The Need for Modified Surfaces on Solar Applications in the MENA Region

Transcription

1 The Need for Modified Surfaces on Solar Applications in the MENA Region Intersolar Middle East Conference 2017, September 27 th, Dubai Session: PV Power Plants: Soiling - Drones and Robots Zaha Hadid Architects Ltd.

2 It s a material world

3 Fraunhofer ISC: Our core competencies Materials Glass/Ceramics/ Fibers Nanoparticles Battery materials ORMOCER s Smart materials Analytics Materials characterization Failure analysis Quality control In situ test equipment Solutions for industrial partners Processing (Wet) Coatings Roll-to-Roll Clean room Pilot plants Demonstrators pictures: Fraunhofer ISC

4 Fraunhofer Institutes: Part-time R&D-Partners to meet specific industry needs 9 TRL Applied R&D Industry and SMEs part-time Fraunhofer partner Max Planck/ Helmholtz/ Universities part-time industry partner Basic research Technology development & prototypes Commercial application

5 We offer development towards product Coating solution Application method Quality assurance Upscaling Matching for industrial production

6 The Need for Modified Surfaces on Solar Applications in the MENA Region Mark Mirza ISC, Walther Glaubitt ISC, Klemens Ilse CSP ISC CSP ISC ISC Fraunhofer ISC ISC

7 The Need for Modified Surfaces on Solar Applications in the MENA Region General motivation Introduction to the soiling problem Possible root causes of soiling Physics of soiling Physics of soiling process Microstructural investigations of cementation Mitigation strategies Dust-Repellent Coating with Antireflective Properties Conclusion Former & ongoing field tests in Saudi-Arabia ISC ISC ISC ISC ISC

8 General Motivation Anti-Reflective Sol-Gel Coatings with Dust-Repellent Properties on Glass Better visual transmission (e.g. for architectural glazing) Transmission gain increasing with angle of incidence CSP Decreasing the power loss due to scattered light & shading Enhanced performance of photovoltaic and solar-thermal systems Larger intervals between dust mitigation activities Protection of glass surface from sandblasting Less maintenance costs, longer life Higher long-term energy yields Development of a base technology tailored to local climate conditions Better understanding of the root causes of sustainable soiling Exploitation of ISC patents e.g. EP B1 (WO ) ISC

9 Introduction to the soiling problem in the middle east How do the PV systems look like after being treated like this for years? Do the promises and the warranties of the industry cover this issue? (e.g. 25 years life time, etc.) Buying cheap and then paying for life => the solution? ISC

10 Possible Root Cause of Soiling PV-System tilt angle and orientation => includes exposure movements of the sun & wind Ambient temperature and humidity Site characteristics => includes local vegetation, traffic, industrial air-pollution, etc. Wind velocity Dust properties => includes dust type, chemical, biological, electrostatic property, size, shape & weight Glazing characteristics => includes PV system architecture, surface texture, coating characteristics ISC

11 Physics of soiling Dust properties: size and shape Dust properties: chemical composition Dust properties: adhesion forces between particles and surfaces Dust grain examples showing differences in morphology and size from different regions: (a), (c) Libya; (b) Iraq; (d) Oman Mineralogy evaluations from MENA region and Brazil, comparing differences in minerals distributions. Disregarding the solid bridge bonds, liquid bridge is the dominating adhesion force (if applicable) Qatar desert: High humidity during night and morning hours Chemical reaction with glass and dust particles Whereas the water film on the glass surface can react with e.g. CO 2, SO 2, NO 2 from the atmosphere together with leached elements from the glass, e.g. Na+, K+, Ca+ to insoluble salts, such as KSO 4, CaCO 3, CaSO 4 forming so called glass corrosion KEY Factor DEW ISC [3] Tomas, J.: Mechanics of Particle Adhesion. (2004) Otto-von-Guericke-University, Magdeburg, Germany.

12 Physics of soiling process Dust type and concentration Solar radiation Temperature (ambient + module) Humidity Wind speed and direction Tilt angle KEY Factor DEW Daily cycle Qatar desert: High humidity during night and morning hours Cementation process Particles are baked to the surface due to humid/dry-cycles Need for physically washing the surfaces with high demand of water and labor Favorable mitigation approach should avoid cementation ISC processes [3] Tomas, J.: Mechanics of Particle Adhesion. (2004) Otto-von-Guericke-University, Magdeburg, Germany.

13 Microstructural investigations of cementation Qatar 1 month Needles => clay mineral palygorskite [1] Chile 1 month Small platelets => clay mineral kaolinite ISC [1] K. Ilse et al., Microstructural analysis of the cementation process during soiling on glass surfaces in arid and semi-arid climates, physica status solidi (RRL) 10 (7), (2016).

