NORUT NARVIK. Solvåg with a technological perspective. Øystein Kleven, senior scientist at Norut Narvik Piteå, 29 th August 2018

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2 NORUT NARVIK Solvåg with a technological perspective Øystein Kleven, senior scientist at Norut Narvik Piteå, 29 th August 2018

3 AGENDA Solvåg with a technological perspective - Solvåg design - Bifacial history and development - Performance of bifacial systems - Conclusions - Future of bifacial systems

4 Narvik Norut: 4 companies in the 3 northernmost counties in Norway Research institute with offices in Tromsø, Alta, Bodø, Harstad and Narvik Norinnova Technology Transfer innovation company (Tromsø) Barents Biocentre Lab advanced research laboratory (Tromsø)

5 SOLVÅG DESIGN Freedom and wishes - Multiple angles and orientations - Sensors - Individual optimization of modules - Choose best bifacial module - Minimize shadowing ቐ ቊ Experimentally look at optimization of bifacial systems - Fully exploit bifacial potential

6 SOLVÅG DESIGN Compromises and limitations - Park layout Angles and orientations Mechanical strength Self-shading Aesthetics

7 SOLVÅG DESIGN Compromises and limitations - Economics Sensors Data acquisition / monitoring Visualisation Mounting structure PV-components - Available components Solution: SolarEdge - Inverter with DC/DC optimizer on individual solar module - Monitoring portal for both sensors and PV-system Sensors - 10x solar irradiance - 2x air temperature - 1x wind intensity Clamps - Schletter

8 BIFACIAL HISTORY AND DEVELOPMENT Solvåg project

9 CELL DEVELOPMENT Side-effect of cell development in the pursuit of higher efficiency - Passivation of backside - Bowing of cell - Better contacts International Technology Roadmap for Photovoltaic (ITRPV, 9th edition) Bifacial PERC+ solar cells: (bifipv2017 Workshop, T. Dullweber et. al.)

10 CELL DEVELOPMENT Bifacial solar cells Capture the irradiation from both sides Ratio between efficiency on front side vs. the rear side is called bifaciality - Range; 75-95% Simplified there is a trade-off between front side efficiency and bifaciality Bifacial solar cells a brief overview (5 th bifipv workshop 2017, I. Romijn)

11 MODULE DEVELOPMENT Bifacial solar cells in mono-facial modules Piteå tracking systems 2011 Bifacial solar cells in glass-glass modules Market survey 2016 True bifacial solar cell modules Solvåg

12 MODULE DEVELOPMENT true bifacial modules limitations - Glass-glass modules have increased costs - Bifacial Junction box is relatively new => higher cost - Frame causes self-shading International Technology Roadmap for Photovoltaic (ITRPV, 9th edition)

13 SYSTEM DEVELOPMENT Bifacial solar modules in niche installations 1998 Noise barriers Switzerland Bifacial solar modules in standard systems ,25 MWp Hokuto, Japan Special system design for bifacial modules Piteå 2018, still room for improvement Luleå 2018,? currently being installed

14 SYSTEM DEVELOPMENT Bifacial solar modules in niche installations 1998 Noise barriers Switzerland Bifacial solar modules in standard systems ,25 MWp Hokuto, Japan Special system design for bifacial modules Piteå 2018, still room for improvement Luleå 2018,? currently being installed

15 SYSTEM DEVELOPMENT Solar parks utilizing bifacial modules are constantly breaking size records 2019: Benban solar park, Egypt MWp > 325 MWp could be bifacial solar modules Bifacial systems overview (bifipv workshop 2017, M. Joanny et. al.)

16 PERFORMANCE OF BIFACIAL SYSTEMS Why are bifacial systems difficult? In addition to normal challenges - Albedo - Surface roughness - Self-shading - Module properties ቊ 0 0 Reflection from the surface Quantify what do you gain from using bifacial? Normal challenges Insolation - Direct irradiation - Diffuse irradiation - In-plane transposition Unknowns - Dirt, snow cover, etc. Modelling of solar modules - Efficiency - Angle of incidence losses Modelling of inverters - Efficiency - String losses Modelling of system - Near and far shading

17 PERFORMANCE OF BIFACIAL SYSTEMS Albedo, the reflection from the ground, plays an important role Introduction to bifacial modules and modelling (4 th PVPMC 2015, T. W. Zhang)

18 BIFACIAL GAIN How to measure gain? Monofacial vs. bifacial only? Monofacial optimal vs. bifacial actual? Monofacial optimal vs. bifacial optimal*? * but what s optimal? Varies in literature how the bifacial gain has been calculated, but definition: Definition: bifacial gain = Energy bifacial Energy monofacial Energy monofacial Energy bifacial = specific energy yield with bifacial modules (kwh/kwp) Energy monofacial = specific energy yield with monofacial modules (kwh/kwp) Note for same site, with the same configuration and during the same time period

19 Geographical mapping of the performance... (EU PVSEC 2016, M. Ito et. al.)

20 Freiburg (Germany) kwh/m 2 Piteå (Sweden) kwh/m 2 Bodø (Norway) kwh/m 2 Nordkapp (Norway) kwh/m 2 Fixed optimal Two-axis tracking Bifacial Geographical mapping of the performance... (EU PVSEC 2016, M. Ito et. al.)

21 BIFACIAL GAIN THEORETICAL RESULTS Predicting Yields for Bifacial PV Systems (Fraunhofer ISE 2017, Dr. C. Reise)

22 BIFACIAL GAIN PRACTICAL RESULTS Predicting Yields for Bifacial PV Systems (Fraunhofer ISE 2017, Dr. C. Reise)

23 UIT BIFACIAL TROMSØR&D - BIFACIAL SYSTEM IN TROMSØ Bifacial vs. monofacial * * Bifacial modules with opaque sheet

24 UIT TROMSØ - BIFACIAL

25 UIT TROMSØ - BIFACIAL

26 UIT TROMSØ - BIFACIAL Bifacial gain ~12 % Range From -17 % to 62 % Common consensus In general at least 10 % increase

27 CONCLUSIONS Maturing market and products but still a way to go High potential for bifacial in the north, less sensitive to latitude Bifacial gain uncertain, but at least a 10 % gain Solvåg a unique bifacial solar park that can give some answers

28 FUTURE OF BIFACIAL Optimization still more to do - On cell level - On module level - On system level - Modelling / simulations - Next big thing? Bifacial on tracking systems

29 THANKS FOR THE ATTENTION