Introduction Sun is the main source of life and prosperous to mankind and organism at all times from ancient era to modern age. The solar energy emanating from the sun, by virtue of its unlimited resources, always proves it can compete with other conventional depleted resources. This is evident, as the world has seen recently, the solar technology advanced enough to unveil the scale of benefits; when utilizing full potential. Generation from wind is complementing the efforts from solar generation and competing favorably in countries with sufficient wind blows. NREL-National Renewable Energy Lab, US predicated that the cost of solar and wind generation, to be the lowest cost in near future compared to other generations and share 1000 GW worldwide. 1. Challenges with Generation Integration PV and CSP maximum instantaneous generation depends on how much sunlight is available at any given instant, which makes their generation variable (VRE) and difficult to predict. VRE can be installed in bulk at utility level or at commercial and industrial buildings or at homes. Utility solar generations can be located in areas with less loads and their energy needs to be transmitted to load centers. Operation of variable solar

1. Journal Name
2017; X(X): XX-XX
Published online MM DD 2017 (http://www.sciencepublishinggroup.com)
doi: 10.11648/j.XXXX.2017XXXX.XX
Operational Challenges of Renewable Generation
Integration in GCC
Hatim I. Elsayed1, *, Hashim A. Al Zahrani1, Ikram Rahim1, Nasser A. Al Sharani1
Operations & Control Department, Gulf Cooperation Council Interconnection Authority (GCCIA), Dammam, Kingdom of Saudia Arabia
Email address:
helsayed@gccia.com.sa, hzahrani@gccia.com.sa, nshahrani@gccia.com.sa
To cite this article:
Authors Name. Paper Title. International Journal of XXXXXX. Vol. x, No. x, 2017, pp. x-x. doi: 10.11648/j.xxx.xxxxxxxx.xx.
Received: MM DD, 2017; Accepted: MM DD, 2017; Published: MM DD, 2017
Abstract: This article covers, the present and future utilization of renewables with focus on solar generation (photo-voltaic
panels PVs, CSPs) at Gulf Cooperation Council (GCC) and the operational challenges facing GCC utilities during its first
integration. The article will also present operational challenges from Variable Renewables (VRE) in the US for 30%, 50% and
100%
Keywords: Operational Challenges, Renewables, GCC, Variable Renewable, PV, CSP, Solar
1. Introduction
Sun is the main source of life and prosperous to mankind
and organism at all times from ancient era to modern age.
The solar energy emanating from the sun, by virtue of its
unlimited resources, always proves it can compete with
other conventional depleted resources. This is evident, as
the world has seen recently, the solar technology advanced
enough to unveil the scale of benefits; when utilizing full
potential. Generation from wind is complementing the
efforts from solar generation and competing favorably in
countries with sufficient wind blows. NREL-National
Renewable Energy Lab, US predicated that the cost of solar
and wind generation, to be the lowest cost in near future
compared to other generations and share 1000 GW
worldwide.
1. Challenges with Generation
Integration
PV and CSP maximum instantaneous generation depends
on how much sunlight is available at any given instant, which
makes their generation variable (VRE) and difficult to predict.
VRE can be installed in bulk at utility level or at commercial
and industrial buildings or at homes. Utility solar generations
can be located in areas with less loads and their energy needs
to be transmitted to load centers. Operation of variable solar
generation with mixed conventional power generation is a
new challenge of load/generation balance. The control
systems within most control centers are well trained to deal
with variation in conventional generation while they should be
educated and adapted to deal with operational response and
technical characteristics of solar generation during incidents.
There are trials of wind generation connection in some GCC
Member States (MSs). Two case studies are presented, the
first case highlights the operational challenges from
introducing solar generation in GCC and the second is from
global practice from variable renewable integration.
2. Benefit to GCC from Common Clean
Energy Policy
Europe is still working in the energy policy targets of
20-20-20 (20% increase in energy efficiency, 20% reduction
of CO2 emissions, and 20% renewables by 2020). Although
GCC has no similar common energy policy; nevertheless
every GCC member has its own strategic vision and target
towards RES. Europe and GCC countries have joint group
called ‘EU-GCC Clean Energy Technology Network’. It is
about the right time that GCC could agree for similar energy
policy. Incentive and gained benefits can encourage GCC
policy makers to adopt the proposed target, and the MSs will
have something to work on, until 2025-2030. GCC can set a
common energy policy in the area with target; say 25-25-25
(25% increase in energy efficiency, 25% reduction of CO2
emissions, and 25% renewables by 2025).

