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Feasibility Analysis of a Tonle Sap Floating Solar Project

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This is a feasibility analysis for a floating solar power system with battery storage on the Tonle Sap (Cambodia's "Great Lake"), configured to meet Cambodia's incremental energy requirements to 2045 and thereby rendering unnecessary the Sambor and Stung Treng hydroelectric power projects proposed to be built on the Mekong River mainstream.
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Viet Ecology Foundation Page | 1
Sun on the Lake Saves the Mekong
Simple Feasibility Analysis of a Tonle Sap Floating Solar Project with Storage System
November 13, 2019
Long P. Pham, P.E.
Viet Ecology Foundation
INTRODUCTION
Already Cambodia's Great Lake (the Tonle Sap) and Vietnam's Mekong Delta are suffering harmful
impacts from the suppression of the Mekong River's annual flood pulse, a consequence of the operation
of hydroelectric dams far upstream in Yunnan, China, and on tributaries of the Mekong in Laos and
Vietnam. Many more dams are planned; if they are built, Cambodia will see the end of the reverse flow
that supports the enormously fecund flood pulse at the Tonle Sap. Subsequently, in the dry season,
Vietnam will be starved of the fresh water that supports its delta ecosystem and food security.
This brief proposes an alternative approach, a floating solar power system on the Tonle Sap, built on a
scale that will satisfy Cambodia's power needs at lower cost.
Can the Sun on the Great Lake Project Save the Mekong and Vietnam?
The answer is YES and the feasibility analysis in this report seeks to prove that a 25-year program for a
28 GW floating solar project with 4-hours battery storage will meet Cambodia's projected energy need
to 2045 at the cost of $31 Billion USD.
The high cost of electricity in Cambodia
Cambodia is the least developed and most energy-thirsty country in Southeast Asia. The price of
electricity in Cambodia is the highest
1
in the region, ranging from $0.15 to $0.18 per kWh. In some rural
areas the price reaches $0.50 to $1.00 per kWh.
2
By comparison, the price in Thailand ranges from
$0.105 to $0.143 per kWh, and in Vietnam from $0.072 to $0.126 per kWh.
1
https://aecnewstoday.com/2019/cambodia-electricity-to-stay-higher-than-neighbours-as-eba-jitters-emerge/
2
https://energypedia.info/wiki/Cambodia_Energy_Situation
Viet Ecology Foundation Page | 2
Figure 1. Electricity Prices
3
Hydroelectricity in Cambodia is not cheap
Cambodia’s 2030 energy plan includes several new coal and gas fired power plants plus two giant
hydroelectric projectsthe run-of-river Stung Treng
4
(980 MW) and Sambor
5
(2600 MW) power plants
on the Mekong mainstream. These two hydroelectric projects face strong objection from local
communities and from Vietnam.
The International Rivers organization reports that: The Sambor Dam would be a tragic and costly
mistake for Cambodia. Cambodia’s fisheries safeguard the food security of millions of subsistence fishers
and contribute over 15% to the country’s Gross Domestic Product (GDP).
6
The Natural Heritage Institute (“NHI”), a U.S.-based international research organization, studied the
Sambor Dam project and recommended the Cambodian Government defer any commitment to Sambor
Dam and, instead, pursue better alternatives. The NHI reports:
• Out of a total sustainable fisheries yield in Vietnam and Cambodia of 1.2 million tonnes/year, 38% of all
fish are migratory -- 70% of these would be affected because they have their spawning grounds above
Sambor, and these will suffer a 100% reduction (because mitigation is not feasible). At a net value to
fishermen of USD 1.50/kg, this represents a loss of USD 479 million/year.
• On the basis of productivity differences of paddy fields in An Giang province, between fields that
receive 2.5cm/year sediment deposition or none, a total value of the sediment load at Sambor of USD
3
http://www.eria.org/uploads/media/CAMBODIA_BEP_Fullreport_1.pdf
4
https://en.m.wikipedia.org/wiki/Stung_Treng_Dam
5
https://en.m.wikipedia.org/wiki/Sambor_Dam
6
https://www.internationalrivers.org/campaigns/sambor-dam
Viet Ecology Foundation Page | 3
120 million/year is estimated. At a trapping efficiency of 62%, the Sambor reservoir would reduce this
value by USD 74 million/year.
The two hydropower projects together will hold back in their reservoirs 3.8 km3 water and permanently
inundate 831 km2 of land. The Sambor and Stung Treng dams will inflict costly damage on the
livelihoods of the surrounding population and offer them no compensation. What they produce for the
people instead is expensive electricity with harmful effects.
