Floating PV Technologies and Singapore’s Testbed Experiences Dr. Thomas REINDL Deputy CEO; Cluster Director, Solar Energy Systems Dr. ZHAO Lu Head, Solar System Technology; Project Leader, Floating PV Solar Energy Research Institute of Singapore (SERIS) National University of Singapore (NUS) World Bank Webinar October 9, 2017, 4:30pm (Singapore time) SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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SERIS Solar Energy Research Institute of Singapore Founded in 2008; focuses on applied solar energy research Part of the National University of Singapore (NUS) Rapid growth (now > 200 people and > 6000 m2 of space) State-of-the-art laboratories R&D focus is on solar cells, PV modules and PV systems Specialised in professional services for the PV industry ISO 9001 & ISO 17025* certified (* PV Module Testing Lab) SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Main R&D areas of SERIS
Solar cells:
PV modules:
PV systems:
▪ Silicon wafer solar cells (various cell architectures) ▪ Tandem solar cells on silicon (e.g. GaAs, perovskites) ▪ Characterisation & simulation
▪ Module development ▪ Module testing (indoor & outdoor) ▪ Module certification ▪ Characterisation and simulation
▪ System technologies, incl. Floating PV ▪ PV grid integration ▪ Solar potential & energy meteorology ▪ Urban Solar, incl. BIPV ▪ Quality assurance of PV systems ▪ Solar thermal systems
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Disclaimer Disclaimer, limitation of liability This presentation represents the professional opinions of the members of the evaluation team. The evaluation team members, the Solar Energy Research Institute of Singapore (SERIS) and the National University of Singapore (NUS), exclude any legal liability for any statement made in the report. In no event shall the evaluation team members, SERIS, and NUS of any tier be liable in contract, tort, strict liability, warranty or otherwise, for any special, incidental or consequential damages, such as, but not limited to, delay, disruption, loss of product, loss of anticipated profits or revenue, loss of use of the equipment or system, non-operation or increased expense of operation of other equipment or systems, cost of capital, or cost of purchase or replacement equipment systems or power.
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Outline Introduction to floating PV technologies ➢ Motivations ➢ Overview & state-of-the-art ➢ Technical concepts
Floating PV Testbed in Singapore ➢ Layout and participants ➢ Preliminary findings Economic modeling for large-scale floating PV Hybrid operation with hydropower ➢ Motivations ➢ Case study: Longyangxia Conclusions The inaugural "International Floating Solar Symposium" (IFSS) SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Floating Solar is unlocking 400,000 km2 − and thereby a new TW-scale opportunity for photovoltaics − on freshwater reservoirs alone [1]
Photo: SERIS
[1] Shiklomanov, Igor A., 1993, “Chapter 2: World Fresh Water Ressources”, in: “Water in Crisis”, ed. Gleick, Peter H., Oxford University Press SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Motivations for Floating PV (FPV) Advantages of Floating Photovoltaics ➢ Better use of land resources ▪ Suitable for countries/regions with limited land area ▪ Multiple use of water surface ➢ Better performance ▪ Cooling effect of the water on PV modules 5~20% depending on location, climate, etc. ▪ Less prone to external shading ▪ Generally, less soiling ➢ Environmental benefits ▪ Reduction in evaporation loss, algae growth, etc. Challenges of FPV (vs. typical ground-mounted systems) ➢ Higher installation cost (as of today) ➢ More difficult O&M (if not part of the design) ➢ More stringent requirements on anti-corrosion, anti-PID (potential-induced degradation), electrical safety ➢ Possible environmental impact on water flora & fauna SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Proposed benefits of Floating PV Taken from various international studies
Natural evaporative cooling for increased PV energy yield1), hence lowering the “levelised cost of energy” (LCOE)
Make use of existing water bodies (where there is no competing use, e.g. for recreational purposes), especially when land is scarce
Reduces evaporation from the water surface, hence “saving drinking water”; for example: ~1000 liters per m2 per year saved in Spain2)
Expected reduction in algae growth3)
2.3 MWp floating PV, Kasai City , Japan 1) Y. K. Choi, "A study on power generation analysis of floating PV system considering environmental impact," International Journal of Software Engineering and its Applications, vol. 8, pp. 75-84, 2014. 2) M. R. Santafé, P. S. Ferrer Gisbert, F. J. Sánchez Romero, J. B. Torregrosa Soler, J. J. Ferrán Gozálvez, and C. M. Ferrer Gisbert, "Implementation of a photovoltaic floating cover for irrigation reservoirs," Journal of Cleaner Production, vol. 66, pp. 568-570, 2014. 3) http://www.waterworld.com/articles/2011/09/floatingsolar-systems-provide-power-environmental-benefits.html
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Overview of FPV technologies Waterbodies / locations ➢ Inland reservoirs ▪ Hybrid with hydro dams, pumped hydro ▪ Lakes, reservoirs, irrigation pond, fish ponds ▪ Quarries and mine lakes
➢ Off-shore ▪ Coastal sea, lagoons
SPG Solar, Far Niente Winery 218 kWp C&T, at Alto Rabagão dam, Portugal
96kWp Swimsol, Maldives
Viteos floating CSP, lake Neuchâtel, CH
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Overview of FPV technologies Installation & Mounting Method ➢ On piles (non-floating) ➢ Floats + support structure ➢ Floats only ➢ Submerged floating module
Floating a-Si TF PV array prototype, Sudbury CA MIRARCO
SCINTEC submergible floating PV concept. Patent Rosa Clot. et al.