2. 2 Hatim Elsayed et al.: Operational Challenges of Renewable Generation Integration in GCC
The drive for this movement is the decreased cost of RES,
to the economic level that has made it a very cost-effective
solution. New solar PV bids inside GCC unveiled prices of
less than 3 cents (USD 0.03) per kW/h and CSP of 7.3 cents
per kW/h. This operational cost is less than the cost of some
conventional generation in the region [1]. Capital cost has also
been downsized drastically to reach competitive level per MW
compared to conventional generation. UAE and KSA had
released record bids of cost-effective solar power compared to
fossil generation.
The integration of RES together with the specific measures
including smart meters and smart appliances to address the
resulted operational challenges, converts GCC conventional
grid into smart grid. The GCC MSs with preciousness of land
making it insufficient enough to satisfy the RES policy; can
engage into agreement with other spacious GCC countries for
land lease, power purchase agreement and/or energy trading.
3. Renewable Generation at GCC
(2014-2018 & 2030)
IRENA Report ‘Renewable Energy Market Analysis: GCC
2019’ [1], is showing RES generation capacity has progressed
fast at GCC since 2014, to reach almost 867 MW by 2018
including 813 MW of PV and CSP generation. The figure
below shows the installed RES capacity at GCC by 2018
including PVs and CSPs [1].
Table 1. Installed RES capacity at GCC 2014-2018
IRENA report anticipates installed RES capacity by 2030 for
each GCC MS as per the table below [1]:
Table 2. RES capacity for each GCC MS- 2030
The report indicated total capacity 65.49 GW of PV (utility
and roof-top) and CSP. UAE is a leader in this field with about
2% share on the total generation [1]. The figures in IRENA
report require update as the information received from GCC
MSs they have more RES in 2018, than what is written in the
report. Also the estimation reported by 2030 looks lesser than
what is planned by the GCC State’s utilities.
4. Energy Efficiency, Emissions Saving
from RES at GCC (2030)
The table below shows the ‘Energy efficiency targets’of the
GCC countries (2021-2050) [1]. Each GCC country is having
its own target of energy generation, consumption and carbon
efficiency, from 2021 to 2050.
Table 3. GCC Generation Consumption and Carbon Efficiency -2021-2050

3. The issue name 2017; X(X): XX-XX 3
Below graph forecasts ‘Emission Savings’ on 2020, 2025
and 2030 by realizing renewable energy deployment plan [1].
Figure 1. GCC Emission Savings [1].
The total number of jobs expected to be created by RES, is
estimated as 220500 by 2030. The IRENA report categorizes
job per cent for each GCC country by 2030 [1]. UAE and KSA
dominate the job market by occupying three quarters (78%, 45%
& 33% respectively) of the total created jobs, followed by
Kuwiat (10%), Oman (7%), Qatar (4%) and Bahrain (1%).
5. Operational Challenges from RES
integration
There is an attraction from monetary side from installing
RES, while from the other supply security and reliability point
of view, there are operational concerns. The main power
system components dominate the operational challenges of
integrating solar generation are the voltage support, frequency
management and active power control. The operational
challenges arise from dealing with these components fall in
the following areas:
1. Voltage Support
a. Reactive Power/Power Factor Control
b. Voltage Disturbance Performance
2. Frequency Management
a. Inertia
b. Frequency Disturbance Performance
c. Operating Reserves
3. Active Power Control (APC)
a. Management of Ramping Capability
b. Economic Dispatch
c. Curtailment
The control room shall be prepared to cope well with such
large generation/load variation to maintain the three physical
power system components (voltage, frequency and MW flow).
The Case Study-1 reports measurement from GCCIA
phasor measurement system (PMUs) how the large variation
of solar generation poses new operational challenges on MS
utilities as well as on GCCIA. In some scenario of large solar
generation drop, it appears to be the control staff increased
other reserve of generation units to feed the demand and
recover the frequency to operating limits. When the clouds
disappeared in few minutes the solar panels resumes
generation that caused the frequency to shoot above working
limits.
5.1 NERA and CAISO future scenario of MW ramping
Benchmarking with other studies, NERAand CAISO report
additionally highlights anticipated operational challenges that
based load scenario for ramping in the year 2020. Snap
below [2]. 6.7 GW baseload ramp-up in 3 hours is a possible
scenario coupled with 7 GW ramp-down in subsequent 3
hours and again 12.7 GW baseload ramp-up in 3 hours.
Figure 2. Baseload ramp-up, ramp-down [2].
Source: Joint NERC and CAISO special reliability assessment report, 2013
From the case study, the operational issues from ramping
the active power will require to educate the control engineers
on how to behave in short time. Other utilities and regulators
anticipate a scenario of baseload ramping with solar and wind
variation.
5.2 VRE Deployment and Curtailment
The article published by IEA in February-2019 [3]
highlighted the challenges of integrating RES. According to
the analysis several countries have experienced decelerating
VRE deployment due to system integration concerns or