It appears the N.H.I report may have turned Cambodia definitely away from hydropower. Cambodia has
signed a 30-year Power Purchase Agreement
7
at 7.7 cents/kWh
8
with Sekong Power and Mineral
Company Limited and Xekong Thermal Power Company Ltd from Laos for electricity from coal, a project
which will take at least 4 years to construct.
What does this study offer Cambodia?
In July, 2019, the Director General of Electricité Du Cambodge (EDC) said that he does not wish to see
the Sambor and Stung Treng hydroelectric projects as part of Cambodia's future energy development
plan.
9
He did not mention an alternative that will meet the country's power needs. Cambodia
desperately needs an alternate energy source, and this situation prompts the author of this paper to
explore the technical and economic feasibility of a floating solar power generation system (FSS) on the
Tonle Sap Lake and propose it as an alternative to the hydroelectric projects and perhaps also some of
the coal and gas plants in the current Cambodia energy plan (summarized in Figure 2 below).
Figure 2. Cambodia Energy Plan
10
WHY CHOOSE THE TONLE SAP (“THE GREAT LAKE”) for THE FLOATING SOLAR SYSTEM?
The Great Lake (also known as the Tonle Sap) offers overwhelming advantages for a floating solar
energy plant:
1. The Great Lake is a huge, centrally located public surface near to Cambodia's capital, Phnom
Penh, where 90% or electric demand is concentrated.
7
https://www.phnompenhpost.com/business/kingdom-okays-2400mw-power-purchase-laos
8
https://www.khmertimeskh.com/50642313/cambodia-and-laos-to-sign-2400-megawatt-power-deal-
today/
9
https://www.phnompenhpost.com/opinion/good-news-mekong
10
http://www.eria.org/uploads/media/CAMBODIA_BEP_Fullreport_1.pdf
Viet Ecology Foundation Page | 4
2. The Great Lake receives the highest level of solar irradiance in the Mekong River Basin
11
.
3. Floating solar arrays produce 11%
12
to 16% more energy
13
than arrays sited on land.
4. Proximity to existing 230 kV national grids means that connection costs will be relatively low
(see Figure 3).
Figure 3: Project Location and Cambodia National Grid
11
https://www.dropbox.com/s/z8yvyum07wcjcaf/Volume%203_Solar%20Alternative%20to%20Sambor%20Dam.p
df?dl=0
12
https://res.mdpi.com/d_attachment/applsci/applsci-09-00395/article_deploy/applsci-09-00395.pdf
13
"Although floating panels are more expensive to install, they are up to 16 percent more efficient because the
water’s cooling effect helps reduce thermal losses and extend their life."
https://www.weforum.org/agenda/2019/02/in-land-scarce-southeast-asia-solar-panels-float-on-water/
Floating Solar Project
Viet Ecology Foundation Page | 5
DESCRIPTION OF THE FLOATING SOLAR PLANT
Table 1: LCOE for this project is 7.73 cents/kWh and 4.93 cents/kWh if avoided loss is credited.
1. This proposed FSS is to be constructed in phases over 25 years on the Great Lake. The total
capacity is 28.5 GW, with 88 GWh storage, generating 508 tWh in 25 years.
2. The entire project would cover a direct area of 330 km2, gross area of up to 400 km2, which is
15% of the Great Lake’s dry season surface and about 2.4% of its wet season surface. At this
relatively small percentage of the Great Lake’s total area, the impact of the project on aquatic
life would be insignificant. It may even benefit the Great Lake by lessening algae growth and
reducing the loss of oxygen.
533,597
31.04
3.71
6.51
Total Cost, Billin USD 41.26
0.077
77.32
0.599
14.975
26.28
0.049
49.25
$/kWh
$/MWh
Fixed O&M, Billion USD
Battery Replace, Billion USD
Capex, Billion USD
25 yrs Energy Generation, GWh
Floating Solar Energy Project on Tonle Sap Lake
Saving for riparians, Billions/year
Total
Net cost
$/kWh
$/MWh
Viet Ecology Foundation Page | 6
3. The FSS requires 400 km2 of open water surface area but helps save 831 km2 of permanent land
loss to the Sambor and Stung Treng reservoirs (if constructed). The FSS would preserve 15 Billion
USD in the inland fisheries economy (as avoided loss to them).
4. The LCOE of 7.73 cents/kWh is slightly more than 7.7 cents/kWh Cambodia would pay for
electricity generated at LaosXekong coal-fired power plant. The real LOCE to the Cambodia
should only be 4.93 cents/kWh since the riparian population will not have to bear the losses
associated with the hydroelectric plan.