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Overview of FPV technologies Tracking & Concentrator ➢ Fixed tilt ➢ 1-Axis or 2-Axis tracking ➢ Concentrator PV (CPV), Concentrating Solar Power (CSP)
Floating Tracking Cooling Concentrator, Pisa Italy
Pyron solar, US
Infratech, wastewater facility, Jamestown, AU
Sunengy Liquid Solar Array, Tata Power hydro dam, India SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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The largest floating PV plants (1) Rank
Size (kw)
1
40,000
2
Name of reservoir (lake) / Name of Plant
Country
City/Province
Operating from
Coal mining subsidence area of Huainan City
China
Anhui Province
May, 2017
20,000
Coal mining subsidence area of Huainan City
China
Anhui Province
April, 2016
3
20,000
Lake near Sanduzhen, Hang Zhou City
China
Zhejiang Province
Aug, 2017
4
8,500
Wuhu, Sanshan
China
Anhui Province
July, 2015
5
8,000
Ling Xi Lake
China
Hebei Province
August, 2015
6
7,500
Kawashima Taiyou to shizen no megumi Solarpark
Japan
Saitama
October, 2015
7
6,338
Queen Elizabeth II reservoir
UK
London
March, 2016
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3,000
Otae Province
South Korea
Sangju City Gyeongsang Bukdo
October, 2015
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3,000
Jipyeong Province
Sounth Korea
Sangju City Gyeongsang Bukdo
October, 2015
10
2,991
Godley Reservoir Floating Solar PV
UK
Godley
January, 2016
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2,449
Tsuga Ike
Japan
Mie
August, 2016
12
2,398
Sohara Ike
Japan
Mie
March, 2016
13
2,313
Sakasama Ike
Japan
Hyogo
April, 2015
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2,000
Reservoir in Kumagaya city
Japan
Saitama
December, 2014
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2,000
Reservoir in Shiroishi-chou
Japan
Saga
Mar, 2015
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2,000
Kinuura Lumberyard
Japan
Aichi
February, 2016
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2,000
Yado Ooike (Sun Lakes Yado)
Japan
Hyogo
January, 2016
Source: FLOATING SOLAR PLANTS: NICHE RISING TO THE SURFACE? Solarplaza article; SERIS communications SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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The largest floating PV plants (2)
40MW, Huainan, Anhui, China
8MW, Lingxi lake, Lingxi, Hebei
8.5MW, Sanshan, Wuhu, Anhui
Coal mining subsidence area, Huainan, Anhui
Image sources: Google Map and Sungrow press release. SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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String / central inverters on land Most small-scale floating PV systems have AC electrical infrastructure on nearby land ➢ String / central inverters and transformers on land ➢ Only DC portion is on water, sometimes with DC combiner boxes
572 kWp floating PV system, at GOJIGA-IKE, Japan SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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String inverters on floating platform String inverters mounted directly on the floating platform ➢ Passive cooling (without fan), entire casing is IP65 ➢ String inverters & AC combiner boxes
Floating Smart PV Plant, Kasai-shi, Hyōgo, Japan
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Central inverters on floating platform Central inverters & Transformers mounted directly on the floating platform ➢ Standardized design of 2.5MWac floating arrays (2500kVA inverter & transformer) ➢ 3MWp PV Array (1.2 DC-AC ratio) ➢ DC combiner box IP67 casing, galvanized steel with extra 3 layers anti-corrosion coatings
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Outline Introduction to floating PV technologies ➢ Motivations ➢ Overview & state-of-the-art ➢ Technical concepts
Floating PV Testbed in Singapore ➢ Layout and participants ➢ Preliminary findings Economic modeling for large-scale floating PV Hybrid operation with hydropower ➢ Motivations ➢ Case study: Longyangxia Conclusions The inaugural "International Floating Solar Symposium" (IFSS) SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Floating PV Testbed (1) ď ą Project time lapse video