4. 4 Hatim Elsayed et al.: Operational Challenges of Renewable Generation Integration in GCC
periods of high curtailment, even during the early days of
VRE expansion. VRE shares in many countries are forecasted
much greater in 2023 than in 2017 [3]. The challenges are to
maintain reliability and with less additional costs and keep
curtailment at healthy levels, below 2% [3]. The difficulty is
to integrate higher amounts of VRE comes from variability,
partial predictability, and location constraints. Flexible grids
required to deal effectively with supply and demand balance
in instant control [3]. The report advises to have four phases of
gradual VRE integration from local effect to supply provision
in most periods of demand [3]. accIn 2017, VRE generation
occurred in countries with shares of 5-10% annually and
system integration challenges handled through direct control
techniques [6]. On excess of 10% share, with VRE depending
more on solar technology, a more systematic approach is
required to cope with integration [3]. Second, challenges tend
to occur sooner for technologies with lower capacity factors.
The report claims that, shift from wind to solar generations
requires more integration measures [3].
Figure 3. VRE integration phases, transition challenges, flexibility measures
The following are two case studies; first case study
highlights how the system behaved during some incidents of
PV/CSP generation drops at one GCC country side on
Feb-April 2019. The records are from phasor measurement
units. In Feb. 2019, the solar generation drop has caused the
Frequency Control of HVDC to operate. The second case
study is from outside GCC, carried out by NREL (National
Renewable Energy Lab) for 30%, 50% and 100% VRE.
6. Case Study-1: Operational Challenges
with GCC solar generation drop
6.1 Load Variation (24 Jan. 2019)
The graphs show response for Frequency, MS to Tie-flow
MW, Phases and Voltages and Poles MW on Thursday
24/01/2019 11:10 to 12:00 Hrs. GCCIA, ICC noticed end
load variation with a GCC MS as per below chart. There was
a tie line flow variation from 133 MW export to 177 MW
import (sum of 310 MW), while another GCC MS network
responded by importing from 75 MW to 310MW. The flow
variation was mainly due to solar generation drop at a GCC
MS side [4].
Figure 4. MS to GCCIA Tie-line MW flow, Frequency [4].
Figure 5. MS to GCCIA Tie-line MW flow [4].

5. The issue name 2017; X(X): XX-XX 5
Figure 6. 50 Hz System Frequency [4].
6.2 Operation of HVDC Frequency Control
Generation drop at a GCC MS PV Solar PS by 500 MW
starting at 10:49:44 Hrs. -25 Feb. 2019, due to cloud cover
which caused under-frequency operation at HVDC 50 Hz
Frequency Control (FC) function at 10:53:13 Hrs, as
frequency declined from 49.986 to 49.899 Hz. GCCIA system
frequency deviated by 0.087 Hz and returned to operational
limit at 10:53:16 Hrs. The GCC MS import normalized at
10:56:12 Hrs. HVDC blocked at 11:03:32 Hrs [4].
Other MSs supported the GCC MS with a maximum of
419 MW, including HVDC, 60 Hz side support of 350 MW,
after FC operation. GCCIA coordinated all MSs for support
and HVDC support regulated in coordination with the affected
GCC MS . GCC HVDC support reduced in steps and blocked
at 11:05:50. Variation of the GCC MS PV generation was
ongoing for some time [4]. The GCC MS tie line flow
changed from 26 export to 192 MW import prior to FC
operation and max of 419 MW import after FC operation,
which resulted in an unscheduled deviation of tie line flows
among 50 Hz and 60 Hz MSs.
Table 4. Member State data during the incident
Mem
ber
States
Pre–
Trip
Prim
ary
SR
Pre-Tr
ip SR
Pre-T
rip
Tie
Line
Flow
Tie
Line
Flow
10
Sec
After
the
start
of
incid
ent
Tie
Line
Flow
30
Sec
After
the
start
of
incid
ent
Total
Generat
ion
Total
Dema
nd
K (50
Hz)
115 1735 60 181 183 7088 5353
Q (50
Hz)
119 51427
9
-37 27 -7 4331 3817
B (50
Hz)
47 25921 -261 -245 -261 1827 1307
U (50
Hz)
211 82851
16
192 350 391 7876 5597
O (50
Hz)
84 447 32 81 38 3378 2928
S (60
Hz)
52 65147
2
0 -349 -343 15624 11273
Figure 5. Frequency, Tie-line MW, Angles & Voltages, Poles MW [4].
6.3 A GCC MS solar generation variation and tie-line
power flows incident-28 Feb. 2019

6. 6 Hatim Elsayed et al.: Operational Challenges of Renewable Generation Integration in GCC
On 28 Feb 2019, at 14:09 Hrs, PV at a GCC MS output
reduced from 716 MW to 229 MW in 16 minutes [4].
Minimum Frequency recorded as 49.92 Hz and maximum
frequency recorded as 50.10 Hz between 08:57 Hrs to 14:57
Hrs ( GCC MS time). Maximum Frequency drop of 0.070 Hz
was recorded over 10 minutes. Maximum The GCC MS tie
line variation recorded 470 MW over 11 minutes.
6.3.1 Sequence of Events [4]
1) 6:57 the tie-line exchange showed increase from 0 MW
2) 10:00 Hrs The GCC MS exported 245 MW caused
system frequency go up to 50.090 Hz
3) 10:10 Hrs The GCC MS tie line changed to 170 MW
import caused system Frequency drop to 49.92 Hz. A GCC
MS tie line changed by 415 MW during this frequency
change.
4) 11:34:50 Hrs System frequency Maximum recorded
50.10 Hz with Transco export of 293 MW which was
maximum export for the duration at peak solar generation.
5) 11:38:40 Hrs The GCC MS tie line export of 293 MW
changed to 177 MW import over 11 minutes duration and
system frequency dropped from 50.10 Hz to 49.96 Hz with
this.
6) Around 12:30 the tie-line exchange reached a peak of
814 MW
7) 17:57the tie-line exchange dropped to 0 MW.
System frequency reached below nominal for five instances
and above nominal for twelve instances at different times for
the chart duration. The GCC MS imported 170 MW and 191
MW when system frequency recorded 49.92 Hz at two
different times. The GCC MS 460 MW generation regulation
is seen from difference between maximum and minimum
generation for the chart duration.
(a) (b) (c)
Figure 6. Frequency, Tie-line MW at different MSs[4].

7. The issue name 2017; X(X): XX-XX 7
Figure 6. Frequency, Tie-line MW at different MSs[4].
The below snap from the MS utility [5] showed the tie-line
exchange graph jumps up to 814 MW. At 14:09, on 28 Feb
2019, the PV output reduced from 716 to 229 MW in 16
minutes.
Figure 6. Frequency, Tie-line MW at different MSs[5].
Source: Transmission and Dispatching Company, A GCC Utility [5]
6.4 The GCC MS Solar Generation Variation on 21 April
2019
At 08:16 Hrs on 21 April 2019, PV generation dropped at
the GCC MS from 820 MW to 280 MW due to sun outage.
This generation variation of around 540 MW, caused
frequency to drop below operational limit; from 50.020 Hz to
49.914 Hz in five minutes. At 08:25 Hrs the frequency
recovered to operational limit and went high to 50.080 Hz at
08:33 Hrs. The overall operational process of frequency
decrease/increase took about 17 minutes but the frequency
hasn’t reached the triggering threshold setting of the HVDC
Frequency Control. The behavior of operation both automatic
and manual requires more analysis with reference to AGC
(Automatic Generator Control) setting and other power
control devices.
Figure 7. System Frequency [4].
7. Case Study2: Operating Challenges
with Achieving 100% Renewable Energy
The second case is a study performed by NREL-National
Renewable Energy Lab. (www.nrel.gov/grid) on challenges to
‘Achieving 100% Renewable Energy Operating Challenges’
in IEEE ISGT Conference held at Washington DC on Feb.
17-20, 2019 [6].
NREL provides solutions to grid integration challenges.
The case covered topics below:
• Understanding current and future power systems
• Current state of variable renewable energy (VRE):
solar and wind
• Current power systems operating with VRE
• Challenges and solutions of operating power
systems with very high levels of VRE
• Research needs
The report claimed that solar and wind cost will become the
lowest cost energy options in near future and expected to have
a worldwide share of 1000 GW. The capacity addition in the
US witnessed an increase in solar, wind and other renewable
generations. New Generation Additions in the United States
Are Mostly Gas, Wind, and Solar [6]. In the year 2016, the
addition of solar, wind capacity together is 16 GW, double that
of natural gas as 8 GW approximately (figure below).

8. 8 Hatim Elsayed et al.: Operational Challenges of Renewable Generation Integration in GCC
Figure 8. US Utility Scale Capacity Addition [6]. Source: EIA,
https://www.eia.gov/todayinenergy/detail.php?id=30112 [6]
7.1 Operational Challenges with RES in the US
The topics highlighted the new challenges in modern grid
with increasing level of power electronics- based VRE solar
and wind, increased use of ICT like in smart grid, electric
vehicles, distributed storage, flexible loads, distributed control
systems [6]. NREL, Eastern Renewable Energy Integration
Study (ERGIS) (2016) (http://www.nrel.gov/grid/ergis.html)
demonstrated that very large power systems can operate at
5-minute dispatch with 30% VRE. The operational areas of
interest are Reserves (types, quantities & sharing),
Commitment and dispatch (Day-ahead, Four-hour-ahead,
Real-time) and Inter-regional transactions (1-hour, 15-minute
& 5-minute).
Western Wind and Solar Integration Study highlighted
challenges to operate with significant variable wind and solar
generation as:-
• Wind power plants: voltage regulation and
ridethrough
• Utility-scale PV: voltage regulation and
ridethrough
• Rooftop PV: embedded in composite load model,
no controls.
Impact study on Western Interconnection can survive a
major contingency outage with 30% variable generation
(inverter-based).
7.2 Achieving 30% VRE is possible, what is required for 50%
VRE
NREL have done the research and demonstrated that
achieving 30% VRE is possible with minimal system changes.
What do we need to do to achieve very high levels (more than
50%) of wind and solar integration?
Variability and Uncertainty of VRE has the following
Challenges:
• Energy shifting (VRE produces energy when
resources are available— variable and uncertain)
• Forecasting (renewable resources and load)
Dark shadows in the following graph [6], highlight the
variability and uncertainty of PVs integration with the electric
power system
Figure 9. VRE with PV Integration [6]: Source: A Mills et al.
Curtailment from various generation sources indicates
about 380 GW at 00:00 and 640 GW at 12:00 on April 30 with
a difference of 260 MW between night and day [6].
Figure 10. Curtailment from various generation [6]: Source: NREL, REF: 80%
Renewables Case [6], http://www.nrel.gov/analysis/re_futures/

9. The issue name 2017; X(X): XX-XX 9
NREL Proposed Solutions:
• Utilize geographic diversity.
• Utilize flexible conventional generation.
• Increase sharing among balancing authority areas.
• Expand the transmission system.
• Curtail excess VRE production.
• Coordinate flexible loads (active demand
response).
• Enhance VRE and load forecasting.
• Add electrical storage.
• Interact with other energy carriers.
7.3 VRE Curtailment and Energy Storage
Currently, there is 21 GW of pumped hydro in the United
States [6]. The study reports that by 2050, storage capacity is
estimated at 28 GW in the Low-Demand Baseline scenario (8%
of the total generated electricity), 31 GW in the 30% RE
scenario (14% of the total generated electricity), 74 GW in the
60% RE scenario (34% of the total generated electricity), and
94 GW in the 90% RE scenario (48% of the total generated
electricity).
(a)
(b)
Figure 11. Curtailed Electricity (a) Storage and variable generation (b) [6]:
Source: NREL, REF [6]:
7.4 Ireland: Examples of High Levels of VRE
In Ireland Island power system is 6.5 GW peak and has 23%
wind on annual energy basis (2015). Currently limiting grid to
65% instantaneous nonsynchronous penetration [6].
Figure 12. Wind Penetration in Ireland: Source: EirGrid, All Island TSO
Facilitation of Renewable Studies: Final Report (2010)
7.5 Power System Operation
High renewable penetrations require paradigm change in
need advanced controls and technologies to integrate wind and
solar while maintaining grid stability and reliability [6].
Figure 13. Advanced controls to integrate wind and solar:
Power System Stability with different generation reserves

10. 10 Hatim Elsayed et al.: Operational Challenges of Renewable Generation Integration in GCC
Figure 14. Generation Reserves with VRE:
7.6 Operational Challenges
• Transient and dynamic stability (loss of system
inertia could reduce ability to respond to
disturbances—need ride-though capabilities in
VRE)
• Frequency regulation (need primary, secondary,
and tertiary response from VRE)
• Volt/VAR regulation (need ability to locally
change voltage to stay within nominal limits)
•
• Solutions:
• Use smart inverters with advanced functionality.
• Mimic synchronous generator characteristics.
• Provide active power, reactive power, voltage, and
frequency control.
7.7 Active Power Control from Wind and Solar Inverters
Technology addressed, understanding how variable
generation (wind and solar) can provide primary and
secondary reserves and impact on inertial control, primary
frequency control, and automatic generation control (AGC)
from wind and solar are feasible [6]
Figure 15. Power Control and frequency:
7.8 Large-Scale Photovoltaic Plant Regulation
NREL/FirstSolar/CAISO experiment: 300-MW plant
following AGC signal, It has been demonstrated that PV
plants (and wind power plants) can deliver essential grid
services.
Figure 15. Plant Requlation:
7.9 Additional Technical Challenges
There are other technical challenges face achieving 100%
VRE including the protection coordination, islanding,
blackstart and distributed controls [6].

11. The issue name 2017; X(X): XX-XX 11
Figure 16. Generators and Inverters:
Source: B. Kroposki et al., “Achieving a 100% Renewable Grid – Operating
Electric Power Systems with Extremely High Levels of Variable Renewable
Energy,” [6], http://ieeexplore.ieee.org/document/7866938/
The solutions to these technical challenges can be devised
as follows [6]:
Table 5. Operational Challenges and Solutions
Challenges Solutions
Protection coordination (loss
of high shortcircuit current may
affect protection schemes)
Synchronous condensers,
new protection schemes
Unintentional islanding (need
methods to
protect against unintentional
New artificial intelligence
options
islanding)
Black-start—ability to restore
system from
outage
New system restoration
methods
Distributed controls. New control architectures
and management systems.
Acknowledgements
The Authors acknowledge the effort from Operations and
Control Department, at GCCIA of KSA and the Member
States of GCC.
References
[1] The International Renewable Energy Agency (ARENA):
Renewable Energy Market Analysis: GCC 2019. (Quoting
source of KAPSARC)
[2] Joint NERC and CAISO special reliability assessment report,
2013
[3] Will system integration of renewables be a major challenge by
2023? : http://bit.ly/2Gkzuws
Analysis from Renewables 2018, 20 February 2019
[4] GCCIA, Interconnection Control Center, Operation and
Control Department
[5] TSO, GCC MS
[6] Benjamin Krosposki (Ph.D, PE, FIEEE) Director, Power
System Engineering Center Achieving 100% Renewable
Energy Operating Challenges: NREL-National Renewable
Energy Lab. (www.nrel.gov/grid), presentation, IEEE ISGT
Conference held at Washington DC on Feb. 17-20, 2019.