or constructing EHV or
UHV (Ultra High Voltage) lines in new corridors.
• This is the genesis of having new high capacity corridors in
southern and western parts of India connecting northern
and eastern parts as shown in the figure following wind
and solar maps of India.
34

35. Perspective Transmission Plan by 2030 with RES (Contd.)
35

36. Generation & Demand Projection
Assuming 175 GW RE capacity
• Demand: The national electricity demand has been collected from
Electric Power Survey of CEA.
• Solar, Wind, Nuclear & Hydro: The generation of Solar, Wind, Nuclear &
Hydro are predicted on the basis of their past generation trend.
• Gas: The gas generation data has been taken from CEA.
• Small Hydro, Biomass: Since no reliable data is available for these small
renewable sources, straight-line assumptions have been used. Small
Hydro is taken as 1000 MW and Biomass as 2000 MW as constant values.
• Coal: It is calculated figure. Added hourly generation of all generation
sources except coal and subtracted from hourly demand and the result is
the required hourly generation from coal.
36

37. Demand & Generation on the most critical day 37
180
177
174
172
171
172
175
178
179
180
182
181
181
179
178
178
178
175
175
185
190
189.882
187
186
29
27
25
22
23
23
23
41
59
80
94
102
108.082
105
93
81
62
44
33
32
29
29
29
29
111
111
110
111
110
111
112
96
77
58
46
39
32.665
35
45
57
76
92
102
109
117
116.769
115
114
0
25
50
75
100
125
150
175
200
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
GW
Hours
Total Load (2021-22) Nuclear BAU Small Hydro BAU Biomass BAU
Gas BAU Hydro BAU RES (S+W) BAU Coal BAU

38. Integration of 108 GW Renewable Generation
• Step 1 - Hydro flexing
• Step 2 - Gas flexing
• Step 3 - 2-shift operation
• Step 4 - Pump storage/Battery Storage
• Step 5 - RES Curtailment
• Step 6 - Demand side Management
38

39. Step-1: Coordinated Effort – Hydro Flexing 39
• Graph includes 1205 MW
of under construction PS.
• Energy recovery of 70% is
considered for PS
• Pumped storage solve
flexibilization problem in two ways
– Consumes power in afternoon
– Supplies power in morn./even. Peak
• Regulatory intervention: incentives
or high tariff for supporting grid
32
31
30
29
29
30
31
23
21
21
21
20
19
18
18
19
19
19
20
33
36
36
34
34
0
10
20
30
40
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
GW
Hours
Hydro Power
Hydro BAU Hydro after reallocation

40. Step-2: Coordinated Effort – Gas Flexing
40
8 8 8 8 8 7 7
5
4
3 3 3 3 3 3
4
5
6
7
8
9 10 9 9
0
3
6
9
12
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
GW Hours
Gas Power
Gas BAU Gas after reallocation
• Gas plants do not flex much
as of today
• In 2022, we need Gas to
vary from 3 to 8.5 GW
• Minimum Technical
Loading (MTL)  36%

41. Step-3 & 4: Coordinated Effort – 2- Shift Operation, Battery/PS
41

42. Step-5: RES Curtailment
S.No. Season MU of RES
produced
MU of RES
curtailed
% of RES
curtailed
1 Monsoon 100815 2555 2.53%
2 Non- Monsoon 173488 73 0.04%
3 Overall 274303 2628 0.96%
Overall % RES curtailed 0.96%
42
Monsoon : June – August (3 Months)
Non Monsoon : Sept – May (9 Months)
• Negligible amount of RES
curtailment goes a long way in
ensuring integration of clean power.
• The period June to August is period
of high RES.
• Almost all curtailment of RES will
happen in this period
• RES curtailment in addition to Step
1 & 2 improve MTL to 56%

43. Step-6: Demand Side Management
1. Supply of electricity to agriculture sector by dedicated feeders
• Agricultural consumption = 173185 MU
• Agricultural consumption = 17.30 %
• Connected load = 108834529 kW
• Nos. of consumers = 20,918,824
1000 MW load shifted from night hours to peak solar gen. hour improves 1% MTL
2. Demand side management including measure targeted at domestic, industrial and
e-mobility sector would enable more rational consumption pattern of electricity.
• least cost during high solar period,
• highest cost in evening/ morning peak.
It encourages consumption of energy during day time and reduction in peak hours.
43

44. Flexible Operation of Coal Fired Power Plant
• Categorization of thermal generating units based on Factors considered -
1. Unit heat rate
2. Load center unit
3. Pit head unit
4. Old units
5. New units
6. Merit Order/ ECR
7. Super critical/ Sub-critical
8. Size of unit
• Merit order dispatch and low load operation for Scheduling
• Increase in tariff due to increase in Net Heat Rate for 200 / 210 MW, & 500 MW
(Subcritical), 660 MW (Supercritical), 800 MW (Ultra Supercritical)
• Increased O & M Cost, Increased Oil Consumption due to frequent start / stops
44

45. Flexible Operation of Coal Fired Power Plant (Contd.)
Test/study conducted
1. Unit # 2, 500 MW Dadri TPS, NTPC study conducted on 21.06.2018
2. Unit # 2, 500 MW, Mouda TPS, NTPC study conducted on 29.05.2019
3. Sagardighi, 500 MW unit# 3, WBPDCL study conducted on 27.06.2019
4. Vindhyachal,500 MW unit# 11, NTPC study conducted on 06.03.2019
5. Anpara B, 500 MW unit# 4, UPRVNL study conducted in May & Dec 2019
6. Anpara B, 500 MW unit# 5, UPRVNL study conducted in May & Dec 2019
7. Unit # 6, 500 MW, Ukai TPS, GSECL study conducted on 04.03.2020
Test/study is being conducted
1. DSTPS, 500 MW unit#1, DVC
2. MRBTPS, 525 MW, unit#1, MPL
45