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Floating PV Testbed (2) Project Site Plan
Floating PV Systems SolarGy / NRG Energia SolarGy / 4C Solar Phoenix Solar / C&T Sunseap / C&T
Sunseap / C&T BBR Greentech / Solaris Rooftop Reference System
Upsolar / Koiné Multimedia Floating Pontoon
Reservoir
REC / Takiron Sharp / SMCC Million Lighting/ATS / HDB
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Floating PV Testbed (3) ď ą Supporting Infrastructure Works
Substation / Inverter room Launch ramp
Floating pontoon
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Floating PV Testbed (4) Large scale FPV test-bed ➢ Side-by-side comparison of major commercial FPV technologies ➢ Detailed monitoring of all FPV systems ▪ Energy yield ▪ Cooling effect ▪ Bi-facial module ▪ Active cooling ➢ Economics, LCOE ➢ Environmental impact ▪ Water evap. losses ▪ Water quality ▪ Biodiversity SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Floating PV Testbed (5) ď ą Floating platform technologies in the testbed
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Floating PV Testbed (6) Comprehensive monitoring infrastructure, with >500 parameters ➢ Meteorological station (reservoir & rooftop)
➢ PV System performance monitoring
DC (PV String)
AC (PV array)
Motion sensor
Module Temp.
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Testbed operating conditions (1) Ambient temperatures ➢ Tambient on water (vs. rooftop) is consistently lower
Wind Speed ➢ Wind speed on water (vs. rooftop) is generally higher
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Testbed operating conditions (2) Humidity ➢
Humidity on water is generally higher
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Testbed operating conditions (3) Albedo ➢ Albedo of water surface is rather small, 5~6% measured Albedo for 15 Mar 2017
Daily average
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Testbed operating conditions (4) Albedo ➢ Water surface reflectivity is usually less than 10% at high incident angles (around 3 ~ 6% according to most reported measurements).
Source: Wikipedia
Reflectivity of smooth water at 20 °C (refractive index=1.333) SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Comparison of operating conditions On-shore and off-shore module temperatures Module temperatures depend on floating structures as well as location within the floats. FPV modules have cooler operating temperatures (by ~5 C). Float structure A
Float structure B
Daily weighted average module temperatures SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Cooling effect on PV module Temp Free Standing Minimized Footprint on water Very Good convective cooling Small Footprint on water Good convective cooling
Large Footprint on water Water surface partially blocked
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Module cooling ď ą Cooling effect (indicated by heat loss coefficient) is dependent on floating structure. Thermal loss factors (U in W/m²¡k) đ?‘ˆ ∙ đ?‘‡đ?‘?đ?‘’đ?‘™đ?‘™ − đ?‘‡đ?‘Žđ?‘šđ?‘? = đ??´đ?‘™đ?‘?â„Žđ?‘Ž ∙ đ??şđ?‘–đ?‘›đ?‘? ∙ (1 − đ??¸đ?‘“đ?‘“) v = wind speed in [m/s] đ?‘ˆ = đ?‘ˆđ?‘? + đ?‘ˆđ?‘Ł ∙ đ?‘Ł Well-ventilated system
Insulated system
Compact, dual-pitch design SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Testbed system performance (1) FPV system performance ratio (from Apr till Sep 2017) ➢ Up to about 15% higher than typical rooftop PV systems in Singapore (with PR of 75 ~ 80%) Severe soiling due to bird droppings
Good ventilation, partially flattened tilt
Frequent inverter fault, significant downtime Typical rooftop system PR in Sg
High PR for ref system: • Good ventilation • Much shorter DC cables • Bi-facial modules • Low mismatch loss Note: This reference system is much better than typical rooftop systems in Singapore.
