Developing Solutions for the Environmental Challenges to Deploying PV Plants in Desert Areas Zia Malik Technology Application and Advancement Group (TAAG), Economic Development King Abdullah University of Science and Technology, Saudi Arabia Emirates Solar Industry Association, Dubai 2013
Main Environmental Challenges Temperature Encapsulation and packaging External cooling (Phase change material) Dust Dry type cleaning Wet type cleaning Surface coatings Humidity Encapsulation and packaging KAUST King Abdullah University of Science and Technology 2
Temperature: Impact on different PV technologies Technology Manufacturing Costs Commercial Efficiency Theoretical Efficiency Temperature Coeff. Mono c-si >90 /Wp ~18% ~25% -0.38%/ C Multi c-si >75 /Wp ~14.5% <25% -0.45%/ C CIGS thin film CdTe thin film >80 /Wp??? ~12.2% <30% -0.31%/ C <60 /Wp 12.8% <30% -0.25%/ C Source: First Solar KAUST King Abdullah University of Science and Technology 3
Temperature: KAUST experience KAUST King Abdullah University of Science and Technology 4
Temperature: 2 MWp roof-top at KAUST KAUST King Abdullah University of Science and Technology 5
Temperature: Performance of 2 MW Roof top at KAUST KAUST King Abdullah University of Science and Technology 6
Temperature: Performance of 2 MW Roof top at KAUST 18% Module Temperature Effect on Efficiency 17% Energy Conversion Efficiency 16% 15% 14% 13% 12% 11% 10% 20 25 30 35 40 45 50 55 60 65 70 Linear Eu Daily Maximum Module Temperature o C Eu = Generated Energy / Incident Irradia>on Energy (%) 7
Temperature: Performance of 2 MW Roof top at KAUST Annual yield simulated 1676+1605= 3,281 MWh/year Simulated energy yield from 01 May 10 to 01 March 11: 1,372 MWh + 1,312 MWh = 2,684 MWh Actual energy yield 1,399 MWh + 1,410 MWh = 2,809 MWh Increase in actual yield above plan = 126 MWh = 4.7%
PV module thermal management Needed for hot climates to improve performance and reduce aging! Energy Generated (kwh) 1300 1200 1100 1000 900 800 700 Standard Module Utility Module 600 500 45 40 35 30 25 20 15 10 Jul-10 Aug-10 Sep-10 Oct-10 Nov-10 Dec-10 Jan-11 Feb-11 Mar-11 Apr-11 May-11 Jun-11 Jul-11 Aug-11 Aug-10 Sep-10 Ambient Temperature ( C) Oct-10 Nov-10 Dec-10 Jan-11 Feb-11 Mar-11 Apr-11 May-11 Jun-11 Jul-11 * ½ cell design. Reduced losses KAUST King Abdullah University of Science and Technology * Modified EVA. improved thermal encapsulation 9
Dust: Revise your O&M clacs The drop in solar energy efficiency over 3 months without cleaning was measured between 30-45%. The decrease in solar energy efficiency due to dust storms was measured to be 60%. Dust effect on performance varies per location and per technology Needed models for recommended frequency of cleaning KAUST King Abdullah University of Science and Technology 10
Dust: Dust Mitigation Initiative 1 st Understand & quantify the impact of soiling on regionspecific solar technology performance. 2 nd Evaluate & develop different dust mitigation solutions to reduce cleaning frequency for both existing & emerging technologies. 3 rd Develop an optimum site & technology-specific cleaning schedule based on various cleaning methods. 4 th Develop a dust prediction model for the Kingdom of Saudi Arabia. KAUST King Abdullah University of Science and Technology 11
Dust: Dust Mitigation Initiative Hydrophobic Passive Coatings Hydrophilic Cleaning Dry Wet Active EDS Rotary Brush Anti-Static Technology Maturity Field Application Economics Reliability Dust Effect on Performance Environmental Durability O&M Coating Performance KAUST King Abdullah University of Science and Technology 12
Dust: Coatings potential Ideal coating would have mechanical and optical characteristics Coating life is at best 3 to 5 years and site specific Multiple re application of coatings can degrade performance Standards needed for coatings on PV panels KAUST King Abdullah University of Science and Technology 13
Dust: Electrostatic Discharge Screens Ionizes dust particles using electric pulses R&D needed in polymer based EDS and ionization process KAUST King Abdullah University of Science and Technology 14
Dust: Dry type brush based cleaning Dry-type cleaning/dusting robot for PV panels Using minimal amounts of water for cleaning PV panels Aimed for high reliability long life operation with minimal maintenance Automated robotic device KAUST King Abdullah University of Science and Technology 15
Dust: Simple solutions are possible KAUST King Abdullah University of Science and Technology 16
Dust: Performance impact on PV Spectral Analysis & Effects on Transmission Effect of Dust on Glass Transmission 1.10 1.00 0.90 Relative Glass Transmission 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 0.00 Week 1 Week 2 Week 3 Week 4 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Wavelength (nm) Direct-light behavior of different soiling levels KAUST King Abdullah University of Science and Technology 17
Dust: Performance impact on PV 60-day duration of panel exposure to dust Particle Size Distribution Information to be extracted: Most common particle size Total number of particles (particle/m 2 ) Estimation of area blockage (%) King Abdullah University of Science and Technology 18
Dust: Performance impact on PV Irregular particle shapes Particle-to-surface interaction and particle charge upon contact Detailed study on local dust characteristics Dust deposition rate on solar surfaces is approximately 12.5g/cm 2 / month in Thuwal Saudi Arabia. 19
Cleaning OPEX for 2 MW Roof top at KAUST Total system cleaning duration/week is 15 hours/week at approximately 3 hours of cleaning/day Detergent usage is biweekly (5L of glass cleaner/month) amounts to SR100/month Water flow rate is ca 1 m 3 /hr at SR6/m 3 cost of water 4 workers/day at SR3,000/month/worker Project manager wage is 4,000/month Total wages amount to SR16,000/month Total monthly material amounts to SR550/month Total monthly cost to clean 2MW solar rooftop panels at KAUST is ca SR16,550/month About 53,000 $US per year for cleaning only KAUST King Abdullah University of Science and Technology 20
Summary The drop in system efficiency has been measured to be 8-15% per month due to dust accumulation; Dust deposition rate on solar surfaces is approximately 12.5g/cm 2 / month; Dust deposition rate at ground level & building rooftops prove to be identical; Need to include MENA environmental conditions in existing standards; There are solutions to dust that are practical; PV module manufacturers need to consider a desert module. KAUST King Abdullah University of Science and Technology 21