46. Regulation and Certification
• In India, regulators have reduced Renewable Energy Plant Size for grid
connection to 50 MW,
– As the state power utilities were initially reluctant to connect Green
Plants (mainly Wind and Solar based) to the grid.
– This may not solve the problem of connection of solar plants created
under National Solar Mission to the grid.
– In most of the countries to promote Renewable, priority is being
accorded to access the grid.
• Central Electricity Authority (CEA) contemplated regulations on technical
standards and grid connection
– Present regulations on grid connectivity do not cover Distributed
Generation and Renewable (DGR) to accommodate small generators
below 33 kV level also.
46

47. Salient Features of Regulation
• All wind farms connected at 66 kV and above shall remain connected to the grid
when voltage at interconnection point on any or all phases dips to the level, based
on Voltage Ride Through (VRT) Characteristics.
• While synchronizing fluctuation should be within + 5% at the interconnection point
with no objectionable flicker.
• Permissible limit of voltage fluctuation to unit step change is 1.5% while for other
changes it is 3%.
• While individual voltage harmonic distortion is limited to 3%, total shall not exceed
5% and similarly for current, total shall not exceed 8%.
• Over and under voltage trip functions for above 110% and below 80% respectively
with clearing time of 2 seconds and similarly over and under frequency trip
functions for above 52 Hz and below 47.5 Hz with clearing time of 0.2 seconds.
47

48. Regulatory Provisions in India
• In general from the era of predictable generation dispatch, now, smart grid has to
cope up with variable generation.
• Regulatory mechanism vis-à-vis storage and / or quick starting system is constantly
evolving.
• In India in order to promote the development of Renewables for green energy
certain obligatory provisions have been enacted.
• For meeting Renewable Purchase Obligation (RPO), state specific RPO compliance
requirement exists.
• Competitive procurement of power has been mandated in the Electricity Act 2003
and the National Electricity Policy 2005.
• There is need for market based mechanisms for promoting investment and
penetration of renewable energy on a large scale basis.
48

49. Renewable Energy Certification (REC) Mechanism
• Registry of Renewable Energy Generators comprises of basically four
stages, namely
– Accreditation
– Registration
– Issuance
– Trade and Redemption
49

50. Overall Conclusions
• Renewable is gradually forming a sizable part of generation feeding the grid, shifting
from fossil-fuel based plant, thereby reducing pollution.
• Integration of smart grid utilizing advanced technologies of digital computing and
communication addresses variability issues in addition to technology.
• Constant evolution of Regulatory Mechanism in India encourages Distributed
Generation and Renewable.
• With India’s Intended Nationally Determined Contribution in a reasonable period of 8-
9 years (by 2029-30) it is possible to meet Peak Electricity Demand with 64% installed
capacity from non-fossil-fuel based plants out of a total capacity 817.254 GW and
44.7% of total Electrical Energy Requirement out of 2,518 BU.
• At the same time CO2 emission growth is restricted to 1,287 MT (2029-30) from 922
MT (2017-18), while for each unit of energy (kWh) it reduces from 0.705 to 0.511 Kg
during the same period.
• With technological progress in lowering Minimum Technical Loading of thermal plants,
it is possible to enhance absorption of Variable Renewable Energy Generation further.
50

51. References
• Central Electricity Authority, Executive Summary on Power Sector, May 2021, https://cea.nic.in/wp-
content/uploads/executive/2021/05/Executive_Summary_May_2021-2.pdf.
• Long Term Planning for Indian Power Sector with Integration of Renewable Energy Sources,
presented in the 2020 IEEE Ninth Power India International Conference, DCRUST, Murthal,
Haryana, India, Feb 28-Mar 01, 2020, paper #1570621522, Pankaj Batra, Sandesh Sharma, Praveen
Gupta, Brijesh K Arya, Ashok K Rajput, Vijay Menghani , and Subrata Mukhopadhyay.
• Renewable Energy Integration in India - Present State and Long-Term Perspective to Serve the
Requirement, to be presented in the IEEE PES Power Tech 2019 at Milan, Italy, Jun 23-27, 2019,
paper #587, Sushil K Soonee, Samir C Saxena, K V S Baba, S R Narasimhan, K V N Pawan Kumar,
Praveen K Agarwal, Pankaj Batra, and Subrata Mukhopadhyay.
• Flexibility in Indian Grid Operation with High Penetration of Grid-Connected Renewable Energy,
presented in the 2018 IEEE Eighth Power India International Conference, National Institute of
Technology, Kurukshetra, Haryana, India, Dec 10-13, 2018, paper #1570471614, Sushil K Soonee,
Samir C Saxena, KVS Baba, S R Narasimhan, KVN Pawan Kumar, and Subrata Mukhopadhyay.
• Wind-Solar Hybrid System – An Innovative and Smart Approach to Augment Renewable Generation
and Moderate Variability to the Grid, 2016 IEEE Seventh Power India International Conference,
Bikaner, Rajasthan, India, Nov 25-27, 2016, paper no. 110, Subrata Mukhopadhyay, Vinod K
Agrawal, Archit Khemka, Krishna Manoharan, and Dheeraj Jain.
51

52. Thank You
Grid Integration of Renewable Energy in India 52