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Testbed system performance (2) Bifacial modules ➢ On rooftop, bi-facial string outperforms mono-facial strings ➢ On water, bi-facial string does not seem to outperform monofacial strings, due to low albedo on water ➢ However, bi-facial might have benefit in the long term (dual glass, slower moisture ingress)
Daily PR (DC side)
Bifacial string vs. mono-facial strings
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Issues encountered (1) Soiling – from bird droppings Bird droppings observed on floating PV modules ➢ Partial shading ➢ Reduced performance, less energy yield ➢ Cell reserve biased, hot spots, => can lead to accelerated module degradation Solutions ➢ Part of the O&M routine (i.e. immediate actions / cleaning) ➢ Barrier methods ➢ Non-barrier methods ▪ Ultrasonic, Sonic Repeller ▪ Visual Scare Device
Singapore floating PV Testbed
Queen Elizabeth II reservoir, UK
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Issues encountered (2) Constant movement of floating platform Mechanical stress ➢ At the joints of rigid structures ➢ On equipotential bonding tape/wire ➢ At the earthing tape connection for grounding
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Issues encountered (3) Insulation faults Insulation test failure for inverters ➢ The insulation resistance (Riso) dropped over time for floating PV strings ➢ Inverters measure Riso. When Riso does not meet the preset threshold inverters do not start. ➢ Common result: inverters start late (till the Riso limit is passed).
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Other potential issues Due to proximity to water, high humidity Potential Induced Degradation (PID) ➢ Anti-PID modules preferred Corrosions (more aggravated for off-shore environments) ➢ Combiner boxes ➢ Inverters ➢ Metal supporting structures Risk of solar cables submerged in water ➢ Electrical safety, earth leakage ➢ Performance drop, system downtime Structural ➢ Anchoring / mooring needs to be carefully assessed during feasibility study
Highly valuable results from this testbed shall lead to new technical standards for Floating PV (via IEC TC 82) SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Floating PV Design Considerations Example: wind load testing (1) Most floating PV platforms are designed for high wind load, and tested in wind tunnel C&T Hydrelio®
Tested by ONERA (the French aerospace lab), C&T Hydrelio® can withstand up to 210 km/h (≈58.3 m/s) winds. Projects can be specifically studied and adapted to deliver higher system wind-resistance.
Laser tomoscopy in wind tunnel L2 (Lille) to test the wind resistance of solar panels intended to equip the first "industrial" floating photovoltaic power plant in the world, near Tokyo (Ciel et Terre Company).
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Floating PV Design Considerations Example: wind load testing (2) Most floating PV platforms are designed for high wind load, and tested in wind tunnel
Sumitomo Mitsui Construction Co., Ltd.
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Floating PV Design Considerations Example: storm incident report 7.55MW Floating Solar Plant Damaged by Typhoon ➢ Umenoki Furugori Water Reservoir, Japan ➢ 152 panels (41.8kW in total) damaged by strong winds and high waves, caused by Typhoon No. 9 on Aug 22, 2016
➢ Possible causes for the damage ▪ Anchor points are not at the perimeter floats, but a few rows inside the floating island ▪ The perimeter floats were installed with PV modules, which captures the up-lift ▪ The water level is about 1 meter higher than designed water height, larger waves. SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Floating PV Design Considerations Example: storm impact mitigation Engineering solutions for storm resilience ➢ Proper civil and structure design & calculations (based on extreme rather than “typical” weather conditions) ➢ Adapt floating structure design
Dual-pitch configuration (C&T) Weights around the perimeter floats (Ibiden Engineering) SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Outline Introduction to floating PV technologies ➢ Motivations ➢ Overview & state-of-the-art ➢ Technical concepts
Floating PV Testbed in Singapore ➢ Layout and participants ➢ Preliminary findings Economic modeling for large-scale floating PV Hybrid operation with hydropower ➢ Motivations ➢ Case study: Longyangxia Conclusions The inaugural "International Floating Solar Symposium" (IFSS) SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Global PV installed capacity 2017 installation expected to grow thanks to strong Chinese demand ď ą Since August, PVTech, IHS Markit and EnergyTrend revised their forecast upward to > 90, 90 and 100.4 GW, respectively.