14 Mitigation strategies Manual and automatic cleaning of PV Systems in Middle-East Except for thin-film modules AR coated surfaces are state of the art and there is no way back because of the PV producers need to classify their panels into higher power output classes. Physical mitigation, if not using water, may lead to unpredictable losses of investment because of destroying of the functional surfaces in long term. Thin film modules may suffer from scratches leading to severe glass corrosion in areas with high dew and near sea sides. Method Advantage Disadvantage Water soft cloth wiping AR coating unaffected in long term, immediate higher output labor, water consumption, costs Short and mid term advantages due to higher yields in middle east Dry cleaning using broom or similar Cleaning robots fast cleaning, immediate higher output fast cleaning, automatically, immediate higher output, better and more effective than labor destroying of AR coating and glass surface possible, labor, costs destroying of AR coating and glass surface possible, maintenance, investments, labor, costs Long and mid term disadvantages due to higher costs and unpredictable investments, e.g. warranty issues in middle east

15 Mitigation strategies Smart Surfaces for PV ISC

16 Dust-Repellent Coating with Antireflective Properties Smart Surfaces for PV from Fraunhofer ISC: Anti-Reflective Sol-Gel Coatings with Dust-Repellent Properties on Glass transmittance gain self-cleaning by wind and humidity or rain weather resistance (UV, temperature fluctuations, humidity) resistant to ageing (low tendency to corrosion and adsorption) contact angle adjustable from hydrophilic to hydrophobic (taylored to local conditions) resistant to dust and sand blasting wipe resistance acc. DIN EN suitable for glass toughening process low production costs: < 0,5 /m2 ISC ISC

17 Dust-Repellent Coating with Antireflective Properties Fraunhofer ISC

18 Dust-Repellent Coating with Antireflective Properties Working principle SEM images of corrugated nanoporous anti-reflective SiO2 coatings with excellent dust repellent properties Essential parameters: porosity pore size distribution morphology of porous layer (pore shape) surface relief structure (flat, blister-like relief, corrugation, trench, groove) ISC ISC Antireflective and anti-soiling coating from Fraunhofer ISC: patent EP B1 (WO )

19 The Need for Modified Surfaces on Solar Applications in the MENA Region Conclusion Do we need a modification of PV panel surfaces in the MENA region? Do the installed PV systems have the appropriate surface modifications? YES, but do we have a choice, since nearly all surfaces are already modified? => e.g. AR coatings, state of the art NO, tailored solutions on the MENA market addressing the customers, instead of the producers needs are missing We need to increase R&D efforts in order to take root causes of soiling and local climate conditions into account AR coatings generate benefits for producers, anti-soiling coatings generate benefits for the customers, combining both => may satisfy both parties soiling rates of up to 1% per day show the necessity for a sustainable solution self-cleaning surfaces may lead to lower maintenance efforts & costs the industry has to react with innovative solutions for the customer protective coatings with lower initial output due to lack of AR coatings could also lead to long term disabilities of solar fields? Less material & equipment losses due to harsh mitigation strategies? (e.g. for thin-film and PV systems)

20 Former & ongoing field tests in Saudi-Arabia Joint Projects with King Abdulaziz City for Science and Technology (KACST) Test stands in desert, urban and coastal areas Two test stands per site, one in upright position, the other tilted Monitoring and data transfer ~20 % higher transmission after two years without any cleaning Projekt duration New project started, Development technology methods for dust repellent on solar panels Yanbou Al Khafji Al Qassim Makkah Riyadh Al Ahsa Building up pilot plant for antisoiling coatings for PV Upscale of coating liquid production Project duration

21 Field Tests in Saudi Arabia: Dust-Repellent Coating Transmittance Analysis Two Year Exposure

22 Field Tests in Saudi Arabia: Dust-Repellent Coatings Coated glass panes after two years of outdoor weathering ISC ISC Uncoated areas appear hazy & opaque compared to hardly polluted dust repellent coatings, which look more clear & transparent Δ Tv [acc. EN410] = > up to ~20% ISC

23 Thank you for your interest Mark Mirza Sol-Gel-Materials and Products Fraunhofer Institute for Silicate Research ISC Neunerplatz 2, Würzburg, Germany Phone: +49(0) Mail: Walther Glaubitt Klemens Ilse Sol-Gel-Materials and Products Diagnostics of Solar Cells Fraunhofer Institute for Silicate Research ISC Neunerplatz 2, Würzburg, Germany Phone: +49(0) Mail: Fraunhofer Center for Silicon Photovoltaics CSP Otto-Eißfeldt-Straße 12, Halle, Germany Phone: +49(0) Mail: