Clearness-Index-Driven Assessment of Solar Energy Potential in Saudi Arabia's Empty Quarter: A Comparative Study with Abqaiq and Hail (2005–2024)

Clea ness -Index-D i en A ssessmen o
Sola Ene g y Po en ial in Saudi A abia’s
Emp y Qua e : A Compa a i e S udy
wi h Abqaiq and Hail (󾙔󾙒󾙒󾙗‒󾙔󾙒󾙔󾙖)
Au ho : Mohammed Alma i
Affilia ion: King Fahd Uni e si y o Pe oleum and Mine als
P og am: M.Sc. in Sus ainabili y & Renewable Ene g y
Yea : 󾙔󾙒󾙔󾙗
Abs ac
Saudi A abia possesses some o he wo ld’s highes -quali y sola esou ces,
pa icula ly ac oss i s hype -a id dese s. This s udy pe o ms a 󾙔󾙒-yea clea ness -
index-based assessmen (󾙔󾙒󾙒󾙗‒󾙔󾙒󾙔󾙖) o sola ene gy po en ial in he Emp y Qua e ,
using Sha u ah (󾙓󾙙.󾙖󾙚°N, 󾙖󾙙.󾙓󾙔°E) as a ep esen a i e sou he n si e. Two addi ional
loca ions—Abqaiq in he eas e n oil egion and Hail in he inland no h—a e used o
clima ic compa ison. Using NASA POWER clima olog y, we de i e mon hly and annual
global ho izon al i adia ion (H), compu e ex a e es ial i adia ion (H₀) om sola
geome y, and ob ain he clea ness index K_ = H/H₀.
Sha u ah (Emp y Qua e ) exhibi s an annual H ≈ 󾙔󾙖󾙕󾙚 kWh/m²·y and K_ ≈ 󾙒.󾙘󾙛󾙛,
indica ing ex emely clea , beam-domina ed dese skies. Hail also shows excellen
esou ce wi h H ≈ 󾙔󾙔󾙘󾙔 kWh/m²·y and K_ ≈ 󾙒.󾙘󾙛󾙔, while Abqaiq, affec ed by
indus ial/u ban ae osols, has H ≈ 󾙔󾙓󾙛󾙖 kWh/m²·y and K_ ≈ 󾙒.󾙘󾙘󾙓. A ssuming fixed-
il PV wi h il ≈ la i ude, plane-o -a ay gain = 󾙓.󾙓󾙗, and pe o mance a io PR = 󾙒.󾙚󾙒,
he Sha u ah/Emp y Qua e si e deli e s a specific PV yield o app oxima ely 󾙔󾙔󾙖󾙕
kWh/kWp·y , compa ed o ~󾙔󾙒󾙚󾙓 kWh/kWp·y o Hail and ~󾙔󾙒󾙓󾙚 kWh/kWp·y o
Abqaiq.
A land-use scena io in which 󾙗% o he Saudi po ion o he Emp y Qua e (~󾙔󾙓,󾙗󾙒󾙒
km²) is co e ed wi h PV a an ins alled densi y o 󾙘󾙒 MWp/km² yields an annual
elec ici y gene a ion o ≈ 󾙔󾙚󾙛󾙖 TWh/y , equi alen o a ound 󾙚.󾙚‒󾙛.󾙘 imes he
cu en na ional elec ici y consump ion (󾙕󾙒󾙔‒󾙕󾙔󾙙 TWh/y ). This co esponds o a
con inuous a e age powe o ≈ 󾙕󾙕󾙒 GW, compa ed o a na ional a e age load o 󾙕󾙗‒󾙕󾙙
GW and peak summe load o 󾙛󾙒‒󾙛󾙗 GW.
Using a CAPEX o 󾙕,󾙒󾙒󾙒 SAR/kWp and an in e nal elec ici y alue o 󾙒.󾙔󾙔󾙗‒󾙒.󾙕󾙒󾙒
SAR/kWh, he simple payback pe iod is ≈ 󾙖.󾙗‒󾙗.󾙛 yea s, while ca bon payback occu s
in less han one yea . The analysis confi ms he Emp y Qua e , ep esen ed by
Sha u ah, as a globally significan s a egic ese e o mega-scale sola deploymen ,
g een hyd ogen, and long- e m deca bonisa ion.
󾙓. In oduc ion
Saudi A abia is unde going a majo ans o ma ion o i s ene g y sys em as pa o
Vision 󾙔󾙒󾙕󾙒 and long- e m ne -ze o ambi ions. Na ional elec ici y consump ion has
g own s eadily, eaching oughly 󾙕󾙒󾙔 TWh in 󾙔󾙒󾙔󾙓, abou 󾙕󾙒󾙛‒󾙕󾙓󾙒 TWh in 󾙔󾙒󾙔󾙔, and ≈
󾙕󾙔󾙙 TWh in 󾙔󾙒󾙔󾙕. Con e ing his ene g y o a e age powe gi es:
Hence, Saudi A abia’s a e age na ional elec ical demand is abou 󾙕󾙗‒󾙕󾙙 GW.
Howe e , peak summe demand—d i en mainly by ai -condi ioning— eaches 󾙛󾙒‒󾙛󾙗
GW in July‒Augus a e noon hou s. This s ong seasonali y and daily peak coincide
wi h maximum sola i adiance, making sola PV pa icula ly well aligned wi h he
coun y’s load p ofile.
The Rubʿ al-Khali (Emp y Qua e ) is he la ges con iguous sand dese on Ea h, wi h
app oxima ely 󾙖󾙕󾙒,󾙒󾙒󾙒 km² inside Saudi bo de s. I is ex emely spa sely popula ed,
cha ac e ized by hype -a id clima e, low cloud co e , and high sola i adiance. This
combina ion o excellen sola esou ce and as a ailable land makes he Emp y
Qua e a p ime candida e o giga- and e a-scale sola deploymen , especially linked
o g een hyd ogen and po en ial elec ici y expo s.
To cha ac e ise he sola po en ial o he Emp y Qua e in a scien ifically obus way,
his s udy uses Sha u ah (󾙓󾙙.󾙖󾙚°N, 󾙖󾙙.󾙓󾙔°E) as a ep esen a i e sou he n Emp y
A e ageload = ≈
8760h/y
327TWh/y 37.3GW
Qua e si e, and compa es i wi h Abqaiq (eas e n oil/ indus ial egion) and Hail
(inland no he n dese ci y). The analysis is based on clea ness -index-d i en
modelling, which p o ides a compac way o e alua e sky condi ions and diffuse
ac ion.
󾙓.󾙓 Objec i es
The main objec i es o his wo k a e:
To quan i y H, H₀, and K_ o Sha u ah (Emp y Qua e ), Abqaiq, and Hail using
󾙔󾙒󾙒󾙗‒󾙔󾙒󾙔󾙖 NASA POWER clima ology.
To compa e he sola esou ce quali y among hese h ee loca ions, wi h
pa icula ocus on Emp y Qua e s. Hail.
To es ima e PV specific yields unde ealis ic fixed- il sys em assump ions.
To e alua e a 󾙗% land-use scena io in he Emp y Qua e and compa e i s ou pu
o na ional consump ion, in bo h ene g y (TWh) and powe (GW).
To es ima e economic payback in SAR and CO₂ emission educ ions, highligh ing
he ole o he Emp y Qua e in Saudi A abia’s long- e m ene g y s a eg y.
󾙔. Backg ound
󾙔.󾙓 Sola Resou ce in he A abian Peninsula
P e ious sola esou ce assessmen s ha e shown ha la ge pa s o Saudi A abia
achie e global ho izon al i adia ion abo e 󾙔󾙒󾙒󾙒 kWh/m²·y , placing he Kingdom in
he op ie o global sola egions. Many s udies, howe e , ocus on popula ed o
indus ial a eas such as Riyadh, Dhah an, o Abqaiq, while he Emp y Qua e emains
less explo ed, despi e i s eno mous heo e ical capaci y.
󾙔.󾙔 Clea ness Index
The clea ness index K_ is defined as:
K =
H
0
H
whe e:
H is he global ho izon al i adia ion a he g ound (kWh/m²·day o
kWh/m²·y )
H₀ is he ex a e es ial i adia ion on a ho izon al plane a he op o he
a mosphe e
Typical in e p e a ion:
K_ < 󾙒.󾙕󾙗: Cloudy condi ions
󾙒.󾙕󾙗 < K_ < 󾙒.󾙘󾙒: Mixed/cloudy
K_ > 󾙒.󾙘󾙒: Clea sky
K_ > 󾙒.󾙘󾙗‒󾙒.󾙙󾙒: Ve y clea , dese -like condi ions
Thus, K_ is a key pa ame e o classi ying he quali y o he sola esou ce and o
d i ing diffuse ac ion models.
󾙔.󾙕 Diffuse F ac ion and Clea ness -Index-D i en Modelling
Recen wo k p oposes empi ical co ela ions ha exp ess he diffuse ac ion k_d =
D/H (whe e D is diffuse i adia ion) as a unc ion o K_ . Fo high K_ , diffuse ac ion is
low and beam i adiance domina es. This has se e al implica ions:
Til ed PV yields highe gains ela i e o ho izon al
T acking o bi acial sys ems can benefi significan ly om he s ong beam
componen
The pe o mance o PV sys ems is mo e p edic able
In his p ojec , he ocus is on K_ i sel , bu he same da a can la e be used in
Enginee ing Equa ion Sol e (EES) o apply clea ness-index-based diffuse ac ion
co ela ions.
󾙕. Me hodolog y
󾙕.󾙓 S udy Loca ions
Th ee si es in Saudi A abia we e selec ed o his comp ehensi e analysis:
Si e
La i ude
(°N)
Longi ude
(°E)
Desc ip ion
Sha u ah (Emp y
Qua e )
󾙓󾙙.󾙖󾙚 󾙖󾙙.󾙓󾙔
Hype -a id sou he n Emp y
Qua e
Abqaiq 󾙔󾙗.󾙗󾙘 󾙖󾙛.󾙕󾙛 Eas e n oil/ indus ial egion
Hail 󾙔󾙙.󾙗󾙔 󾙖󾙓.󾙘󾙛 Inland no he n dese ci y
Sha u ah ep esen s he sou he n sec o o he Emp y Qua e , cha ac e ized by
ex ensi e sand dunes, low popula ion, and s ong sola esou ce. This loca ion se es
as he p ima y ocus o assessing he Emp y Qua e ’s po en ial, while Abqaiq and
Hail p o ide impo an compa a i e baselines o unde s anding egional a ia ions in
sola esou ce quali y.
󾙕.󾙔 NASA POWER Clima ology (󾙔󾙒󾙒󾙗‒󾙔󾙒󾙔󾙖)
Fo each si e, mon hly and annual clima olog y da a (Janua y 󾙔󾙒󾙒󾙗‒Decembe 󾙔󾙒󾙔󾙖)
we e ob ained om he NASA POWER p ojec in CSV o ma . The ollowing pa ame e s
we e used:
ALLSKY_SFC_SW_DWN → H (kWh/m²·day): Global ho izon al sola i adia ion
ALLSKY_KT → K_ (dimensionless): All-sky clea ness index
Mon hly alues o H (󾙓󾙔 mon hs) and an annual a e age (ANN) a e p o ided. Fo his
analysis:
󾙓. Mon hly H (kWh/m²·day) was mul iplied by he numbe o days in each mon h
o ob ain mon hly sums (kWh/m²·mon h).
󾙔. These we e summed o e all mon hs o ob ain annual H (kWh/m²·y ).
󾙕. H₀ was compu ed om s anda d sola geome y a he han aken om he file,
using si e la i ude, declina ion, and eccen ici y co ec ion, a a ep esen a i e

day in each mon h.
󾙖. Annual K_ was hen calcula ed as:
whe e he summa ion is o e he 󾙓󾙔 mon hs.
󾙕.󾙕 PV Sys em and Yield Model
To ela e he sola esou ce o PV ou pu , a simple bu ealis ic model is employed:
Fixed- il PV a ays, wi h il angle ≈ local la i ude
Plane-o -a ay (POA) gain ac o = 󾙓.󾙓󾙗 ( a io o annual POA i adia ion o
annual ho izon al i adia ion in hese clea dese clima es)
Pe o mance a io (PR) = 󾙒.󾙚󾙒, accoun ing o in e e , empe a u e, wi ing,
misma ch, soiling (assuming easonable main enance), and down ime
Then he specific yield pe ins alled kWp is:
This is compu ed o Sha u ah (Emp y Qua e ), Abqaiq, and Hail.
󾙕.󾙖 Economic Model (SAR Cu ency)
To assess financial pe o mance in local e ms:
Capi al cos (CAPEX): 󾙚󾙒󾙒 USD/kWp ⇒ 󾙚󾙒󾙒 × 󾙕.󾙙󾙗 = 󾙕󾙒󾙒󾙒 SAR/kWp
In e nal alue o elec ici y / a oided uel cos : 󾙒.󾙒󾙘‒󾙒.󾙒󾙚 USD/kWh ≈ 󾙒.󾙔󾙔󾙗‒󾙒.󾙕󾙒󾙒
SAR/kWh
Annual sa ings pe kWp:
Simple payback pe iod (yea s):
K =
,annual
H
∑m0,m
H ∑mm
Y ≈
PV H ×
annual 1.15 × 0.80 [kWh/kWp cdo py ]
S =
annual Y ⋅
PV aluepe kWh [SAR/kWp cdo py ]
Payback =
S
annual
3000SAR/kWp
󾙕.󾙗 Land-Use Scena io in he Emp y Qua e
The Saudi po ion o he Emp y Qua e is es ima ed a ≈ 󾙖󾙕󾙒,󾙒󾙒󾙒 km². A hypo he ical
bu illus a i e scena io o 󾙗% land co e age wi h PV gi es:
A ssuming ins alled capaci y densi y:
o al ins alled PV capaci y is:
The o al annual gene a ion is:
which is con e ed o TWh/y and compa ed agains na ional elec ici y consump ion.
󾙖. Resul s
󾙖.󾙓 Annual Sola Resou ce Me ics
Based on he NASA POWER clima olog y and compu ed H₀, he annual esul s a e
p esen ed in he ollowing able:
Si e H (kWh/m²·y ) H₀ (kWh/m²·y ) K_ (annual)
Sha u ah (Emp y Qua e ) 󾙔󾙖󾙕󾙚.󾙖 󾙕󾙖󾙛󾙒.󾙖 󾙒.󾙘󾙛󾙛
Hail 󾙔󾙔󾙘󾙓.󾙙 󾙕󾙔󾙙󾙒.󾙓 󾙒.󾙘󾙛󾙔
Abqaiq 󾙔󾙓󾙛󾙕.󾙛 󾙕󾙕󾙔󾙒.󾙔 󾙒.󾙘󾙘󾙓
Key obse a ions:
Sha u ah (Emp y Qua e ) has he highes annual H o he h ee si es and he highes
K_ , almos 󾙒.󾙙󾙒, confi ming an ex emely clea dese a mosphe e. Hail also has
excellen esou ce and high K_ , bu bo h H and K_ a e sligh ly lowe han Sha u ah.
A =
PV 0.05 × 430, 000 ≈ 21, 500km2
D =
PV 60MWp/km2
C =
ins alled A ⋅
PV D =
PV 21, 500 × 60 ≈ 1, 290GWp
E =
annual C ⋅
ins alled Y [kWh/y ]
PV
Abqaiq shows lowe H and K_ , consis en wi h highe ae osol load and pa ial
cloudiness nea indus ial egions.
Thus, Sha u ah clea ly eme ges as he bes o he h ee si es, bo h in e ms o o al
sola ene gy and a mosphe ic cla i y.
Figu e 󾙓: Sola Resou ce Compa ison (H, H₀, and K_ )
The abo e figu e illus a es he compa a i e analysis o global ho izon al i adia ion
(H), ex a e es ial i adia ion (H₀), and clea ness index (K_ ) ac oss he h ee s udy
loca ions. Sha u ah demons a es supe io pe o mance in all h ee me ics,
confi ming i s s a us as he op imal si e o sola ene g y de elopmen in he egion.
󾙖.󾙔 PV Specific Yield
Using he o mula:
we ob ain he ollowing specific yields:
Sha u ah (Emp y Qua e ): $
$
Hail: $ $
Abqaiq: $ $
Y =
PV H ×
annual 1.15 × 0.80
Y ≈
PV,Sha u ah 2438.4 × 1.15 × 0.80 ≈
2243kWh/kWp cdo py
Y ≈
PV,Hail 2261.7 × 1.15 × 0.80 ≈ 2081kWh/kWp cdo py
Y ≈
PV,Abqaiq 2193.9 × 1.15 × 0.80 ≈ 2018kWh/kWp cdo py
Si e PV Yield (kWh/kWp·y )
Sha u ah (Emp y Qua e ) 󾙔󾙔󾙖󾙕
Hail 󾙔󾙒󾙚󾙓
Abqaiq 󾙔󾙒󾙓󾙚
This means Sha u ah deli e s ~󾙚% mo e ene gy pe kWp han Hail and ~󾙓󾙓% mo e
han Abqaiq, which has impo an implica ions o LCOE and payback .
Figu e 󾙔: PV Specific Yield Compa ison
The figu e abo e demons a es he significan ad an age o Sha u ah in e ms o PV
sys em ou pu . The 󾙚% imp o emen o e Hail and 󾙓󾙓% imp o emen o e Abqaiq
ansla e di ec ly in o as e payback pe iods and supe io long- e m economic e u ns
o sola p ojec s in he Emp y Qua e .
󾙖.󾙕 Na ional Load, Peak Demand, and G id In eg a ion
Saudi A abia’s o al elec ici y consump ion o 󾙕󾙒󾙔‒󾙕󾙔󾙙 TWh/y co esponds o an
a e age load o 󾙕󾙗‒󾙕󾙙 GW. In summe , peak demand eaches 󾙛󾙒‒󾙛󾙗 GW, mainly due o
ai condi ioning.
Re e ences
[󾙓] NASA POWER P ojec . (󾙔󾙒󾙔󾙖). “P edic ion o Wo ldwide Ene gy Resou ces.” NASA
POWER Ag oclima olog y. Re ie ed om h ps://powe .la c.nasa.go /
[󾙔] Paulescu, M., Paulescu, E., G a ila, P., & Badescu, V. (󾙔󾙒󾙔󾙕). “Wea he Modeling and
Fo ecas ing o PV Sys ems Ope a ion.” Sp inge .
[󾙕] Zell, E., Gasim, S., Wilcox , S., Ka amou a, S., So e is, K., Pe ez, R., & Renne, D. (󾙔󾙒󾙓󾙗).
“A ssessmen o Sola Radia ion Resou ces in Saudi A abia.” Sola Ene gy, 󾙓󾙓󾙛, 󾙖󾙔󾙔‒
󾙖󾙕󾙚.
[󾙖] Saudi Elec ici y Company (SEC). (󾙔󾙒󾙔󾙖). “Na ional Elec ici y Consump ion and
Peak Demand Da a.” SEC Annual Repo .
[󾙗] Vision 󾙔󾙒󾙕󾙒. (󾙔󾙒󾙔󾙖). “Saudi A abia’s Long- e m Ene gy S a egy and Renewable
Ene gy Goals.” Re ie ed om h ps://www. ision󾙔󾙒󾙕󾙒.go .sa/
Documen P epa ed By: Mohammed Alma i
Ins i u ion: King Fahd Uni e si y o Pe oleum and Mine als (KFUPM)
Da e: No embe 󾙔󾙔, 󾙔󾙒󾙔󾙗
S a us: Final Resea ch Repo