Data source: 2000-2016: IEA, F2017: average forecast based on different sources such as Mercom, IHS, BNEF, Energy Trend, GTM, Solar Power Europe, Morgan Stanley, PV Market Alliance, EuPD Research, F2020: SERIS market research SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Learning curve for PV modules ($/W) Price forecast for Si wafer PV modules Source: ITRPV 2015 1985 1998
2006
2010
• Nov 2016 2020 2021
21.5% - PV has fastest learning rate among all energy technologies 0.39 USD/Wp ~0.30 USD/Wp
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Research focus in PV (2016-2020) “Classic” topics: ▪ Reduce the cost ($/W) of PV cells and modules ▪ Improve the efficiency of PV cells and modules ▪ Increase the technical lifetime of PV modules ▪ Goal (“Holy grail”): PV module < 0.3 $/W, > 20%, > 25 years New topics: ▪ LCOE (Levelised cost of energy) in $/kWh ▪ Annual energy yield and reliability of PV modules & systems in different climate zones (including the tropics) Cost of a PV system, $/W (“new era”, > 2016):
Modul Module BOS
BOS = “Balance of system”. BOS (in $/W) ↓ for Eff ↑ SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Levelised Cost of Energy (LCOE) Up-front investment +
O&M + Insurance
LCOE* =
Loan + Payment
+/-
Residual Tax +/value
Total life cycle cost
Total lifetime energy production
Irradiance (kwh/m2)
x
Performance Ratio (%) =
Initial energy yield (kWh/kWp)
-
Annual degradation rate
*net present value figure, all input factors are annually discounted by the project hurdle rate (e.g. average weighted cost of capital) SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singaporeâ&#x20AC;&#x2122;s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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System cost break-down – base case Grid-connection cost is highly project dependent, ~USD 1.135/Wp1)
System cost should not be too different from ground-mounted projects, while floats are added, the purchase of the land is not needed and civil works/ground preparation is much lower 1) Using latest module price average of 0.34/Wp SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Country specific: cost of financing Example: WACC calculation across different cities, 60% debt ratio Cambodia: high country risk
US: high tax rate
Germany, Switzerland, Japan: low risk-free rates
India: high inflation rate
Thailand: favourable financing
RFR = risk-free rates, MRP = market risk premium, b = beta, CoE = Cost of Equity, DP = debt premium, CoD = Cost of Debt, TR = tax rate, WACC = weighted average cost of capital, IF = inflation rate SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singaporeâ&#x20AC;&#x2122;s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Discount rate – base case assumption Example: South East Asia region WACC (Weighted average cost of capital) Risk-free rate Market risk premium Current beta Cost of equity
3.27% 8.40% 1.2 13.35%
Risk-free rate Debt premium Cost of debt
2.70% 5.30% 8.00%
Equity ratio Debt ratio Corporate income tax rate WACC
40.00% 60.00% 20.0% 9.18%
Risk Adjustment for Uncertainties Discount rate (nominal)
-% 9.18%
Inflation Discount rate (real)
3.50% 5.7%
Debt Term (years) Construction period (months)
10 6
Cost of equity: ~13% Cost of debt: ~8% Discount rate: ~9% Debt portion: 60% Corporate tax rate: 20% Inflation: 3.5% (influences O&M, inverter replacement and insurance cost) Debt term: 10 years (amortising) Construction period: 6 months
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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LCOE calculation, other assumptions Irradiance: 1,670 kWh/m2 (P75) Performance ratio: 85%, energy yield 1st year: ~1,420 kWh/kWp, ~70.9 GWh production in 1st year 1.0% degradation rate p.a., 20 years of operational life Annual operating expense (~1.3% of initial capex): Annual operating expensive (rounded) 1)
O&M (manpower & monitoring system) Insurance (0.3% of investment)1) Replacement cost (mainly inverter)2) Total
USD/kWp 350,000 175,000 220,000 745,000
7.0 3.5 4.4 14.8
1) rounded annual expense for the 1 st year, adjusted by inflation of 3.5% thereafter 2) annualised cost of inverter warranty extension expenditure, every five year with premium of 20%, 45% and 60% of prevailing inverter price (assuming a decline to ~USD 0.5/W p in 10 years' time)
~25% higher than groundmounted utilityscale solar benchmark*
Depreciation in-line with operational lifetime assumption Pre-tax basis *9-12 USD/kWp according to Lazard's levelised cost of energy analysis – Version 10.0, December 2016 SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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LCOE base case: 10.4 USD-cents/kWh Sensitivity analysis: financing and low upfront cost are important
Range: 7.51)
15.42)
1) Combination of 3% interest, 80% debt portion and 20 years debt term (instead of 10 years) 2) No debt financing available, investment cost +15% SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singaporeâ&#x20AC;&#x2122;s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Grid parity remains challenging in SEA Biggest disadvantage for solar are ongoing fossil fuel subsidies in some of the countries Grid parity reached in Cambodia, Lao and Philippines Favourable financing could accelerated competitiveness