5. Vietnam was disclosed to be the buyer of 70% electricity generated by the Sambor hydroelectric
project,
14
a plant that may not be built. Vietnam’s government can look hard at its own energy
plan, where the fast-falling costs of renewable energies (including wind and tidal wave energy in
addition to solar) should permit it to satisfy its needs more economically and with greatly
reduced external costs.
6. Considering that there will be 28 job-years needed for each MWp
15
, this project will support
500,000 job-years for Cambodian fishermen.
7. Considering the ecological importance of the environmental flow and the livelihoods of 30
million Mekong people, the next question is, will Cambodia and Vietnam’s governments take a
step back from hydropower and fossil fuels and formally investigate the feasibility of the floating
solar energy as demonstrated in this report?
Based on this feasibility analysis, the Sun on the Lake project can save the Mekong for Cambodia and
Vietnam. Solar energy requires that a smart grid and transmission network be put in place and in time
to balance fluctuating demand, however solar plants can be constructed to supply electricity in matter
of months and can be phased in as demand is confirmed, a feature that no other source can match.
About the Author
Long P. Pham has 40 years of experience as a Professional Mechanical Engineer in California, he is the founder of
the Viet Ecology Foundation, an NGO’s based in the US. Mr. Pham founded Moraes/Pham & Associates, Inc. and
Advanced Technologies Consultant Inc. and serves as its Principal-in-Charge, directing Facility, Safety and Code
Compliance projects for advanced semiconductor and pharmaceutical companies such as Hughes, Genentech,
ASML Cymer, AMCC, ABOTT, Solar Turbines. He was the responsible design engineer for the HVAC system at the
Orange County GWR Advanced Water Treatment Plant, the project is recognized as a significant engineering
contribution of the Century that won the Orange County the prestigious international Centenary Award.
16
Awards
1985 Engineer of the Year, American Institute of Plant Engineers, San Diego, CA.
1986 Award of Merit - Facility Management Excellence for Pioneering Semiconductor Safety, AIPE.
1987 Water Conservation Award Best Industrial Water Conservation Project San Diego County Water
Authority.
2008 HVAC Engineering California Recycled Water Project of the Year by American Society of Civil
Engineers
14
https://en.wikipedia.org/wiki/Sambor_Dam
15
http://stalix.com/Solar%20Energy%20Job%20Creation.pdf
16
https://csengineermag.com/ocwd-groundwater-replenishment-system-honored-with-fidic-centenary-award/
Viet Ecology Foundation Page | 7
Appendix 1
METHODOLOGY
The purpose of this study is to formulate a floating solar system with battery storage over the next 25
years that can meet the projected Cambodian demand for electricity in lieu of the planned hydroelectric
and possibly some additional the thermoelectric plants. This study follows the following approach:
1. Energy Demand: The Asian Development Bank provided an energy forecast in GWh for
Cambodia to 2030
17
. Their data is further extrapolated to 2045, using trend line technique and
polynomial function.
2. Global Tilt Irradiance and Optimal Tilt Angle: Utilize Global Solar Atlas Solar Calculator
1819
on-
line to select project coordination, determine energy generation potential based on the panel
optimal tilt angle (“OPTA”).
3. Lake-use footprint: The National Renewable Energy Laboratory provided Calculations Method
for Solar Energy’s direct (net) and total (gross) land-use footprint
20
in terms of acres/MWac and
acres/GWh/year. They equate to capacity of 42.59 MW/km2 and energy generation of 88.9
GWh/km2/year direct land area. With 10% additional energy credit due to lower ambient
floating surface, the energy generation level of 97 GWh/km2/year direct land area is used in this
report. Note that Dau Tieng achieves 138 GWh/km2/year. A service factor 130% is applied to
allow for service access to the floating panels.
4. Solar panel degradation: The direct area, km2 of solar panel required to harvest the GWh
needed each year for the 25 years can then be calculated. SunPower report
21
that solar panel
degradation to 78.8% in 25 years life.
5. Floating solar system cost: NHI estimated the cost of $900/kWp for their proposed 400 MW
floating solar project on LSS2 reservoir, and the 1.17 GW Noor Abu Dahbi costs $769/kWp
22
, for
this project World Banks low cost figure $800/kWp
23
is used.
6. Battery storage: This project is initially to have a 2, then 3 and then 4-hours energy storage
system. $4-Hour is the same practice as several recent energy storage projects for utilities in
Hawaii
24
, California PG&E
25
and Los Angeles LADWP
26
.
17
https://www.adb.org/documents/cambodia-energy-assessment-strategy-road-map
18
https://photovoltaic-software.com/principle-ressources/how-calculate-solar-energy-power-pv-systems
19
https://globalsolaratlas.info/
20
https://www.renewableenergyworld.com/2013/08/08/calculating-solar-energys-land-use-footprint/#gref
21
https://businessfeed.sunpower.com/articles/what-to-know-about-commercial-solar-panel-degradation
22
https://bigthink.com/technology-innovation/uae-solar-power?rebelltitem=3#rebelltitem3
23
http://documents.worldbank.org/curated/en/670101560451219695/Floating-Solar-Market-Report
24
https://www.greentechmedia.com/articles/read/hawaiian-electric-industries-announces-mind-blowing-solar-
plus-storage-cont#gs.6wrfpv
25
https://www.utilitydive.com/news/storage-will-replace-3-california-gas-plants-as-pge-nabs-approval-for-
worl/541870/
26
https://www.utilitydive.com/news/los-angeles-approves-historically-low-cost-solarstorage-project/562681/
Viet Ecology Foundation Page | 8
7. This study uses NREL
27
published utility battery price of $375/kWh in 2020 decreasing to
$110/kWh in 2045 for 4-hour lithium-ion systems.
8. This study allows battery cost to decrease 2% annually.
9. Battery storage facility and transmission network is included in battery cost.
10. Compare cost of energy between FSS and current hydroelectric and thermoelectric plans.
11. Estimate number of jobs generated by this project.
Appendix 2
FLOATING SOLAR PROJECT INPUT PARAMETERS
The following are parameters used in this report for analysis:
Figure 6: Floating Solar System Proposed Location and Size
27
https://www.nrel.gov/docs/fy19osti/73222.pdf
Viet Ecology Foundation Page | 9
Figure 7: Typical Schematic Diagram Solar Power System
1. Projected harvestable solar energy is generated from World Bank Global Solar Atlas
28
for this
report and presented in Figure 5. Photovoltaic output (“PVOUT”) of 1567 kWh/kWp/yr, Global
Horizontal Irradiance, GHI 2032 kWh/m2/year.
Figure 8: Tonle Sap Lake PVOUT Solar Resource 1567 kWh/kWp/year
29
2. The amount of the Great Lake’s surface area required depends on the solar cell efficiency. The
Global Solar Atlas model is based on a crystalline silicon (c-Silicon) module at about 17%
efficiency. The OPTA is 20 degrees. A 20% extra area is allowed for service access allowance.
3. The life span for the project is generally accepted to be 25 years.
4. Solar panel degradation is 0.848% per year, to 78.8%
30
after 25 years is factored in this report.
28
https://globalsolaratlas.info/
29
https://globalsolaratlas.info/?c=12.570648,104.787598,8&s=12.640338,104.353638
30
https://businessfeed.sunpower.com/articles/what-to-know-about-commercial-solar-panel-degradation
Viet Ecology Foundation Page | 10
5. Capital expenditure for energy storage starts at $375/kWh for 2020 and gradually drops to
$110/kWh (National Renewable Energy Laboratory
31
reports that the storage cost is
$380/kWh).
6. Battery is sized for 2, 3 and then 4 full load hours to provide dispatch ability.
7. Battery is to be replaced in year 12.
8. Fixed O&M cost is $10 Mil/GW/year
32
.
9. Capacity factor is 17%, although 20% is likely possible.
10. Project to have 25 phases over 25 years.
11. Generation is to produce enough energy to fully satisfy Cambodia’s projected growth demand.
12. Note that LCOE does not include financing issues, discount issues, future replacement, or
disposal costs. Each of these would need to be included for a thorough analysis.
Appendix 3
CALCULATIONS TABLE
Table 2: Energy and Cost Calculations
31
https://wattsupwiththat.com/2019/07/16/nrel-energy-storage-system-cost-benchmark/
32
https://www.nrel.gov/analysis/tech-cost-om-dg.html
A B C D E F G H I J K L M N O P Q R S T U R
Project Phase Year
Accum
Lake Area
used (km2)
Accum Solar
(% Lake area)
Solar
Area
(% Lake)
Solar Area
(km2)
Min
reservoir
area
(km2)
Max
reservoir
area (km2)
Solar
(GW)
Total
(GW)
Cost
Solar
Mil/GW
@2%
Less/yr
Cost solar
(Bil USD)
Cost
Battery
Mil/GW
Cost of
Storage (Bil
USD)
Storage
hours
Replace
battery
Year 12
(Bil USD)
Fixed O&M
$10 (Mil
USD/GW/yr)
Capex
Solar w
Storage (Bil
USD)
Total Solar
Generation
(GWh/yr)
Solar
Capacity
Added
(GWh/yr)
Demand
(GWh)
12021 13 0.49% 0.49% 13.20 1.14 1.14 770 0.88 300 0.68 2.00 11 1.57 1,690 1690
22022 26 0.96% 0.49% 13.20 1.14 2.28 755 0.86 285 0.65 2.00 23 1.53 3,111 1690
32023 40 1.43% 0.49% 13.20 1.14 3.42 740 0.84 271 0.62 2.00 34 1.49 4,775 1690
42024 53 1.90% 0.49% 13.20 1.14 4.56 725 0.83 257 0.59 2.00 46 1.46 6,424 1690
52025 66 2.38% 0.49% 13.20 1.14 5.70 710 0.81 244 0.56 2.00 57 1.42 8,060 1690
62026 79 2.85% 0.49% 13.20 1.14 6.84 696 0.79 232 0.53 2.00 68 1.39 9,681 1690
72027 92 3.32% 0.49% 13.20 1.14 7.98 682 0.78 221 0.50 2.00 80 1.36 11,289 1690
82028 106 3.79% 0.49% 13.20 1.14 9.12 668 0.76 210 0.48 2.00 91 1.33 12,883 1690
92029 119 4.26% 0.49% 13.20 1.14 10.26 655 0.75 199 0.68 3.00 103 1.53 14,464 1690
10 2030 132 4.74% 0.49% 13.20 1.14 11.40 642 0.73 189 0.65 3.00 114 1.49 16,032 1690
11 2031 145 5.21% 0.49% 13.20 1.14 12.54 629 0.72 180 0.61 3.00 125 1.46 17,586 1690
12 2032 158 5.68% 0.49% 13.20 1.14 13.68 617 0.70 171 0.58 3.00 137 1.42 19,126 1690
13 2033 172 6.15% 0.49% 13.20 1.14 14.82 604 0.69 162 0.55 3.00 0.55 148 1.95 20,654 1690
14 2034 185 6.62% 0.49% 13.20 1.14 15.96 592 0.68 154 0.53 3.00 0.53 160 1.89 22,169 1690
15 2035 198 7.10% 0.49% 13.20 1.14 17.10 580 0.66 146 0.50 3.00 0.50 171 1.83 23,671 1690
16 2036 211 7.57% 0.49% 13.20 1.14 18.24 569 0.65 139 0.48 3.00 0.48 182 1.78 25,160 1690
17 2037 224 8.04% 0.49% 13.20 1.14 19.38 557 0.64 132 0.60 4.00 0.60 194 2.03 26,637 1690
18 2038 238 8.51% 0.49% 13.20 1.14 20.52 546 0.62 125 0.57 4.00 0.57 205 1.97 28,101 1690
19 2039 251 8.98% 0.49% 13.20 1.14 21.66 535 0.61 119 0.54 4.00 0.54 217 1.91 29,553 1690
20 2040 264 9.46% 0.49% 13.20 1.14 22.80 525 0.60 113 0.52 4.00 0.52 228 1.86 30,992 1690
21 2041 277 9.93% 0.49% 13.20 1.14 23.94 514 0.59 108 0.49 4.00 0.49 239 1.81 32,419 1690
22 2042 290 10.40% 0.49% 13.20 1.14 25.08 504 0.57 102 0.47 4.00 0.47 251 1.76 33,835 1690
23 2043 304 10.87% 0.49% 13.20 1.14 26.22 494 0.56 97 0.44 4.00 0.44 262 1.71 35,238 1690
24 2044 317 11.34% 0.49% 13.20 1.14 27.36 484 0.55 92 0.42 4.00 0.42 274 1.67 36,629 1690
25 2045 330 11.82% 0.49% 13.20 1.14 28.50 474 0.54 88 0.40 4.00 0.40 285 1.62 38,008 1690
28.50 Total 15267 17.40 Total 13.64 Total 6.51 3705 41.26 508188
Cambodia - Floating Solar Energy Project Potential on Tonle Sap Lake
Tonle
Sap
Floating
Solar
and
Storage
System
2,700
16000
Total
Viet Ecology Foundation Page | 11
Figure 9: World Bank FPV Cost Projection
33
33
http://documents.worldbank.org/curated/en/670101560451219695/Floating-Solar-Market-Report
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