Government incentives might help to grow solar in countries with no grid parity Source for implied subsidy estimates: International Energy Consultants (IEC), Regional/Global Comparison of Retail Electricity Tariffs, provided for Meralco SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Outline Introduction to floating PV technologies ➢ Motivations ➢ Overview & state-of-the-art ➢ Technical concepts
Floating PV Testbed in Singapore ➢ Layout and participants ➢ Preliminary findings Economic modeling for large-scale floating PV Hybrid operation with hydropower ➢ Motivations ➢ Case study: Longyangxia Conclusions The inaugural "International Floating Solar Symposium" (IFSS) SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Hydropower status - globally Installed capacity (2016): 1,064 GW
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singaporeâ&#x20AC;&#x2122;s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Hydropower status - regionally Asia-Pacific
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singaporeâ&#x20AC;&#x2122;s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Hydropower Benefits: ➢ Flexible: quick-start, fastadjustable, excellent loadfollowing ➢ Predictable and reliable: little fluctuations in electrical output ➢ Clean and renewable
Example: 22,500 MWp Three Gorges Dam, China
Disadvantages: ➢ Heavy environmental impacts ➢ High initial capital cost ➢ Affected by droughts
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Hybrid FPV and hydropower Motivations ➢ Deployment of PV on existing reservoirs ➢ Existing electrical infrastructure and grid connection, leading to lower overall capex ➢ Improve the power quality of FPV power and reduce FPV power curtailment: ✓ fast-responding hydro turbines can smooth the intermittency and variability of FPV power ✓ provide good-quality, safe and reliable power to the grid ➢ Maintain daily / short-term water flow hydropower through advanced power forecasting and dispatching techniques (depending on reservoir operation mode and upstream dispatch) ➢ Allow for complementary operation to bridge seasonal / long-term variations (e.g. wet and dry seasons) ➢ Mooring may be challenging depending on water fluctuation levels SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Complimentary FPV and hydropower 1. Reduction of PV variability and uncertainty through hydropower
Stage 1
Stage 2
➢ Stage 1: Smooth the sawtooth-shaped output curve of FPV ➢ Stage 2: Eliminate the randomness and intermittency of the PV output and maintain a constant total output
Stage 2
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Complimentary FPV and hydropower 2. Compensation hydropower through FPV ➢ FPV can compensate for the hydro energy deficiency in dry season ➢ FPV can support day-time peak load and more hydropower is reserved for evening peak ➢ The dispatching of hydropower is more flexible and the system peakload regulation capacity increases Summary of complimentary operation ➢ In short-term scheduling, hydropower supports FPV through its rapidly adjustable power output ➢ In mid- to long-term scheduling and peak load regulation, FPV compensates the energy deficiency of hydropower via its generated electricity
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Complimentary PV and hydro operation
Longyangxia hydropower plant ➢ Commissioned in 1989 ➢ Installed capacity: 1,280MW (4× 320MW) ➢ Electricity production: 5,942GWh/year ➢ Reservoir area: 380 km2
➢ Normal storage water level: 2600m; Dead water level: 2530m ➢ Regulation storage: 193.5×108m3 SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Complimentary PV and hydro operation
Gonghe solar PV station (30km away from Longyangxia Hydro) ➢ Largest PV station in the world
✓ Phase I (2013): 320MW, electricity production : 498GWh/year ✓ Phase II (2015): 530MW, electricity production: 824GWh/year ➢ Hybrid: the solar power plant is coupled to the existing hydropower substation through 330kV transmission line
➢ Solar power station is treated as an additional non-adjustable unit of hydro power plant SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Daily operation curve (July, Dry year) Daily output curve before and after complimentary operation
Comparison before and after complimentary operation
祁生晶， “龙羊峡水光互补320MWp并网光伏电站工程水 光互补分析”，西安理工大学专业硕士学位论文， 2014. SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Daily operation curve (Dec, Dry year) Daily output curve before and after complimentary operation
Comparison before and after complimentary operation
祁生晶， “龙羊峡水光互补320MWp并网光伏电站工程水 光互补分析”，西安理工大学专业硕士学位论文， 2014. SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Daily operation curve (July, Wet year)
Daily output curve before and after complimentary operation
➢ Complimentary operation between hydro and solar is not possible. If the system cannot absorb the excess power from solar, either water “spill” or solar “curtailment” will happen.
祁生晶， “龙羊峡水光互补320MWp并网光伏电站工程水 光互补分析”，西安理工大学专业硕士学位论文， 2014. SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Daily operation curve (Dec, Wet year) Daily output curve before and after complimentary operation
Comparison before and after complimentary operation
祁生晶， “龙羊峡水光互补320MWp并网光伏电站工程水 光互补分析”，西安理工大学专业硕士学位论文， 2014. SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Actual performance
Complimentary operation: ➢ Solar PV is treated as an additional non-adjustable unit of hydropower station ➢ Automatic regulation of the hydro output to balance solar resource’ variability before dispatching to the grid 龚传利，王英鑫，等，“龙羊峡水光互补自动发电控制策略及应用”， 水电站机电技术，Vol.37 No.3 SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Outline Introduction to floating PV technologies ➢ Motivations ➢ Overview & state-of-the-art ➢ Technical concepts
Floating PV Testbed in Singapore ➢ Layout and participants ➢ Preliminary findings Economic modeling for large-scale floating PV Hybrid operation with hydropower ➢ Motivations ➢ Case study: Longyangxia Conclusions The inaugural "International Floating Solar Symposium" (IFSS) SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Conclusions Floating PV market is taking the industry by storm ➢ Large potential globally, with enormous opportunities in Asia: China, Japan, Taiwan, India, Pakistan, Sri Lanka, ASEAN FPV system performance in the Singapore Tengeh reservoir testbed ➢ FPV PR ranges 78% ~ 94% Up to 15% higher than typical rooftop system in Singapore ➢ FPV modules generally cooler. Cooling effect of FPV modules depends on floating structures and weather conditions ➢ Bifacial modules does not seem to outperform mono-facial modules on water, due to low albedo ➢ Initial technical issues identified, but no major obstacle Floating solar economics do not differ significantly from groundmounted installations, most crucial: access to financing, source of irradiance and high-quality system components / implementation Hybrid operation of Hydropower and Floating PV has numerous advantages and huge deployment potential SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Outline Introduction to floating PV technologies ➢ Motivations ➢ Overview & state-of-the-art ➢ Technical concepts
Floating PV Testbed in Singapore ➢ Layout and participants ➢ Preliminary findings Economic modeling for large-scale floating PV Hybrid operation with hydropower ➢ Motivations ➢ Case study: Longyangxia Conclusions The inaugural "International Floating Solar Symposium" (IFSS) SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singapore’s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singaporeâ&#x20AC;&#x2122;s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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IFSS 2017 - selected highlights (1) Day 1 (Oct 24th)
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singaporeâ&#x20AC;&#x2122;s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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IFSS 2017 - selected highlights (2) Day 1 (Oct 24th)
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singaporeâ&#x20AC;&#x2122;s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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IFSS 2017 - selected highlights (3) Day 2 (Oct 25th)
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singaporeâ&#x20AC;&#x2122;s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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IFSS 2017 - selected highlights (4) Day 2 (Oct 25th)
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singaporeâ&#x20AC;&#x2122;s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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IFSS 2017 - selected highlights (5) Day 2 (Oct 25th)
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singaporeâ&#x20AC;&#x2122;s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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IFSS 2017 - selected highlights (6) Day 2 (Oct 25th)
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singaporeâ&#x20AC;&#x2122;s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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IFSS 2017 - selected highlights (7) Day 3 (Oct 26th)
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singaporeâ&#x20AC;&#x2122;s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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IFSS 2017 - selected highlights (8) Day 3 (Oct 26th)
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singaporeâ&#x20AC;&#x2122;s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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Donâ&#x20AC;&#x2DC;t hesitate to contact us: thomas.reindl@nus.edu.sg lu.zhao@nus.edu.sg
More information at www.seris.sg www.solar-repository.sg We are also on:
SERIS is a research institute at the National University of Singapore (NUS). SERIS is sponsored by the National University of Singapore (NUS) and Singaporeâ&#x20AC;&#x2122;s National Research Foundation (NRF) through the Singapore Economic Development Board (EDB).
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